/**************************************************************************************************
"POLYMOST" code written by Ken Silverman
Ken Silverman's official web site: http://www.advsys.net/ken

Motivation:
When 3D Realms released the Duke Nukem 3D source code, I thought somebody would do a OpenGL or
Direct3D port. Well, after a few months passed, I saw no sign of somebody working on a true
hardware-accelerated port of Build, just people saying it wasn't possible. Eventually, I realized
the only way this was going to happen was for me to do it myself. First, I needed to port Build to
Windows. I could have done it myself, but instead I thought I'd ask my Australian buddy, Jonathon
Fowler, if he would upgrade his Windows port to my favorite compiler (MSVC) - which he did. Once
that was done, I was ready to start the "POLYMOST" project.

About:
This source file is basically a complete rewrite of the entire rendering part of the Build engine.
There are small pieces in ENGINE.C to activate this code, and other minor hacks in other source
files, but most of it is in here. If you're looking for polymost-related code in the other source
files, you should find most of them by searching for either "polymost" or "rendmode". Speaking of
rendmode, there are now 4 rendering modes in Build:

	rendmode 0: The original code I wrote from 1993-1997
	rendmode 1: Solid-color rendering: my debug code before I did texture mapping
	rendmode 2: Software rendering before I started the OpenGL code (Note: this is just a quick
						hack to make testing easier - it's not optimized to my usual standards!)
	rendmode 3: The OpenGL code

The original Build engine did hidden surface removal by using a vertical span buffer on the tops
and bottoms of walls. This worked nice back in the day, but it it's not suitable for a polygon
engine. So I decided to write a brand new hidden surface removal algorithm - using the same idea
as the original Build - but one that worked with vectors instead of already rasterized data.

Brief history:
06/20/2000: I release Build Source code
04/01/2003: 3D Realms releases Duke Nukem 3D source code
10/04/2003: Jonathon Fowler gets his Windows port working in Visual C
10/04/2003: I start writing POLYMOST.BAS, a new hidden surface removal algorithm for Build that
					works on a polygon level instead of spans.
10/16/2003: Ported POLYMOST.BAS to C inside JonoF KenBuild's ENGINE.C; later this code was split
					out of ENGINE.C and put in this file, POLYMOST.C.
12/10/2003: Started OpenGL code for POLYMOST (rendmode 3)
12/23/2003: 1st public release
01/01/2004: 2nd public release: fixed stray lines, status bar, mirrors, sky, and lots of other bugs.

----------------------------------------------------------------------------------------------------

Todo list (in approximate chronological order):

High priority:
	*   BOTH: Do accurate software sorting/chopping for sprites: drawing in wrong order is bad :/
	*   BOTH: Fix hall of mirrors near "zenith". Call polymost_drawrooms twice?
	* OPENGL: drawmapview()

Low priority:
	* SOFT6D: Do back-face culling of sprites during up/down/tilt transformation (top of drawpoly)
	* SOFT6D: Fix depth shading: use saturation&LUT
	* SOFT6D: Optimize using hyperbolic mapping (similar to KUBE algo)
	* SOFT6D: Slab6-style voxel sprites. How to accelerate? :/
	* OPENGL: KENBUILD: Write flipping code for floor mirrors
	*   BOTH: KENBUILD: Parallaxing sky modes 1&2
	*   BOTH: Masked/1-way walls don't clip correctly to sectors of intersecting ceiling/floor slopes
	*   BOTH: Editart x-center is not working correctly with Duke's camera/turret sprites
	*   BOTH: Get rid of horizontal line above Duke full-screen status bar
	*   BOTH: Combine ceilings/floors into a single triangle strip (should lower poly count by 2x)
	*   BOTH: Optimize/clean up texture-map setup equations

**************************************************************************************************/

int animateoffs(short tilenum, short fakevar);
int rendmode = 0;
int usemodels=1, usehightile=1;

#include <math.h> //<-important!
typedef struct { float x, cy[2], fy[2]; int n, p, tag, ctag, ftag; } vsptyp;
#define VSPMAX 4096 //<- careful!
static vsptyp vsp[VSPMAX];
static int vcnt, gtag;

static double dxb1[MAXWALLSB], dxb2[MAXWALLSB];

#define SCISDIST 1.0 //1.0: Close plane clipping distance
#define USEZBUFFER 1 //1:use zbuffer (slow, nice sprite rendering), 0:no zbuffer (fast, bad sprite rendering)
#define LINTERPSIZ 4 //log2 of interpolation size. 4:pretty fast&acceptable quality, 0:best quality/slow!
#define DEPTHDEBUG 0 //1:render distance instead of texture, for debugging only!, 0:default
#define FOGSCALE 0.0000640
#define PI 3.14159265358979323

static float shadescale = 1.050;

static double gyxscale, gxyaspect, gviewxrange, ghalfx, grhalfxdown10, grhalfxdown10x, ghoriz;
static double gcosang, gsinang, gcosang2, gsinang2;
static double gchang, gshang, gctang, gstang, gvisibility;
float gtang = 0.0;
double guo, gux, guy; //Screen-based texture mapping parameters
double gvo, gvx, gvy;
double gdo, gdx, gdy;

#if (USEZBUFFER != 0)
int zbufmem = 0, zbufysiz = 0, zbufbpl = 0, *zbufoff = 0;
#endif

#ifdef USE_OPENGL
static int srepeat = 0, trepeat = 0;

int glredbluemode = 0;
static int lastglredbluemode = 0, redblueclearcnt = 0;

static struct glfiltermodes
{
    char *name;
    int min,mag;
} glfiltermodes[] =
{
    {"GL_NEAREST",GL_NEAREST,GL_NEAREST},
    {"GL_LINEAR",GL_LINEAR,GL_LINEAR},
    {"GL_NEAREST_MIPMAP_NEAREST",GL_NEAREST_MIPMAP_NEAREST,GL_NEAREST},
    {"GL_LINEAR_MIPMAP_NEAREST",GL_LINEAR_MIPMAP_NEAREST,GL_LINEAR},
    {"GL_NEAREST_MIPMAP_LINEAR",GL_NEAREST_MIPMAP_LINEAR,GL_NEAREST},
    {"GL_LINEAR_MIPMAP_LINEAR",GL_LINEAR_MIPMAP_LINEAR,GL_LINEAR}
};
#define numglfiltermodes (sizeof(glfiltermodes)/sizeof(glfiltermodes[0]))

int glanisotropy = 1;            // 0 = maximum supported by card
int glusetexcompr = 1;
int gltexfiltermode = 2; // GL_NEAREST_MIPMAP_NEAREST
int glusetexcache = 0;
int glusetexcachecompression = 1;
int glmultisample = 0, glnvmultisamplehint = 0;
int gltexmaxsize = 0;      // 0 means autodetection on first run
int gltexmiplevel = 0;		// discards this many mipmap levels
static int lastglpolygonmode = 0; //FUK
int glpolygonmode = 0;     // 0:GL_FILL,1:GL_LINE,2:GL_POINT //FUK
int glwidescreen = 0;
int glprojectionhacks = 1;
static GLuint polymosttext = 0;
extern char nofog;

// Those THREE globals control the drawing of fullbright tiles
static int fullbrightloadingpass = 0;
static int fullbrightdrawingpass = 0;
static int shadeforfullbrightpass;

// Depth peeling control
int r_depthpeeling = 0;    // cvar toggling general depth peeling usage
int r_peelscount = 5;      // cvar controlling the number of peeling layers
int r_curpeel = -1;        // cvar controlling the display of independant peeling layers
static float curpolygonoffset;     // internal polygon offset stack for drawing flat sprites to avoid depth fighting
static int peelcompiling = 0;     // internal control var to disable blending when compiling the peeling display list
static int newpeelscount = 0;     // temporary var for peels count changing during the game

// Depth peeling data
static GLuint ztexture[3];         // secondary Z-buffers identifier
static GLuint *peels;              // peels identifiers
static GLuint *peelfbos;           // peels FBOs identifiers
static GLuint peelprogram[2];      // ARBfp peeling fragment program

// Detail mapping cvar
int r_detailmapping = 1;

// Glow mapping cvar
int r_glowmapping = 1;

// Vertex Array model drawing cvar
int r_vertexarrays = 1;

// Vertex Buffer Objects model drawing cvars
int r_vbos = 0;
int r_vbocount = 64;

// model animation smoothing cvar
int r_animsmoothing = 1;

// polymost ART sky control
int r_parallaxskyclamping = 1;
int r_parallaxskypanning = 0;

static float fogresult, fogcol[4];

// making this a macro should speed things up at the expense of code size
#define fogcalc(shade, vis, pal) \
{ \
    fogresult = (float)gvisibility*(vis+16+(shade<0?(-shade*shade)*0.125f:(shade*shade)*0.125f)); \
    if (vis > 239) fogresult = (float)gvisibility*((vis-240+(shade<0?(-shade*shade)*0.125f:(shade*shade)*0.125f))/(klabs(vis-256))); \
    fogresult = min(max(fogresult, 0.01f),10.f); \
    fogcol[0] = (float)palookupfog[pal].r / 63.f; \
    fogcol[1] = (float)palookupfog[pal].g / 63.f; \
    fogcol[2] = (float)palookupfog[pal].b / 63.f; \
    fogcol[3] = 0; \
}
#endif

#if defined(USE_MSC_PRAGMAS)
static inline void ftol(float f, int *a)
{
    _asm
    {
        mov eax, a
        fld f
        fistp dword ptr [eax]
    }
}

static inline void dtol(double d, int *a)
{
    _asm
    {
        mov eax, a
        fld d
        fistp dword ptr [eax]
    }
}
#elif defined(USE_WATCOM_PRAGMAS)

#pragma aux ftol =\
	"fistp dword ptr [eax]",\
	parm [eax 8087]
#pragma aux dtol =\
	"fistp dword ptr [eax]",\
	parm [eax 8087]

#elif defined(USE_GCC_PRAGMAS)

static inline void ftol(float f, int *a)
{
    __asm__ __volatile__(
#if 0 //(__GNUC__ >= 3)
        "flds %1; fistpl %0;"
#else
"flds %1; fistpl (%0);"
#endif
    : "=r"(a) : "m"(f) : "memory","cc");
}

static inline void dtol(double d, int *a)
{
    __asm__ __volatile__(
#if 0 //(__GNUC__ >= 3)
        "fldl %1; fistpl %0;"
#else
"fldl %1; fistpl (%0);"
#endif
    : "=r"(a) : "m"(d) : "memory","cc");
}

#else
static inline void ftol(float f, int *a)
{
    *a = (int)f;
}

static inline void dtol(double d, int *a)
{
    *a = (int)d;
}
#endif

static inline int imod(int a, int b)
{
    if (a >= 0) return(a%b);
    return(((a+1)%b)+b-1);
}

void drawline2d(float x0, float y0, float x1, float y1, char col)
{
    float f, dx, dy, fxres, fyres;
    int e, inc, x, y;
    unsigned int up16;

    dx = x1-x0; dy = y1-y0; if ((dx == 0) && (dy == 0)) return;
    fxres = (float)xdimen; fyres = (float)ydimen;
    if (x0 >= fxres) { if (x1 >= fxres) return; y0 += (fxres-x0)*dy/dx; x0 = fxres; }
    else if (x0 <      0) { if (x1 <      0) return; y0 += (0-x0)*dy/dx; x0 =     0; }
    if (x1 >= fxres) {                          y1 += (fxres-x1)*dy/dx; x1 = fxres; }
    else if (x1 <      0) {                          y1 += (0-x1)*dy/dx; x1 =     0; }
    if (y0 >= fyres) { if (y1 >= fyres) return; x0 += (fyres-y0)*dx/dy; y0 = fyres; }
    else if (y0 <      0) { if (y1 <      0) return; x0 += (0-y0)*dx/dy; y0 =     0; }
    if (y1 >= fyres) {                          x1 += (fyres-y1)*dx/dy; y1 = fyres; }
    else if (y1 <      0) {                          x1 += (0-y1)*dx/dy; y1 =     0; }

    if (fabs(dx) > fabs(dy))
    {
        if (x0 > x1) { f = x0; x0 = x1; x1 = f; f = y0; y0 = y1; y1 = f; }
        y = (int)(y0*65536.f)+32768;
        inc = (int)(dy/dx*65536.f+.5f);
        x = (int)(x0+.5); if (x < 0) { y -= inc*x; x = 0; } //if for safety
        e = (int)(x1+.5); if (e > xdimen) e = xdimen;       //if for safety
        up16 = (ydimen<<16);
        for (;x<e;x++,y+=inc) if ((unsigned int)y < up16) *(char *)(ylookup[y>>16]+x+frameoffset) = col;
    }
    else
    {
        if (y0 > y1) { f = x0; x0 = x1; x1 = f; f = y0; y0 = y1; y1 = f; }
        x = (int)(x0*65536.f)+32768;
        inc = (int)(dx/dy*65536.f+.5f);
        y = (int)(y0+.5); if (y < 0) { x -= inc*y; y = 0; } //if for safety
        e = (int)(y1+.5); if (e > ydimen) e = ydimen;       //if for safety
        up16 = (xdimen<<16);
        for (;y<e;y++,x+=inc) if ((unsigned int)x < up16) *(char *)(ylookup[y]+(x>>16)+frameoffset) = col;
    }
}

#ifdef USE_OPENGL
typedef struct { unsigned char r, g, b, a; } coltype;

static void uploadtexture(int doalloc, int xsiz, int ysiz, int intexfmt, int texfmt, coltype *pic, int tsizx, int tsizy, int dameth);

#include "md4.h"

#define USELZF
#define USEKENFILTER 1

#ifdef USELZF
#	include "lzf.h"
#else
#	include "lzwnew.h"
#endif

static char TEXCACHEDIR[] = "texcache";
typedef struct
{
    char magic[8];	// 'Polymost'
    int xdim, ydim;	// of image, unpadded
    int flags;		// 1 = !2^x, 2 = has alpha, 4 = lzw compressed
} texcacheheader;
typedef struct
{
    int size;
    int format;
    int xdim, ydim;	// of mipmap (possibly padded)
    int border, depth;
} texcachepicture;

int dxtfilter(int fil, texcachepicture *pict, char *pic, void *midbuf, char *packbuf, unsigned int miplen);
int dedxtfilter(int fil, texcachepicture *pict, char *pic, void *midbuf, char *packbuf, int ispacked);

static inline void phex(unsigned char v, char *s);
void writexcache(char *fn, int len, int dameth, char effect, texcacheheader *head);

int mdtims, omdtims;
float alphahackarray[MAXTILES];
#include "mdsprite.c"

//--------------------------------------------------------------------------------------------------
//TEXTURE MANAGEMENT: treats same texture with different .PAL as a separate texture. This makes the
//   max number of virtual textures very large (MAXTILES*256). Instead of allocating a handle for
//   every virtual texture, I use a cache where indexing is managed through a hash table.
//

// moved into polymost.h
/*typedef struct pthtyp_t
{
    struct pthtyp_t *next;
    GLuint glpic;
    short picnum;
    char palnum;
    char effects;
    char flags;      // 1 = clamped (dameth&4), 2 = hightile, 4 = skybox face, 8 = hasalpha, 16 = hasfullbright, 128 = invalidated
    char skyface;
    hicreplctyp *hicr;

    unsigned short sizx, sizy;
    float scalex, scaley;
    struct pthtyp_t *wofb; // without fullbright
    struct pthtyp_t *ofb; // only fullbright
} pthtyp;*/

#define GLTEXCACHEADSIZ 8192
static pthtyp *gltexcachead[GLTEXCACHEADSIZ];

static int drawingskybox = 0;

pthtyp *pichead;

int gloadtile_art(int,int,int,pthtyp*,int);
int gloadtile_hi(int,int,int,hicreplctyp*,int,pthtyp*,int,char);
static int hicprecaching = 0;
pthtyp * gltexcache(int dapicnum, int dapalnum, int dameth)
{
    int i, j;
    hicreplctyp *si;
    pthtyp *pth, *pth2;

    j = (dapicnum&(GLTEXCACHEADSIZ-1));

    if (usehightile) si = hicfindsubst(dapicnum,dapalnum,drawingskybox);
    else si = NULL;
    if (!si)
    {
        if (drawingskybox) return NULL;
        goto tryart;
    }

    /* if palette > 0 && replacement found
     *    no effects are applied to the texture
     * else if palette > 0 && no replacement found
     *    effects are applied to the palette 0 texture if it exists
     */

    pichead=gltexcachead[j]; // for palmaps
    // load a replacement
    for (pth=pichead; pth; pth=pth->next)
    {
        if (pth->picnum == dapicnum &&
                pth->palnum == si->palnum &&
                (si->palnum>0 ? 1 : (pth->effects == hictinting[dapalnum].f)) &&
                (pth->flags & (1+2+4)) == (((dameth&4)>>2)+2+((drawingskybox>0)<<2)) &&
                (drawingskybox>0 ? (pth->skyface == drawingskybox) : 1)
           )
        {
            if (pth->flags & 128)
            {
                pth->flags &= ~128;
                if (gloadtile_hi(dapicnum,dapalnum,drawingskybox,si,dameth,pth,0,
                                 (si->palnum>0) ? 0 : hictinting[dapalnum].f))    // reload tile
                {
                    if (drawingskybox) return NULL;
                    goto tryart;   // failed, so try for ART
                }
            }
            return(pth);
        }
    }


    pth = (pthtyp *)calloc(1,sizeof(pthtyp));
    if (!pth) return NULL;

    // possibly fetch an already loaded multitexture :_)
    if (dapalnum >= (MAXPALOOKUPS - RESERVEDPALS))
        for (i = (GLTEXCACHEADSIZ - 1); i >= 0; i--)
            for (pth2=gltexcachead[i]; pth2; pth2=pth2->next)
            {
                if ((pth2->hicr) && (pth2->hicr->filename) && (Bstrcasecmp(pth2->hicr->filename, si->filename) == 0))
                {
                    memcpy(pth, pth2, sizeof(pthtyp));
                    pth->picnum = dapicnum;
                    pth->flags = ((dameth&4)>>2) + 2 + ((drawingskybox>0)<<2);
                    if (pth2->flags & 8) pth->flags |= 8; //hasalpha
                    pth->hicr = si;
                    pth->next = gltexcachead[j];
                    if (pth->palmap)
                    {
                        //_initprintf("Realloc #%d->#%d\n",pth2->palmap, pth->palmap);
                        pth->palmap=malloc(pth->size*4);
                        memcpy(pth->palmap, pth2->palmap, pth->size*4);
                    }
                    gltexcachead[j] = pth;
                    return(pth);
                }
            }

    if (gloadtile_hi(dapicnum,dapalnum,drawingskybox,si,dameth,pth,1, (si->palnum>0) ? 0 : hictinting[dapalnum].f))
    {
        free(pth);
        if (drawingskybox) return NULL;
        goto tryart;   // failed, so try for ART
    }
    pth->palnum = si->palnum;
    pth->next = gltexcachead[j];
    gltexcachead[j] = pth;
    return(pth);

tryart:
    if (hicprecaching) return NULL;

    // load from art
    for (pth=gltexcachead[j]; pth; pth=pth->next)
        if (pth->picnum == dapicnum &&
                pth->palnum == dapalnum &&
                (pth->flags & (1+2)) == ((dameth&4)>>2)
           )
        {
            if (pth->flags & 128)
            {
                pth->flags &= ~128;
                if (gloadtile_art(dapicnum,dapalnum,dameth,pth,0)) return NULL; //reload tile (for animations)
            }
            return(pth);
        }

    pth = (pthtyp *)calloc(1,sizeof(pthtyp));
    if (!pth) return NULL;

    if (gloadtile_art(dapicnum,dapalnum,dameth,pth,1))
    {
        free(pth);
        return NULL;
    }
    pth->next = gltexcachead[j];
    gltexcachead[j] = pth;

    return(pth);
}

int gltexmayhavealpha(int dapicnum, int dapalnum)
{
    int j = (dapicnum&(GLTEXCACHEADSIZ-1));
    pthtyp *pth;

    for (pth=gltexcachead[j]; pth; pth=pth->next)
        if ((pth->picnum == dapicnum) && (pth->palnum == dapalnum))
            return((pth->flags&8) != 0);
    return(1);
}

void gltexinvalidate(int dapicnum, int dapalnum, int dameth)
{
    int i, j;
    pthtyp *pth;

    j = (dapicnum&(GLTEXCACHEADSIZ-1));
    for (pth=gltexcachead[j]; pth; pth=pth->next)
        if (pth->picnum == dapicnum && pth->palnum == dapalnum && (pth->flags & 1) == ((dameth&4)>>2))
        {
            pth->flags |= 128;
            if (pth->flags & 16)
                pth->ofb->flags |= 128;
        }
}

//Make all textures "dirty" so they reload, but not re-allocate
//This should be much faster than polymost_glreset()
//Use this for palette effects ... but not ones that change every frame!
void gltexinvalidateall()
{
    int j;
    pthtyp *pth;

    for (j=GLTEXCACHEADSIZ-1;j>=0;j--)
        for (pth=gltexcachead[j];pth;pth=pth->next)
        {
            pth->flags |= 128;
            if (pth->flags & 16)
                pth->ofb->flags |= 128;
        }
    clearskins();
#ifdef DEBUGGINGAIDS
    OSD_Printf("gltexinvalidateall()\n");
#endif
}

void gltexinvalidate8()
{
    int j;
    pthtyp *pth;

    for (j=GLTEXCACHEADSIZ-1;j>=0;j--)
        for (pth=gltexcachead[j];pth;pth=pth->next)
        {
            if (pth->hicr == NULL)
            {
                pth->flags |= 128;
                if (pth->flags & 16)
                    pth->ofb->flags |= 128;
            }
        }
#ifdef DEBUGGINGAIDS
    OSD_Printf("gltexinvalidate8()\n");
#endif
}

void gltexapplyprops(void)
{
    int i;
    pthtyp *pth;

    if (glinfo.maxanisotropy > 1.0)
    {
        if (glanisotropy <= 0 || glanisotropy > glinfo.maxanisotropy) glanisotropy = (int)glinfo.maxanisotropy;
    }

    if (gltexfiltermode < 0) gltexfiltermode = 0;
    else if (gltexfiltermode >= (int)numglfiltermodes) gltexfiltermode = numglfiltermodes-1;
    for (i=GLTEXCACHEADSIZ-1;i>=0;i--)
    {
        for (pth=gltexcachead[i];pth;pth=pth->next)
        {
            bglBindTexture(GL_TEXTURE_2D,pth->glpic);
            bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,glfiltermodes[gltexfiltermode].mag);
            bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,glfiltermodes[gltexfiltermode].min);
            if (glinfo.maxanisotropy > 1.0)
                bglTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAX_ANISOTROPY_EXT,glanisotropy);
            if (pth->flags & 16)
            {
                bglBindTexture(GL_TEXTURE_2D,pth->ofb->glpic);
                bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,glfiltermodes[gltexfiltermode].mag);
                bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,glfiltermodes[gltexfiltermode].min);
                if (glinfo.maxanisotropy > 1.0)
                    bglTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAX_ANISOTROPY_EXT,glanisotropy);
            }
        }
    }

    {
        int j;
        mdskinmap_t *sk;
        md2model *m;

        for (i=0;i<nextmodelid;i++)
        {
            m = (md2model *)models[i];
            if (m->mdnum < 2) continue;
            for (j=0;j<m->numskins*(HICEFFECTMASK+1);j++)
            {
                if (!m->texid[j]) continue;
                bglBindTexture(GL_TEXTURE_2D,m->texid[j]);
                bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,glfiltermodes[gltexfiltermode].mag);
                bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,glfiltermodes[gltexfiltermode].min);
                if (glinfo.maxanisotropy > 1.0)
                    bglTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAX_ANISOTROPY_EXT,glanisotropy);
            }

            for (sk=m->skinmap;sk;sk=sk->next)
                for (j=0;j<(HICEFFECTMASK+1);j++)
                {
                    if (!sk->texid[j]) continue;
                    bglBindTexture(GL_TEXTURE_2D,sk->texid[j]);
                    bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,glfiltermodes[gltexfiltermode].mag);
                    bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,glfiltermodes[gltexfiltermode].min);
                    if (glinfo.maxanisotropy > 1.0)
                        bglTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAX_ANISOTROPY_EXT,glanisotropy);
                }
        }
    }
}

//--------------------------------------------------------------------------------------------------

static float glox1, gloy1, glox2, gloy2;

//Use this for both initialization and uninitialization of OpenGL.
static int gltexcacnum = -1;
void polymost_glreset()
{
    int i;
    pthtyp *pth, *next;
    //Reset if this is -1 (meaning 1st texture call ever), or > 0 (textures in memory)
    if (gltexcacnum < 0)
    {
        gltexcacnum = 0;

        //Hack for polymost_dorotatesprite calls before 1st polymost_drawrooms()
        gcosang = gcosang2 = ((double)16384)/262144.0;
        gsinang = gsinang2 = ((double)    0)/262144.0;
    }
    else
    {
        for (i=GLTEXCACHEADSIZ-1; i>=0; i--)
        {
            for (pth=gltexcachead[i]; pth;)
            {
                next = pth->next;
                if (pth->flags & 16) // fullbright textures
                {
                    bglDeleteTextures(1,&pth->ofb->glpic);
                    free(pth->ofb);
                }
                bglDeleteTextures(1,&pth->glpic);
                if (pth->palmap)
                {
                    //_initprintf("Kill #%d\n",pth->palmap);
                    free(pth->palmap);pth->palmap=0;
                }
                free(pth);
                pth = next;
            }
            gltexcachead[i] = NULL;
        }
        clearskins();
    }

    if (polymosttext) bglDeleteTextures(1,&polymosttext);
    polymosttext=0;

    memset(gltexcachead,0,sizeof(gltexcachead));
    glox1 = -1;

    // Depth peeling cleanup
    if (peels)
    {
        bglDeleteProgramsARB(2, peelprogram);
        bglDeleteFramebuffersEXT(r_peelscount + 1, peelfbos);
        bglDeleteTextures(r_peelscount + 1, peels);
        bglDeleteTextures(3, ztexture);
        free(peels);
        free(peelfbos);

        peels = NULL;
    }
}

// one-time initialisation of OpenGL for polymost
void polymost_glinit()
{
    GLfloat col[4];
    int     i;
    char    notpeeledprogramstring[] =
        "!!ARBfp1.0\n"
        "OPTION ARB_fog_exp2;\n"
        "OPTION ARB_fragment_program_shadow;\n"
        "TEMP texsample;\n"
        "TEMP depthresult;\n"
        "TEX depthresult, fragment.position, texture[1], SHADOWRECT;\n"
        "ADD depthresult.a, depthresult.a, -0.5;\n"
        "KIL depthresult.a;\n"
        "TEX texsample, fragment.texcoord[0], texture[0], 2D;\n"
        "MUL result.color, fragment.color, texsample;\n"
        "END\n";
    char    peeledprogramstring[] =
        "!!ARBfp1.0\n"
        "OPTION ARB_fog_exp2;\n"
        "OPTION ARB_fragment_program_shadow;\n"
        "TEMP texsample;\n"
        "TEMP depthresult;\n"
        "TEX depthresult, fragment.position, texture[2], SHADOWRECT;\n"
        "ADD depthresult.a, depthresult.a, -0.5;\n"
        "KIL depthresult.a;\n"
        "TEX depthresult, fragment.position, texture[1], SHADOWRECT;\n"
        "ADD depthresult.a, depthresult.a, -0.5;\n"
        "KIL depthresult.a;\n"
        "TEX texsample, fragment.texcoord[0], texture[0], 2D;\n"
        "MUL result.color, fragment.color, texsample;\n"
        "END\n";

#if 1
    if (!Bstrcmp(glinfo.vendor, "ATI Technologies Inc."))
    {
        initprintf("polymost_glinit(): ATI detected, GL_FOG_HINT = GL_DONT_CARE\n");
        bglHint(GL_FOG_HINT,GL_DONT_CARE);
    }
    else
    {
        bglHint(GL_FOG_HINT,GL_NICEST);
    }
#else
    bglHint(GL_FOG_HINT,GL_DONT_CARE);
#endif

    bglFogi(GL_FOG_MODE,GL_EXP2);
    bglFogf(GL_FOG_DENSITY,1.0); //must be > 0, default is 1
    /*    bglFogf(GL_FOG_START,0.0); //default is 0
        bglFogf(GL_FOG_END,1.0); //default is 1 */
    col[0] = 0; col[1] = 0; col[2] = 0; col[3] = 0; //range:0 to 1
    bglFogfv(GL_FOG_COLOR,col); //default is 0,0,0,0

    bglBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);

    //bglHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
    //bglEnable(GL_LINE_SMOOTH);

    if (glmultisample > 0 && glinfo.multisample)
    {
        if (glinfo.nvmultisamplehint)
            bglHint(GL_MULTISAMPLE_FILTER_HINT_NV, glnvmultisamplehint ? GL_NICEST:GL_FASTEST);
        bglEnable(GL_MULTISAMPLE_ARB);
    }

    if (r_depthpeeling && (!glinfo.arbfp || !glinfo.depthtex || !glinfo.shadow || !glinfo.fbos || !glinfo.rect || !glinfo.multitex))
    {
        OSD_Printf("Your OpenGL implementation doesn't support depth peeling. Disabling...\n");
        r_depthpeeling = 0;
    }

    if (r_detailmapping && (!glinfo.multitex || !glinfo.envcombine))
    {
        OSD_Printf("Your OpenGL implementation doesn't support detail mapping. Disabling...\n");
        r_detailmapping = 0;
    }

    if (r_glowmapping && (!glinfo.multitex || !glinfo.envcombine))
    {
        OSD_Printf("Your OpenGL implementation doesn't support glow mapping. Disabling...\n");
        r_glowmapping = 0;
    }

    if (r_vbos && (!glinfo.vbos))
    {
        OSD_Printf("Your OpenGL implementation doesn't support Vertex Buffer Objects. Disabling...\n");
        r_vbos = 0;
    }

    //depth peeling initialization
    if (r_depthpeeling)
    {
        if (newpeelscount)
        {
            r_peelscount = newpeelscount;
            newpeelscount = 0;
        }
        // create the secondary Z-buffers and the Z-backbuffer
        bglGenTextures(3, ztexture);

        i = 0;
        while (i < 3)
        {
            bglBindTexture(GL_TEXTURE_RECTANGLE, ztexture[i]);
            bglCopyTexImage2D(GL_TEXTURE_RECTANGLE, 0, GL_DEPTH_COMPONENT, 0, 0, xdim, ydim, 0);
            bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
            bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
            bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_S, GL_CLAMP);
            bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_T, GL_CLAMP);
            bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_COMPARE_MODE_ARB, GL_COMPARE_R_TO_TEXTURE_ARB);
            if (i < 2)
                bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_COMPARE_FUNC_ARB, GL_GREATER);
            else
                bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_COMPARE_FUNC_ARB, GL_LESS);
            bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_DEPTH_TEXTURE_MODE_ARB, GL_ALPHA);

            i++;
        }

        // create the various peeling layers as well as the FBOs to render to them
        peels = malloc((r_peelscount + 1) * sizeof(GLuint));
        bglGenTextures(r_peelscount + 1, peels);

        peelfbos = malloc((r_peelscount + 1) * sizeof(GLuint));
        bglGenFramebuffersEXT(r_peelscount + 1, peelfbos);

        i = 0;
        while (i <= r_peelscount)
        {
            bglBindTexture(GL_TEXTURE_RECTANGLE, peels[i]);
            bglCopyTexImage2D(GL_TEXTURE_RECTANGLE, 0, GL_RGBA, 0, 0, xdim, ydim, 0);
            bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
            bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
            bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_S, GL_CLAMP);
            bglTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_T, GL_CLAMP);

            bglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, peelfbos[i]);
            bglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_RECTANGLE, peels[i], 0);
            if (i == r_peelscount) // bakcbuffer
                bglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_TEXTURE_RECTANGLE, ztexture[2], 0);
            else if (i < (r_peelscount - 1))
                bglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_TEXTURE_RECTANGLE, ztexture[i % 2], 0);

            if (bglCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT) != GL_FRAMEBUFFER_COMPLETE_EXT)
            {
                OSD_Printf("FBO #%d initialization failed.\n", i);
            }

            bglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

            i++;
        }

        // create the peeling fragment programs
        bglGenProgramsARB(2, peelprogram);
        bglBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, peelprogram[0]);
        bglProgramStringARB(GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB, strlen(notpeeledprogramstring), notpeeledprogramstring);
        bglBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, peelprogram[1]);
        bglProgramStringARB(GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB, strlen(peeledprogramstring), peeledprogramstring);
    }

    bglEnableClientState(GL_VERTEX_ARRAY);
    bglEnableClientState(GL_TEXTURE_COORD_ARRAY);
}

void resizeglcheck()
{
    float m[4][4];
    int fovcorrect;

    if (glredbluemode < lastglredbluemode)
    {
        glox1 = -1;
        bglColorMask(1,1,1,1);
    }
    else if (glredbluemode != lastglredbluemode)
    {
        redblueclearcnt = 0;
    }
    lastglredbluemode = glredbluemode;

    //FUK
    if (lastglpolygonmode != glpolygonmode)
    {
        lastglpolygonmode = glpolygonmode;
        switch (glpolygonmode)
        {
        default:
        case 0:
            bglPolygonMode(GL_FRONT_AND_BACK,GL_FILL); break;
        case 1:
            bglPolygonMode(GL_FRONT_AND_BACK,GL_LINE); break;
        case 2:
            bglPolygonMode(GL_FRONT_AND_BACK,GL_POINT); break;
        }
    }
    if (glpolygonmode) //FUK
    {
        bglClearColor(1.0,1.0,1.0,0.0);
        bglClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
        bglDisable(GL_TEXTURE_2D);
    }

    if ((glox1 != windowx1) || (gloy1 != windowy1) || (glox2 != windowx2) || (gloy2 != windowy2))
    {
        glox1 = windowx1; gloy1 = windowy1;
        glox2 = windowx2; gloy2 = windowy2;

        fovcorrect = glprojectionhacks?(glwidescreen?0:(((windowx2-windowx1+1) * 1.2) - (windowx2-windowx1+1))):0;

        bglViewport(windowx1 - (fovcorrect / 2), yres-(windowy2+1),windowx2-windowx1+1 + fovcorrect, windowy2-windowy1+1);

        bglMatrixMode(GL_PROJECTION);
        memset(m,0,sizeof(m));
        m[0][0] = (float)ydimen / (glprojectionhacks?1.2:1); m[0][2] = 1.0;
        m[1][1] = (float)xdimen; m[1][2] = 1.0;
        m[2][2] = 1.0; m[2][3] = (float)ydimen / (glprojectionhacks?1.2:1);
        m[3][2] =-1.0;
        bglLoadMatrixf(&m[0][0]);
        //bglLoadIdentity();

        bglMatrixMode(GL_MODELVIEW);
        bglLoadIdentity();

        if (!nofog) bglEnable(GL_FOG);

        //bglEnable(GL_TEXTURE_2D);
    }
}

void fixtransparency(coltype *dapic, int daxsiz, int daysiz, int daxsiz2, int daysiz2, int dameth)
{
    coltype *wpptr;
    int j, x, y, r, g, b, dox, doy, naxsiz2;

    dox = daxsiz2-1; doy = daysiz2-1;
    if (dameth&4) { dox = min(dox,daxsiz); doy = min(doy,daysiz); }
    else { daxsiz = daxsiz2; daysiz = daysiz2; } //Make repeating textures duplicate top/left parts

    daxsiz--; daysiz--; naxsiz2 = -daxsiz2; //Hacks for optimization inside loop

    //Set transparent pixels to average color of neighboring opaque pixels
    //Doing this makes bilinear filtering look much better for masked textures (I.E. sprites)
    for (y=doy;y>=0;y--)
    {
        wpptr = &dapic[y*daxsiz2+dox];
        for (x=dox;x>=0;x--,wpptr--)
        {
            if (wpptr->a) continue;
            r = g = b = j = 0;
            if ((x>     0) && (wpptr[     -1].a)) { r += (int)wpptr[     -1].r; g += (int)wpptr[     -1].g; b += (int)wpptr[     -1].b; j++; }
            if ((x<daxsiz) && (wpptr[     +1].a)) { r += (int)wpptr[     +1].r; g += (int)wpptr[     +1].g; b += (int)wpptr[     +1].b; j++; }
            if ((y>     0) && (wpptr[naxsiz2].a)) { r += (int)wpptr[naxsiz2].r; g += (int)wpptr[naxsiz2].g; b += (int)wpptr[naxsiz2].b; j++; }
            if ((y<daysiz) && (wpptr[daxsiz2].a)) { r += (int)wpptr[daxsiz2].r; g += (int)wpptr[daxsiz2].g; b += (int)wpptr[daxsiz2].b; j++; }
            switch (j)
            {
            case 1:
                wpptr->r =   r            ; wpptr->g =   g            ; wpptr->b =   b            ; break;
            case 2:
                wpptr->r = ((r   +  1)>>1); wpptr->g = ((g   +  1)>>1); wpptr->b = ((b   +  1)>>1); break;
            case 3:
                wpptr->r = ((r*85+128)>>8); wpptr->g = ((g*85+128)>>8); wpptr->b = ((b*85+128)>>8); break;
            case 4:
                wpptr->r = ((r   +  2)>>2); wpptr->g = ((g   +  2)>>2); wpptr->b = ((b   +  2)>>2); break;
            default:
                break;
            }
        }
    }
}

static void uploadtexture(int doalloc, int xsiz, int ysiz, int intexfmt, int texfmt, coltype *pic, int tsizx, int tsizy, int dameth)
{
    coltype *wpptr, *rpptr;
    int x2, y2, j, js=0, x3, y3, y, x, r, g, b, a, k;

    if (gltexmaxsize <= 0)
    {
        GLint i = 0;
        bglGetIntegerv(GL_MAX_TEXTURE_SIZE, &i);
        if (!i) gltexmaxsize = 6;   // 2^6 = 64 == default GL max texture size
        else
        {
            gltexmaxsize = 0;
            for (; i>1; i>>=1) gltexmaxsize++;
        }
    }

    js = max(0,min(gltexmaxsize-1,gltexmiplevel));
    gltexmiplevel = js;
    while ((xsiz>>js) > (1<<gltexmaxsize) || (ysiz>>js) > (1<<gltexmaxsize)) js++;

    /*
    OSD_Printf("Uploading %dx%d %s as %s\n", xsiz,ysiz,
    		(texfmt==GL_RGBA?"GL_RGBA":
    		 texfmt==GL_RGB?"GL_RGB":
    		 texfmt==GL_BGR?"GL_BGR":
    		 texfmt==GL_BGRA?"GL_BGRA":"other"),
    		(intexfmt==GL_RGBA?"GL_RGBA":
    		 intexfmt==GL_RGB?"GL_RGB":
    		 intexfmt==GL_COMPRESSED_RGBA_ARB?"GL_COMPRESSED_RGBA_ARB":
    		 intexfmt==GL_COMPRESSED_RGB_ARB?"GL_COMPRESSED_RGB_ARB":"other"));
    */

    if (js == 0)
    {
        if (doalloc&1)
            bglTexImage2D(GL_TEXTURE_2D,0,intexfmt,xsiz,ysiz,0,texfmt,GL_UNSIGNED_BYTE,pic); //loading 1st time
        else
            bglTexSubImage2D(GL_TEXTURE_2D,0,0,0,xsiz,ysiz,texfmt,GL_UNSIGNED_BYTE,pic); //overwrite old texture
    }

#if 0
    gluBuild2DMipmaps(GL_TEXTURE_2D,GL_RGBA8,xsiz,ysiz,texfmt,GL_UNSIGNED_BYTE,pic); //Needs C++ to link?
#elif 1
    x2 = xsiz; y2 = ysiz;
    for (j=1;(x2 > 1) || (y2 > 1);j++)
    {
        //x3 = ((x2+1)>>1); y3 = ((y2+1)>>1);
        x3 = max(1, x2 >> 1); y3 = max(1, y2 >> 1);		// this came from the GL_ARB_texture_non_power_of_two spec
        for (y=0;y<y3;y++)
        {
            wpptr = &pic[y*x3]; rpptr = &pic[(y<<1)*x2];
            for (x=0;x<x3;x++,wpptr++,rpptr+=2)
            {
                r = g = b = a = k = 0;
                if (rpptr[0].a)                  { r += (int)rpptr[0].r; g += (int)rpptr[0].g; b += (int)rpptr[0].b; a += (int)rpptr[0].a; k++; }
                if ((x+x+1 < x2) && (rpptr[1].a)) { r += (int)rpptr[1].r; g += (int)rpptr[1].g; b += (int)rpptr[1].b; a += (int)rpptr[1].a; k++; }
                if (y+y+1 < y2)
                {
                    if ((rpptr[x2].a)) { r += (int)rpptr[x2  ].r; g += (int)rpptr[x2  ].g; b += (int)rpptr[x2  ].b; a += (int)rpptr[x2  ].a; k++; }
                    if ((x+x+1 < x2) && (rpptr[x2+1].a)) { r += (int)rpptr[x2+1].r; g += (int)rpptr[x2+1].g; b += (int)rpptr[x2+1].b; a += (int)rpptr[x2+1].a; k++; }
                }
                switch (k)
                {
                case 0:
                case 1:
                    wpptr->r = r; wpptr->g = g; wpptr->b = b; wpptr->a = a; break;
                case 2:
                    wpptr->r = ((r+1)>>1); wpptr->g = ((g+1)>>1); wpptr->b = ((b+1)>>1); wpptr->a = ((a+1)>>1); break;
                case 3:
                    wpptr->r = ((r*85+128)>>8); wpptr->g = ((g*85+128)>>8); wpptr->b = ((b*85+128)>>8); wpptr->a = ((a*85+128)>>8); break;
                case 4:
                    wpptr->r = ((r+2)>>2); wpptr->g = ((g+2)>>2); wpptr->b = ((b+2)>>2); wpptr->a = ((a+2)>>2); break;
                default:
                    break;
                }
                //if (wpptr->a) wpptr->a = 255;
            }
        }
        if (tsizx >= 0) fixtransparency(pic,(tsizx+(1<<j)-1)>>j,(tsizy+(1<<j)-1)>>j,x3,y3,dameth);
        if (j >= js)
        {
            if (doalloc&1)
                bglTexImage2D(GL_TEXTURE_2D,j-js,intexfmt,x3,y3,0,texfmt,GL_UNSIGNED_BYTE,pic); //loading 1st time
            else
                bglTexSubImage2D(GL_TEXTURE_2D,j-js,0,0,x3,y3,texfmt,GL_UNSIGNED_BYTE,pic); //overwrite old texture
        }
        x2 = x3; y2 = y3;
    }
#endif
}

int gloadtile_art(int dapic, int dapal, int dameth, pthtyp *pth, int doalloc)
{
    coltype *pic, *wpptr;
    int j, x, y, x2, y2, xsiz, ysiz, dacol, tsizx, tsizy;
    char hasalpha = 0, hasfullbright = 0;

    tsizx = tilesizx[dapic];
    tsizy = tilesizy[dapic];
    if (!glinfo.texnpot)
    {
        for (xsiz=1;xsiz<tsizx;xsiz+=xsiz);
        for (ysiz=1;ysiz<tsizy;ysiz+=ysiz);
    }
    else
    {
        if ((tsizx|tsizy) == 0)
        {
            xsiz = ysiz = 1;
        }
        else
        {
            xsiz = tsizx;
            ysiz = tsizy;
        }
    }

    pic = (coltype *)malloc(xsiz*ysiz*sizeof(coltype));
    if (!pic) return 1;

    if (!waloff[dapic])
    {
        //Force invalid textures to draw something - an almost purely transparency texture
        //This allows the Z-buffer to be updated for mirrors (which are invalidated textures)
        pic[0].r = pic[0].g = pic[0].b = 0; pic[0].a = 1;
        tsizx = tsizy = 1; hasalpha = 1;
    }
    else
    {
        for (y=0;y<ysiz;y++)
        {
            if (y < tsizy) y2 = y; else y2 = y-tsizy;
            wpptr = &pic[y*xsiz];
            for (x=0;x<xsiz;x++,wpptr++)
            {
                if ((dameth&4) && ((x >= tsizx) || (y >= tsizy))) //Clamp texture
                    { wpptr->r = wpptr->g = wpptr->b = wpptr->a = 0; continue; }
                if (x < tsizx) x2 = x; else x2 = x-tsizx;
                dacol = (int)(*(unsigned char *)(waloff[dapic]+x2*tsizy+y2));
                if (!fullbrightloadingpass)
                {
                    // regular texture
                    if ((dacol > 239) && (dacol != 255))
                        hasfullbright = 1;
                    wpptr->a = 255;
                }
                else if (fullbrightloadingpass == 1)
                {
                    // texture with only fullbright areas
                    if (dacol < 240)    // regular colors
                    {
                        wpptr->a = 0; hasalpha = 1;
                    }
                    else   // fullbright
                    {
                        wpptr->a = 255;
                    }
                }
                if (dacol != 255)
                    dacol = (int)((unsigned char)palookup[dapal][dacol]);
                else
                {
                    wpptr->a = 0; hasalpha = 1;
                }
                if (gammabrightness)
                {
                    wpptr->r = curpalette[dacol].r;
                    wpptr->g = curpalette[dacol].g;
                    wpptr->b = curpalette[dacol].b;
                }
                else
                {
                    wpptr->r = britable[curbrightness][ curpalette[dacol].r ];
                    wpptr->g = britable[curbrightness][ curpalette[dacol].g ];
                    wpptr->b = britable[curbrightness][ curpalette[dacol].b ];
                }
            }
        }
    }

    if (doalloc) bglGenTextures(1,(GLuint*)&pth->glpic);  //# of textures (make OpenGL allocate structure)
    bglBindTexture(GL_TEXTURE_2D,pth->glpic);

    fixtransparency(pic,tsizx,tsizy,xsiz,ysiz,dameth);
    uploadtexture(doalloc,xsiz,ysiz,hasalpha?GL_RGBA:GL_RGB,GL_RGBA,pic,tsizx,tsizy,dameth);

    if (gltexfiltermode < 0) gltexfiltermode = 0;
    else if (gltexfiltermode >= (int)numglfiltermodes) gltexfiltermode = numglfiltermodes-1;
    bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,glfiltermodes[gltexfiltermode].mag);
    bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,glfiltermodes[gltexfiltermode].min);

    if (glinfo.maxanisotropy > 1.0)
    {
        if (glanisotropy <= 0 || glanisotropy > glinfo.maxanisotropy) glanisotropy = (int)glinfo.maxanisotropy;
        bglTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAX_ANISOTROPY_EXT,glanisotropy);
    }

    if (!(dameth&4))
    {
        bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
        bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
    }
    else
    {
        //For sprite textures, clamping looks better than wrapping
        bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP);
        bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP);
    }

    if (pic) free(pic);

    pth->picnum = dapic;
    pth->palnum = dapal;
    pth->effects = 0;
    pth->flags = ((dameth&4)>>2) | (hasalpha<<3) | (hasfullbright<<4);
    pth->hicr = NULL;

    if ((hasfullbright) && (!fullbrightloadingpass))
    {
        // load the ONLY texture that'll be assembled with the regular one to make the final texture with fullbright pixels
        fullbrightloadingpass = 1;
        pth->ofb = (pthtyp *)calloc(1,sizeof(pthtyp));
        if (!pth->ofb) return 1;
        if (gloadtile_art(dapic, dapal, dameth, pth->ofb, 1)) return 1;

        fullbrightloadingpass = 0;
    }
    return 0;
}

// JONOF'S COMPRESSED TEXTURE CACHE STUFF ---------------------------------------------------
static inline void phex(unsigned char v, char *s)
{
    int x;
    x = v>>4;
    s[0] = x<10 ? (x+'0') : (x-10+'a');
    x = v&15;
    s[1] = x<10 ? (x+'0') : (x-10+'a');
}

int trytexcache(char *fn, int len, int dameth, char effect, texcacheheader *head)
{
    int fil, fp;
    char cachefn[BMAX_PATH], *cp;
    unsigned char mdsum[16];

    if (!glinfo.texcompr || !glusetexcompr || !glusetexcache) return -1;
    if (!bglCompressedTexImage2DARB || !bglGetCompressedTexImageARB)
    {
        // lacking the necessary extensions to do this
        initprintf("Warning: the GL driver lacks necessary functions to use caching\n");
        glusetexcache = 0;
        return -1;
    }

    md4once((unsigned char *)fn, strlen(fn), mdsum);
    for (cp = cachefn, fp = 0; (*cp = TEXCACHEDIR[fp]); cp++,fp++);
    *(cp++) = '/';
    for (fp = 0; fp < 16; phex(mdsum[fp++], cp), cp+=2);
    sprintf(cp, "-%x-%x%x", len, dameth, effect);

    fil = kopen4load(cachefn, 0);
    if (fil < 0) return -1;

    /* initprintf("Loading cached tex: %s\n", cachefn); */

    if (kread(fil, head, sizeof(texcacheheader)) < (int)sizeof(texcacheheader)) goto failure;
    if (memcmp(head->magic, "Polymost", 8)) goto failure;

    head->xdim = B_LITTLE32(head->xdim);
    head->ydim = B_LITTLE32(head->ydim);
    head->flags = B_LITTLE32(head->flags);

    if (!glinfo.texnpot && (head->flags & 1)) goto failure;

    return fil;
failure:
    kclose(fil);
    return -1;
}

void writexcache(char *fn, int len, int dameth, char effect, texcacheheader *head)
{
    int fil=-1, fp;
    char cachefn[BMAX_PATH], *cp;
    unsigned char mdsum[16];
    texcachepicture pict;
    char *pic = NULL, *packbuf = NULL;
    void *midbuf = NULL;
    unsigned int alloclen=0, level, miplen;
    unsigned int padx=0, pady=0;
    GLuint gi;
    int j, k;

    if (!glinfo.texcompr || !glusetexcompr || !glusetexcache) return;
    if (!bglCompressedTexImage2DARB || !bglGetCompressedTexImageARB)
    {
        // lacking the necessary extensions to do this
        initprintf("Warning: the GL driver lacks necessary functions to use caching\n");
        glusetexcache = 0;
        return;
    }

    {
        struct stat st;
        if (stat(TEXCACHEDIR, &st) < 0)
        {
            if (errno == ENOENT)     // path doesn't exist
            {
                // try to create the cache directory
                if (Bmkdir(TEXCACHEDIR, S_IRWXU) < 0)
                {
                    initprintf("Failed to create texture cache directory %s\n", TEXCACHEDIR);
                    glusetexcache = 0;
                    return;
                }
                else initprintf("Created texture cache directory %s\n", TEXCACHEDIR);
            }
            else
            {
                // another type of failure
                glusetexcache = 0;
                return;
            }
        }
        else if ((st.st_mode & S_IFDIR) != S_IFDIR)
        {
            // cache directory isn't a directory
            glusetexcache = 0;
            return;
        }
    }

    gi = GL_FALSE;
    bglGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_COMPRESSED_ARB, (GLint *)&gi);
    if (gi != GL_TRUE) return;

    md4once((unsigned char *)fn, strlen(fn), mdsum);
    for (cp = cachefn, fp = 0; (*cp = TEXCACHEDIR[fp]); cp++,fp++);
    *(cp++) = '/';
    for (fp = 0; fp < 16; phex(mdsum[fp++], cp), cp+=2);
    sprintf(cp, "-%x-%x%x", len, dameth, effect);

    initprintf("Writing cached tex: %s\n", cachefn);

    fil = Bopen(cachefn,BO_BINARY|BO_CREAT|BO_TRUNC|BO_RDWR,BS_IREAD|BS_IWRITE);
    if (fil < 0) return;

    memcpy(head->magic, "Polymost", 8);   // sizes are set by caller

    if (glusetexcachecompression) head->flags |= 4;

    head->xdim = B_LITTLE32(head->xdim);
    head->ydim = B_LITTLE32(head->ydim);
    head->flags = B_LITTLE32(head->flags);

    if (Bwrite(fil, head, sizeof(texcacheheader)) != sizeof(texcacheheader)) goto failure;

    bglGetError();
    for (level = 0; level==0 || (padx > 1 || pady > 1); level++)
    {
        bglGetTexLevelParameteriv(GL_TEXTURE_2D, level, GL_TEXTURE_COMPRESSED_ARB, (GLint *)&gi);
        if (bglGetError() != GL_NO_ERROR) goto failure;
        if (gi != GL_TRUE) goto failure;   // an uncompressed mipmap
        bglGetTexLevelParameteriv(GL_TEXTURE_2D, level, GL_TEXTURE_INTERNAL_FORMAT, (GLint *)&gi);
        if (bglGetError() != GL_NO_ERROR) goto failure;
        pict.format = B_LITTLE32(gi);
        bglGetTexLevelParameteriv(GL_TEXTURE_2D, level, GL_TEXTURE_WIDTH, (GLint *)&gi);
        if (bglGetError() != GL_NO_ERROR) goto failure;
        padx = gi; pict.xdim = B_LITTLE32(gi);
        bglGetTexLevelParameteriv(GL_TEXTURE_2D, level, GL_TEXTURE_HEIGHT, (GLint *)&gi);
        if (bglGetError() != GL_NO_ERROR) goto failure;
        pady = gi; pict.ydim = B_LITTLE32(gi);
        bglGetTexLevelParameteriv(GL_TEXTURE_2D, level, GL_TEXTURE_BORDER, (GLint *)&gi);
        if (bglGetError() != GL_NO_ERROR) goto failure;
        pict.border = B_LITTLE32(gi);
        bglGetTexLevelParameteriv(GL_TEXTURE_2D, level, GL_TEXTURE_DEPTH, (GLint *)&gi);
        if (bglGetError() != GL_NO_ERROR) goto failure;
        pict.depth = B_LITTLE32(gi);
        bglGetTexLevelParameteriv(GL_TEXTURE_2D, level, GL_TEXTURE_COMPRESSED_IMAGE_SIZE_ARB, (GLint *)&gi);
        if (bglGetError() != GL_NO_ERROR) goto failure;
        miplen = (int)gi; pict.size = B_LITTLE32(gi);

        if (alloclen < miplen)
        {
            void *picc = realloc(pic, miplen);
            if (!picc) goto failure; else pic = picc;
            alloclen = miplen;

            picc = realloc(packbuf, alloclen+16);
            if (!picc) goto failure; else packbuf = picc;

            picc = realloc(midbuf, miplen);
            if (!picc) goto failure; else midbuf = picc;
        }

        bglGetCompressedTexImageARB(GL_TEXTURE_2D, level, pic);
        if (bglGetError() != GL_NO_ERROR) goto failure;

        if (Bwrite(fil, &pict, sizeof(texcachepicture)) != sizeof(texcachepicture)) goto failure;
        if (dxtfilter(fil, &pict, pic, midbuf, packbuf, miplen)) goto failure;
    }

failure:
    if (fil>=0) Bclose(fil);
    if (midbuf) free(midbuf);
    if (pic) free(pic);
    if (packbuf) free(packbuf);
}

int gloadtile_cached(int fil, texcacheheader *head, int *doalloc, pthtyp *pth,int dapalnum)
{
    int level, r;
    texcachepicture pict;
    char *pic = NULL, *packbuf = NULL;
    void *midbuf = NULL;
    int alloclen=0;

    if (*doalloc&1)
    {
        bglGenTextures(1,(GLuint*)&pth->glpic);  //# of textures (make OpenGL allocate structure)
        *doalloc |= 2;   // prevents bglGenTextures being called again if we fail in here
    }
    bglBindTexture(GL_TEXTURE_2D,pth->glpic);

    pth->sizx = head->xdim;
    pth->sizy = head->ydim;

    bglGetError();

    // load the mipmaps
    for (level = 0; level==0 || (pict.xdim > 1 || pict.ydim > 1); level++)
    {
        r = kread(fil, &pict, sizeof(texcachepicture));
        if (r < (int)sizeof(texcachepicture)) goto failure;

        pict.size = B_LITTLE32(pict.size);
        pict.format = B_LITTLE32(pict.format);
        pict.xdim = B_LITTLE32(pict.xdim);
        pict.ydim = B_LITTLE32(pict.ydim);
        pict.border = B_LITTLE32(pict.border);
        pict.depth = B_LITTLE32(pict.depth);

        if (alloclen < pict.size)
        {
            void *picc = realloc(pic, pict.size);
            if (!picc) goto failure; else pic = picc;
            alloclen = pict.size;

            picc = realloc(packbuf, alloclen+16);
            if (!picc) goto failure; else packbuf = picc;

            picc = realloc(midbuf, pict.size);
            if (!picc) goto failure; else midbuf = picc;
        }

        if (dedxtfilter(fil, &pict, pic, midbuf, packbuf, (head->flags&4)==4)) goto failure;

        bglCompressedTexImage2DARB(GL_TEXTURE_2D,level,pict.format,pict.xdim,pict.ydim,pict.border,
                                   pict.size,pic);
        if (bglGetError() != GL_NO_ERROR) goto failure;

        {
            GLint format;
            bglGetTexLevelParameteriv(GL_TEXTURE_2D, level, GL_TEXTURE_INTERNAL_FORMAT, &format);
            if (bglGetError() != GL_NO_ERROR) goto failure;
            format = B_LITTLE32(format);
            if (pict.format != format)
            {
                initprintf("invalid texture cache file format %d %d\n",pict.format, format);
                goto failure;
            }
        }

    }

    if (midbuf) free(midbuf);
    if (pic) free(pic);
    if (packbuf) free(packbuf);
    return 0;
failure:
    if (midbuf) free(midbuf);
    if (pic) free(pic);
    if (packbuf) free(packbuf);
    return -1;
}
// --------------------------------------------------- JONOF'S COMPRESSED TEXTURE CACHE STUFF
static void applypalmapsT(char *pic, int sizx, int sizy, int pal)
{
    //_initprintf("%d\n",pal);
    int stage;
    for (stage=0;stage<MAXPALCONV;stage++)
    {
        int pal1=0,pal2=pal;
        pthtyp *pth;
        getpalmap(stage,&pal1,&pal2);
        if (!pal1)return;

        for (pth=pichead; pth; pth=pth->next)
            if (pth->palnum ==pal1&&pth->palmap)break;
        if (!pth||pth->size!=sizx*sizy)continue;

        applypalmap(pic,pth->palmap,pth->size,pal2);
    }
}

int gloadtile_hi(int dapic,int dapalnum, int facen, hicreplctyp *hicr, int dameth, pthtyp *pth, int doalloc, char effect)
{
    coltype *pic = NULL, *rpptr;
    int j, x, y, x2, y2, xsiz=0, ysiz=0, tsizx, tsizy;

    char *picfil = NULL, *fn, hasalpha = 255;
    int picfillen, texfmt = GL_RGBA, intexfmt = GL_RGBA, filh;

    int cachefil = -1;
    texcacheheader cachead;

    if (!hicr) return -1;
    if (facen > 0)
    {
        if (!hicr->skybox) return -1;
        if (facen > 6) return -1;
        if (!hicr->skybox->face[facen-1]) return -1;
        fn = hicr->skybox->face[facen-1];
    }
    else
    {
        if (!hicr->filename) return -1;
        fn = hicr->filename;
    }

    if ((filh = kopen4load(fn, 0)) < 0)
    {
        initprintf("hightile: %s (pic %d) not found\n", fn, dapic);
        if (facen > 0)
            hicr->skybox->ignore = 1;
        else
            hicr->ignore = 1;
        return -1;
    }
    picfillen = kfilelength(filh);

    kclose(filh);	// FIXME: shouldn't have to do this. bug in cache1d.c

    cachefil = trytexcache(fn, picfillen+(dapalnum<<8), dameth, effect, &cachead);
    if (cachefil >= 0 && !gloadtile_cached(cachefil, &cachead, &doalloc, pth, dapalnum))
    {
        tsizx = cachead.xdim;
        tsizy = cachead.ydim;
        hasalpha = (cachead.flags & 2) ? 0 : 255;
        kclose(cachefil);
        //kclose(filh);	// FIXME: uncomment when cache1d.c is fixed
        // cachefil >= 0, so it won't be rewritten
    }
    else
    {
        if (cachefil >= 0) kclose(cachefil);
        cachefil = -1;	// the compressed version will be saved to disk

        if ((filh = kopen4load(fn, 0)) < 0) return -1;

        picfil = (char *)malloc(picfillen); if (!picfil) { kclose(filh); return 1; }
        kread(filh, picfil, picfillen);
        kclose(filh);

        // tsizx/y = replacement texture's natural size
        // xsiz/y = 2^x size of replacement

        kpgetdim(picfil,picfillen,&tsizx,&tsizy);
        if (tsizx == 0 || tsizy == 0) { free(picfil); return -1; }
        pth->sizx = tsizx;
        pth->sizy = tsizy;

        if (!glinfo.texnpot)
        {
            for (xsiz=1;xsiz<tsizx;xsiz+=xsiz);
            for (ysiz=1;ysiz<tsizy;ysiz+=ysiz);
        }
        else
        {
            xsiz = tsizx;
            ysiz = tsizy;
        }
        pic = (coltype *)calloc(xsiz,ysiz*sizeof(coltype)); if (!pic) { free(picfil); return 1; }

        if (kprender(picfil,picfillen,(int)pic,xsiz*sizeof(coltype),xsiz,ysiz,0,0)) { free(picfil); free(pic); return -2; }
        applypalmapsT((char *)pic,tsizx,tsizy,dapalnum);
        for (y=0,j=0;y<tsizy;y++,j+=xsiz)
        {
            coltype tcol;
            char *cptr = &britable[gammabrightness ? 0 : curbrightness][0];
            rpptr = &pic[j];

            for (x=0;x<tsizx;x++)
            {
                tcol.b = cptr[rpptr[x].b];
                tcol.g = cptr[rpptr[x].g];
                tcol.r = cptr[rpptr[x].r];
                tcol.a = rpptr[x].a; hasalpha &= rpptr[x].a;

                if (effect & 1)
                {
                    // greyscale
                    tcol.b = max(tcol.b, max(tcol.g, tcol.r));
                    tcol.g = tcol.r = tcol.b;
                }
                if (effect & 2)
                {
                    // invert
                    tcol.b = 255-tcol.b;
                    tcol.g = 255-tcol.g;
                    tcol.r = 255-tcol.r;
                }

                rpptr[x].b = tcol.b;
                rpptr[x].g = tcol.g;
                rpptr[x].r = tcol.r;
                rpptr[x].a = tcol.a;
            }
        }
        if ((!(dameth&4)) || (facen)) //Duplicate texture pixels (wrapping tricks for non power of 2 texture sizes)
        {
            if (xsiz > tsizx) //Copy left to right
            {
                int *lptr = (int *)pic;
                for (y=0;y<tsizy;y++,lptr+=xsiz)
                    memcpy(&lptr[tsizx],lptr,(xsiz-tsizx)<<2);
            }
            if (ysiz > tsizy)  //Copy top to bottom
                memcpy(&pic[xsiz*tsizy],pic,(ysiz-tsizy)*xsiz<<2);
        }
        if (!glinfo.bgra)
        {
            for (j=xsiz*ysiz-1;j>=0;j--)
            {
                swapchar(&pic[j].r, &pic[j].b);
            }
        }
        else texfmt = GL_BGRA;
        free(picfil); picfil = 0;

        if (glinfo.texcompr && glusetexcompr && !(hicr->flags & 1))
            intexfmt = (hasalpha == 255) ? GL_COMPRESSED_RGB_ARB : GL_COMPRESSED_RGBA_ARB;
        else if (hasalpha == 255) intexfmt = GL_RGB;

        if ((doalloc&3)==1) bglGenTextures(1,(GLuint*)&pth->glpic);  //# of textures (make OpenGL allocate structure)
        bglBindTexture(GL_TEXTURE_2D,pth->glpic);

        if (dapalnum>=SPECPAL&&dapalnum<=REDPAL)
        {
            //_initprintf("%cLoaded palamp %d(%dx%d)",pth->palmap?'+':'-',dapalnum,xsiz,ysiz);
            if (!pth->palmap)
            {
                pth->size=xsiz*ysiz;
                pth->palmap=malloc(pth->size*4);
                memcpy(pth->palmap,pic,pth->size*4);
            }
            cachefil=0;
            //_initprintf("#%d\n",pth->palmap);
        }
        fixtransparency(pic,tsizx,tsizy,xsiz,ysiz,dameth);
        uploadtexture(doalloc,xsiz,ysiz,intexfmt,texfmt,pic,-1,tsizy,dameth);
    }

    // precalculate scaling parameters for replacement
    if (facen > 0)
    {
        pth->scalex = ((float)tsizx) / 64.0;
        pth->scaley = ((float)tsizy) / 64.0;
    }
    else
    {
        pth->scalex = ((float)tsizx) / ((float)tilesizx[dapic]);
        pth->scaley = ((float)tsizy) / ((float)tilesizy[dapic]);
    }

    if (gltexfiltermode < 0) gltexfiltermode = 0;
    else if (gltexfiltermode >= (int)numglfiltermodes) gltexfiltermode = numglfiltermodes-1;
    bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,glfiltermodes[gltexfiltermode].mag);
    bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,glfiltermodes[gltexfiltermode].min);

    if (glinfo.maxanisotropy > 1.0)
    {
        if (glanisotropy <= 0 || glanisotropy > glinfo.maxanisotropy) glanisotropy = (int)glinfo.maxanisotropy;
        bglTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAX_ANISOTROPY_EXT,glanisotropy);
    }

    if (!(dameth&4))
    {
        bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
        bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
    }
    else
    {
        //For sprite textures, clamping looks better than wrapping
        bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP);
        bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP);
    }

    if (pic) free(pic);

    pth->picnum = dapic;
    pth->effects = effect;
    pth->flags = ((dameth&4)>>2) + 2 + ((facen>0)<<2); if (hasalpha != 255) pth->flags |= 8;
    pth->skyface = facen;
    pth->hicr = hicr;

    if (cachefil < 0)
    {
        // save off the compressed version
        cachead.xdim = tsizx;
        cachead.ydim = tsizy;
        x = 0;
        for (j=0;j<31;j++)
        {
            if (xsiz == pow2long[j]) { x |= 1; }
            if (ysiz == pow2long[j]) { x |= 2; }
        }
        cachead.flags = (x!=3) | (hasalpha != 255 ? 2 : 0);
        writexcache(fn, picfillen+(dapalnum<<8), dameth, effect, &cachead);
    }

    return 0;
}

#endif

//(dpx,dpy) specifies an n-sided polygon. The polygon must be a convex clockwise loop.
//    n must be <= 8 (assume clipping can double number of vertices)
//method: 0:solid, 1:masked(255 is transparent), 2:transluscent #1, 3:transluscent #2
//    +4 means it's a sprite, so wraparound isn't needed
static int pow2xsplit = 0, skyclamphack = 0;

void drawpoly(double *dpx, double *dpy, int n, int method)
{
#define PI 3.14159265358979323
    double ngdx = 0.0, ngdy = 0.0, ngdo = 0.0, ngux = 0.0, nguy = 0.0, nguo = 0.0;
    double ngvx = 0.0, ngvy = 0.0, ngvo = 0.0, dp, up, vp, rdp, du0 = 0.0, du1 = 0.0, dui, duj;
    double ngdx2, ngux2, ngvx2;
    double f, r, ox, oy, oz, ox2, oy2, oz2, dd[16], uu[16], vv[16], px[16], py[16], uoffs;
    int i, j, k, x, y, z, nn, ix0, ix1, mini, maxi, tsizx, tsizy, tsizxm1 = 0, tsizym1 = 0, ltsizy = 0;
    int xx, yy, xi, d0, u0, v0, d1, u1, v1, xmodnice = 0, ymulnice = 0, dorot;
    char dacol = 0, *walptr, *palptr = NULL, *vidp, *vide;
    GLfloat pc1[4];
#ifdef USE_OPENGL
    pthtyp *pth, *detailpth, *glowpth, *palpth;
    int texunits = GL_TEXTURE0_ARB;
#endif
    // backup of the n for possible redrawing of fullbright
    int n_ = n, method_ = method;

    if (method == -1) return;

    if (n == 3)
    {
        if ((dpx[0]-dpx[1])*(dpy[2]-dpy[1]) >= (dpx[2]-dpx[1])*(dpy[0]-dpy[1])) return; //for triangle
    }
    else
    {
        f = 0; //f is area of polygon / 2
        for (i=n-2,j=n-1,k=0;k<n;i=j,j=k,k++) f += (dpx[i]-dpx[k])*dpy[j];
        if (f <= 0) return;
    }

    //Load texture (globalpicnum)
    if ((unsigned int)globalpicnum >= MAXTILES) globalpicnum = 0;
    setgotpic(globalpicnum);
    tsizx = tilesizx[globalpicnum];
    tsizy = tilesizy[globalpicnum];
    if (palookup[globalpal] == NULL)
        globalpal = 0;
    if (!waloff[globalpicnum])
    {
        loadtile(globalpicnum);
        if (!waloff[globalpicnum])
        {
            if (rendmode < 3) return;
            tsizx = tsizy = 1; method = 1; //Hack to update Z-buffer for invalid mirror textures
        }
    }
    walptr = (char *)waloff[globalpicnum];

    j = 0; dorot = ((gchang != 1.0) || (gctang != 1.0));
    if (dorot)
    {
        for (i=0;i<n;i++)
        {
            ox = dpx[i]-ghalfx;
            oy = dpy[i]-ghoriz;
            oz = ghalfx;

            //Up/down rotation
            ox2 = ox;
            oy2 = oy*gchang - oz*gshang;
            oz2 = oy*gshang + oz*gchang;

            //Tilt rotation
            ox = ox2*gctang - oy2*gstang;
            oy = ox2*gstang + oy2*gctang;
            oz = oz2;

            if ((oz < SCISDIST) && (rendmode < 3)) return; //annoying hack to avoid bugs in software rendering

            r = ghalfx / oz;

            dd[j] = (dpx[i]*gdx + dpy[i]*gdy + gdo)*r;
            uu[j] = (dpx[i]*gux + dpy[i]*guy + guo)*r;
            vv[j] = (dpx[i]*gvx + dpy[i]*gvy + gvo)*r;

            px[j] = ox*r + ghalfx;
            py[j] = oy*r + ghoriz;
            if ((!j) || (px[j] != px[j-1]) || (py[j] != py[j-1])) j++;
        }
    }
    else
    {
        for (i=0;i<n;i++)
        {
            px[j] = dpx[i];
            py[j] = dpy[i];
            if ((!j) || (px[j] != px[j-1]) || (py[j] != py[j-1])) j++;
        }
    }
    while ((j >= 3) && (px[j-1] == px[0]) && (py[j-1] == py[0])) j--;
    if (j < 3) return;
    n = j;

#ifdef USE_OPENGL
    if (rendmode >= 3)
    {
        float hackscx, hackscy;

        int pal1;
        if (usehightile)
            for (pal1=SPECPAL;pal1<=REDPAL;pal1++)
                if (hicfindsubst(globalpicnum, pal1, 0))
                    gltexcache(globalpicnum, pal1, method&(~3));

        if (skyclamphack) method |= 4;
        pth = gltexcache(globalpicnum,globalpal,method&(~3));

        if (pth->flags & 16)
            if (indrawroomsandmasks)
            {
                if (!fullbrightdrawingpass)
                    fullbrightdrawingpass = 1;
                else if (fullbrightdrawingpass == 2)
                    pth = pth->ofb;
            }

        bglBindTexture(GL_TEXTURE_2D, pth ? pth->glpic : 0);

        if (srepeat)
            bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
        if (trepeat)
            bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);

        // texture scale by parkar request
        if (pth && pth->hicr && ((pth->hicr->xscale != 1.0f) || (pth->hicr->yscale != 1.0f)) && !drawingskybox)
        {
            bglMatrixMode(GL_TEXTURE);
            bglLoadIdentity();
            bglScalef(pth->hicr->xscale, pth->hicr->yscale, 1.0f);
            bglMatrixMode(GL_MODELVIEW);
        }

        // detail texture
        detailpth = NULL;
        if (r_detailmapping && usehightile && !r_depthpeeling && !drawingskybox &&
                hicfindsubst(globalpicnum, DETAILPAL, 0))
            detailpth = gltexcache(globalpicnum, DETAILPAL, method&(~3));

        if (detailpth && (detailpth->hicr->palnum == DETAILPAL))
        {
            bglActiveTextureARB(++texunits);

            bglEnable(GL_TEXTURE_2D);
            bglBindTexture(GL_TEXTURE_2D, detailpth ? detailpth->glpic : 0);

            bglTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
            bglTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE);

            bglTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_PREVIOUS_ARB);
            bglTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);

            bglTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_TEXTURE);
            bglTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR);

            bglTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE);
            bglTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS_ARB);
            bglTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_ALPHA_ARB, GL_SRC_ALPHA);

            bglTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2.0f);

            bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
            bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);


            f = detailpth ? detailpth->hicr->xscale : 1.0;

            bglMatrixMode(GL_TEXTURE);
            bglLoadIdentity();

            if (pth && pth->hicr && ((pth->hicr->xscale != 1.0f) || (pth->hicr->yscale != 1.0f)))
                bglScalef(pth->hicr->xscale, pth->hicr->yscale, 1.0f);

            if (detailpth && detailpth->hicr && ((detailpth->hicr->xscale != 1.0f) || (detailpth->hicr->yscale != 1.0f)))
                bglScalef(detailpth->hicr->xscale, detailpth->hicr->yscale, 1.0f);

            bglMatrixMode(GL_MODELVIEW);
        }

        // glow texture
        glowpth = NULL;
        if (r_glowmapping && usehightile && !r_depthpeeling && !drawingskybox &&
                hicfindsubst(globalpicnum, GLOWPAL, 0))
            glowpth = gltexcache(globalpicnum, GLOWPAL, method&(~3));

        if (glowpth && (glowpth->hicr->palnum == GLOWPAL))
        {
            bglActiveTextureARB(++texunits);

            bglEnable(GL_TEXTURE_2D);
            bglBindTexture(GL_TEXTURE_2D, glowpth ? glowpth->glpic : 0);

            bglTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
            bglTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_INTERPOLATE_ARB);

            bglTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_PREVIOUS_ARB);
            bglTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);

            bglTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_TEXTURE);
            bglTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR);

            bglTexEnvf(GL_TEXTURE_ENV, GL_SOURCE2_RGB_ARB, GL_TEXTURE);
            bglTexEnvf(GL_TEXTURE_ENV, GL_OPERAND2_RGB_ARB, GL_ONE_MINUS_SRC_ALPHA);

            bglTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE);
            bglTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS_ARB);
            bglTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_ALPHA_ARB, GL_SRC_ALPHA);

            bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
            bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
        }

        if (pth && (pth->flags & 2))
        {
            hackscx = pth->scalex;
            hackscy = pth->scaley;
            tsizx = pth->sizx;
            tsizy = pth->sizy;
        }
        else { hackscx = 1.0; hackscy = 1.0; }

        if (!glinfo.texnpot)
        {
            for (xx=1;xx<tsizx;xx+=xx); ox2 = (double)1.0/(double)xx;
            for (yy=1;yy<tsizy;yy+=yy); oy2 = (double)1.0/(double)yy;
        }
        else
        {
            xx = tsizx; ox2 = (double)1.0/(double)xx;
            yy = tsizy; oy2 = (double)1.0/(double)yy;
        }

        if ((!(method&3)) && (!fullbrightdrawingpass))
        {
            bglDisable(GL_BLEND);
            if (!peelcompiling)
                bglDisable(GL_ALPHA_TEST);
        }
        else
        {
            float al = 0.0; // PLAG : default alphacut was 0.32 before goodalpha
            if (pth && pth->hicr && pth->hicr->alphacut >= 0.0) al = pth->hicr->alphacut;
            if (alphahackarray[globalpicnum])
                al=alphahackarray[globalpicnum];
            if (!waloff[globalpicnum]) al = 0.0;	// invalid textures ignore the alpha cutoff settings
            if (!peelcompiling)
                bglEnable(GL_BLEND);
            bglEnable(GL_ALPHA_TEST);
            bglAlphaFunc(GL_GREATER,al);
        }

        if (!dorot)
        {
            for (i=n-1;i>=0;i--)
            {
                dd[i] = px[i]*gdx + py[i]*gdy + gdo;
                uu[i] = px[i]*gux + py[i]*guy + guo;
                vv[i] = px[i]*gvx + py[i]*gvy + gvo;
            }
        }

        {
            float pc[4];
            f = ((float)(numpalookups-min(max(globalshade * shadescale,0),numpalookups)))/((float)numpalookups);
            pc[0] = pc[1] = pc[2] = f;
            switch (method&3)
            {
            default:
            case 0:
                pc[3] = 1.0; break;
            case 1:
                pc[3] = 1.0; break;
            case 2:
                pc[3] = 0.66; break;
            case 3:
                pc[3] = 0.33; break;
            }
            // tinting happens only to hightile textures, and only if the texture we're
            // rendering isn't for the same palette as what we asked for
            if (pth && (pth->flags & 2))
            {
                if (pth->palnum != globalpal)
                {
                    // apply tinting for replaced textures
                    pc[0] *= (float)hictinting[globalpal].r / 255.0;
                    pc[1] *= (float)hictinting[globalpal].g / 255.0;
                    pc[2] *= (float)hictinting[globalpal].b / 255.0;
                }
                if (hictinting[MAXPALOOKUPS-1].r != 255 || hictinting[MAXPALOOKUPS-1].g != 255 || hictinting[MAXPALOOKUPS-1].b != 255)
                {
                    pc[0] *= (float)hictinting[MAXPALOOKUPS-1].r / 255.0;
                    pc[1] *= (float)hictinting[MAXPALOOKUPS-1].g / 255.0;
                    pc[2] *= (float)hictinting[MAXPALOOKUPS-1].b / 255.0;
                }
            }

            bglColor4f(pc[0],pc[1],pc[2],pc[3]);
        }

        //Hack for walls&masked walls which use textures that are not a power of 2
        if ((pow2xsplit) && (tsizx != xx))
        {
            if (!dorot)
            {
                ngdx = gdx; ngdy = gdy; ngdo = gdo+(ngdx+ngdy)*.5;
                ngux = gux; nguy = guy; nguo = guo+(ngux+nguy)*.5;
                ngvx = gvx; ngvy = gvy; ngvo = gvo+(ngvx+ngvy)*.5;
            }
            else
            {
                ox = py[1]-py[2]; oy = py[2]-py[0]; oz = py[0]-py[1];
                r = 1.0 / (ox*px[0] + oy*px[1] + oz*px[2]);
                ngdx = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
                ngux = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
                ngvx = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
                ox = px[2]-px[1]; oy = px[0]-px[2]; oz = px[1]-px[0];
                ngdy = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
                nguy = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
                ngvy = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
                ox = px[0]-.5; oy = py[0]-.5; //.5 centers texture nicely
                ngdo = dd[0] - ox*ngdx - oy*ngdy;
                nguo = uu[0] - ox*ngux - oy*nguy;
                ngvo = vv[0] - ox*ngvx - oy*ngvy;
            }

            ngux *= hackscx; nguy *= hackscx; nguo *= hackscx;
            ngvx *= hackscy; ngvy *= hackscy; ngvo *= hackscy;
            uoffs = ((double)(xx-tsizx)*.5);
            ngux -= ngdx*uoffs;
            nguy -= ngdy*uoffs;
            nguo -= ngdo*uoffs;

            //Find min&max u coordinates (du0...du1)
            for (i=0;i<n;i++)
            {
                ox = px[i]; oy = py[i];
                f = (ox*ngux + oy*nguy + nguo) / (ox*ngdx + oy*ngdy + ngdo);
                if (!i) { du0 = du1 = f; continue; }
                if (f < du0) du0 = f;
                else if (f > du1) du1 = f;
            }

            f = 1.0/(double)tsizx;
            ix0 = (int)floor(du0*f);
            ix1 = (int)floor(du1*f);
            for (;ix0<=ix1;ix0++)
            {
                du0 = (double)((ix0)*tsizx);   // + uoffs;
                du1 = (double)((ix0+1)*tsizx); // + uoffs;

                i = 0; nn = 0;
                duj = (px[i]*ngux + py[i]*nguy + nguo) / (px[i]*ngdx + py[i]*ngdy + ngdo);
                do
                {
                    j = i+1; if (j == n) j = 0;

                    dui = duj; duj = (px[j]*ngux + py[j]*nguy + nguo) / (px[j]*ngdx + py[j]*ngdy + ngdo);

                    if ((du0 <= dui) && (dui <= du1)) { uu[nn] = px[i]; vv[nn] = py[i]; nn++; }
                    if (duj <= dui)
                    {
                        if ((du1 < duj) != (du1 < dui))
                        {
                            //ox*(ngux-ngdx*du1) + oy*(nguy-ngdy*du1) + (nguo-ngdo*du1) = 0
                            //(px[j]-px[i])*f + px[i] = ox
                            //(py[j]-py[i])*f + py[i] = oy

                            ///Solve for f
                            //((px[j]-px[i])*f + px[i])*(ngux-ngdx*du1) +
                            //((py[j]-py[i])*f + py[i])*(nguy-ngdy*du1) + (nguo-ngdo*du1) = 0

                            f = -(px[i] *(ngux-ngdx*du1) +  py[i]       *(nguy-ngdy*du1) + (nguo-ngdo*du1)) /
                                ((px[j]-px[i])*(ngux-ngdx*du1) + (py[j]-py[i])*(nguy-ngdy*du1));
                            uu[nn] = (px[j]-px[i])*f + px[i];
                            vv[nn] = (py[j]-py[i])*f + py[i]; nn++;
                        }
                        if ((du0 < duj) != (du0 < dui))
                        {
                            f = -(px[i] *(ngux-ngdx*du0) +        py[i] *(nguy-ngdy*du0) + (nguo-ngdo*du0)) /
                                ((px[j]-px[i])*(ngux-ngdx*du0) + (py[j]-py[i])*(nguy-ngdy*du0));
                            uu[nn] = (px[j]-px[i])*f + px[i];
                            vv[nn] = (py[j]-py[i])*f + py[i]; nn++;
                        }
                    }
                    else
                    {
                        if ((du0 < duj) != (du0 < dui))
                        {
                            f = -(px[i] *(ngux-ngdx*du0) +        py[i] *(nguy-ngdy*du0) + (nguo-ngdo*du0)) /
                                ((px[j]-px[i])*(ngux-ngdx*du0) + (py[j]-py[i])*(nguy-ngdy*du0));
                            uu[nn] = (px[j]-px[i])*f + px[i];
                            vv[nn] = (py[j]-py[i])*f + py[i]; nn++;
                        }
                        if ((du1 < duj) != (du1 < dui))
                        {
                            f = -(px[i] *(ngux-ngdx*du1) +  py[i]       *(nguy-ngdy*du1) + (nguo-ngdo*du1)) /
                                ((px[j]-px[i])*(ngux-ngdx*du1) + (py[j]-py[i])*(nguy-ngdy*du1));
                            uu[nn] = (px[j]-px[i])*f + px[i];
                            vv[nn] = (py[j]-py[i])*f + py[i]; nn++;
                        }
                    }
                    i = j;
                }
                while (i);
                if (nn < 3) continue;

                bglBegin(GL_TRIANGLE_FAN);
                for (i=0;i<nn;i++)
                {
                    ox = uu[i]; oy = vv[i];
                    dp = ox*ngdx + oy*ngdy + ngdo;
                    up = ox*ngux + oy*nguy + nguo;
                    vp = ox*ngvx + oy*ngvy + ngvo;
                    r = 1.0/dp;
                    if (texunits > GL_TEXTURE0_ARB)
                    {
                        j = GL_TEXTURE0_ARB;
                        while (j <= texunits)
                            bglMultiTexCoord2dARB(j++, (up*r-du0+uoffs)*ox2,vp*r*oy2);
                    }
                    else
                        bglTexCoord2d((up*r-du0+uoffs)*ox2,vp*r*oy2);
                    bglVertex3d((ox-ghalfx)*r*grhalfxdown10x,(ghoriz-oy)*r*grhalfxdown10,r*(1.0/1024.0));
                }
                bglEnd();
            }
        }
        else
        {
            ox2 *= hackscx; oy2 *= hackscy;
            bglBegin(GL_TRIANGLE_FAN);
            for (i=0;i<n;i++)
            {
                r = 1.0/dd[i];
                if (texunits > GL_TEXTURE0_ARB)
                {
                    j = GL_TEXTURE0_ARB;
                    while (j <= texunits)
                        bglMultiTexCoord2dARB(j++, uu[i]*r*ox2,vv[i]*r*oy2);
                }
                else
                    bglTexCoord2d(uu[i]*r*ox2,vv[i]*r*oy2);
                bglVertex3d((px[i]-ghalfx)*r*grhalfxdown10x,(ghoriz-py[i])*r*grhalfxdown10,r*(1.0/1024.0));
            }
            bglEnd();
        }

        while (texunits >= GL_TEXTURE0_ARB)
        {
            bglMatrixMode(GL_TEXTURE);
            bglLoadIdentity();
            bglMatrixMode(GL_MODELVIEW);
            if (texunits > GL_TEXTURE0_ARB)
            {
                bglTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 1.0f);
                bglDisable(GL_TEXTURE_2D);
            }
            bglActiveTextureARB(--texunits);
        }

        if (srepeat)
            bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP);
        if (trepeat)
            bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,glinfo.clamptoedge?GL_CLAMP_TO_EDGE:GL_CLAMP);

        if (fullbrightdrawingpass == 1) // tile has fullbright colors ?
        {
            fullbrightdrawingpass = 2;
            shadeforfullbrightpass = globalshade; // save the current shade
            globalshade = -128; // fullbright
            bglDisable(GL_FOG);
            drawpoly(dpx, dpy, n_, method_); // draw them afterwards, then. :)
            bglEnable(GL_FOG);
            globalshade = shadeforfullbrightpass;
            fullbrightdrawingpass = 0;
        }
        return;
    }
#endif

    if (rendmode == 2)
    {
#if (USEZBUFFER != 0)
        if ((!zbufmem) || (zbufbpl != bytesperline) || (zbufysiz != ydim))
        {
            zbufbpl = bytesperline;
            zbufysiz = ydim;
            zbufmem = (int)realloc((void *)zbufmem,zbufbpl*zbufysiz*4);
        }
        zbufoff = (int *)(zbufmem-(frameplace<<2));
#endif
        if ((!transluc)) method = (method&~3)+1; //In case translucent table doesn't exist

        if (!dorot)
        {
            ngdx = gdx; ngdy = gdy; ngdo = gdo+(ngdx+ngdy)*.5;
            ngux = gux; nguy = guy; nguo = guo+(ngux+nguy)*.5;
            ngvx = gvx; ngvy = gvy; ngvo = gvo+(ngvx+ngvy)*.5;
        }
        else
        {
            //General equations:
            //dd[i] = (px[i]*gdx + py[i]*gdy + gdo)
            //uu[i] = (px[i]*gux + py[i]*guy + guo)/dd[i]
            //vv[i] = (px[i]*gvx + py[i]*gvy + gvo)/dd[i]
            //
            //px[0]*gdx + py[0]*gdy + 1*gdo = dd[0]
            //px[1]*gdx + py[1]*gdy + 1*gdo = dd[1]
            //px[2]*gdx + py[2]*gdy + 1*gdo = dd[2]
            //
            //px[0]*gux + py[0]*guy + 1*guo = uu[0]*dd[0] (uu[i] premultiplied by dd[i] above)
            //px[1]*gux + py[1]*guy + 1*guo = uu[1]*dd[1]
            //px[2]*gux + py[2]*guy + 1*guo = uu[2]*dd[2]
            //
            //px[0]*gvx + py[0]*gvy + 1*gvo = vv[0]*dd[0] (vv[i] premultiplied by dd[i] above)
            //px[1]*gvx + py[1]*gvy + 1*gvo = vv[1]*dd[1]
            //px[2]*gvx + py[2]*gvy + 1*gvo = vv[2]*dd[2]
            ox = py[1]-py[2]; oy = py[2]-py[0]; oz = py[0]-py[1];
            r = 1.0 / (ox*px[0] + oy*px[1] + oz*px[2]);
            ngdx = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
            ngux = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
            ngvx = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
            ox = px[2]-px[1]; oy = px[0]-px[2]; oz = px[1]-px[0];
            ngdy = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
            nguy = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
            ngvy = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
            ox = px[0]-.5; oy = py[0]-.5; //.5 centers texture nicely
            ngdo = dd[0] - ox*ngdx - oy*ngdy;
            nguo = uu[0] - ox*ngux - oy*nguy;
            ngvo = vv[0] - ox*ngvx - oy*ngvy;
        }
        palptr = &palookup[globalpal][min(max(globalshade,0),numpalookups-1)<<8]; //<-need to make shade not static!

        tsizxm1 = tsizx-1; xmodnice = (!(tsizxm1&tsizx));
        tsizym1 = tsizy-1; ymulnice = (!(tsizym1&tsizy));
        if ((method&4) && (!xmodnice)) //Sprites don't need a mod on texture coordinates
            { xmodnice = 1; for (tsizxm1=1;tsizxm1<tsizx;tsizxm1=(tsizxm1<<1)+1); }
        if (!ymulnice) { for (tsizym1=1;tsizym1+1<tsizy;tsizym1=(tsizym1<<1)+1); }
        ltsizy = (picsiz[globalpicnum]>>4);
    }
    else
    {
        dacol = palookup[0][(int)(*(char *)(waloff[globalpicnum]))+(min(max(globalshade,0),numpalookups-1)<<8)];
    }

    if (grhalfxdown10x < 0) //Hack for mirrors
    {
        for (i=((n-1)>>1);i>=0;i--)
        {
            r = px[i]; px[i] = ((double)xdimen)-px[n-1-i]; px[n-1-i] = ((double)xdimen)-r;
            r = py[i]; py[i] = py[n-1-i]; py[n-1-i] = r;
        }
        ngdo += ((double)xdimen)*ngdx; ngdx = -ngdx;
        nguo += ((double)xdimen)*ngux; ngux = -ngux;
        ngvo += ((double)xdimen)*ngvx; ngvx = -ngvx;
    }

    ngdx2 = ngdx*(1<<LINTERPSIZ);
    ngux2 = ngux*(1<<LINTERPSIZ);
    ngvx2 = ngvx*(1<<LINTERPSIZ);

    mini = (py[0] >= py[1]); maxi = 1-mini;
    for (z=2;z<n;z++)
    {
        if (py[z] < py[mini]) mini = z;
        if (py[z] > py[maxi]) maxi = z;
    }

    i = maxi; dtol(py[i],&yy); if (yy > ydimen) yy = ydimen;
    do
    {
        j = i+1; if (j == n) j = 0;
        dtol(py[j],&y); if (y < 0) y = 0;
        if (y < yy)
        {
            f = (px[j]-px[i])/(py[j]-py[i]); dtol(f*16384.0,&xi);
            dtol((((double)yy-.5-py[j])*f + px[j])*16384.0+8192.0,&x);
            for (;yy>y;yy--,x-=xi) lastx[yy-1] = (x>>14);
        }
        i = j;
    }
    while (i != mini);
    do
    {
        j = i+1; if (j == n) j = 0;
        dtol(py[j],&yy); if (yy > ydimen) yy = ydimen;
        if (y < yy)
        {
            f = (px[j]-px[i])/(py[j]-py[i]); dtol(f*16384.0,&xi);
            dtol((((double)y+.5-py[j])*f + px[j])*16384.0+8192.0,&x);
            for (;y<yy;y++,x+=xi)
            {
                ix0 = lastx[y]; if (ix0 < 0) ix0 = 0;
                ix1 = (x>>14); if (ix1 > xdimen) ix1 = xdimen;
                if (ix0 < ix1)
                {
                    if (rendmode == 1)
                        memset((void *)(ylookup[y]+ix0+frameoffset),dacol,ix1-ix0);
                    else
                    {
                        vidp = (char *)(ylookup[y]+frameoffset+ix0);
                        dp = ngdx*(double)ix0 + ngdy*(double)y + ngdo;
                        up = ngux*(double)ix0 + nguy*(double)y + nguo;
                        vp = ngvx*(double)ix0 + ngvy*(double)y + ngvo;
                        rdp = 65536.0/dp; dp += ngdx2;
                        dtol(rdp,&d0);
                        dtol(up*rdp,&u0); up += ngux2;
                        dtol(vp*rdp,&v0); vp += ngvx2;
                        rdp = 65536.0/dp;

                        switch (method&3)
                        {
                        case 0:
                            if (xmodnice&ymulnice) //both u&v texture sizes are powers of 2 :)
                            {
                                for (xx=ix0;xx<ix1;xx+=(1<<LINTERPSIZ))
                                {
                                    dtol(rdp,&d1); dp += ngdx2; d1 = ((d1-d0)>>LINTERPSIZ);
                                    dtol(up*rdp,&u1); up += ngux2; u1 = ((u1-u0)>>LINTERPSIZ);
                                    dtol(vp*rdp,&v1); vp += ngvx2; v1 = ((v1-v0)>>LINTERPSIZ);
                                    rdp = 65536.0/dp; vide = &vidp[min(ix1-xx,1<<LINTERPSIZ)];
                                    while (vidp < vide)
                                    {
#if (DEPTHDEBUG == 0)
#if (USEZBUFFER != 0)
                                        zbufoff[(int)vidp] = d0+16384; //+ hack so wall&floor sprites don't disappear
#endif
                                        vidp[0] = palptr[walptr[(((u0>>16)&tsizxm1)<<ltsizy) + ((v0>>16)&tsizym1)]]; //+((d0>>13)&0x3f00)];
#else
                                        vidp[0] = ((d0>>16)&255);
#endif
                                        d0 += d1; u0 += u1; v0 += v1; vidp++;
                                    }
                                }
                            }
                            else
                            {
                                for (xx=ix0;xx<ix1;xx+=(1<<LINTERPSIZ))
                                {
                                    dtol(rdp,&d1); dp += ngdx2; d1 = ((d1-d0)>>LINTERPSIZ);
                                    dtol(up*rdp,&u1); up += ngux2; u1 = ((u1-u0)>>LINTERPSIZ);
                                    dtol(vp*rdp,&v1); vp += ngvx2; v1 = ((v1-v0)>>LINTERPSIZ);
                                    rdp = 65536.0/dp; vide = &vidp[min(ix1-xx,1<<LINTERPSIZ)];
                                    while (vidp < vide)
                                    {
#if (DEPTHDEBUG == 0)
#if (USEZBUFFER != 0)
                                        zbufoff[(int)vidp] = d0;
#endif
                                        vidp[0] = palptr[walptr[imod(u0>>16,tsizx)*tsizy + ((v0>>16)&tsizym1)]]; //+((d0>>13)&0x3f00)];
#else
                                        vidp[0] = ((d0>>16)&255);
#endif
                                        d0 += d1; u0 += u1; v0 += v1; vidp++;
                                    }
                                }
                            }
                            break;
                        case 1:
                            if (xmodnice) //both u&v texture sizes are powers of 2 :)
                            {
                                for (xx=ix0;xx<ix1;xx+=(1<<LINTERPSIZ))
                                {
                                    dtol(rdp,&d1); dp += ngdx2; d1 = ((d1-d0)>>LINTERPSIZ);
                                    dtol(up*rdp,&u1); up += ngux2; u1 = ((u1-u0)>>LINTERPSIZ);
                                    dtol(vp*rdp,&v1); vp += ngvx2; v1 = ((v1-v0)>>LINTERPSIZ);
                                    rdp = 65536.0/dp; vide = &vidp[min(ix1-xx,1<<LINTERPSIZ)];
                                    while (vidp < vide)
                                    {
                                        dacol = walptr[(((u0>>16)&tsizxm1)*tsizy) + ((v0>>16)&tsizym1)];
#if (DEPTHDEBUG == 0)
#if (USEZBUFFER != 0)
                                        if ((dacol != 255) && (d0 <= zbufoff[(int)vidp]))
                                        {
                                            zbufoff[(int)vidp] = d0;
                                            vidp[0] = palptr[((int)dacol)]; //+((d0>>13)&0x3f00)];
                                        }
#else
                                        if (dacol != 255) vidp[0] = palptr[((int)dacol)]; //+((d0>>13)&0x3f00)];
#endif
#else
                                        if ((dacol != 255) && (vidp[0] > (d0>>16))) vidp[0] = ((d0>>16)&255);
#endif
                                        d0 += d1; u0 += u1; v0 += v1; vidp++;
                                    }
                                }
                            }
                            else
                            {
                                for (xx=ix0;xx<ix1;xx+=(1<<LINTERPSIZ))
                                {
                                    dtol(rdp,&d1); dp += ngdx2; d1 = ((d1-d0)>>LINTERPSIZ);
                                    dtol(up*rdp,&u1); up += ngux2; u1 = ((u1-u0)>>LINTERPSIZ);
                                    dtol(vp*rdp,&v1); vp += ngvx2; v1 = ((v1-v0)>>LINTERPSIZ);
                                    rdp = 65536.0/dp; vide = &vidp[min(ix1-xx,1<<LINTERPSIZ)];
                                    while (vidp < vide)
                                    {
                                        dacol = walptr[imod(u0>>16,tsizx)*tsizy + ((v0>>16)&tsizym1)];
#if (DEPTHDEBUG == 0)
#if (USEZBUFFER != 0)
                                        if ((dacol != 255) && (d0 <= zbufoff[(int)vidp]))
                                        {
                                            zbufoff[(int)vidp] = d0;
                                            vidp[0] = palptr[((int)dacol)]; //+((d0>>13)&0x3f00)];
                                        }
#else
                                        if (dacol != 255) vidp[0] = palptr[((int)dacol)]; //+((d0>>13)&0x3f00)];
#endif
#else
                                        if ((dacol != 255) && (vidp[0] > (d0>>16))) vidp[0] = ((d0>>16)&255);
#endif
                                        d0 += d1; u0 += u1; v0 += v1; vidp++;
                                    }
                                }
                            }
                            break;
                        case 2: //Transluscence #1
                            for (xx=ix0;xx<ix1;xx+=(1<<LINTERPSIZ))
                            {
                                dtol(rdp,&d1); dp += ngdx2; d1 = ((d1-d0)>>LINTERPSIZ);
                                dtol(up*rdp,&u1); up += ngux2; u1 = ((u1-u0)>>LINTERPSIZ);
                                dtol(vp*rdp,&v1); vp += ngvx2; v1 = ((v1-v0)>>LINTERPSIZ);
                                rdp = 65536.0/dp; vide = &vidp[min(ix1-xx,1<<LINTERPSIZ)];
                                while (vidp < vide)
                                {
                                    dacol = walptr[imod(u0>>16,tsizx)*tsizy + ((v0>>16)&tsizym1)];
                                    //dacol = walptr[(((u0>>16)&tsizxm1)<<ltsizy) + ((v0>>16)&tsizym1)];
#if (DEPTHDEBUG == 0)
#if (USEZBUFFER != 0)
                                    if ((dacol != 255) && (d0 <= zbufoff[(int)vidp]))
                                    {
                                        zbufoff[(int)vidp] = d0;
                                        vidp[0] = transluc[(((int)vidp[0])<<8)+((int)palptr[((int)dacol)])]; //+((d0>>13)&0x3f00)])];
                                    }
#else
                                    if (dacol != 255)
                                        vidp[0] = transluc[(((int)vidp[0])<<8)+((int)palptr[((int)dacol)])]; //+((d0>>13)&0x3f00)])];
#endif
#else
                                    if ((dacol != 255) && (vidp[0] > (d0>>16))) vidp[0] = ((d0>>16)&255);
#endif
                                    d0 += d1; u0 += u1; v0 += v1; vidp++;
                                }
                            }
                            break;
                        case 3: //Transluscence #2
                            for (xx=ix0;xx<ix1;xx+=(1<<LINTERPSIZ))
                            {
                                dtol(rdp,&d1); dp += ngdx2; d1 = ((d1-d0)>>LINTERPSIZ);
                                dtol(up*rdp,&u1); up += ngux2; u1 = ((u1-u0)>>LINTERPSIZ);
                                dtol(vp*rdp,&v1); vp += ngvx2; v1 = ((v1-v0)>>LINTERPSIZ);
                                rdp = 65536.0/dp; vide = &vidp[min(ix1-xx,1<<LINTERPSIZ)];
                                while (vidp < vide)
                                {
                                    dacol = walptr[imod(u0>>16,tsizx)*tsizy + ((v0>>16)&tsizym1)];
                                    //dacol = walptr[(((u0>>16)&tsizxm1)<<ltsizy) + ((v0>>16)&tsizym1)];
#if (DEPTHDEBUG == 0)
#if (USEZBUFFER != 0)
                                    if ((dacol != 255) && (d0 <= zbufoff[(int)vidp]))
                                    {
                                        zbufoff[(int)vidp] = d0;
                                        vidp[0] = transluc[((int)vidp[0])+(((int)palptr[((int)dacol)/*+((d0>>13)&0x3f00)*/])<<8)];
                                    }
#else
                                    if (dacol != 255)
                                        vidp[0] = transluc[((int)vidp[0])+(((int)palptr[((int)dacol)/*+((d0>>13)&0x3f00)*/])<<8)];
#endif
#else
                                    if ((dacol != 255) && (vidp[0] > (d0>>16))) vidp[0] = ((d0>>16)&255);
#endif
                                    d0 += d1; u0 += u1; v0 += v1; vidp++;
                                }
                            }
                            break;
                        }
                    }
                }
            }
        }
        i = j;
    }
    while (i != maxi);

    if (rendmode == 1)
    {
        if (method&3) //Only draw border around sprites/maskwalls
        {
            for (i=0,j=n-1;i<n;j=i,i++) drawline2d(px[i],py[i],px[j],py[j],31); //hopefully color index 31 is white
        }

        //ox = 0; oy = 0;
        //for(i=0;i<n;i++) { ox += px[i]; oy += py[i]; }
        //ox /= (double)n; oy /= (double)n;
        //for(i=0,j=n-1;i<n;j=i,i++) drawline2d(px[i]+(ox-px[i])*.125,py[i]+(oy-py[i])*.125,px[j]+(ox-px[j])*.125,py[j]+(oy-py[j])*.125,31);
    }
}

/*Init viewport boundary (must be 4 point convex loop):
//      (px[0],py[0]).----.(px[1],py[1])
//                  /      \
//                /          \
// (px[3],py[3]).--------------.(px[2],py[2])
*/
void initmosts(double *px, double *py, int n)
{
    int i, j, k, imin;

    vcnt = 1; //0 is dummy solid node

    if (n < 3) return;
    imin = (px[1] < px[0]);
    for (i=n-1;i>=2;i--) if (px[i] < px[imin]) imin = i;


    vsp[vcnt].x = px[imin];
    vsp[vcnt].cy[0] = vsp[vcnt].fy[0] = py[imin];
    vcnt++;
    i = imin+1; if (i >= n) i = 0;
    j = imin-1; if (j < 0) j = n-1;
    do
    {
        if (px[i] < px[j])
        {
            if ((vcnt > 1) && (px[i] <= vsp[vcnt-1].x)) vcnt--;
            vsp[vcnt].x = px[i];
            vsp[vcnt].cy[0] = py[i];
            k = j+1; if (k >= n) k = 0;
            //(px[k],py[k])
            //(px[i],?)
            //(px[j],py[j])
            vsp[vcnt].fy[0] = (px[i]-px[k])*(py[j]-py[k])/(px[j]-px[k]) + py[k];
            vcnt++;
            i++; if (i >= n) i = 0;
        }
        else if (px[j] < px[i])
        {
            if ((vcnt > 1) && (px[j] <= vsp[vcnt-1].x)) vcnt--;
            vsp[vcnt].x = px[j];
            vsp[vcnt].fy[0] = py[j];
            k = i-1; if (k < 0) k = n-1;
            //(px[k],py[k])
            //(px[j],?)
            //(px[i],py[i])
            vsp[vcnt].cy[0] = (px[j]-px[k])*(py[i]-py[k])/(px[i]-px[k]) + py[k];
            vcnt++;
            j--; if (j < 0) j = n-1;
        }
        else
        {
            if ((vcnt > 1) && (px[i] <= vsp[vcnt-1].x)) vcnt--;
            vsp[vcnt].x = px[i];
            vsp[vcnt].cy[0] = py[i];
            vsp[vcnt].fy[0] = py[j];
            vcnt++;
            i++; if (i >= n) i = 0; if (i == j) break;
            j--; if (j < 0) j = n-1;
        }
    }
    while (i != j);
    if (px[i] > vsp[vcnt-1].x)
    {
        vsp[vcnt].x = px[i];
        vsp[vcnt].cy[0] = vsp[vcnt].fy[0] = py[i];
        vcnt++;
    }


    for (i=0;i<vcnt;i++)
    {
        vsp[i].cy[1] = vsp[i+1].cy[0]; vsp[i].ctag = i;
        vsp[i].fy[1] = vsp[i+1].fy[0]; vsp[i].ftag = i;
        vsp[i].n = i+1; vsp[i].p = i-1;
    }
    vsp[vcnt-1].n = 0; vsp[0].p = vcnt-1;
    gtag = vcnt;

    //VSPMAX-1 is dummy empty node
    for (i=vcnt;i<VSPMAX;i++) { vsp[i].n = i+1; vsp[i].p = i-1; }
    vsp[VSPMAX-1].n = vcnt; vsp[vcnt].p = VSPMAX-1;
}

void vsdel(int i)
{
    int pi, ni;
    //Delete i
    pi = vsp[i].p;
    ni = vsp[i].n;
    vsp[ni].p = pi;
    vsp[pi].n = ni;

    //Add i to empty list
    vsp[i].n = vsp[VSPMAX-1].n;
    vsp[i].p = VSPMAX-1;
    vsp[vsp[VSPMAX-1].n].p = i;
    vsp[VSPMAX-1].n = i;
}

int vsinsaft(int i)
{
    int r;
    //i = next element from empty list
    r = vsp[VSPMAX-1].n;
    vsp[vsp[r].n].p = VSPMAX-1;
    vsp[VSPMAX-1].n = vsp[r].n;

    vsp[r] = vsp[i]; //copy i to r

    //insert r after i
    vsp[r].p = i; vsp[r].n = vsp[i].n;
    vsp[vsp[i].n].p = r; vsp[i].n = r;

    return(r);
}

int testvisiblemost(float x0, float x1)
{
    int i, newi;

    for (i=vsp[0].n;i;i=newi)
    {
        newi = vsp[i].n;
        if ((x0 < vsp[newi].x) && (vsp[i].x < x1) && (vsp[i].ctag >= 0)) return(1);
    }
    return(0);
}

static int domostpolymethod = 0;

void domost(float x0, float y0, float x1, float y1)
{
    double dpx[4], dpy[4];
    float d, f, n, t, slop, dx, dx0, dx1, nx, nx0, ny0, nx1, ny1;
    float spx[4], spy[4], cy[2], cv[2];
    int i, j, k, z, ni, vcnt = 0, scnt, newi, dir, spt[4];

    if (x0 < x1)
    {
        dir = 1; //clip dmost (floor)
        y0 -= .01; y1 -= .01;
    }
    else
    {
        if (x0 == x1) return;
        f = x0; x0 = x1; x1 = f;
        f = y0; y0 = y1; y1 = f;
        dir = 0; //clip umost (ceiling)
        //y0 += .01; y1 += .01; //necessary?
    }

    slop = (y1-y0)/(x1-x0);
    for (i=vsp[0].n;i;i=newi)
    {
        newi = vsp[i].n; nx0 = vsp[i].x; nx1 = vsp[newi].x;
        if ((x0 >= nx1) || (nx0 >= x1) || (vsp[i].ctag <= 0)) continue;
        dx = nx1-nx0;
        cy[0] = vsp[i].cy[0]; cv[0] = vsp[i].cy[1]-cy[0];
        cy[1] = vsp[i].fy[0]; cv[1] = vsp[i].fy[1]-cy[1];

        scnt = 0;

        //Test if left edge requires split (x0,y0) (nx0,cy(0)),<dx,cv(0)>
        if ((x0 > nx0) && (x0 < nx1))
        {
            t = (x0-nx0)*cv[dir] - (y0-cy[dir])*dx;
            if (((!dir) && (t < 0)) || ((dir) && (t > 0)))
                { spx[scnt] = x0; spy[scnt] = y0; spt[scnt] = -1; scnt++; }
        }

        //Test for intersection on umost (j == 0) and dmost (j == 1)
        for (j=0;j<2;j++)
        {
            d = (y0-y1)*dx - (x0-x1)*cv[j];
            n = (y0-cy[j])*dx - (x0-nx0)*cv[j];
            if ((fabs(n) <= fabs(d)) && (d*n >= 0) && (d != 0))
            {
                t = n/d; nx = (x1-x0)*t + x0;
                if ((nx > nx0) && (nx < nx1))
                {
                    spx[scnt] = nx; spy[scnt] = (y1-y0)*t + y0;
                    spt[scnt] = j; scnt++;
                }
            }
        }

        //Nice hack to avoid full sort later :)
        if ((scnt >= 2) && (spx[scnt-1] < spx[scnt-2]))
        {
            f = spx[scnt-1]; spx[scnt-1] = spx[scnt-2]; spx[scnt-2] = f;
            f = spy[scnt-1]; spy[scnt-1] = spy[scnt-2]; spy[scnt-2] = f;
            j = spt[scnt-1]; spt[scnt-1] = spt[scnt-2]; spt[scnt-2] = j;
        }

        //Test if right edge requires split
        if ((x1 > nx0) && (x1 < nx1))
        {
            t = (x1-nx0)*cv[dir] - (y1-cy[dir])*dx;
            if (((!dir) && (t < 0)) || ((dir) && (t > 0)))
                { spx[scnt] = x1; spy[scnt] = y1; spt[scnt] = -1; scnt++; }
        }

        vsp[i].tag = vsp[newi].tag = -1;
        for (z=0;z<=scnt;z++,i=vcnt)
        {
            if (z < scnt)
            {
                vcnt = vsinsaft(i);
                t = (spx[z]-nx0)/dx;
                vsp[i].cy[1] = t*cv[0] + cy[0];
                vsp[i].fy[1] = t*cv[1] + cy[1];
                vsp[vcnt].x = spx[z];
                vsp[vcnt].cy[0] = vsp[i].cy[1];
                vsp[vcnt].fy[0] = vsp[i].fy[1];
                vsp[vcnt].tag = spt[z];
            }

            ni = vsp[i].n; if (!ni) continue; //this 'if' fixes many bugs!
            dx0 = vsp[i].x; if (x0 > dx0) continue;
            dx1 = vsp[ni].x; if (x1 < dx1) continue;
            ny0 = (dx0-x0)*slop + y0;
            ny1 = (dx1-x0)*slop + y0;

            //      dx0           dx1
            //       ~             ~
            //----------------------------
            //     t0+=0         t1+=0
            //   vsp[i].cy[0]  vsp[i].cy[1]
            //============================
            //     t0+=1         t1+=3
            //============================
            //   vsp[i].fy[0]    vsp[i].fy[1]
            //     t0+=2         t1+=6
            //
            //     ny0 ?         ny1 ?

            k = 1+3;
            if ((vsp[i].tag == 0) || (ny0 <= vsp[i].cy[0]+.01)) k--;
            if ((vsp[i].tag == 1) || (ny0 >= vsp[i].fy[0]-.01)) k++;
            if ((vsp[ni].tag == 0) || (ny1 <= vsp[i].cy[1]+.01)) k -= 3;
            if ((vsp[ni].tag == 1) || (ny1 >= vsp[i].fy[1]-.01)) k += 3;

            if (!dir)
            {
                switch (k)
                {
                case 1:
                case 2:
                    dpx[0] = dx0; dpy[0] = vsp[i].cy[0];
                    dpx[1] = dx1; dpy[1] = vsp[i].cy[1];
                    dpx[2] = dx0; dpy[2] = ny0; drawpoly(dpx,dpy,3,domostpolymethod);
                    vsp[i].cy[0] = ny0; vsp[i].ctag = gtag; break;
                case 3:
                case 6:
                    dpx[0] = dx0; dpy[0] = vsp[i].cy[0];
                    dpx[1] = dx1; dpy[1] = vsp[i].cy[1];
                    dpx[2] = dx1; dpy[2] = ny1; drawpoly(dpx,dpy,3,domostpolymethod);
                    vsp[i].cy[1] = ny1; vsp[i].ctag = gtag; break;
                case 4:
                case 5:
                case 7:
                    dpx[0] = dx0; dpy[0] = vsp[i].cy[0];
                    dpx[1] = dx1; dpy[1] = vsp[i].cy[1];
                    dpx[2] = dx1; dpy[2] = ny1;
                    dpx[3] = dx0; dpy[3] = ny0; drawpoly(dpx,dpy,4,domostpolymethod);
                    vsp[i].cy[0] = ny0; vsp[i].cy[1] = ny1; vsp[i].ctag = gtag; break;
                case 8:
                    dpx[0] = dx0; dpy[0] = vsp[i].cy[0];
                    dpx[1] = dx1; dpy[1] = vsp[i].cy[1];
                    dpx[2] = dx1; dpy[2] = vsp[i].fy[1];
                    dpx[3] = dx0; dpy[3] = vsp[i].fy[0]; drawpoly(dpx,dpy,4,domostpolymethod);
                    vsp[i].ctag = vsp[i].ftag = -1; break;
                default:
                    break;
                }
            }
            else
            {
                switch (k)
                {
                case 7:
                case 6:
                    dpx[0] = dx0; dpy[0] = ny0;
                    dpx[1] = dx1; dpy[1] = vsp[i].fy[1];
                    dpx[2] = dx0; dpy[2] = vsp[i].fy[0]; drawpoly(dpx,dpy,3,domostpolymethod);
                    vsp[i].fy[0] = ny0; vsp[i].ftag = gtag; break;
                case 5:
                case 2:
                    dpx[0] = dx0; dpy[0] = vsp[i].fy[0];
                    dpx[1] = dx1; dpy[1] = ny1;
                    dpx[2] = dx1; dpy[2] = vsp[i].fy[1]; drawpoly(dpx,dpy,3,domostpolymethod);
                    vsp[i].fy[1] = ny1; vsp[i].ftag = gtag; break;
                case 4:
                case 3:
                case 1:
                    dpx[0] = dx0; dpy[0] = ny0;
                    dpx[1] = dx1; dpy[1] = ny1;
                    dpx[2] = dx1; dpy[2] = vsp[i].fy[1];
                    dpx[3] = dx0; dpy[3] = vsp[i].fy[0]; drawpoly(dpx,dpy,4,domostpolymethod);
                    vsp[i].fy[0] = ny0; vsp[i].fy[1] = ny1; vsp[i].ftag = gtag; break;
                case 0:
                    dpx[0] = dx0; dpy[0] = vsp[i].cy[0];
                    dpx[1] = dx1; dpy[1] = vsp[i].cy[1];
                    dpx[2] = dx1; dpy[2] = vsp[i].fy[1];
                    dpx[3] = dx0; dpy[3] = vsp[i].fy[0]; drawpoly(dpx,dpy,4,domostpolymethod);
                    vsp[i].ctag = vsp[i].ftag = -1; break;
                default:
                    break;
                }
            }
        }
    }

    gtag++;

    //Combine neighboring vertical strips with matching collinear top&bottom edges
    //This prevents x-splits from propagating through the entire scan
    i = vsp[0].n;
    while (i)
    {
        ni = vsp[i].n;
        if ((vsp[i].cy[0] >= vsp[i].fy[0]) && (vsp[i].cy[1] >= vsp[i].fy[1])) { vsp[i].ctag = vsp[i].ftag = -1; }
        if ((vsp[i].ctag == vsp[ni].ctag) && (vsp[i].ftag == vsp[ni].ftag))
            { vsp[i].cy[1] = vsp[ni].cy[1]; vsp[i].fy[1] = vsp[ni].fy[1]; vsdel(ni); }
        else i = ni;
    }
}

static void polymost_scansector(int sectnum);

static void polymost_drawalls(int bunch)
{
    sectortype *sec, *nextsec;
    walltype *wal, *wal2, *nwal;
    double ox, oy, oz, ox2, oy2, px[3], py[3], dd[3], uu[3], vv[3];
    double fx, fy, x0, x1, y0, y1, cy0, cy1, fy0, fy1, xp0, yp0, xp1, yp1, ryp0, ryp1, nx0, ny0, nx1, ny1;
    double t, r, t0, t1, ocy0, ocy1, ofy0, ofy1, oxp0, oyp0, ft[4];
    double oguo, ogux, oguy;
    int i, x, y, z, cz, fz, wallnum, sectnum, nextsectnum;

    sectnum = thesector[bunchfirst[bunch]]; sec = &sector[sectnum];

#if 0 // USE_OPENGL
    if (!nofog)
    {
        if (rendmode >= 3)
        {
            float col[4];
            col[0] = (float)palookupfog[sec->floorpal].r / 63.f;
            col[1] = (float)palookupfog[sec->floorpal].g / 63.f;
            col[2] = (float)palookupfog[sec->floorpal].b / 63.f;
            col[3] = 0;
            bglFogfv(GL_FOG_COLOR,col);
            bglFogf(GL_FOG_DENSITY,fogcalc(sec->floorshade,sec->visibility));

            //            bglFogf(GL_FOG_DENSITY,gvisibility*((float)((unsigned char)(sec->visibility<240?sec->visibility+16:sec->visibility-239))));
        }
    }
#endif

    //DRAW WALLS SECTION!
    for (z=bunchfirst[bunch];z>=0;z=p2[z])
    {
        wallnum = thewall[z]; wal = &wall[wallnum]; wal2 = &wall[wal->point2];
        nextsectnum = wal->nextsector; nextsec = &sector[nextsectnum];

        //Offset&Rotate 3D coordinates to screen 3D space
        x = wal->x-globalposx; y = wal->y-globalposy;
        xp0 = (double)y*gcosang  - (double)x*gsinang;
        yp0 = (double)x*gcosang2 + (double)y*gsinang2;
        x = wal2->x-globalposx; y = wal2->y-globalposy;
        xp1 = (double)y*gcosang  - (double)x*gsinang;
        yp1 = (double)x*gcosang2 + (double)y*gsinang2;

        oxp0 = xp0; oyp0 = yp0;

        //Clip to close parallel-screen plane
        if (yp0 < SCISDIST)
        {
            if (yp1 < SCISDIST) continue;
            t0 = (SCISDIST-yp0)/(yp1-yp0); xp0 = (xp1-xp0)*t0+xp0; yp0 = SCISDIST;
            nx0 = (wal2->x-wal->x)*t0+wal->x;
            ny0 = (wal2->y-wal->y)*t0+wal->y;
        }
        else { t0 = 0.f; nx0 = wal->x; ny0 = wal->y; }
        if (yp1 < SCISDIST)
        {
            t1 = (SCISDIST-oyp0)/(yp1-oyp0); xp1 = (xp1-oxp0)*t1+oxp0; yp1 = SCISDIST;
            nx1 = (wal2->x-wal->x)*t1+wal->x;
            ny1 = (wal2->y-wal->y)*t1+wal->y;
        }
        else { t1 = 1.f; nx1 = wal2->x; ny1 = wal2->y; }

        ryp0 = 1.f/yp0; ryp1 = 1.f/yp1;

        //Generate screen coordinates for front side of wall
        x0 = ghalfx*xp0*ryp0 + ghalfx;
        x1 = ghalfx*xp1*ryp1 + ghalfx;
        if (x1 <= x0) continue;

        ryp0 *= gyxscale; ryp1 *= gyxscale;

        getzsofslope(sectnum,(int)nx0,(int)ny0,&cz,&fz);
        cy0 = ((float)(cz-globalposz))*ryp0 + ghoriz;
        fy0 = ((float)(fz-globalposz))*ryp0 + ghoriz;
        getzsofslope(sectnum,(int)nx1,(int)ny1,&cz,&fz);
        cy1 = ((float)(cz-globalposz))*ryp1 + ghoriz;
        fy1 = ((float)(fz-globalposz))*ryp1 + ghoriz;


        globalpicnum = sec->floorpicnum; globalshade = sec->floorshade; globalpal = (int)((unsigned char)sec->floorpal);
        globalorientation = sec->floorstat;
        if (picanm[globalpicnum]&192) globalpicnum += animateoffs(globalpicnum,sectnum);
        if (!(globalorientation&1))
        {
            //(singlobalang/-16384*(sx-ghalfx) + 0*(sy-ghoriz) + (cosviewingrangeglobalang/16384)*ghalfx)*d + globalposx    = u*16
            //(cosglobalang/ 16384*(sx-ghalfx) + 0*(sy-ghoriz) + (sinviewingrangeglobalang/16384)*ghalfx)*d + globalposy    = v*16
            //(                  0*(sx-ghalfx) + 1*(sy-ghoriz) + (                             0)*ghalfx)*d + globalposz/16 = (sec->floorz/16)
            if (!(globalorientation&64))
                { ft[0] = globalposx; ft[1] = globalposy; ft[2] = cosglobalang; ft[3] = singlobalang; }
            else
            {
                //relative alignment
                fx = (double)(wall[wall[sec->wallptr].point2].x-wall[sec->wallptr].x);
                fy = (double)(wall[wall[sec->wallptr].point2].y-wall[sec->wallptr].y);
                r = 1.0/sqrt(fx*fx+fy*fy); fx *= r; fy *= r;
                ft[2] = cosglobalang*fx + singlobalang*fy;
                ft[3] = singlobalang*fx - cosglobalang*fy;
                ft[0] = ((double)(globalposx-wall[sec->wallptr].x))*fx + ((double)(globalposy-wall[sec->wallptr].y))*fy;
                ft[1] = ((double)(globalposy-wall[sec->wallptr].y))*fx - ((double)(globalposx-wall[sec->wallptr].x))*fy;
                if (!(globalorientation&4)) globalorientation ^= 32; else globalorientation ^= 16;
            }
            gdx = 0;
            gdy = gxyaspect; if (!(globalorientation&2)) gdy /= (double)(sec->floorz-globalposz);
            gdo = -ghoriz*gdy;
            if (globalorientation&8) { ft[0] /= 8; ft[1] /= -8; ft[2] /= 2097152; ft[3] /= 2097152; }
            else { ft[0] /= 16; ft[1] /= -16; ft[2] /= 4194304; ft[3] /= 4194304; }
            gux = (double)ft[3]*((double)viewingrange)/-65536.0;
            gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
            guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
            guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
            guo += (double)(ft[2]-gux)*ghalfx;
            gvo -= (double)(ft[3]+gvx)*ghalfx;

            //Texture flipping
            if (globalorientation&4)
            {
                r = gux; gux = gvx; gvx = r;
                r = guy; guy = gvy; gvy = r;
                r = guo; guo = gvo; gvo = r;
            }
            if (globalorientation&16) { gux = -gux; guy = -guy; guo = -guo; }
            if (globalorientation&32) { gvx = -gvx; gvy = -gvy; gvo = -gvo; }

            //Texture panning
            fx = (float)sec->floorxpanning*((float)(1<<(picsiz[globalpicnum]&15)))/256.0;
            fy = (float)sec->floorypanning*((float)(1<<(picsiz[globalpicnum]>>4)))/256.0;
            if ((globalorientation&(2+64)) == (2+64)) //Hack for panning for slopes w/ relative alignment
            {
                r = (float)sec->floorheinum / 4096.0; r = 1.0/sqrt(r*r+1);
                if (!(globalorientation&4)) fy *= r; else fx *= r;
            }
            guy += gdy*fx; guo += gdo*fx;
            gvy += gdy*fy; gvo += gdo*fy;

            if (globalorientation&2) //slopes
            {
                px[0] = x0; py[0] = ryp0 + ghoriz;
                px[1] = x1; py[1] = ryp1 + ghoriz;

                //Pick some point guaranteed to be not collinear to the 1st two points
                ox = nx0 + (ny1-ny0);
                oy = ny0 + (nx0-nx1);
                ox2 = (double)(oy-globalposy)*gcosang  - (double)(ox-globalposx)*gsinang;
                oy2 = (double)(ox-globalposx)*gcosang2 + (double)(oy-globalposy)*gsinang2;
                oy2 = 1.0/oy2;
                px[2] = ghalfx*ox2*oy2 + ghalfx; oy2 *= gyxscale;
                py[2] = oy2 + ghoriz;

                for (i=0;i<3;i++)
                {
                    dd[i] = px[i]*gdx + py[i]*gdy + gdo;
                    uu[i] = px[i]*gux + py[i]*guy + guo;
                    vv[i] = px[i]*gvx + py[i]*gvy + gvo;
                }

                py[0] = fy0;
                py[1] = fy1;
                py[2] = (getflorzofslope(sectnum,(int)ox,(int)oy)-globalposz)*oy2 + ghoriz;

                ox = py[1]-py[2]; oy = py[2]-py[0]; oz = py[0]-py[1];
                r = 1.0 / (ox*px[0] + oy*px[1] + oz*px[2]);
                gdx = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
                gux = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
                gvx = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
                ox = px[2]-px[1]; oy = px[0]-px[2]; oz = px[1]-px[0];
                gdy = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
                guy = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
                gvy = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
                gdo = dd[0] - px[0]*gdx - py[0]*gdy;
                guo = uu[0] - px[0]*gux - py[0]*guy;
                gvo = vv[0] - px[0]*gvx - py[0]*gvy;

                if (globalorientation&64) //Hack for relative alignment on slopes
                {
                    r = (float)sec->floorheinum / 4096.0;
                    r = sqrt(r*r+1);
                    if (!(globalorientation&4)) { gvx *= r; gvy *= r; gvo *= r; }
                    else { gux *= r; guy *= r; guo *= r; }
                }
            }
            domostpolymethod = (globalorientation>>7)&3;
            if (globalposz >= getflorzofslope(sectnum,globalposx,globalposy)) domostpolymethod = -1; //Back-face culling
#ifdef USE_OPENGL
            if (!nofog)
            {
                fogcalc(sec->floorshade,sec->visibility,sec->floorpal);
                bglFogf(GL_FOG_DENSITY,fogresult);
                bglFogfv(GL_FOG_COLOR,fogcol);
            }
#endif
            pow2xsplit = 0; domost(x0,fy0,x1,fy1); //flor
            domostpolymethod = 0;
        }
        else if ((nextsectnum < 0) || (!(sector[nextsectnum].floorstat&1)))
        {
            //Parallaxing sky... hacked for Ken's mountain texture; paper-sky only :/
#ifdef USE_OPENGL
            if (rendmode >= 3)
            {
                /*                if (!nofog) {
                                    bglDisable(GL_FOG);
                                    //r = ((float)globalpisibility)*((float)((unsigned char)(sec->visibility<240?sec->visibility+16:sec->visibility-239)))*FOGSCALE;
                                    //r *= ((double)xdimscale*(double)viewingrange*gdo) / (65536.0*65536.0);
                                    //bglFogf(GL_FOG_DENSITY,r);
                                } */

                if (!nofog)
                {
                    fogcalc(sec->floorshade,sec->visibility,sec->floorpal);
                    bglFogf(GL_FOG_DENSITY,fogresult * 0.005);
                    bglFogfv(GL_FOG_COLOR,fogcol);
                }

                //Use clamping for tiled sky textures
                for (i=(1<<pskybits)-1;i>0;i--)
                    if (pskyoff[i] != pskyoff[i-1])
                        { skyclamphack = r_parallaxskyclamping; break; }
            }
#endif
            if (bpp == 8 || !usehightile || !hicfindsubst(globalpicnum,globalpal,1))
            {
                dd[0] = (float)xdimen*.0000001; //Adjust sky depth based on screen size!
                t = (double)((1<<(picsiz[globalpicnum]&15))<<pskybits);
                vv[1] = dd[0]*((double)xdimscale*(double)viewingrange)/(65536.0*65536.0);
                vv[0] = dd[0]*((double)((tilesizy[globalpicnum]>>1)+parallaxyoffs)) - vv[1]*ghoriz;
                i = (1<<(picsiz[globalpicnum]>>4)); if (i != tilesizy[globalpicnum]) i += i;
                vv[0] += dd[0]*((double)((r_parallaxskypanning)?sec->floorypanning:0))*((double)i)/256.0;


                //Hack to draw black rectangle below sky when looking down...
                gdx = 0; gdy = gxyaspect / 262144.0; gdo = -ghoriz*gdy;
                gux = 0; guy = 0; guo = 0;
                gvx = 0; gvy = (double)(tilesizy[globalpicnum]-1)*gdy; gvo = (double)(tilesizy[globalpicnum-1])*gdo;
                oy = (((double)tilesizy[globalpicnum])*dd[0]-vv[0])/vv[1];
                if ((oy > fy0) && (oy > fy1)) domost(x0,oy,x1,oy);
                else if ((oy > fy0) != (oy > fy1))
                {
                    //  fy0                      fy1
                    //     \                    /
                    //oy----------      oy----------
                    //        \              /
                    //         fy1        fy0
                    ox = (oy-fy0)*(x1-x0)/(fy1-fy0) + x0;
                    if (oy > fy0) { domost(x0,oy,ox,oy); domost(ox,oy,x1,fy1); }
                    else { domost(x0,fy0,ox,oy); domost(ox,oy,x1,oy); }
                }
                else domost(x0,fy0,x1,fy1);


                gdx = 0; gdy = 0; gdo = dd[0];
                gux = gdo*(t*((double)xdimscale)*((double)yxaspect)*((double)viewingrange))/(16384.0*65536.0*65536.0*5.0*1024.0);
                guy = 0; //guo calculated later
                gvx = 0; gvy = vv[1]; gvo = vv[0];

                i = globalpicnum; r = (fy1-fy0)/(x1-x0); //slope of line
                oy = ((double)viewingrange)/(ghalfx*256.0); oz = 1/oy;

                y = ((((int)((x0-ghalfx)*oy))+globalang)>>(11-pskybits));
                fx = x0;
                do
                {
                    globalpicnum = pskyoff[y&((1<<pskybits)-1)]+i;
                    guo = gdo*(t*((double)(globalang-(y<<(11-pskybits))))/2048.0 + (double)((r_parallaxskypanning)?sec->floorxpanning:0)) - gux*ghalfx;
                    y++;
                    ox = fx; fx = ((double)((y<<(11-pskybits))-globalang))*oz+ghalfx;
                    if (fx > x1) { fx = x1; i = -1; }

                    pow2xsplit = 0; domost(ox,(ox-x0)*r+fy0,fx,(fx-x0)*r+fy0); //flor
                }
                while (i >= 0);

            }
            else  //NOTE: code copied from ceiling code... lots of duplicated stuff :/
            {
                //Skybox code for parallax ceiling!
                double _xp0, _yp0, _xp1, _yp1, _oxp0, _oyp0, _t0, _t1, _nx0, _ny0, _nx1, _ny1;
                double _ryp0, _ryp1, _x0, _x1, _cy0, _fy0, _cy1, _fy1, _ox0, _ox1;
                double nfy0, nfy1;
                int skywalx[4] = {-512,512,512,-512}, skywaly[4] = {-512,-512,512,512};

                pow2xsplit = 0;
                skyclamphack = 1;

                for (i=0;i<4;i++)
                {
                    x = skywalx[i&3]; y = skywaly[i&3];
                    _xp0 = (double)y*gcosang  - (double)x*gsinang;
                    _yp0 = (double)x*gcosang2 + (double)y*gsinang2;
                    x = skywalx[(i+1)&3]; y = skywaly[(i+1)&3];
                    _xp1 = (double)y*gcosang  - (double)x*gsinang;
                    _yp1 = (double)x*gcosang2 + (double)y*gsinang2;

                    _oxp0 = _xp0; _oyp0 = _yp0;

                    //Clip to close parallel-screen plane
                    if (_yp0 < SCISDIST)
                    {
                        if (_yp1 < SCISDIST) continue;
                        _t0 = (SCISDIST-_yp0)/(_yp1-_yp0); _xp0 = (_xp1-_xp0)*_t0+_xp0; _yp0 = SCISDIST;
                        _nx0 = (skywalx[(i+1)&3]-skywalx[i&3])*_t0+skywalx[i&3];
                        _ny0 = (skywaly[(i+1)&3]-skywaly[i&3])*_t0+skywaly[i&3];
                    }
                    else { _t0 = 0.f; _nx0 = skywalx[i&3]; _ny0 = skywaly[i&3]; }
                    if (_yp1 < SCISDIST)
                    {
                        _t1 = (SCISDIST-_oyp0)/(_yp1-_oyp0); _xp1 = (_xp1-_oxp0)*_t1+_oxp0; _yp1 = SCISDIST;
                        _nx1 = (skywalx[(i+1)&3]-skywalx[i&3])*_t1+skywalx[i&3];
                        _ny1 = (skywaly[(i+1)&3]-skywaly[i&3])*_t1+skywaly[i&3];
                    }
                    else { _t1 = 1.f; _nx1 = skywalx[(i+1)&3]; _ny1 = skywaly[(i+1)&3]; }

                    _ryp0 = 1.f/_yp0; _ryp1 = 1.f/_yp1;

                    //Generate screen coordinates for front side of wall
                    _x0 = ghalfx*_xp0*_ryp0 + ghalfx;
                    _x1 = ghalfx*_xp1*_ryp1 + ghalfx;
                    if (_x1 <= _x0) continue;
                    if ((_x0 >= x1) || (x0 >= _x1)) continue;

                    _ryp0 *= gyxscale; _ryp1 *= gyxscale;

                    _cy0 = -8192.f*_ryp0 + ghoriz;
                    _fy0 =  8192.f*_ryp0 + ghoriz;
                    _cy1 = -8192.f*_ryp1 + ghoriz;
                    _fy1 =  8192.f*_ryp1 + ghoriz;

                    _ox0 = _x0; _ox1 = _x1;

                    //Make sure: x0<=_x0<_x1<=_x1
                    nfy0 = fy0; nfy1 = fy1;
                    if (_x0 < x0)
                    {
                        t = (x0-_x0)/(_x1-_x0);
                        _cy0 += (_cy1-_cy0)*t;
                        _fy0 += (_fy1-_fy0)*t;
                        _x0 = x0;
                    }
                    else if (_x0 > x0) nfy0 += (_x0-x0)*(fy1-fy0)/(x1-x0);
                    if (_x1 > x1)
                    {
                        t = (x1-_x1)/(_x1-_x0);
                        _cy1 += (_cy1-_cy0)*t;
                        _fy1 += (_fy1-_fy0)*t;
                        _x1 = x1;
                    }
                    else if (_x1 < x1) nfy1 += (_x1-x1)*(fy1-fy0)/(x1-x0);

                    //   (skybox floor)
                    //(_x0,_fy0)-(_x1,_fy1)
                    //   (skybox wall)
                    //(_x0,_cy0)-(_x1,_cy1)
                    //   (skybox ceiling)
                    //(_x0,nfy0)-(_x1,nfy1)

                    //ceiling of skybox
                    ft[0] = 512/16; ft[1] = 512/-16;
                    ft[2] = ((float)cosglobalang)*(1.f/2147483648.f);
                    ft[3] = ((float)singlobalang)*(1.f/2147483648.f);
                    gdx = 0;
                    gdy = gxyaspect*(1.f/4194304.f);
                    gdo = -ghoriz*gdy;
                    gux = (double)ft[3]*((double)viewingrange)/-65536.0;
                    gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
                    guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
                    guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
                    guo += (double)(ft[2]-gux)*ghalfx;
                    gvo -= (double)(ft[3]+gvx)*ghalfx;
                    gvx = -gvx; gvy = -gvy; gvo = -gvo; //y-flip skybox floor
#ifdef USE_OPENGL
                    drawingskybox = 6; //ceiling/5th texture/index 4 of skybox
#endif
                    if ((_fy0 > nfy0) && (_fy1 > nfy1)) domost(_x0,_fy0,_x1,_fy1);
                    else if ((_fy0 > nfy0) != (_fy1 > nfy1))
                    {
                        //(ox,oy) is intersection of: (_x0,_cy0)-(_x1,_cy1)
                        //                            (_x0,nfy0)-(_x1,nfy1)
                        //ox = _x0 + (_x1-_x0)*t
                        //oy = _cy0 + (_cy1-_cy0)*t
                        //oy = nfy0 + (nfy1-nfy0)*t
                        t = (_fy0-nfy0)/(nfy1-nfy0-_fy1+_fy0);
                        ox = _x0 + (_x1-_x0)*t;
                        oy = _fy0 + (_fy1-_fy0)*t;
                        if (nfy0 > _fy0) { domost(_x0,nfy0,ox,oy); domost(ox,oy,_x1,_fy1); }
                        else { domost(_x0,_fy0,ox,oy); domost(ox,oy,_x1,nfy1); }
                    }
                    else domost(_x0,nfy0,_x1,nfy1);

                    //wall of skybox
#ifdef USE_OPENGL
                    drawingskybox = i+1; //i+1th texture/index i of skybox
#endif
                    gdx = (_ryp0-_ryp1)*gxyaspect*(1.f/512.f) / (_ox0-_ox1);
                    gdy = 0;
                    gdo = _ryp0*gxyaspect*(1.f/512.f) - gdx*_ox0;
                    gux = (_t0*_ryp0 - _t1*_ryp1)*gxyaspect*(64.f/512.f) / (_ox0-_ox1);
                    guo = _t0*_ryp0*gxyaspect*(64.f/512.f) - gux*_ox0;
                    guy = 0;
                    _t0 = -8192.0*_ryp0 + ghoriz;
                    _t1 = -8192.0*_ryp1 + ghoriz;
                    t = ((gdx*_ox0 + gdo)*8.f) / ((_ox1-_ox0) * _ryp0 * 2048.f);
                    gvx = (_t0-_t1)*t;
                    gvy = (_ox1-_ox0)*t;
                    gvo = -gvx*_ox0 - gvy*_t0;
                    if ((_cy0 > nfy0) && (_cy1 > nfy1)) domost(_x0,_cy0,_x1,_cy1);
                    else if ((_cy0 > nfy0) != (_cy1 > nfy1))
                    {
                        //(ox,oy) is intersection of: (_x0,_fy0)-(_x1,_fy1)
                        //                            (_x0,nfy0)-(_x1,nfy1)
                        //ox = _x0 + (_x1-_x0)*t
                        //oy = _fy0 + (_fy1-_fy0)*t
                        //oy = nfy0 + (nfy1-nfy0)*t
                        t = (_cy0-nfy0)/(nfy1-nfy0-_cy1+_cy0);
                        ox = _x0 + (_x1-_x0)*t;
                        oy = _cy0 + (_cy1-_cy0)*t;
                        if (nfy0 > _cy0) { domost(_x0,nfy0,ox,oy); domost(ox,oy,_x1,_cy1); }
                        else { domost(_x0,_cy0,ox,oy); domost(ox,oy,_x1,nfy1); }
                    }
                    else domost(_x0,nfy0,_x1,nfy1);
                }

                //Floor of skybox
#ifdef USE_OPENGL
                drawingskybox = 5; //floor/6th texture/index 5 of skybox
#endif
                ft[0] = 512/16; ft[1] = -512/-16;
                ft[2] = ((float)cosglobalang)*(1.f/2147483648.f);
                ft[3] = ((float)singlobalang)*(1.f/2147483648.f);
                gdx = 0;
                gdy = gxyaspect*(-1.f/4194304.f);
                gdo = -ghoriz*gdy;
                gux = (double)ft[3]*((double)viewingrange)/-65536.0;
                gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
                guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
                guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
                guo += (double)(ft[2]-gux)*ghalfx;
                gvo -= (double)(ft[3]+gvx)*ghalfx;
                domost(x0,fy0,x1,fy1);

                skyclamphack = 0;
#ifdef USE_OPENGL
                drawingskybox = 0;
#endif
            }
#ifdef USE_OPENGL
            if (rendmode >= 3)
            {
                skyclamphack = 0;
                if (!nofog)
                {
                    bglEnable(GL_FOG);
                    //bglFogf(GL_FOG_DENSITY,gvisibility*((float)((unsigned char)(sec->visibility<240?sec->visibility+16:sec->visibility-239))));
                }
            }
#endif
        }

        globalpicnum = sec->ceilingpicnum; globalshade = sec->ceilingshade; globalpal = (int)((unsigned char)sec->ceilingpal);
        globalorientation = sec->ceilingstat;
        if (picanm[globalpicnum]&192) globalpicnum += animateoffs(globalpicnum,sectnum);
        if (!(globalorientation&1))
        {
            if (!(globalorientation&64))
                { ft[0] = globalposx; ft[1] = globalposy; ft[2] = cosglobalang; ft[3] = singlobalang; }
            else
            {
                //relative alignment
                fx = (double)(wall[wall[sec->wallptr].point2].x-wall[sec->wallptr].x);
                fy = (double)(wall[wall[sec->wallptr].point2].y-wall[sec->wallptr].y);
                r = 1.0/sqrt(fx*fx+fy*fy); fx *= r; fy *= r;
                ft[2] = cosglobalang*fx + singlobalang*fy;
                ft[3] = singlobalang*fx - cosglobalang*fy;
                ft[0] = ((double)(globalposx-wall[sec->wallptr].x))*fx + ((double)(globalposy-wall[sec->wallptr].y))*fy;
                ft[1] = ((double)(globalposy-wall[sec->wallptr].y))*fx - ((double)(globalposx-wall[sec->wallptr].x))*fy;
                if (!(globalorientation&4)) globalorientation ^= 32; else globalorientation ^= 16;
            }
            gdx = 0;
            gdy = gxyaspect;
            if (!(globalorientation&2)) gdy /= (double)(sec->ceilingz-globalposz);
            gdo = -ghoriz*gdy;
            if (globalorientation&8) { ft[0] /= 8; ft[1] /= -8; ft[2] /= 2097152; ft[3] /= 2097152; }
            else { ft[0] /= 16; ft[1] /= -16; ft[2] /= 4194304; ft[3] /= 4194304; }
            gux = (double)ft[3]*((double)viewingrange)/-65536.0;
            gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
            guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
            guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
            guo += (double)(ft[2]-gux)*ghalfx;
            gvo -= (double)(ft[3]+gvx)*ghalfx;

            //Texture flipping
            if (globalorientation&4)
            {
                r = gux; gux = gvx; gvx = r;
                r = guy; guy = gvy; gvy = r;
                r = guo; guo = gvo; gvo = r;
            }
            if (globalorientation&16) { gux = -gux; guy = -guy; guo = -guo; }
            if (globalorientation&32) { gvx = -gvx; gvy = -gvy; gvo = -gvo; }

            //Texture panning
            fx = (float)sec->ceilingxpanning*((float)(1<<(picsiz[globalpicnum]&15)))/256.0;
            fy = (float)sec->ceilingypanning*((float)(1<<(picsiz[globalpicnum]>>4)))/256.0;
            if ((globalorientation&(2+64)) == (2+64)) //Hack for panning for slopes w/ relative alignment
            {
                r = (float)sec->ceilingheinum / 4096.0; r = 1.0/sqrt(r*r+1);
                if (!(globalorientation&4)) fy *= r; else fx *= r;
            }
            guy += gdy*fx; guo += gdo*fx;
            gvy += gdy*fy; gvo += gdo*fy;

            if (globalorientation&2) //slopes
            {
                px[0] = x0; py[0] = ryp0 + ghoriz;
                px[1] = x1; py[1] = ryp1 + ghoriz;

                //Pick some point guaranteed to be not collinear to the 1st two points
                ox = nx0 + (ny1-ny0);
                oy = ny0 + (nx0-nx1);
                ox2 = (double)(oy-globalposy)*gcosang  - (double)(ox-globalposx)*gsinang ;
                oy2 = (double)(ox-globalposx)*gcosang2 + (double)(oy-globalposy)*gsinang2;
                oy2 = 1.0/oy2;
                px[2] = ghalfx*ox2*oy2 + ghalfx; oy2 *= gyxscale;
                py[2] = oy2 + ghoriz;

                for (i=0;i<3;i++)
                {
                    dd[i] = px[i]*gdx + py[i]*gdy + gdo;
                    uu[i] = px[i]*gux + py[i]*guy + guo;
                    vv[i] = px[i]*gvx + py[i]*gvy + gvo;
                }

                py[0] = cy0;
                py[1] = cy1;
                py[2] = (getceilzofslope(sectnum,(int)ox,(int)oy)-globalposz)*oy2 + ghoriz;

                ox = py[1]-py[2]; oy = py[2]-py[0]; oz = py[0]-py[1];
                r = 1.0 / (ox*px[0] + oy*px[1] + oz*px[2]);
                gdx = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
                gux = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
                gvx = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
                ox = px[2]-px[1]; oy = px[0]-px[2]; oz = px[1]-px[0];
                gdy = (ox*dd[0] + oy*dd[1] + oz*dd[2])*r;
                guy = (ox*uu[0] + oy*uu[1] + oz*uu[2])*r;
                gvy = (ox*vv[0] + oy*vv[1] + oz*vv[2])*r;
                gdo = dd[0] - px[0]*gdx - py[0]*gdy;
                guo = uu[0] - px[0]*gux - py[0]*guy;
                gvo = vv[0] - px[0]*gvx - py[0]*gvy;

                if (globalorientation&64) //Hack for relative alignment on slopes
                {
                    r = (float)sec->ceilingheinum / 4096.0;
                    r = sqrt(r*r+1);
                    if (!(globalorientation&4)) { gvx *= r; gvy *= r; gvo *= r; }
                    else { gux *= r; guy *= r; guo *= r; }
                }
            }
            domostpolymethod = (globalorientation>>7)&3;
            if (globalposz <= getceilzofslope(sectnum,globalposx,globalposy)) domostpolymethod = -1; //Back-face culling
#ifdef USE_OPENGL
            if (!nofog)
            {
                fogcalc(sec->ceilingshade,sec->visibility,sec->ceilingpal);
                bglFogf(GL_FOG_DENSITY,fogresult);
                bglFogfv(GL_FOG_COLOR,fogcol);
            }
#endif
            pow2xsplit = 0; domost(x1,cy1,x0,cy0); //ceil
            domostpolymethod = 0;
        }
        else if ((nextsectnum < 0) || (!(sector[nextsectnum].ceilingstat&1)))
        {
#ifdef USE_OPENGL
            if (rendmode >= 3)
            {
                /*                if (!nofog) {
                                    bglDisable(GL_FOG);
                                    //r = ((float)globalpisibility)*((float)((unsigned char)(sec->visibility<240?sec->visibility+16:sec->visibility-239)))*FOGSCALE;
                                    //r *= ((double)xdimscale*(double)viewingrange*gdo) / (65536.0*65536.0);
                                    //bglFogf(GL_FOG_DENSITY,r);
                                }
                */
                if (!nofog)
                {
                    fogcalc(sec->ceilingshade,sec->visibility,sec->ceilingpal);
                    bglFogf(GL_FOG_DENSITY,fogresult * 0.005);
                    bglFogfv(GL_FOG_COLOR,fogcol);
                }
                //Use clamping for tiled sky textures
                for (i=(1<<pskybits)-1;i>0;i--)
                    if (pskyoff[i] != pskyoff[i-1])
                        { skyclamphack = r_parallaxskyclamping; break; }
            }
#endif
            //Parallaxing sky...
            if (bpp == 8 || !usehightile || !hicfindsubst(globalpicnum,globalpal,1))
            {
                //Render for parallaxtype == 0 / paper-sky
                dd[0] = (float)xdimen*.0000001; //Adjust sky depth based on screen size!
                t = (double)((1<<(picsiz[globalpicnum]&15))<<pskybits);
                vv[1] = dd[0]*((double)xdimscale*(double)viewingrange)/(65536.0*65536.0);
                vv[0] = dd[0]*((double)((tilesizy[globalpicnum]>>1)+parallaxyoffs)) - vv[1]*ghoriz;
                i = (1<<(picsiz[globalpicnum]>>4)); if (i != tilesizy[globalpicnum]) i += i;
                vv[0] += dd[0]*((double)((r_parallaxskypanning)?sec->ceilingypanning:0))*((double)i)/256.0;

                //Hack to draw black rectangle below sky when looking down...
                gdx = 0; gdy = gxyaspect / -262144.0; gdo = -ghoriz*gdy;
                gux = 0; guy = 0; guo = 0;
                gvx = 0; gvy = 0; gvo = 0;
                oy = -vv[0]/vv[1];
                if ((oy < cy0) && (oy < cy1)) domost(x1,oy,x0,oy);
                else if ((oy < cy0) != (oy < cy1))
                {      /*         cy1        cy0
                                                                    		//        /             \
                                                                    		//oy----------      oy---------
                                                                    		//    /                    \
                                                                    		//  cy0                     cy1
                                                                    		*/
                    ox = (oy-cy0)*(x1-x0)/(cy1-cy0) + x0;
                    if (oy < cy0) { domost(ox,oy,x0,oy); domost(x1,cy1,ox,oy); }
                    else { domost(ox,oy,x0,cy0); domost(x1,oy,ox,oy); }
                }
                else domost(x1,cy1,x0,cy0);

                gdx = 0; gdy = 0; gdo = dd[0];
                gux = gdo*(t*((double)xdimscale)*((double)yxaspect)*((double)viewingrange))/(16384.0*65536.0*65536.0*5.0*1024.0);
                guy = 0; //guo calculated later
                gvx = 0; gvy = vv[1]; gvo = vv[0];

                i = globalpicnum; r = (cy1-cy0)/(x1-x0); //slope of line
                oy = ((double)viewingrange)/(ghalfx*256.0); oz = 1/oy;

                y = ((((int)((x0-ghalfx)*oy))+globalang)>>(11-pskybits));
                fx = x0;
                do
                {
                    globalpicnum = pskyoff[y&((1<<pskybits)-1)]+i;
                    guo = gdo*(t*((double)(globalang-(y<<(11-pskybits))))/2048.0 + (double)((r_parallaxskypanning)?sec->ceilingxpanning:0)) - gux*ghalfx;
                    y++;
                    ox = fx; fx = ((double)((y<<(11-pskybits))-globalang))*oz+ghalfx;
                    if (fx > x1) { fx = x1; i = -1; }
                    pow2xsplit = 0; domost(fx,(fx-x0)*r+cy0,ox,(ox-x0)*r+cy0); //ceil
                }
                while (i >= 0);
            }
            else
            {
                //Skybox code for parallax ceiling!
                double _xp0, _yp0, _xp1, _yp1, _oxp0, _oyp0, _t0, _t1, _nx0, _ny0, _nx1, _ny1;
                double _ryp0, _ryp1, _x0, _x1, _cy0, _fy0, _cy1, _fy1, _ox0, _ox1;
                double ncy0, ncy1;
                int skywalx[4] = {-512,512,512,-512}, skywaly[4] = {-512,-512,512,512};

                pow2xsplit = 0;
                skyclamphack = 1;

                for (i=0;i<4;i++)
                {
                    x = skywalx[i&3]; y = skywaly[i&3];
                    _xp0 = (double)y*gcosang  - (double)x*gsinang;
                    _yp0 = (double)x*gcosang2 + (double)y*gsinang2;
                    x = skywalx[(i+1)&3]; y = skywaly[(i+1)&3];
                    _xp1 = (double)y*gcosang  - (double)x*gsinang;
                    _yp1 = (double)x*gcosang2 + (double)y*gsinang2;

                    _oxp0 = _xp0; _oyp0 = _yp0;

                    //Clip to close parallel-screen plane
                    if (_yp0 < SCISDIST)
                    {
                        if (_yp1 < SCISDIST) continue;
                        _t0 = (SCISDIST-_yp0)/(_yp1-_yp0); _xp0 = (_xp1-_xp0)*_t0+_xp0; _yp0 = SCISDIST;
                        _nx0 = (skywalx[(i+1)&3]-skywalx[i&3])*_t0+skywalx[i&3];
                        _ny0 = (skywaly[(i+1)&3]-skywaly[i&3])*_t0+skywaly[i&3];
                    }
                    else { _t0 = 0.f; _nx0 = skywalx[i&3]; _ny0 = skywaly[i&3]; }
                    if (_yp1 < SCISDIST)
                    {
                        _t1 = (SCISDIST-_oyp0)/(_yp1-_oyp0); _xp1 = (_xp1-_oxp0)*_t1+_oxp0; _yp1 = SCISDIST;
                        _nx1 = (skywalx[(i+1)&3]-skywalx[i&3])*_t1+skywalx[i&3];
                        _ny1 = (skywaly[(i+1)&3]-skywaly[i&3])*_t1+skywaly[i&3];
                    }
                    else { _t1 = 1.f; _nx1 = skywalx[(i+1)&3]; _ny1 = skywaly[(i+1)&3]; }

                    _ryp0 = 1.f/_yp0; _ryp1 = 1.f/_yp1;

                    //Generate screen coordinates for front side of wall
                    _x0 = ghalfx*_xp0*_ryp0 + ghalfx;
                    _x1 = ghalfx*_xp1*_ryp1 + ghalfx;
                    if (_x1 <= _x0) continue;
                    if ((_x0 >= x1) || (x0 >= _x1)) continue;

                    _ryp0 *= gyxscale; _ryp1 *= gyxscale;

                    _cy0 = -8192.f*_ryp0 + ghoriz;
                    _fy0 =  8192.f*_ryp0 + ghoriz;
                    _cy1 = -8192.f*_ryp1 + ghoriz;
                    _fy1 =  8192.f*_ryp1 + ghoriz;

                    _ox0 = _x0; _ox1 = _x1;

                    //Make sure: x0<=_x0<_x1<=_x1
                    ncy0 = cy0; ncy1 = cy1;
                    if (_x0 < x0)
                    {
                        t = (x0-_x0)/(_x1-_x0);
                        _cy0 += (_cy1-_cy0)*t;
                        _fy0 += (_fy1-_fy0)*t;
                        _x0 = x0;
                    }
                    else if (_x0 > x0) ncy0 += (_x0-x0)*(cy1-cy0)/(x1-x0);
                    if (_x1 > x1)
                    {
                        t = (x1-_x1)/(_x1-_x0);
                        _cy1 += (_cy1-_cy0)*t;
                        _fy1 += (_fy1-_fy0)*t;
                        _x1 = x1;
                    }
                    else if (_x1 < x1) ncy1 += (_x1-x1)*(cy1-cy0)/(x1-x0);

                    //   (skybox ceiling)
                    //(_x0,_cy0)-(_x1,_cy1)
                    //   (skybox wall)
                    //(_x0,_fy0)-(_x1,_fy1)
                    //   (skybox floor)
                    //(_x0,ncy0)-(_x1,ncy1)

                    //ceiling of skybox
#ifdef USE_OPENGL
                    drawingskybox = 5; //ceiling/5th texture/index 4 of skybox
#endif
                    ft[0] = 512/16; ft[1] = -512/-16;
                    ft[2] = ((float)cosglobalang)*(1.f/2147483648.f);
                    ft[3] = ((float)singlobalang)*(1.f/2147483648.f);
                    gdx = 0;
                    gdy = gxyaspect*-(1.f/4194304.f);
                    gdo = -ghoriz*gdy;
                    gux = (double)ft[3]*((double)viewingrange)/-65536.0;
                    gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
                    guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
                    guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
                    guo += (double)(ft[2]-gux)*ghalfx;
                    gvo -= (double)(ft[3]+gvx)*ghalfx;
                    if ((_cy0 < ncy0) && (_cy1 < ncy1)) domost(_x1,_cy1,_x0,_cy0);
                    else if ((_cy0 < ncy0) != (_cy1 < ncy1))
                    {
                        //(ox,oy) is intersection of: (_x0,_cy0)-(_x1,_cy1)
                        //                            (_x0,ncy0)-(_x1,ncy1)
                        //ox = _x0 + (_x1-_x0)*t
                        //oy = _cy0 + (_cy1-_cy0)*t
                        //oy = ncy0 + (ncy1-ncy0)*t
                        t = (_cy0-ncy0)/(ncy1-ncy0-_cy1+_cy0);
                        ox = _x0 + (_x1-_x0)*t;
                        oy = _cy0 + (_cy1-_cy0)*t;
                        if (ncy0 < _cy0) { domost(ox,oy,_x0,ncy0); domost(_x1,_cy1,ox,oy); }
                        else { domost(ox,oy,_x0,_cy0); domost(_x1,ncy1,ox,oy); }
                    }
                    else domost(_x1,ncy1,_x0,ncy0);

                    //wall of skybox
#ifdef USE_OPENGL
                    drawingskybox = i+1; //i+1th texture/index i of skybox
#endif
                    gdx = (_ryp0-_ryp1)*gxyaspect*(1.f/512.f) / (_ox0-_ox1);
                    gdy = 0;
                    gdo = _ryp0*gxyaspect*(1.f/512.f) - gdx*_ox0;
                    gux = (_t0*_ryp0 - _t1*_ryp1)*gxyaspect*(64.f/512.f) / (_ox0-_ox1);
                    guo = _t0*_ryp0*gxyaspect*(64.f/512.f) - gux*_ox0;
                    guy = 0;
                    _t0 = -8192.0*_ryp0 + ghoriz;
                    _t1 = -8192.0*_ryp1 + ghoriz;
                    t = ((gdx*_ox0 + gdo)*8.f) / ((_ox1-_ox0) * _ryp0 * 2048.f);
                    gvx = (_t0-_t1)*t;
                    gvy = (_ox1-_ox0)*t;
                    gvo = -gvx*_ox0 - gvy*_t0;
                    if ((_fy0 < ncy0) && (_fy1 < ncy1)) domost(_x1,_fy1,_x0,_fy0);
                    else if ((_fy0 < ncy0) != (_fy1 < ncy1))
                    {
                        //(ox,oy) is intersection of: (_x0,_fy0)-(_x1,_fy1)
                        //                            (_x0,ncy0)-(_x1,ncy1)
                        //ox = _x0 + (_x1-_x0)*t
                        //oy = _fy0 + (_fy1-_fy0)*t
                        //oy = ncy0 + (ncy1-ncy0)*t
                        t = (_fy0-ncy0)/(ncy1-ncy0-_fy1+_fy0);
                        ox = _x0 + (_x1-_x0)*t;
                        oy = _fy0 + (_fy1-_fy0)*t;
                        if (ncy0 < _fy0) { domost(ox,oy,_x0,ncy0); domost(_x1,_fy1,ox,oy); }
                        else { domost(ox,oy,_x0,_fy0); domost(_x1,ncy1,ox,oy); }
                    }
                    else domost(_x1,ncy1,_x0,ncy0);
                }

                //Floor of skybox
#ifdef USE_OPENGL
                drawingskybox = 6; //floor/6th texture/index 5 of skybox
#endif
                ft[0] = 512/16; ft[1] = 512/-16;
                ft[2] = ((float)cosglobalang)*(1.f/2147483648.f);
                ft[3] = ((float)singlobalang)*(1.f/2147483648.f);
                gdx = 0;
                gdy = gxyaspect*(1.f/4194304.f);
                gdo = -ghoriz*gdy;
                gux = (double)ft[3]*((double)viewingrange)/-65536.0;
                gvx = (double)ft[2]*((double)viewingrange)/-65536.0;
                guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
                guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
                guo += (double)(ft[2]-gux)*ghalfx;
                gvo -= (double)(ft[3]+gvx)*ghalfx;
                gvx = -gvx; gvy = -gvy; gvo = -gvo; //y-flip skybox floor
                domost(x1,cy1,x0,cy0);

                skyclamphack = 0;
#ifdef USE_OPENGL
                drawingskybox = 0;
#endif
            }
#ifdef USE_OPENGL
            if (rendmode >= 3)
            {
                skyclamphack = 0;
                if (!nofog)
                {
                    bglEnable(GL_FOG);
                    //bglFogf(GL_FOG_DENSITY,gvisibility*((float)((unsigned char)(sec->visibility<240?sec->visibility+16:sec->visibility-239))));
                }
            }
#endif
        }

        //(x0,cy0) == (u=             0,v=0,d=)
        //(x1,cy0) == (u=wal->xrepeat*8,v=0)
        //(x0,fy0) == (u=             0,v=v)
        //             u = (gux*sx + guy*sy + guo) / (gdx*sx + gdy*sy + gdo)
        //             v = (gvx*sx + gvy*sy + gvo) / (gdx*sx + gdy*sy + gdo)
        //             0 = (gux*x0 + guy*cy0 + guo) / (gdx*x0 + gdy*cy0 + gdo)
        //wal->xrepeat*8 = (gux*x1 + guy*cy0 + guo) / (gdx*x1 + gdy*cy0 + gdo)
        //             0 = (gvx*x0 + gvy*cy0 + gvo) / (gdx*x0 + gdy*cy0 + gdo)
        //             v = (gvx*x0 + gvy*fy0 + gvo) / (gdx*x0 + gdy*fy0 + gdo)
        //sx = x0, u = t0*wal->xrepeat*8, d = yp0;
        //sx = x1, u = t1*wal->xrepeat*8, d = yp1;
        //d = gdx*sx + gdo
        //u = (gux*sx + guo) / (gdx*sx + gdo)
        //yp0 = gdx*x0 + gdo
        //yp1 = gdx*x1 + gdo
        //t0*wal->xrepeat*8 = (gux*x0 + guo) / (gdx*x0 + gdo)
        //t1*wal->xrepeat*8 = (gux*x1 + guo) / (gdx*x1 + gdo)
        //gdx*x0 + gdo = yp0
        //gdx*x1 + gdo = yp1
        gdx = (ryp0-ryp1)*gxyaspect / (x0-x1);
        gdy = 0;
        gdo = ryp0*gxyaspect - gdx*x0;

        //gux*x0 + guo = t0*wal->xrepeat*8*yp0
        //gux*x1 + guo = t1*wal->xrepeat*8*yp1
        gux = (t0*ryp0 - t1*ryp1)*gxyaspect*(float)wal->xrepeat*8.f / (x0-x1);
        guo = t0*ryp0*gxyaspect*(float)wal->xrepeat*8.f - gux*x0;
        guo += (float)wal->xpanning*gdo;
        gux += (float)wal->xpanning*gdx;
        guy = 0;
        //Derivation for u:
        //   (gvx*x0 + gvy*cy0 + gvo) / (gdx*x0 + gdy*cy0 + gdo) = 0
        //   (gvx*x1 + gvy*cy1 + gvo) / (gdx*x1 + gdy*cy1 + gdo) = 0
        //   (gvx*x0 + gvy*fy0 + gvo) / (gdx*x0 + gdy*fy0 + gdo) = v
        //   (gvx*x1 + gvy*fy1 + gvo) / (gdx*x1 + gdy*fy1 + gdo) = v
        //   (gvx*x0 + gvy*cy0 + gvo*1) = 0
        //   (gvx*x1 + gvy*cy1 + gvo*1) = 0
        //   (gvx*x0 + gvy*fy0 + gvo*1) = t
        ogux = gux; oguy = guy; oguo = guo;

        if (nextsectnum >= 0)
        {
            getzsofslope(nextsectnum,(int)nx0,(int)ny0,&cz,&fz);
            ocy0 = ((float)(cz-globalposz))*ryp0 + ghoriz;
            ofy0 = ((float)(fz-globalposz))*ryp0 + ghoriz;
            getzsofslope(nextsectnum,(int)nx1,(int)ny1,&cz,&fz);
            ocy1 = ((float)(cz-globalposz))*ryp1 + ghoriz;
            ofy1 = ((float)(fz-globalposz))*ryp1 + ghoriz;

            if ((wal->cstat&48) == 16) maskwall[maskwallcnt++] = z;

            if (((cy0 < ocy0) || (cy1 < ocy1)) && (!((sec->ceilingstat&sector[nextsectnum].ceilingstat)&1)))
            {
                globalpicnum = wal->picnum; globalshade = wal->shade; globalpal = (int)((unsigned char)wal->pal);
                if (picanm[globalpicnum]&192) globalpicnum += animateoffs(globalpicnum,wallnum+16384);

                if (!(wal->cstat&4)) i = sector[nextsectnum].ceilingz; else i = sec->ceilingz;
                t0 = ((float)(i-globalposz))*ryp0 + ghoriz;
                t1 = ((float)(i-globalposz))*ryp1 + ghoriz;
                t = ((gdx*x0 + gdo) * (float)wal->yrepeat) / ((x1-x0) * ryp0 * 2048.f);
                i = (1<<(picsiz[globalpicnum]>>4)); if (i < tilesizy[globalpicnum]) i <<= 1;
                fy = (float)wal->ypanning * ((float)i) / 256.0;
                gvx = (t0-t1)*t;
                gvy = (x1-x0)*t;
                gvo = -gvx*x0 - gvy*t0 + fy*gdo; gvx += fy*gdx; gvy += fy*gdy;

                if (wal->cstat&8) //xflip
                {
                    t = (float)(wal->xrepeat*8 + wal->xpanning*2);
                    gux = gdx*t - gux;
                    guy = gdy*t - guy;
                    guo = gdo*t - guo;
                }
                if (wal->cstat&256) { gvx = -gvx; gvy = -gvy; gvo = -gvo; } //yflip
#ifdef USE_OPENGL
                if (!nofog)
                {
                    fogcalc(wal->shade,sec->visibility,sec->floorpal);
                    bglFogf(GL_FOG_DENSITY,fogresult);
                    bglFogfv(GL_FOG_COLOR,fogcol);
                }
#endif
                pow2xsplit = 1; domost(x1,ocy1,x0,ocy0);
                if (wal->cstat&8) { gux = ogux; guy = oguy; guo = oguo; }
            }
            if (((ofy0 < fy0) || (ofy1 < fy1)) && (!((sec->floorstat&sector[nextsectnum].floorstat)&1)))
            {
                if (!(wal->cstat&2)) nwal = wal;
                else
                {
                    nwal = &wall[wal->nextwall];
                    guo += (float)(nwal->xpanning-wal->xpanning)*gdo;
                    gux += (float)(nwal->xpanning-wal->xpanning)*gdx;
                    guy += (float)(nwal->xpanning-wal->xpanning)*gdy;
                }
                globalpicnum = nwal->picnum; globalshade = nwal->shade; globalpal = (int)((unsigned char)nwal->pal);
                if (picanm[globalpicnum]&192) globalpicnum += animateoffs(globalpicnum,wallnum+16384);

                if (!(nwal->cstat&4)) i = sector[nextsectnum].floorz; else i = sec->ceilingz;
                t0 = ((float)(i-globalposz))*ryp0 + ghoriz;
                t1 = ((float)(i-globalposz))*ryp1 + ghoriz;
                t = ((gdx*x0 + gdo) * (float)wal->yrepeat) / ((x1-x0) * ryp0 * 2048.f);
                i = (1<<(picsiz[globalpicnum]>>4)); if (i < tilesizy[globalpicnum]) i <<= 1;
                fy = (float)nwal->ypanning * ((float)i) / 256.0;
                gvx = (t0-t1)*t;
                gvy = (x1-x0)*t;
                gvo = -gvx*x0 - gvy*t0 + fy*gdo; gvx += fy*gdx; gvy += fy*gdy;

                if (wal->cstat&8) //xflip
                {
                    t = (float)(wal->xrepeat*8 + nwal->xpanning*2);
                    gux = gdx*t - gux;
                    guy = gdy*t - guy;
                    guo = gdo*t - guo;
                }
                if (nwal->cstat&256) { gvx = -gvx; gvy = -gvy; gvo = -gvo; } //yflip
#ifdef USE_OPENGL
                if (!nofog)
                {
                    fogcalc(nwal->shade,sec->visibility,sec->floorpal);
                    bglFogf(GL_FOG_DENSITY,fogresult);
                    bglFogfv(GL_FOG_COLOR,fogcol);
                }
#endif
                pow2xsplit = 1; domost(x0,ofy0,x1,ofy1);
                if (wal->cstat&(2+8)) { guo = oguo; gux = ogux; guy = oguy; }
            }
        }

        if ((nextsectnum < 0) || (wal->cstat&32))   //White/1-way wall
        {
            if (nextsectnum < 0) globalpicnum = wal->picnum; else globalpicnum = wal->overpicnum;
            globalshade = wal->shade; globalpal = (int)((unsigned char)wal->pal);
            if (picanm[globalpicnum]&192) globalpicnum += animateoffs(globalpicnum,wallnum+16384);

            if (nextsectnum >= 0) { if (!(wal->cstat&4)) i = nextsec->ceilingz; else i = sec->ceilingz; }
            else { if (!(wal->cstat&4)) i = sec->ceilingz;     else i = sec->floorz; }
            t0 = ((float)(i-globalposz))*ryp0 + ghoriz;
            t1 = ((float)(i-globalposz))*ryp1 + ghoriz;
            t = ((gdx*x0 + gdo) * (float)wal->yrepeat) / ((x1-x0) * ryp0 * 2048.f);
            i = (1<<(picsiz[globalpicnum]>>4)); if (i < tilesizy[globalpicnum]) i <<= 1;
            fy = (float)wal->ypanning * ((float)i) / 256.0;
            gvx = (t0-t1)*t;
            gvy = (x1-x0)*t;
            gvo = -gvx*x0 - gvy*t0 + fy*gdo; gvx += fy*gdx; gvy += fy*gdy;

            if (wal->cstat&8) //xflip
            {
                t = (float)(wal->xrepeat*8 + wal->xpanning*2);
                gux = gdx*t - gux;
                guy = gdy*t - guy;
                guo = gdo*t - guo;
            }
            if (wal->cstat&256) { gvx = -gvx; gvy = -gvy; gvo = -gvo; } //yflip
#ifdef USE_OPENGL
            if (!nofog)
            {
                fogcalc(wal->shade,sec->visibility,sec->floorpal);
                bglFogf(GL_FOG_DENSITY,fogresult);
                bglFogfv(GL_FOG_COLOR,fogcol);
            }
#endif
            pow2xsplit = 1; domost(x0,-10000,x1,-10000);
        }

        if (nextsectnum >= 0)
            if ((!(gotsector[nextsectnum>>3]&pow2char[nextsectnum&7])) && (testvisiblemost(x0,x1)))
                polymost_scansector(nextsectnum);
    }
}

static int wallfront(int, int);
static int polymost_bunchfront(int b1, int b2)
{
    double x1b1, x1b2, x2b1, x2b2;
    int b1f, b2f, i;

    b1f = bunchfirst[b1]; x1b1 = dxb1[b1f]; x2b2 = dxb2[bunchlast[b2]]; if (x1b1 >= x2b2) return(-1);
    b2f = bunchfirst[b2]; x1b2 = dxb1[b2f]; x2b1 = dxb2[bunchlast[b1]]; if (x1b2 >= x2b1) return(-1);

    if (x1b1 >= x1b2)
    {
        for (i=b2f;dxb2[i]<=x1b1;i=p2[i]);
        return(wallfront(b1f,i));
    }
    for (i=b1f;dxb2[i]<=x1b2;i=p2[i]);
    return(wallfront(i,b2f));
}

static void polymost_scansector(int sectnum)
{
    double d, xp1, yp1, xp2, yp2;
    walltype *wal, *wal2;
    spritetype *spr;
    int z, zz, startwall, endwall, numscansbefore, scanfirst, bunchfrst, nextsectnum;
    int xs, ys, x1, y1, x2, y2;

    if (sectnum < 0) return;
    if (automapping) show2dsector[sectnum>>3] |= pow2char[sectnum&7];

    sectorborder[0] = sectnum, sectorbordercnt = 1;
    do
    {
        sectnum = sectorborder[--sectorbordercnt];

        for (z=headspritesect[sectnum];z>=0;z=nextspritesect[z])
        {
            spr = &sprite[z];
            if ((((spr->cstat&0x8000) == 0) || (showinvisibility)) &&
                    (spr->xrepeat > 0) && (spr->yrepeat > 0) &&
                    (spritesortcnt < MAXSPRITESONSCREEN))
            {
                xs = spr->x-globalposx; ys = spr->y-globalposy;
                if ((spr->cstat&48) || (xs*gcosang+ys*gsinang > 0))
                {
                    copybufbyte(spr,&tsprite[spritesortcnt],sizeof(spritetype));
                    tsprite[spritesortcnt++].owner = z;
                }
            }
        }

        gotsector[sectnum>>3] |= pow2char[sectnum&7];

        bunchfrst = numbunches;
        numscansbefore = numscans;

        startwall = sector[sectnum].wallptr; endwall = sector[sectnum].wallnum+startwall;
        scanfirst = numscans;
        xp2 = 0; yp2 = 0;
        for (z=startwall,wal=&wall[z];z<endwall;z++,wal++)
        {
            wal2 = &wall[wal->point2];
            x1 = wal->x-globalposx; y1 = wal->y-globalposy;
            x2 = wal2->x-globalposx; y2 = wal2->y-globalposy;

            nextsectnum = wal->nextsector; //Scan close sectors
            if ((nextsectnum >= 0) && (!(wal->cstat&32)) && (!(gotsector[nextsectnum>>3]&pow2char[nextsectnum&7])))
            {
                d = (double)x1*(double)y2 - (double)x2*(double)y1; xp1 = (double)(x2-x1); yp1 = (double)(y2-y1);
                if (d*d <= (xp1*xp1 + yp1*yp1)*(SCISDIST*SCISDIST*260.0))
                    sectorborder[sectorbordercnt++] = nextsectnum;
            }

            if ((z == startwall) || (wall[z-1].point2 != z))
            {
                xp1 = ((double)y1*(double)cosglobalang             - (double)x1*(double)singlobalang)/64.0;
                yp1 = ((double)x1*(double)cosviewingrangeglobalang + (double)y1*(double)sinviewingrangeglobalang)/64.0;
            }
            else { xp1 = xp2; yp1 = yp2; }
            xp2 = ((double)y2*(double)cosglobalang             - (double)x2*(double)singlobalang)/64.0;
            yp2 = ((double)x2*(double)cosviewingrangeglobalang + (double)y2*(double)sinviewingrangeglobalang)/64.0;
            if ((yp1 >= SCISDIST) || (yp2 >= SCISDIST))
                if ((double)xp1*(double)yp2 < (double)xp2*(double)yp1) //if wall is facing you...
                {
                    if (yp1 >= SCISDIST)
                        dxb1[numscans] = (double)xp1*ghalfx/(double)yp1 + ghalfx;
                    else dxb1[numscans] = -1e32;

                    if (yp2 >= SCISDIST)
                        dxb2[numscans] = (double)xp2*ghalfx/(double)yp2 + ghalfx;
                    else dxb2[numscans] = 1e32;

                    if (dxb1[numscans] < dxb2[numscans])
                        { thesector[numscans] = sectnum; thewall[numscans] = z; p2[numscans] = numscans+1; numscans++; }
                }

            if ((wall[z].point2 < z) && (scanfirst < numscans))
                { p2[numscans-1] = scanfirst; scanfirst = numscans; }
        }

        for (z=numscansbefore;z<numscans;z++)
            if ((wall[thewall[z]].point2 != thewall[p2[z]]) || (dxb2[z] > dxb1[p2[z]]))
                { bunchfirst[numbunches++] = p2[z]; p2[z] = -1; }

        for (z=bunchfrst;z<numbunches;z++)
        {
            for (zz=bunchfirst[z];p2[zz]>=0;zz=p2[zz]);
            bunchlast[z] = zz;
        }
    }
    while (sectorbordercnt > 0);
}

void polymost_drawrooms()
{
    int i, j, k, n, n2, closest;
    double ox, oy, oz, ox2, oy2, oz2, r, px[6], py[6], pz[6], px2[6], py2[6], pz2[6], sx[6], sy[6];

    if (!rendmode) return;

    begindrawing();
    frameoffset = frameplace + windowy1*bytesperline + windowx1;

#ifdef USE_OPENGL
    if (rendmode >= 3)
    {
        resizeglcheck();

        //bglClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
        bglDisable(GL_BLEND);
        bglEnable(GL_TEXTURE_2D);
        //bglTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE); //default anyway
        bglEnable(GL_DEPTH_TEST);
        bglDepthFunc(GL_ALWAYS); //NEVER,LESS,(,L)EQUAL,GREATER,(NOT,G)EQUAL,ALWAYS

        //bglPolygonOffset(1,1); //Supposed to make sprites pasted on walls or floors not disappear
        bglDepthRange(0.00001,1.0); //<- this is more widely supported than glPolygonOffset

        //Enable this for OpenGL red-blue glasses mode :)
        if (glredbluemode)
        {
            float m[4][4];
            static int grbfcnt = 0; grbfcnt++;
            if (redblueclearcnt < numpages) { redblueclearcnt++; bglColorMask(1,1,1,1); bglClear(GL_COLOR_BUFFER_BIT); }
            if (grbfcnt&1)
            {
                bglViewport(windowx1-16,yres-(windowy2+1),windowx2-(windowx1-16)+1,windowy2-windowy1+1);
                bglColorMask(1,0,0,1);
                globalposx += singlobalang/1024;
                globalposy -= cosglobalang/1024;
            }
            else
            {
                bglViewport(windowx1,yres-(windowy2+1),windowx2+16-windowx1+1,windowy2-windowy1+1);
                bglColorMask(0,1,1,1);
                globalposx -= singlobalang/1024;
                globalposy += cosglobalang/1024;
            }
        }
        if (r_depthpeeling)
        {
            bglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, peelfbos[r_peelscount]);
            bglPushAttrib(GL_VIEWPORT_BIT);
            bglViewport(0, 0, xdim, ydim);
            //bglClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
        }
    }
#endif

    //Polymost supports true look up/down :) Here, we convert horizon to angle.
    //gchang&gshang are cos&sin of this angle (respectively)
    gyxscale = ((double)xdimenscale)/131072.0;
    gxyaspect = ((double)xyaspect*(double)viewingrange)*(5.0/(65536.0*262144.0));
    gviewxrange = ((double)viewingrange)*((double)xdimen)/(32768.0*1024.0);
    gcosang = ((double)cosglobalang)/262144.0;
    gsinang = ((double)singlobalang)/262144.0;
    gcosang2 = gcosang*((double)viewingrange)/65536.0;
    gsinang2 = gsinang*((double)viewingrange)/65536.0;
    ghalfx = (double)halfxdimen; grhalfxdown10 = 1.0/(((double)ghalfx)*1024);
    ghoriz = (double)globalhoriz;

    gvisibility = ((float)globalvisibility)*FOGSCALE;

    //global cos/sin height angle
    r = (double)((ydimen>>1)-ghoriz);
    gshang = r/sqrt(r*r+ghalfx*ghalfx);
    gchang = sqrt(1.0-gshang*gshang);
    ghoriz = (double)(ydimen>>1);

    //global cos/sin tilt angle
    gctang = cos(gtang);
    gstang = sin(gtang);
    if (fabs(gstang) < .001) //This hack avoids nasty precision bugs in domost()
        { gstang = 0; if (gctang > 0) gctang = 1.0; else gctang = -1.0; }

    if (inpreparemirror)
        gstang = -gstang;

    //Generate viewport trapezoid (for handling screen up/down)
    px[0] = px[3] = 0-1; px[1] = px[2] = windowx2+1-windowx1+2;
    py[0] = py[1] = 0-1; py[2] = py[3] = windowy2+1-windowy1+2; n = 4;
    for (i=0;i<n;i++)
    {
        ox = px[i]-ghalfx; oy = py[i]-ghoriz; oz = ghalfx;

        //Tilt rotation (backwards)
        ox2 = ox*gctang + oy*gstang;
        oy2 = oy*gctang - ox*gstang;
        oz2 = oz;

        //Up/down rotation (backwards)
        px[i] = ox2;
        py[i] = oy2*gchang + oz2*gshang;
        pz[i] = oz2*gchang - oy2*gshang;
    }

    //Clip to SCISDIST plane
    n2 = 0;
    for (i=0;i<n;i++)
    {
        j = i+1; if (j >= n) j = 0;
        if (pz[i] >= SCISDIST) { px2[n2] = px[i]; py2[n2] = py[i]; pz2[n2] = pz[i]; n2++; }
        if ((pz[i] >= SCISDIST) != (pz[j] >= SCISDIST))
        {
            r = (SCISDIST-pz[i])/(pz[j]-pz[i]);
            px2[n2] = (px[j]-px[i])*r + px[i];
            py2[n2] = (py[j]-py[i])*r + py[i];
            pz2[n2] = SCISDIST; n2++;
        }
    }
    if (n2 < 3) { enddrawing(); return; }
    for (i=0;i<n2;i++)
    {
        r = ghalfx / pz2[i];
        sx[i] = px2[i]*r + ghalfx;
        sy[i] = py2[i]*r + ghoriz;
    }
    initmosts(sx,sy,n2);

    if (searchit == 2)
    {
        short hitsect, hitwall, hitsprite;
        int vx, vy, vz, hitx, hity, hitz;

        ox2 = (searchx-ghalfx)/1.2; oy2 = (searchy-ghoriz)/ 1.2; oz2 = ghalfx;

        //Tilt rotation
        ox = ox2*gctang + oy2*gstang;
        oy = oy2*gctang - ox2*gstang;
        oz = oz2;

        //Up/down rotation
        ox2 = oz*gchang - oy*gshang;
        oy2 = ox;
        oz2 = oy*gchang + oz*gshang;

        //Standard Left/right rotation
        vx = (int)(ox2*((float)cosglobalang) - oy2*((float)singlobalang));
        vy = (int)(ox2*((float)singlobalang) + oy2*((float)cosglobalang));
        vz = (int)(oz2*16384.0);

        hitallsprites = 1;
        hitscan(globalposx,globalposy,globalposz,globalcursectnum, //Start position
                vx>>12,vy>>12,vz>>8,&hitsect,&hitwall,&hitsprite,&hitx,&hity,&hitz,0xffff0030);
        hitallsprites = 0;

        searchsector = hitsect;
        if (hitwall >= 0)
        {
            searchwall = hitwall; searchstat = 0;
            if (wall[hitwall].nextwall >= 0)
            {
                int cz, fz;
                getzsofslope(wall[hitwall].nextsector,hitx,hity,&cz,&fz);
                if (hitz > fz)
                {
                    if (wall[hitwall].cstat&2) //'2' bottoms of walls
                        searchwall = wall[hitwall].nextwall;
                }
                else if ((hitz > cz) && (wall[hitwall].cstat&(16+32))) //masking or 1-way
                    searchstat = 4;
            }
        }
        else if (hitsprite >= 0) { searchwall = hitsprite; searchstat = 3; }
        else
        {
            int cz, fz;
            getzsofslope(hitsect,hitx,hity,&cz,&fz);
            if ((hitz<<1) < cz+fz) searchstat = 1; else searchstat = 2;
            //if (vz < 0) searchstat = 1; else searchstat = 2; //Won't work for slopes :/
        }
        searchit = 0;
    }

    numscans = numbunches = 0;

    if (globalcursectnum >= MAXSECTORS)
        globalcursectnum -= MAXSECTORS;
    else
    {
        i = globalcursectnum;
        updatesector(globalposx,globalposy,&globalcursectnum);
        if (globalcursectnum < 0) globalcursectnum = i;
    }

    polymost_scansector(globalcursectnum);

    if (inpreparemirror)
    {
        grhalfxdown10x = -grhalfxdown10;
        inpreparemirror = 0;
        polymost_drawalls(0);
        numbunches--;
        bunchfirst[0] = bunchfirst[numbunches];
        bunchlast[0] = bunchlast[numbunches];
    }
    else
        grhalfxdown10x = grhalfxdown10;

    while (numbunches > 0)
    {
        memset(tempbuf,0,numbunches+3); tempbuf[0] = 1;

        closest = 0;              //Almost works, but not quite :(
        for (i=1;i<numbunches;i++)
        {
            j = polymost_bunchfront(i,closest); if (j < 0) continue;
            tempbuf[i] = 1;
            if (!j) { tempbuf[closest] = 1; closest = i; }
        }
        for (i=0;i<numbunches;i++) //Double-check
        {
            if (tempbuf[i]) continue;
            j = polymost_bunchfront(i,closest); if (j < 0) continue;
            tempbuf[i] = 1;
            if (!j) { tempbuf[closest] = 1; closest = i; i = 0; }
        }

        polymost_drawalls(closest);

        numbunches--;
        bunchfirst[closest] = bunchfirst[numbunches];
        bunchlast[closest] = bunchlast[numbunches];
    }
#ifdef USE_OPENGL
    if (rendmode >= 3)
    {
        bglDepthFunc(GL_LEQUAL); //NEVER,LESS,(,L)EQUAL,GREATER,(NOT,G)EQUAL,ALWAYS

        //bglPolygonOffset(0,0);
        bglDepthRange(0.0,0.99999); //<- this is more widely supported than glPolygonOffset
    }
#endif

    enddrawing();
}

void polymost_drawmaskwall(int damaskwallcnt)
{
    double dpx[8], dpy[8], dpx2[8], dpy2[8];
    float fx, fy, x0, x1, sx0, sy0, sx1, sy1, xp0, yp0, xp1, yp1, oxp0, oyp0, ryp0, ryp1;
    float f, r, t, t0, t1, nx0, ny0, nx1, ny1, py[4], csy[4], fsy[4];
    int i, j, k, n, n2, x, z, sectnum, z1, z2, lx, rx, cz[4], fz[4], method;
    sectortype *sec, *nsec;
    walltype *wal, *wal2;

    z = maskwall[damaskwallcnt];
    wal = &wall[thewall[z]]; wal2 = &wall[wal->point2];
    sectnum = thesector[z]; sec = &sector[sectnum];
    nsec = &sector[wal->nextsector];
    z1 = max(nsec->ceilingz,sec->ceilingz);
    z2 = min(nsec->floorz,sec->floorz);

    globalpicnum = wal->overpicnum; if ((unsigned int)globalpicnum >= MAXTILES) globalpicnum = 0;
    if (picanm[globalpicnum]&192) globalpicnum += animateoffs(globalpicnum,(short)thewall[z]+16384);
    globalshade = (int)wal->shade;
    globalpal = (int)((unsigned char)wal->pal);
    globalorientation = (int)wal->cstat;

#ifdef USE_OPENGL
    if (r_depthpeeling)
    {
        if ((((wal->cstat&128) || (gltexmayhavealpha(globalpicnum,globalpal)))) && !peelcompiling)
            return; // discard translucent sprite if drawing the backbuffer when doing depth peeling
        if (!(((wal->cstat&128) || (gltexmayhavealpha(globalpicnum,globalpal)))) && peelcompiling)
            return; // discard opaque sprite when composing the depth peels
    }
#endif

    sx0 = (float)(wal->x-globalposx); sx1 = (float)(wal2->x-globalposx);
    sy0 = (float)(wal->y-globalposy); sy1 = (float)(wal2->y-globalposy);
    yp0 = sx0*gcosang2 + sy0*gsinang2;
    yp1 = sx1*gcosang2 + sy1*gsinang2;
    if ((yp0 < SCISDIST) && (yp1 < SCISDIST)) return;
    xp0 = sy0*gcosang - sx0*gsinang;
    xp1 = sy1*gcosang - sx1*gsinang;

    //Clip to close parallel-screen plane
    oxp0 = xp0; oyp0 = yp0;
    if (yp0 < SCISDIST) { t0 = (SCISDIST-yp0)/(yp1-yp0); xp0 = (xp1-xp0)*t0+xp0; yp0 = SCISDIST; }
    else t0 = 0.f;
    if (yp1 < SCISDIST) { t1 = (SCISDIST-oyp0)/(yp1-oyp0); xp1 = (xp1-oxp0)*t1+oxp0; yp1 = SCISDIST; }
    else { t1 = 1.f; }

    getzsofslope(sectnum,(int)((wal2->x-wal->x)*t0+wal->x),(int)((wal2->y-wal->y)*t0+wal->y),&cz[0],&fz[0]);
    getzsofslope(wal->nextsector,(int)((wal2->x-wal->x)*t0+wal->x),(int)((wal2->y-wal->y)*t0+wal->y),&cz[1],&fz[1]);
    getzsofslope(sectnum,(int)((wal2->x-wal->x)*t1+wal->x),(int)((wal2->y-wal->y)*t1+wal->y),&cz[2],&fz[2]);
    getzsofslope(wal->nextsector,(int)((wal2->x-wal->x)*t1+wal->x),(int)((wal2->y-wal->y)*t1+wal->y),&cz[3],&fz[3]);

    ryp0 = 1.f/yp0; ryp1 = 1.f/yp1;

    //Generate screen coordinates for front side of wall
    x0 = ghalfx*xp0*ryp0 + ghalfx;
    x1 = ghalfx*xp1*ryp1 + ghalfx;
    if (x1 <= x0) return;

    ryp0 *= gyxscale; ryp1 *= gyxscale;

    gdx = (ryp0-ryp1)*gxyaspect / (x0-x1);
    gdy = 0;
    gdo = ryp0*gxyaspect - gdx*x0;

    //gux*x0 + guo = t0*wal->xrepeat*8*yp0
    //gux*x1 + guo = t1*wal->xrepeat*8*yp1
    gux = (t0*ryp0 - t1*ryp1)*gxyaspect*(float)wal->xrepeat*8.f / (x0-x1);
    guo = t0*ryp0*gxyaspect*(float)wal->xrepeat*8.f - gux*x0;
    guo += (float)wal->xpanning*gdo;
    gux += (float)wal->xpanning*gdx;
    guy = 0;

    if (!(wal->cstat&4)) i = z1; else i = z2;
    i -= globalposz;
    t0 = ((float)i)*ryp0 + ghoriz;
    t1 = ((float)i)*ryp1 + ghoriz;
    t = ((gdx*x0 + gdo) * (float)wal->yrepeat) / ((x1-x0) * ryp0 * 2048.f);
    i = (1<<(picsiz[globalpicnum]>>4)); if (i < tilesizy[globalpicnum]) i <<= 1;
    fy = (float)wal->ypanning * ((float)i) / 256.0;
    gvx = (t0-t1)*t;
    gvy = (x1-x0)*t;
    gvo = -gvx*x0 - gvy*t0 + fy*gdo; gvx += fy*gdx; gvy += fy*gdy;

    if (wal->cstat&8) //xflip
    {
        t = (float)(wal->xrepeat*8 + wal->xpanning*2);
        gux = gdx*t - gux;
        guy = gdy*t - guy;
        guo = gdo*t - guo;
    }
    if (wal->cstat&256) { gvx = -gvx; gvy = -gvy; gvo = -gvo; } //yflip

    method = 1; pow2xsplit = 1;
    if (wal->cstat&128) { if (!(wal->cstat&512)) method = 2; else method = 3; }

#ifdef USE_OPENGL
    if (!nofog)
    {
        if (rendmode >= 3)
        {
            fogcalc(wal->shade,sec->visibility,sec->floorpal);
            bglFogf(GL_FOG_DENSITY,fogresult);
            bglFogfv(GL_FOG_COLOR,fogcol);
        }
    }
#endif

    for (i=0;i<2;i++)
    {
        csy[i] = ((float)(cz[i]-globalposz))*ryp0 + ghoriz;
        fsy[i] = ((float)(fz[i]-globalposz))*ryp0 + ghoriz;
        csy[i+2] = ((float)(cz[i+2]-globalposz))*ryp1 + ghoriz;
        fsy[i+2] = ((float)(fz[i+2]-globalposz))*ryp1 + ghoriz;
    }

    //Clip 2 quadrilaterals
    //               /csy3
    //             /   |
    // csy0------/----csy2
    //   |     /xxxxxxx|
    //   |   /xxxxxxxxx|
    // csy1/xxxxxxxxxxx|
    //   |xxxxxxxxxxx/fsy3
    //   |xxxxxxxxx/   |
    //   |xxxxxxx/     |
    // fsy0----/------fsy2
    //   |   /
    // fsy1/

    dpx[0] = x0; dpy[0] = csy[1];
    dpx[1] = x1; dpy[1] = csy[3];
    dpx[2] = x1; dpy[2] = fsy[3];
    dpx[3] = x0; dpy[3] = fsy[1];
    n = 4;

    //Clip to (x0,csy[0])-(x1,csy[2])
    n2 = 0; t1 = -((dpx[0]-x0)*(csy[2]-csy[0]) - (dpy[0]-csy[0])*(x1-x0));
    for (i=0;i<n;i++)
    {
        j = i+1; if (j >= n) j = 0;

        t0 = t1; t1 = -((dpx[j]-x0)*(csy[2]-csy[0]) - (dpy[j]-csy[0])*(x1-x0));
        if (t0 >= 0) { dpx2[n2] = dpx[i]; dpy2[n2] = dpy[i]; n2++; }
        if ((t0 >= 0) != (t1 >= 0))
        {
            r = t0/(t0-t1);
            dpx2[n2] = (dpx[j]-dpx[i])*r + dpx[i];
            dpy2[n2] = (dpy[j]-dpy[i])*r + dpy[i];
            n2++;
        }
    }
    if (n2 < 3) return;

    //Clip to (x1,fsy[2])-(x0,fsy[0])
    n = 0; t1 = -((dpx2[0]-x1)*(fsy[0]-fsy[2]) - (dpy2[0]-fsy[2])*(x0-x1));
    for (i=0;i<n2;i++)
    {
        j = i+1; if (j >= n2) j = 0;

        t0 = t1; t1 = -((dpx2[j]-x1)*(fsy[0]-fsy[2]) - (dpy2[j]-fsy[2])*(x0-x1));
        if (t0 >= 0) { dpx[n] = dpx2[i]; dpy[n] = dpy2[i]; n++; }
        if ((t0 >= 0) != (t1 >= 0))
        {
            r = t0/(t0-t1);
            dpx[n] = (dpx2[j]-dpx2[i])*r + dpx2[i];
            dpy[n] = (dpy2[j]-dpy2[i])*r + dpy2[i];
            n++;
        }
    }
    if (n < 3) return;

    drawpoly(dpx,dpy,n,method);
}

void polymost_drawsprite(int snum)
{
    double px[6], py[6];
    float f, r, c, s, fx, fy, sx0, sy0, sx1, sy1, xp0, yp0, xp1, yp1, oxp0, oyp0, ryp0, ryp1, ft[4];
    float x0, y0, x1, y1, sc0, sf0, sc1, sf1, px2[6], py2[6], xv, yv, t0, t1;
    int i, j, spritenum, xoff=0, yoff=0, method, npoints;
    spritetype *tspr;
    int posx,posy;

    tspr = tspriteptr[snum];
    if (tspr->owner < 0 || tspr->picnum < 0) return;

    globalpicnum      = tspr->picnum;
    globalshade       = tspr->shade;
    globalpal         = tspr->pal;
    globalorientation = tspr->cstat;
    spritenum         = tspr->owner;

    if ((globalorientation&48) != 48)  	// only non-voxel sprites should do this
    {
        if (picanm[globalpicnum]&192) globalpicnum += animateoffs(globalpicnum,spritenum+32768);

        xoff = (int)((signed char)((picanm[globalpicnum]>>8)&255))+((int)tspr->xoffset);
        yoff = (int)((signed char)((picanm[globalpicnum]>>16)&255))+((int)tspr->yoffset);
    }

    method = 1+4;
    if (tspr->cstat&2) { if (!(tspr->cstat&512)) method = 2+4; else method = 3+4; }

#ifdef USE_OPENGL
    if (r_depthpeeling)
    {
        if ((((tspr->cstat&2) || (gltexmayhavealpha(globalpicnum,tspr->pal)))) && !peelcompiling)
            return; // discard translucent sprite if drawing the backbuffer when doing depth peeling
        if (!(((tspr->cstat&2) || (gltexmayhavealpha(globalpicnum,tspr->pal)))) && peelcompiling)
            return; // discard opaque sprite when composing the depth peels
    }

    if (!nofog && rendmode >= 3)
    {
        fogcalc(globalshade,sector[tspr->sectnum].visibility,sector[tspr->sectnum].floorpal);
        bglFogf(GL_FOG_DENSITY,fogresult);
        bglFogfv(GL_FOG_COLOR,fogcol);
    }

    while (rendmode >= 3 && !(spriteext[tspr->owner].flags&SPREXT_NOTMD))
    {
        if (usemodels && tile2model[Ptile2tile(tspr->picnum,tspr->pal)].modelid >= 0 && tile2model[Ptile2tile(tspr->picnum,tspr->pal)].framenum >= 0)
        {
            if (mddraw(tspr)) return;
            break;	// else, render as flat sprite
        }
        if (usevoxels && (tspr->cstat&48)!=48 && tiletovox[tspr->picnum] >= 0 && voxmodels[ tiletovox[tspr->picnum] ])
        {
            if (voxdraw(voxmodels[ tiletovox[tspr->picnum] ], tspr)) return;
            break;	// else, render as flat sprite
        }
        if ((tspr->cstat&48)==48 && voxmodels[ tspr->picnum ])
        {
            voxdraw(voxmodels[ tspr->picnum ], tspr);
            return;
        }
        break;
    }
    if (((tspr->cstat&2) || (gltexmayhavealpha(tspr->picnum,tspr->pal))))
    {
        curpolygonoffset += 0.01f;
        bglEnable(GL_POLYGON_OFFSET_FILL);
        bglPolygonOffset(-curpolygonoffset, -curpolygonoffset);
    }
#endif
    posx=tspr->x;
    posy=tspr->y;
    if (spriteext[tspr->owner].flags&SPREXT_AWAY1)
    {
        posx+=(sintable[(tspr->ang+512)&2047]>>13);
        posy+=(sintable[(tspr->ang)&2047]>>13);
    }
    else if (spriteext[tspr->owner].flags&SPREXT_AWAY2)
    {
        posx-=(sintable[(tspr->ang+512)&2047]>>13);
        posy-=(sintable[(tspr->ang)&2047]>>13);
    }

    switch ((globalorientation>>4)&3)
    {
    case 0: //Face sprite
        //Project 3D to 2D
        sx0 = (float)(tspr->x-globalposx);
        sy0 = (float)(tspr->y-globalposy);
        xp0 = sy0*gcosang  - sx0*gsinang;
        yp0 = sx0*gcosang2 + sy0*gsinang2;
        if (yp0 <= SCISDIST) return;
        ryp0 = 1/yp0;
        sx0 = ghalfx*xp0*ryp0 + ghalfx;
        sy0 = ((float)(tspr->z-globalposz))*gyxscale*ryp0 + ghoriz;

        f = ryp0*(float)xdimen/160.0;
        fx = ((float)tspr->xrepeat)*f;
        fy = ((float)tspr->yrepeat)*f*((float)yxaspect/65536.0);
        sx0 -= fx*(float)xoff; if (tilesizx[globalpicnum]&1) sx0 += fx*.5;
        sy0 -= fy*(float)yoff;
        fx *= ((float)tilesizx[globalpicnum]);
        fy *= ((float)tilesizy[globalpicnum]);

        px[0] = px[3] = sx0-fx*.5; px[1] = px[2] = sx0+fx*.5;
        if (!(globalorientation&128)) { py[0] = py[1] = sy0-fy; py[2] = py[3] = sy0; }
        else { py[0] = py[1] = sy0-fy*.5; py[2] = py[3] = sy0+fy*.5; }

        gdx = gdy = guy = gvx = 0; gdo = ryp0*gviewxrange;
        if (!(globalorientation&4))
            { gux = (float)tilesizx[globalpicnum]*gdo/(px[1]-px[0]+.002); guo = -gux*(px[0]-.001); }
        else { gux = (float)tilesizx[globalpicnum]*gdo/(px[0]-px[1]-.002); guo = -gux*(px[1]+.001); }
        if (!(globalorientation&8))
            { gvy = (float)tilesizy[globalpicnum]*gdo/(py[3]-py[0]+.002); gvo = -gvy*(py[0]-.001); }
        else { gvy = (float)tilesizy[globalpicnum]*gdo/(py[0]-py[3]-.002); gvo = -gvy*(py[3]+.001); }

        // sprite panning
        guy -= gdy*((float)(spriteext[spritenum].xpanning)/255.f)*tilesizx[globalpicnum];
        guo -= gdo*((float)(spriteext[spritenum].xpanning)/255.f)*tilesizx[globalpicnum];
        gvy -= gdy*((float)(spriteext[spritenum].ypanning)/255.f)*tilesizy[globalpicnum];
        gvo -= gdo*((float)(spriteext[spritenum].ypanning)/255.f)*tilesizy[globalpicnum];

        //Clip sprites to ceilings/floors when no parallaxing and not sloped
        if (!(sector[tspr->sectnum].ceilingstat&3))
        {
            sy0 = ((float)(sector[tspr->sectnum].ceilingz-globalposz))*gyxscale*ryp0 + ghoriz;
            if (py[0] < sy0) py[0] = py[1] = sy0;
        }
        if (!(sector[tspr->sectnum].floorstat&3))
        {
            sy0 = ((float)(sector[tspr->sectnum].floorz-globalposz))*gyxscale*ryp0 + ghoriz;
            if (py[2] > sy0) py[2] = py[3] = sy0;
        }

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 1;
        if (spriteext[spritenum].ypanning)
            trepeat = 1;
#endif

        pow2xsplit = 0; drawpoly(px,py,4,method);

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 0;
        if (spriteext[spritenum].ypanning)
            trepeat = 0;
#endif

        break;
    case 1: //Wall sprite

        //Project 3D to 2D
        if (globalorientation&4) xoff = -xoff;
        if (globalorientation&8) yoff = -yoff;

        xv = (float)tspr->xrepeat * (float)sintable[(tspr->ang)&2047] / 65536.0;
        yv = (float)tspr->xrepeat * (float)sintable[(tspr->ang+1536)&2047] / 65536.0;
        f = (float)(tilesizx[globalpicnum]>>1) + (float)xoff;
        x0 = (float)(posx-globalposx) - xv*f; x1 = xv*(float)tilesizx[globalpicnum] + x0;
        y0 = (float)(posy-globalposy) - yv*f; y1 = yv*(float)tilesizx[globalpicnum] + y0;

        yp0 = x0*gcosang2 + y0*gsinang2;
        yp1 = x1*gcosang2 + y1*gsinang2;
        if ((yp0 <= SCISDIST) && (yp1 <= SCISDIST)) return;
        xp0 = y0*gcosang - x0*gsinang;
        xp1 = y1*gcosang - x1*gsinang;

        //Clip to close parallel-screen plane
        oxp0 = xp0; oyp0 = yp0;
        if (yp0 < SCISDIST) { t0 = (SCISDIST-yp0)/(yp1-yp0); xp0 = (xp1-xp0)*t0+xp0; yp0 = SCISDIST; }
        else { t0 = 0.f; }
        if (yp1 < SCISDIST) { t1 = (SCISDIST-oyp0)/(yp1-oyp0); xp1 = (xp1-oxp0)*t1+oxp0; yp1 = SCISDIST; }
        else { t1 = 1.f; }

        f = ((float)tspr->yrepeat) * (float)tilesizy[globalpicnum] * 4;

        ryp0 = 1.0/yp0;
        ryp1 = 1.0/yp1;
        sx0 = ghalfx*xp0*ryp0 + ghalfx;
        sx1 = ghalfx*xp1*ryp1 + ghalfx;
        ryp0 *= gyxscale;
        ryp1 *= gyxscale;

        tspr->z -= ((yoff*tspr->yrepeat)<<2);
        if (globalorientation&128)
        {
            tspr->z += ((tilesizy[globalpicnum]*tspr->yrepeat)<<1);
            if (tilesizy[globalpicnum]&1) tspr->z += (tspr->yrepeat<<1); //Odd yspans
        }

        sc0 = ((float)(tspr->z-globalposz-f))*ryp0 + ghoriz;
        sc1 = ((float)(tspr->z-globalposz-f))*ryp1 + ghoriz;
        sf0 = ((float)(tspr->z-globalposz))*ryp0 + ghoriz;
        sf1 = ((float)(tspr->z-globalposz))*ryp1 + ghoriz;

        gdx = (ryp0-ryp1)*gxyaspect / (sx0-sx1);
        gdy = 0;
        gdo = ryp0*gxyaspect - gdx*sx0;

        //Original equations:
        //(gux*sx0 + guo)/(gdx*sx1 + gdo) = tilesizx[globalpicnum]*t0
        //(gux*sx1 + guo)/(gdx*sx1 + gdo) = tilesizx[globalpicnum]*t1
        //
        // gvx*sx0 + gvy*sc0 + gvo = 0
        // gvy*sx1 + gvy*sc1 + gvo = 0
        //(gvx*sx0 + gvy*sf0 + gvo)/(gdx*sx0 + gdo) = tilesizy[globalpicnum]
        //(gvx*sx1 + gvy*sf1 + gvo)/(gdx*sx1 + gdo) = tilesizy[globalpicnum]

        //gux*sx0 + guo = t0*tilesizx[globalpicnum]*yp0
        //gux*sx1 + guo = t1*tilesizx[globalpicnum]*yp1
        if (globalorientation&4) { t0 = 1.f-t0; t1 = 1.f-t1; }

        //sprite panning
        t0 -= ((float)(spriteext[spritenum].xpanning)/255.f);
        t1 -= ((float)(spriteext[spritenum].xpanning)/255.f);
        gux = (t0*ryp0 - t1*ryp1)*gxyaspect*(float)tilesizx[globalpicnum] / (sx0-sx1);
        guy = 0;
        guo = t0*ryp0*gxyaspect*(float)tilesizx[globalpicnum] - gux*sx0;

        //gvx*sx0 + gvy*sc0 + gvo = 0
        //gvx*sx1 + gvy*sc1 + gvo = 0
        //gvx*sx0 + gvy*sf0 + gvo = tilesizy[globalpicnum]*(gdx*sx0 + gdo)
        f = ((float)tilesizy[globalpicnum])*(gdx*sx0 + gdo) / ((sx0-sx1)*(sc0-sf0));
        if (!(globalorientation&8))
        {
            gvx = (sc0-sc1)*f;
            gvy = (sx1-sx0)*f;
            gvo = -gvx*sx0 - gvy*sc0;
        }
        else
        {
            gvx = (sf1-sf0)*f;
            gvy = (sx0-sx1)*f;
            gvo = -gvx*sx0 - gvy*sf0;
        }

        // sprite panning
        gvx -= gdx*((float)(spriteext[spritenum].ypanning)/255.f)*tilesizy[globalpicnum];
        gvy -= gdy*((float)(spriteext[spritenum].ypanning)/255.f)*tilesizy[globalpicnum];
        gvo -= gdo*((float)(spriteext[spritenum].ypanning)/255.f)*tilesizy[globalpicnum];

        //Clip sprites to ceilings/floors when no parallaxing
        if (!(sector[tspr->sectnum].ceilingstat&1))
        {
            f = ((float)tspr->yrepeat) * (float)tilesizy[globalpicnum] * 4;
            if (sector[tspr->sectnum].ceilingz > tspr->z-f)
            {
                sc0 = ((float)(sector[tspr->sectnum].ceilingz-globalposz))*ryp0 + ghoriz;
                sc1 = ((float)(sector[tspr->sectnum].ceilingz-globalposz))*ryp1 + ghoriz;
            }
        }
        if (!(sector[tspr->sectnum].floorstat&1))
        {
            if (sector[tspr->sectnum].floorz < tspr->z)
            {
                sf0 = ((float)(sector[tspr->sectnum].floorz-globalposz))*ryp0 + ghoriz;
                sf1 = ((float)(sector[tspr->sectnum].floorz-globalposz))*ryp1 + ghoriz;
            }
        }

        if (sx0 > sx1)
        {
            if (globalorientation&64) return; //1-sided sprite
            f = sx0; sx0 = sx1; sx1 = f;
            f = sc0; sc0 = sc1; sc1 = f;
            f = sf0; sf0 = sf1; sf1 = f;
        }

        px[0] = sx0; py[0] = sc0;
        px[1] = sx1; py[1] = sc1;
        px[2] = sx1; py[2] = sf1;
        px[3] = sx0; py[3] = sf0;

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 1;
        if (spriteext[spritenum].ypanning)
            trepeat = 1;
#endif

        pow2xsplit = 0; drawpoly(px,py,4,method);

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 0;
        if (spriteext[spritenum].ypanning)
            trepeat = 0;
#endif

        break;
    case 2: //Floor sprite

        if ((globalorientation&64) != 0)
            if ((globalposz > tspr->z) == (!(globalorientation&8)))
                return;
        if ((globalorientation&4) > 0) xoff = -xoff;
        if ((globalorientation&8) > 0) yoff = -yoff;

        i = (tspr->ang&2047);
        c = sintable[(i+512)&2047]/65536.0;
        s = sintable[i]/65536.0;
        x0 = ((tilesizx[globalpicnum]>>1)-xoff)*tspr->xrepeat;
        y0 = ((tilesizy[globalpicnum]>>1)-yoff)*tspr->yrepeat;
        x1 = ((tilesizx[globalpicnum]>>1)+xoff)*tspr->xrepeat;
        y1 = ((tilesizy[globalpicnum]>>1)+yoff)*tspr->yrepeat;

        //Project 3D to 2D
        for (j=0;j<4;j++)
        {
            sx0 = (float)(tspr->x-globalposx);
            sy0 = (float)(tspr->y-globalposy);
            if ((j+0)&2) { sy0 -= s*y0; sx0 -= c*y0; }
            else { sy0 += s*y1; sx0 += c*y1; }
            if ((j+1)&2) { sx0 -= s*x0; sy0 += c*x0; }
            else { sx0 += s*x1; sy0 -= c*x1; }
            px[j] = sy0*gcosang  - sx0*gsinang;
            py[j] = sx0*gcosang2 + sy0*gsinang2;
        }

        if (tspr->z < globalposz) //if floor sprite is above you, reverse order of points
        {
            f = px[0]; px[0] = px[1]; px[1] = f;
            f = py[0]; py[0] = py[1]; py[1] = f;
            f = px[2]; px[2] = px[3]; px[3] = f;
            f = py[2]; py[2] = py[3]; py[3] = f;
        }

        //Clip to SCISDIST plane
        npoints = 0;
        for (i=0;i<4;i++)
        {
            j = ((i+1)&3);
            if (py[i] >= SCISDIST) { px2[npoints] = px[i]; py2[npoints] = py[i]; npoints++; }
            if ((py[i] >= SCISDIST) != (py[j] >= SCISDIST))
            {
                f = (SCISDIST-py[i])/(py[j]-py[i]);
                px2[npoints] = (px[j]-px[i])*f + px[i];
                py2[npoints] = (py[j]-py[i])*f + py[i]; npoints++;
            }
        }
        if (npoints < 3) return;

        //Project rotated 3D points to screen
        f = ((float)(tspr->z-globalposz))*gyxscale;
        for (j=0;j<npoints;j++)
        {
            ryp0 = 1/py2[j];
            px[j] = ghalfx*px2[j]*ryp0 + ghalfx;
            py[j] = f*ryp0 + ghoriz;
        }

        //gd? Copied from floor rendering code
        gdx = 0;
        gdy = gxyaspect / (double)(tspr->z-globalposz);
        gdo = -ghoriz*gdy;
        //copied&modified from relative alignment
        xv = (float)tspr->x + s*x1 + c*y1; fx = (double)-(x0+x1)*s;
        yv = (float)tspr->y + s*y1 - c*x1; fy = (double)+(x0+x1)*c;
        f = 1.0/sqrt(fx*fx+fy*fy); fx *= f; fy *= f;
        ft[2] = singlobalang*fy + cosglobalang*fx;
        ft[3] = singlobalang*fx - cosglobalang*fy;
        ft[0] = ((double)(globalposy-yv))*fy + ((double)(globalposx-xv))*fx;
        ft[1] = ((double)(globalposx-xv))*fy - ((double)(globalposy-yv))*fx;
        gux = (double)ft[3]*((double)viewingrange)/(-65536.0*262144.0);
        gvx = (double)ft[2]*((double)viewingrange)/(-65536.0*262144.0);
        guy = (double)ft[0]*gdy; gvy = (double)ft[1]*gdy;
        guo = (double)ft[0]*gdo; gvo = (double)ft[1]*gdo;
        guo += (double)(ft[2]/262144.0-gux)*ghalfx;
        gvo -= (double)(ft[3]/262144.0+gvx)*ghalfx;
        f = 4.0/(float)tspr->xrepeat; gux *= f; guy *= f; guo *= f;
        f =-4.0/(float)tspr->yrepeat; gvx *= f; gvy *= f; gvo *= f;
        if (globalorientation&4)
        {
            gux = ((float)tilesizx[globalpicnum])*gdx - gux;
            guy = ((float)tilesizx[globalpicnum])*gdy - guy;
            guo = ((float)tilesizx[globalpicnum])*gdo - guo;
        }

        // sprite panning
        guy -= gdy*((float)(spriteext[spritenum].xpanning)/255.f)*tilesizx[globalpicnum];
        guo -= gdo*((float)(spriteext[spritenum].xpanning)/255.f)*tilesizx[globalpicnum];
        gvy -= gdy*((float)(spriteext[spritenum].ypanning)/255.f)*tilesizy[globalpicnum];
        gvo -= gdo*((float)(spriteext[spritenum].ypanning)/255.f)*tilesizy[globalpicnum];

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 1;
        if (spriteext[spritenum].ypanning)
            trepeat = 1;
#endif

        pow2xsplit = 0; drawpoly(px,py,npoints,method);

#ifdef USE_OPENGL
        if (spriteext[spritenum].xpanning)
            srepeat = 0;
        if (spriteext[spritenum].ypanning)
            trepeat = 0;
#endif

        break;

    case 3: //Voxel sprite
        break;
    }
}

//sx,sy       center of sprite; screen coods*65536
//z           zoom*65536. > is zoomed in
//a           angle (0 is default)
//dastat&1    1:translucence
//dastat&2    1:auto-scale mode (use 320*200 coordinates)
//dastat&4    1:y-flip
//dastat&8    1:don't clip to startumost/startdmost
//dastat&16   1:force point passed to be top-left corner, 0:Editart center
//dastat&32   1:reverse translucence
//dastat&64   1:non-masked, 0:masked
//dastat&128  1:draw all pages (permanent)
//cx1,...     clip window (actual screen coords)
void polymost_dorotatesprite(int sx, int sy, int z, short a, short picnum,
                             signed char dashade, char dapalnum, char dastat, int cx1, int cy1, int cx2, int cy2, int uniqid)
{
    static int onumframes = 0;
    int i, n, nn, x, zz, xoff, yoff, xsiz, ysiz, method;
    int ogpicnum, ogshade, ogpal, ofoffset, oxdimen, oydimen, oldviewingrange;
    double ogxyaspect;
    double ogchang, ogshang, ogctang, ogstang, oghalfx, oghoriz, fx, fy, x1, y1, z1, x2, y2;
    double ogrhalfxdown10, ogrhalfxdown10x;
    double d, cosang, sinang, cosang2, sinang2, px[8], py[8], px2[8], py2[8];
    float m[4][4];
    int fovcorrect;

#ifdef USE_OPENGL
    if (rendmode >= 3 && usemodels && hudmem[(dastat&4)>>2][picnum].angadd)
    {
        if ((tile2model[Ptile2tile(picnum,dapalnum)].modelid >= 0) && (tile2model[Ptile2tile(picnum,dapalnum)].framenum >= 0))
        {
            spritetype tspr;
            memset(&tspr,0,sizeof(spritetype));

            if (hudmem[(dastat&4)>>2][picnum].flags&1) return; //"HIDE" is specified in DEF

            ogchang = gchang; gchang = 1.0;
            ogshang = gshang; gshang = 0.0; d = (double)z/(65536.0*16384.0);
            ogctang = gctang; gctang = (double)sintable[(a+512)&2047]*d;
            ogstang = gstang; gstang = (double)sintable[a&2047]*d;
            ogshade  = globalshade;  globalshade  = dashade;
            ogpal    = globalpal;    globalpal    = (int)((unsigned char)dapalnum);
            ogxyaspect = gxyaspect; gxyaspect = 1.0;
            oldviewingrange = viewingrange; viewingrange = 65536;

            x1 = hudmem[(dastat&4)>>2][picnum].xadd;
            y1 = hudmem[(dastat&4)>>2][picnum].yadd;
            z1 = hudmem[(dastat&4)>>2][picnum].zadd;
            if (!(hudmem[(dastat&4)>>2][picnum].flags&2)) //"NOBOB" is specified in DEF
            {
                fx = ((double)sx)*(1.0/65536.0);
                fy = ((double)sy)*(1.0/65536.0);

                if (dastat&16)
                {
                    xsiz = tilesizx[picnum]; ysiz = tilesizy[picnum];
                    xoff = (int)((signed char)((picanm[picnum]>>8)&255))+(xsiz>>1);
                    yoff = (int)((signed char)((picanm[picnum]>>16)&255))+(ysiz>>1);

                    d = (double)z/(65536.0*16384.0);
                    cosang2 = cosang = (double)sintable[(a+512)&2047]*d;
                    sinang2 = sinang = (double)sintable[a&2047]*d;
                    if ((dastat&2) || (!(dastat&8))) //Don't aspect unscaled perms
                        { d = (double)xyaspect/65536.0; cosang2 *= d; sinang2 *= d; }
                    fx += -(double)xoff*cosang2+ (double)yoff*sinang2;
                    fy += -(double)xoff*sinang - (double)yoff*cosang;
                }

                if (!(dastat&2))
                {
                    x1 += fx/((double)(xdim<<15))-1.0; //-1: left of screen, +1: right of screen
                    y1 += fy/((double)(ydim<<15))-1.0; //-1: top of screen, +1: bottom of screen
                }
                else
                {
                    x1 += fx/160.0-1.0; //-1: left of screen, +1: right of screen
                    y1 += fy/100.0-1.0; //-1: top of screen, +1: bottom of screen
                }
            }
            tspr.ang = hudmem[(dastat&4)>>2][picnum].angadd+globalang;
            tspr.xrepeat = tspr.yrepeat = 32;

            if (dastat&4) { x1 = -x1; y1 = -y1; }
            tspr.x = (int)(((double)gcosang*z1 - (double)gsinang*x1)*16384.0 + globalposx);
            tspr.y = (int)(((double)gsinang*z1 + (double)gcosang*x1)*16384.0 + globalposy);
            tspr.z = (int)(globalposz + y1*16384.0*0.8);
            tspr.picnum = picnum;
            tspr.shade = dashade;
            tspr.pal = dapalnum;
            tspr.owner = uniqid+MAXSPRITES;
            globalorientation = (dastat&1)+((dastat&32)<<4)+((dastat&4)<<1);

            if ((dastat&10) == 2)
                bglViewport(windowx1,yres-(windowy2+1),windowx2-windowx1+1,windowy2-windowy1+1);
            else
            {
                bglViewport(0,0,xdim,ydim);
                glox1 = -1; //Force fullscreen (glox1=-1 forces it to restore)
            }

            bglMatrixMode(GL_PROJECTION);
            memset(m,0,sizeof(m));
            if ((dastat&10) == 2)
            {
                float ratioratio = (float)xdim/ydim;
                m[0][0] = (float)ydimen*(ratioratio >= 1.6?1.2:1); m[0][2] = 1.0;
                m[1][1] = (float)xdimen; m[1][2] = 1.0;
                m[2][2] = 1.0; m[2][3] = (float)ydimen*(ratioratio >= 1.6?1.2:1);
                m[3][2] =-1.0;
            }
            else { m[0][0] = m[2][3] = 1.0; m[1][1] = ((float)xdim)/((float)ydim); m[2][2] = 1.0001; m[3][2] = 1-m[2][2]; }
            bglLoadMatrixf(&m[0][0]);
            bglMatrixMode(GL_MODELVIEW);
            bglLoadIdentity();

            if (hudmem[(dastat&4)>>2][picnum].flags&8) //NODEPTH flag
                bglDisable(GL_DEPTH_TEST);
            else
            {
                bglEnable(GL_DEPTH_TEST);
                if (onumframes != numframes)
                {
                    onumframes = numframes;
                    bglClear(GL_DEPTH_BUFFER_BIT);
                }
            }

#if 0
            if (!nofog)
            {
                i = klabs(tspr.shade);
                bglFogf(GL_FOG_DENSITY,fogcalc(tspr.shade,sector[tspr.sectnum].visibility);
                    }
                    mddraw(&tspr);
#else
            if (!nofog) bglDisable(GL_FOG);
            mddraw(&tspr);
            if (!nofog) bglEnable(GL_FOG);
#endif
            viewingrange = oldviewingrange;
            gxyaspect = ogxyaspect;
            globalshade  = ogshade;
            globalpal    = ogpal;
            gchang = ogchang;
            gshang = ogshang;
            gctang = ogctang;
            gstang = ogstang;
            return;
        }
    }
#endif

    ogpicnum = globalpicnum; globalpicnum = picnum;
    ogshade  = globalshade;  globalshade  = dashade;
    ogpal    = globalpal;    globalpal    = (int)((unsigned char)dapalnum);
    oghalfx  = ghalfx;       ghalfx       = (double)(xdim>>1);
    ogrhalfxdown10 = grhalfxdown10;    grhalfxdown10 = 1.0/(((double)ghalfx)*1024);
    ogrhalfxdown10x = grhalfxdown10x;  grhalfxdown10x = grhalfxdown10;
    oghoriz  = ghoriz;       ghoriz       = (double)(ydim>>1);
    ofoffset = frameoffset;  frameoffset  = frameplace;
    oxdimen  = xdimen;       xdimen       = xdim;
    oydimen  = ydimen;       ydimen       = ydim;
    ogchang = gchang; gchang = 1.0;
    ogshang = gshang; gshang = 0.0;
    ogctang = gctang; gctang = 1.0;
    ogstang = gstang; gstang = 0.0;

#ifdef USE_OPENGL
    if (rendmode >= 3)
    {
        bglViewport(0,0,xdim,ydim); glox1 = -1; //Force fullscreen (glox1=-1 forces it to restore)
        bglMatrixMode(GL_PROJECTION);
        memset(m,0,sizeof(m));
        m[0][0] = m[2][3] = 1.0; m[1][1] = ((float)xdim)/((float)ydim); m[2][2] = 1.0001; m[3][2] = 1-m[2][2];
        bglPushMatrix(); bglLoadMatrixf(&m[0][0]);
        bglMatrixMode(GL_MODELVIEW);
        bglLoadIdentity();

        bglDisable(GL_DEPTH_TEST);
        bglDisable(GL_ALPHA_TEST);
        bglEnable(GL_TEXTURE_2D);
    }
#endif

    method = 0;
    if (!(dastat&64))
    {
        method = 1;
        if (dastat&1) { if (!(dastat&32)) method = 2; else method = 3; }
    }
    method |= 4; //Use OpenGL clamping - dorotatesprite never repeats

    xsiz = tilesizx[globalpicnum]; ysiz = tilesizy[globalpicnum];
    if (dastat&16) { xoff = 0; yoff = 0; }
    else
    {
        xoff = (int)((signed char)((picanm[globalpicnum]>>8)&255))+(xsiz>>1);
        yoff = (int)((signed char)((picanm[globalpicnum]>>16)&255))+(ysiz>>1);
    }
    if (dastat&4) yoff = ysiz-yoff;

    if (dastat&2)  //Auto window size scaling
    {
        if (!(dastat&8))
        {
            x = xdimenscale;   //= scale(xdimen,yxaspect,320);
            sx = ((cx1+cx2+2)<<15)+scale(sx-(320<<15),oxdimen,320);
            sy = ((cy1+cy2+2)<<15)+mulscale16(sy-(200<<15),x);
        }
        else
        {
            //If not clipping to startmosts, & auto-scaling on, as a
            //hard-coded bonus, scale to full screen instead
            x = scale(xdim,yxaspect,320);
            sx = (xdim<<15)+32768+scale(sx-(320<<15),xdim,320);
            sy = (ydim<<15)+32768+mulscale16(sy-(200<<15),x);
        }
        z = mulscale16(z,x);
    }

    d = (double)z/(65536.0*16384.0);
    cosang2 = cosang = (double)sintable[(a+512)&2047]*d;
    sinang2 = sinang = (double)sintable[a&2047]*d;
    if ((dastat&2) || (!(dastat&8))) //Don't aspect unscaled perms
        { d = (double)xyaspect/65536.0; cosang2 *= d; sinang2 *= d; }
    px[0] = (double)sx/65536.0 - (double)xoff*cosang2+ (double)yoff*sinang2;
    py[0] = (double)sy/65536.0 - (double)xoff*sinang - (double)yoff*cosang;
    px[1] = px[0] + (double)xsiz*cosang2;
    py[1] = py[0] + (double)xsiz*sinang;
    px[3] = px[0] - (double)ysiz*sinang2;
    py[3] = py[0] + (double)ysiz*cosang;
    px[2] = px[1]+px[3]-px[0];
    py[2] = py[1]+py[3]-py[0];
    n = 4;

    gdx = 0; gdy = 0; gdo = 1.0;
    //px[0]*gux + py[0]*guy + guo = 0
    //px[1]*gux + py[1]*guy + guo = xsiz-.0001
    //px[3]*gux + py[3]*guy + guo = 0
    d = 1.0/(px[0]*(py[1]-py[3]) + px[1]*(py[3]-py[0]) + px[3]*(py[0]-py[1]));
    gux = (py[3]-py[0])*((double)xsiz-.0001)*d;
    guy = (px[0]-px[3])*((double)xsiz-.0001)*d;
    guo = 0 - px[0]*gux - py[0]*guy;

    if (!(dastat&4))
    {
        //px[0]*gvx + py[0]*gvy + gvo = 0
        //px[1]*gvx + py[1]*gvy + gvo = 0
        //px[3]*gvx + py[3]*gvy + gvo = ysiz-.0001
        gvx = (py[0]-py[1])*((double)ysiz-.0001)*d;
        gvy = (px[1]-px[0])*((double)ysiz-.0001)*d;
        gvo = 0 - px[0]*gvx - py[0]*gvy;
    }
    else
    {
        //px[0]*gvx + py[0]*gvy + gvo = ysiz-.0001
        //px[1]*gvx + py[1]*gvy + gvo = ysiz-.0001
        //px[3]*gvx + py[3]*gvy + gvo = 0
        gvx = (py[1]-py[0])*((double)ysiz-.0001)*d;
        gvy = (px[0]-px[1])*((double)ysiz-.0001)*d;
        gvo = (double)ysiz-.0001 - px[0]*gvx - py[0]*gvy;
    }

    cx2++; cy2++;
    //Clippoly4 (converted from int to double)
    nn = z = 0;
    do
    {
        zz = z+1; if (zz == n) zz = 0;
        x1 = px[z]; x2 = px[zz]-x1; if ((cx1 <= x1) && (x1 <= cx2)) { px2[nn] = x1; py2[nn] = py[z]; nn++; }
        if (x2 <= 0) fx = cx2; else fx = cx1;  d = fx-x1;
        if ((d < x2) != (d < 0)) { px2[nn] = fx; py2[nn] = (py[zz]-py[z])*d/x2 + py[z]; nn++; }
        if (x2 <= 0) fx = cx1; else fx = cx2;  d = fx-x1;
        if ((d < x2) != (d < 0)) { px2[nn] = fx; py2[nn] = (py[zz]-py[z])*d/x2 + py[z]; nn++; }
        z = zz;
    }
    while (z);
    if (nn >= 3)
    {
        n = z = 0;
        do
        {
            zz = z+1; if (zz == nn) zz = 0;
            y1 = py2[z]; y2 = py2[zz]-y1; if ((cy1 <= y1) && (y1 <= cy2)) { py[n] = y1; px[n] = px2[z]; n++; }
            if (y2 <= 0) fy = cy2; else fy = cy1;  d = fy-y1;
            if ((d < y2) != (d < 0)) { py[n] = fy; px[n] = (px2[zz]-px2[z])*d/y2 + px2[z]; n++; }
            if (y2 <= 0) fy = cy1; else fy = cy2;  d = fy-y1;
            if ((d < y2) != (d < 0)) { py[n] = fy; px[n] = (px2[zz]-px2[z])*d/y2 + px2[z]; n++; }
            z = zz;
        }
        while (z);
        if (!nofog) bglDisable(GL_FOG);
        pow2xsplit = 0; drawpoly(px,py,n,method);
        if (!nofog) bglEnable(GL_FOG);
    }

#ifdef USE_OPENGL
    if (rendmode >= 3)
    {
        bglMatrixMode(GL_PROJECTION); bglPopMatrix();
    }
#endif

    globalpicnum = ogpicnum;
    globalshade  = ogshade;
    globalpal    = ogpal;
    ghalfx       = oghalfx;
    grhalfxdown10 = ogrhalfxdown10;
    grhalfxdown10x = ogrhalfxdown10x;
    ghoriz       = oghoriz;
    frameoffset  = ofoffset;
    xdimen       = oxdimen;
    ydimen       = oydimen;
    gchang = ogchang;
    gshang = ogshang;
    gctang = ogctang;
    gstang = ogstang;
}

#ifdef USE_OPENGL
static float trapextx[2];
static void drawtrap(float x0, float x1, float y0, float x2, float x3, float y1)
{
    float px[4], py[4];
    int i, n;

    if (y0 == y1) return;
    px[0] = x0; py[0] = y0;  py[2] = y1;
    if (x0 == x1) { px[1] = x3; py[1] = y1; px[2] = x2; n = 3; }
    else if (x2 == x3) { px[1] = x1; py[1] = y0; px[2] = x3; n = 3; }
    else               { px[1] = x1; py[1] = y0; px[2] = x3; px[3] = x2; py[3] = y1; n = 4; }

    bglBegin(GL_TRIANGLE_FAN);
    for (i=0;i<n;i++)
    {
        px[i] = min(max(px[i],trapextx[0]),trapextx[1]);
        bglTexCoord2f(px[i]*gux + py[i]*guy + guo,
                      px[i]*gvx + py[i]*gvy + gvo);
        bglVertex2f(px[i],py[i]);
    }
    bglEnd();
}

static void tessectrap(float *px, float *py, int *point2, int numpoints)
{
    float x0, x1, m0, m1;
    int i, j, k, z, i0, i1, i2, i3, npoints, gap, numrst;

    static int allocpoints = 0, *slist = 0, *npoint2 = 0;
    typedef struct { float x, y, xi; int i; } raster;
    static raster *rst = 0;
    if (numpoints+16 > allocpoints) //16 for safety
    {
        allocpoints = numpoints+16;
        rst = (raster*)realloc(rst,allocpoints*sizeof(raster));
        slist = (int*)realloc(slist,allocpoints*sizeof(int));
        npoint2 = (int*)realloc(npoint2,allocpoints*sizeof(int));
    }

    //Remove unnecessary collinear points:
    for (i=0;i<numpoints;i++) npoint2[i] = point2[i];
    npoints = numpoints; z = 0;
    for (i=0;i<numpoints;i++)
    {
        j = npoint2[i]; if ((point2[i] < i) && (i < numpoints-1)) z = 3;
        if (j < 0) continue;
        k = npoint2[j];
        m0 = (px[j]-px[i])*(py[k]-py[j]);
        m1 = (py[j]-py[i])*(px[k]-px[j]);
        if (m0 < m1) { z |= 1; continue; }
        if (m0 > m1) { z |= 2; continue; }
        npoint2[i] = k; npoint2[j] = -1; npoints--; i--; //collinear
    }
    if (!z) return;
    trapextx[0] = trapextx[1] = px[0];
    for (i=j=0;i<numpoints;i++)
    {
        if (npoint2[i] < 0) continue;
        if (px[i] < trapextx[0]) trapextx[0] = px[i];
        if (px[i] > trapextx[1]) trapextx[1] = px[i];
        slist[j++] = i;
    }
    if (z != 3) //Simple polygon... early out
    {
        bglBegin(GL_TRIANGLE_FAN);
        for (i=0;i<npoints;i++)
        {
            j = slist[i];
            bglTexCoord2f(px[j]*gux + py[j]*guy + guo,
                          px[j]*gvx + py[j]*gvy + gvo);
            bglVertex2f(px[j],py[j]);
        }
        bglEnd();
        return;
    }

    //Sort points by y's
    for (gap=(npoints>>1);gap;gap>>=1)
        for (i=0;i<npoints-gap;i++)
            for (j=i;j>=0;j-=gap)
            {
                if (py[npoint2[slist[j]]] <= py[npoint2[slist[j+gap]]]) break;
                k = slist[j]; slist[j] = slist[j+gap]; slist[j+gap] = k;
            }

    numrst = 0;
    for (z=0;z<npoints;z++)
    {
        i0 = slist[z]; i1 = npoint2[i0]; if (py[i0] == py[i1]) continue;
        i2 = i1; i3 = npoint2[i1];
        if (py[i1] == py[i3]) { i2 = i3; i3 = npoint2[i3]; }

        //i0        i3
        //  \      /
        //   i1--i2
        //  /      \ ~
        //i0        i3

        if ((py[i1] < py[i0]) && (py[i2] < py[i3])) //Insert raster
        {
            for (i=numrst;i>0;i--)
            {
                if (rst[i-1].xi*(py[i1]-rst[i-1].y) + rst[i-1].x < px[i1]) break;
                rst[i+1] = rst[i-1];
            }
            numrst += 2;

            if (i&1) //split inside area
            {
                j = i-1;

                x0 = (py[i1] - rst[j  ].y)*rst[j  ].xi + rst[j  ].x;
                x1 = (py[i1] - rst[j+1].y)*rst[j+1].xi + rst[j+1].x;
                drawtrap(rst[j].x,rst[j+1].x,rst[j].y,x0,x1,py[i1]);
                rst[j  ].x = x0; rst[j  ].y = py[i1];
                rst[j+3].x = x1; rst[j+3].y = py[i1];
            }

            m0 = (px[i0]-px[i1]) / (py[i0]-py[i1]);
            m1 = (px[i3]-px[i2]) / (py[i3]-py[i2]);
            j = ((px[i1] > px[i2]) || ((i1 == i2) && (m0 >= m1))) + i;
            k = (i<<1)+1 - j;
            rst[j].i = i0; rst[j].xi = m0; rst[j].x = px[i1]; rst[j].y = py[i1];
            rst[k].i = i3; rst[k].xi = m1; rst[k].x = px[i2]; rst[k].y = py[i2];
        }
        else
        {
            //NOTE:don't count backwards!
            if (i1 == i2) { for (i=0;i<numrst;i++) if (rst[i].i == i1) break; }
            else { for (i=0;i<numrst;i++) if ((rst[i].i == i1) || (rst[i].i == i2)) break; }
            j = i&~1;

            if ((py[i1] > py[i0]) && (py[i2] > py[i3])) //Delete raster
            {
                for (;j<=i+1;j+=2)
                {
                    x0 = (py[i1] - rst[j  ].y)*rst[j  ].xi + rst[j  ].x;
                    if ((i == j) && (i1 == i2)) x1 = x0; else x1 = (py[i1] - rst[j+1].y)*rst[j+1].xi + rst[j+1].x;
                    drawtrap(rst[j].x,rst[j+1].x,rst[j].y,x0,x1,py[i1]);
                    rst[j  ].x = x0; rst[j  ].y = py[i1];
                    rst[j+1].x = x1; rst[j+1].y = py[i1];
                }
                numrst -= 2; for (;i<numrst;i++) rst[i] = rst[i+2];
            }
            else
            {
                x0 = (py[i1] - rst[j  ].y)*rst[j  ].xi + rst[j  ].x;
                x1 = (py[i1] - rst[j+1].y)*rst[j+1].xi + rst[j+1].x;
                drawtrap(rst[j].x,rst[j+1].x,rst[j].y,x0,x1,py[i1]);
                rst[j  ].x = x0; rst[j  ].y = py[i1];
                rst[j+1].x = x1; rst[j+1].y = py[i1];

                if (py[i0] < py[i3]) { rst[i].x = px[i2]; rst[i].y = py[i2]; rst[i].i = i3; }
                else { rst[i].x = px[i1]; rst[i].y = py[i1]; rst[i].i = i0; }
                rst[i].xi = (px[rst[i].i] - rst[i].x) / (py[rst[i].i] - py[i1]);
            }
        }
    }
}

void polymost_fillpolygon(int npoints)
{
    pthtyp *pth;
    float f,a=0.0;
    int i, j, k;

    globalx1 = mulscale16(globalx1,xyaspect);
    globaly2 = mulscale16(globaly2,xyaspect);
    gux = ((double)asm1)*(1.0/4294967296.0);
    gvx = ((double)asm2)*(1.0/4294967296.0);
    guy = ((double)globalx1)*(1.0/4294967296.0);
    gvy = ((double)globaly2)*(-1.0/4294967296.0);
    guo = (((double)xdim)*gux + ((double)ydim)*guy)*-.5 + ((double)globalposx)*(1.0/4294967296.0);
    gvo = (((double)xdim)*gvx + ((double)ydim)*gvy)*-.5 - ((double)globalposy)*(1.0/4294967296.0);

    //Convert int to float (in-place)
    for (i=npoints-1;i>=0;i--)
    {
        ((float *)rx1)[i] = ((float)rx1[i])/4096.0;
        ((float *)ry1)[i] = ((float)ry1[i])/4096.0;
    }

    if (gloy1 != -1) setpolymost2dview(); //disables blending, texturing, and depth testing
    bglEnable(GL_ALPHA_TEST);
    bglEnable(GL_TEXTURE_2D);
    pth = gltexcache(globalpicnum,globalpal,0);
    bglBindTexture(GL_TEXTURE_2D, pth ? pth->glpic : 0);

    f = ((float)(numpalookups-min(max(globalshade * shadescale,0),numpalookups)))/((float)numpalookups);
    switch ((globalorientation>>7)&3)
    {
    case 0:
    case 1:
        a = 1.0; bglDisable(GL_BLEND); break;
    case 2:
        a = 0.66; bglEnable(GL_BLEND); break;
    case 3:
        a = 0.33; bglEnable(GL_BLEND); break;
    }
    bglColor4f(f,f,f,a);

    tessectrap((float *)rx1,(float *)ry1,xb1,npoints);
}
#endif

int polymost_drawtilescreen(int tilex, int tiley, int wallnum, int dimen, int tilezoom)
{
#ifdef USE_OPENGL
    float xdime, ydime, xdimepad, ydimepad, scx, scy, ratio = 1.0;
    int i;
    pthtyp *pth;

    if ((rendmode < 3) || (qsetmode != 200)) return(-1);

    if (!glinfo.texnpot)
    {
        i = (1<<(picsiz[wallnum]&15)); if (i < tilesizx[wallnum]) i += i; xdimepad = (float)i;
        i = (1<<(picsiz[wallnum]>>4)); if (i < tilesizy[wallnum]) i += i; ydimepad = (float)i;
    }
    else
    {
        xdimepad = (float)tilesizx[wallnum];
        ydimepad = (float)tilesizy[wallnum];
    }
    xdime = (float)tilesizx[wallnum]; xdimepad = xdime/xdimepad;
    ydime = (float)tilesizy[wallnum]; ydimepad = ydime/ydimepad;

    if ((xdime <= dimen) && (ydime <= dimen))
    {
        scx = xdime;
        scy = ydime;
    }
    else
    {
        scx = (float)dimen;
        scy = (float)dimen;
        if (xdime < ydime) scx *= xdime/ydime; else scy *= ydime/xdime;
    }

    pth = gltexcache(wallnum,0,4);
    bglBindTexture(GL_TEXTURE_2D,pth ? pth->glpic : 0);

    bglDisable(GL_ALPHA_TEST);

    if (tilezoom)
    {
        if (scx > scy) ratio = dimen/scx;
        else ratio = dimen/scy;
    }

    if (!pth || (pth->flags & 8))
    {
        bglDisable(GL_TEXTURE_2D);
        bglBegin(GL_TRIANGLE_FAN);
        if (gammabrightness)
            bglColor4f((float)curpalette[255].r/255.0,
                       (float)curpalette[255].g/255.0,
                       (float)curpalette[255].b/255.0,
                       1);
        else
            bglColor4f((float)britable[curbrightness][ curpalette[255].r ] / 255.0,
                       (float)britable[curbrightness][ curpalette[255].g ] / 255.0,
                       (float)britable[curbrightness][ curpalette[255].b ] / 255.0,
                       1);
        bglVertex2f((float)tilex    ,(float)tiley);
        bglVertex2f((float)tilex+(scx*ratio),(float)tiley);
        bglVertex2f((float)tilex+(scx*ratio),(float)tiley+(scy*ratio));
        bglVertex2f((float)tilex    ,(float)tiley+(scy*ratio));
        bglEnd();
    }

    bglColor4f(1,1,1,1);
    bglEnable(GL_TEXTURE_2D);
    bglEnable(GL_BLEND);
    bglBegin(GL_TRIANGLE_FAN);
    bglTexCoord2f(0,       0); bglVertex2f((float)tilex    ,(float)tiley);
    bglTexCoord2f(xdimepad,       0); bglVertex2f((float)tilex+(scx*ratio),(float)tiley);
    bglTexCoord2f(xdimepad,ydimepad); bglVertex2f((float)tilex+(scx*ratio),(float)tiley+(scy*ratio));
    bglTexCoord2f(0,ydimepad); bglVertex2f((float)tilex    ,(float)tiley+(scy*ratio));
    bglEnd();

    return(0);
#else
    return -1;
#endif
}

int polymost_printext256(int xpos, int ypos, short col, short backcol, char *name, char fontsize)
{
#ifndef USE_OPENGL
    return -1;
#else
    GLfloat tx, ty, txc, tyc;
    int c;
    palette_t p,b;

    if (gammabrightness)
    {
        p = curpalette[col];
        b = curpalette[backcol];
    }
    else
    {
        p.r = britable[curbrightness][ curpalette[col].r ];
        p.g = britable[curbrightness][ curpalette[col].g ];
        p.b = britable[curbrightness][ curpalette[col].b ];
        b.r = britable[curbrightness][ curpalette[backcol].r ];
        b.g = britable[curbrightness][ curpalette[backcol].g ];
        b.b = britable[curbrightness][ curpalette[backcol].b ];
    }

    if ((rendmode < 3) || (qsetmode != 200)) return(-1);

    if (!polymosttext)
    {
        // construct a 256x128 8-bit alpha-only texture for the font glyph matrix
        unsigned char *tbuf, *cptr, *tptr;
        int h,i,j,l;

        bglGenTextures(1,&polymosttext);
        if (!polymosttext) return -1;

        tbuf = (unsigned char *)Bmalloc(256*128);
        if (!tbuf)
        {
            bglDeleteTextures(1,&polymosttext);
            polymosttext = 0;
            return -1;
        }
        Bmemset(tbuf, 0, 256*128);

        cptr = (unsigned char*)textfont;
        for (h=0;h<256;h++)
        {
            tptr = tbuf + (h%32)*8 + (h/32)*256*8;
            for (i=0;i<8;i++)
            {
                for (j=0;j<8;j++)
                {
                    if (cptr[h*8+i] & pow2char[7-j]) tptr[j] = 255;
                }
                tptr += 256;
            }
        }

        cptr = (unsigned char*)smalltextfont;
        for (h=0;h<256;h++)
        {
            tptr = tbuf + 256*64 + (h%32)*8 + (h/32)*256*8;
            for (i=1;i<7;i++)
            {
                for (j=2;j<6;j++)
                {
                    if (cptr[h*8+i] & pow2char[7-j]) tptr[j-2] = 255;
                }
                tptr += 256;
            }
        }

        bglBindTexture(GL_TEXTURE_2D, polymosttext);
        bglTexImage2D(GL_TEXTURE_2D,0,GL_ALPHA,256,128,0,GL_ALPHA,GL_UNSIGNED_BYTE,(GLvoid*)tbuf);
        bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
        bglTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
        free(tbuf);
    }
    else bglBindTexture(GL_TEXTURE_2D, polymosttext);

    setpolymost2dview();	// disables blending, texturing, and depth testing
    bglDisable(GL_ALPHA_TEST);
    bglDepthMask(GL_FALSE);	// disable writing to the z-buffer

    if (backcol >= 0)
    {
        bglColor4ub(b.r,b.g,b.b,255);
        c = Bstrlen(name);

        bglBegin(GL_QUADS);
        bglVertex2i(xpos,ypos);
        bglVertex2i(xpos,ypos+(fontsize?6:8));
        bglVertex2i(xpos+(c<<(3-fontsize)),ypos+(fontsize?6:8));
        bglVertex2i(xpos+(c<<(3-fontsize)),ypos);
        bglEnd();
    }

    bglEnable(GL_TEXTURE_2D);
    bglEnable(GL_BLEND);
    bglColor4ub(p.r,p.g,p.b,255);
    txc = fontsize ? (4.0/256.0) : (8.0/256.0);
    tyc = fontsize ? (6.0/128.0) : (8.0/128.0);
    bglBegin(GL_QUADS);
    for (c=0; name[c]; c++)
    {
        tx = (float)(name[c]%32)/32.0;
        ty = (float)((name[c]/32) + (fontsize*8))/16.0;

        bglTexCoord2f(tx,ty);         bglVertex2i(xpos,ypos);
        bglTexCoord2f(tx+txc,ty);     bglVertex2i(xpos+(8>>fontsize),ypos);
        bglTexCoord2f(tx+txc,ty+tyc); bglVertex2i(xpos+(8>>fontsize),ypos+(fontsize?6:8));
        bglTexCoord2f(tx,ty+tyc);     bglVertex2i(xpos,ypos+(fontsize?6:8));

        xpos += (8>>fontsize);
    }
    bglEnd();

    bglDepthMask(GL_TRUE);	// re-enable writing to the z-buffer

    return 0;
#endif
}

// Console commands by JBF
#ifdef USE_OPENGL
static int gltexturemode(const osdfuncparm_t *parm)
{
    int m;
    const char *p;

    if (parm->numparms != 1)
    {
        OSD_Printf("Current texturing mode is %s\n", glfiltermodes[gltexfiltermode].name);
        OSD_Printf("  Vaild modes are:\n");
        for (m = 0; m < (int)numglfiltermodes; m++)
            OSD_Printf("     %d - %s\n",m,glfiltermodes[m].name);

        return OSDCMD_OK;
    }

    m = Bstrtoul(parm->parms[0], (char **)&p, 10);
    if (p == parm->parms[0])
    {
        // string
        for (m = 0; m < (int)numglfiltermodes; m++)
        {
            if (!Bstrcasecmp(parm->parms[0], glfiltermodes[m].name)) break;
        }
        if (m == numglfiltermodes) m = gltexfiltermode;   // no change
    }
    else
    {
        if (m < 0) m = 0;
        else if (m >= (int)numglfiltermodes) m = numglfiltermodes - 1;
    }

    if (m != gltexfiltermode)
    {
        gltexfiltermode = m;
        gltexapplyprops();
    }

    OSD_Printf("Texture filtering mode changed to %s\n", glfiltermodes[gltexfiltermode].name);

    return OSDCMD_OK;
}

static int gltextureanisotropy(const osdfuncparm_t *parm)
{
    int l;
    const char *p;

    if (parm->numparms != 1)
    {
        OSD_Printf("Current texture anisotropy is %d\n", glanisotropy);
        OSD_Printf("  Maximum is %d\n", (int)glinfo.maxanisotropy);

        return OSDCMD_OK;
    }

    l = Bstrtoul(parm->parms[0], (char **)&p, 10);
    if (l < 0 || l > (int)glinfo.maxanisotropy) l = 0;

    if (l != gltexfiltermode)
    {
        glanisotropy = l;
        gltexapplyprops();
    }

    OSD_Printf("Texture anisotropy changed to %d\n", glanisotropy);

    return OSDCMD_OK;
}
#endif

static int osdcmd_polymostvars(const osdfuncparm_t *parm)
{
    int showval = (parm->numparms < 1), val = 0;

    if (!showval) val = atoi(parm->parms[0]);
    if (!Bstrcasecmp(parm->name, "usemodels"))
    {
        if (showval) { OSD_Printf("usemodels is %d\n", usemodels); }
        else usemodels = (val != 0);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "usehightile"))
    {
        if (showval) { OSD_Printf("usehightile is %d\n", usehightile); }
        else usehightile = (val != 0);
        return OSDCMD_OK;
    }
#ifdef USE_OPENGL
    else if (!Bstrcasecmp(parm->name, "glusetexcompr"))
    {
        if (showval) { OSD_Printf("glusetexcompr is %d\n", glusetexcompr); }
        else glusetexcompr = (val != 0);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "glredbluemode"))
    {
        if (showval) { OSD_Printf("glredbluemode is %d\n", glredbluemode); }
        else glredbluemode = (val != 0);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "gltexturemaxsize"))
    {
        if (showval) { OSD_Printf("gltexturemaxsize is %d\n", gltexmaxsize); }
        else gltexmaxsize = val;
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "gltexturemiplevel"))
    {
        if (showval) { OSD_Printf("gltexturemiplevel is %d\n", gltexmiplevel); }
        else gltexmiplevel = val;
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_depthpeeling"))
    {
        if (showval) { OSD_Printf("r_depthpeeling is %d\n", r_depthpeeling); }
        else
        {
            if (!glinfo.arbfp || !glinfo.depthtex || !glinfo.shadow || !glinfo.fbos || !glinfo.rect)
            {
                OSD_Printf("r_depthpeeling: Your OpenGL implementation doesn't support depth peeling.\n");
                r_depthpeeling = 0;
                return OSDCMD_OK;
            }
            r_depthpeeling = (val != 0);
            resetvideomode();
            if (setgamemode(fullscreen,xdim,ydim,bpp))
                OSD_Printf("restartvid: Reset failed...\n");
        }
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_peelscount"))
    {
        if (showval) { OSD_Printf("r_peelscount is %d\n", r_peelscount); }
        else if (val < 1) { OSD_Printf("Value out of range.\n"); }
        else
        {
            newpeelscount = val;
            resetvideomode();
            if (setgamemode(fullscreen,xdim,ydim,bpp))
                OSD_Printf("restartvid: Reset failed...\n");
        }
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_curpeel"))
    {
        if (showval) { OSD_Printf("r_curpeel is %d\n", r_curpeel); }
        else if ((val < -1) || (val >= r_peelscount)) { OSD_Printf("Value out of range.\n"); }
        else r_curpeel = val;
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_detailmapping"))
    {
        if (showval) { OSD_Printf("r_detailmapping is %d\n", r_detailmapping); }
        else
        {
            if (!glinfo.multitex || !glinfo.envcombine)
            {
                OSD_Printf("Your OpenGL implementation doesn't support detail mapping.\n");
                r_detailmapping = 0;
                return OSDCMD_OK;
            }
            r_detailmapping = (val != 0);
        }
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_glowmapping"))
    {
        if (showval) { OSD_Printf("r_glowmapping is %d\n", r_glowmapping); }
        else
        {
            if (!glinfo.multitex || !glinfo.envcombine)
            {
                OSD_Printf("Your OpenGL implementation doesn't support glow mapping.\n");
                r_glowmapping = 0;
                return OSDCMD_OK;
            }
            r_glowmapping = (val != 0);
        }
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_vertexarrays"))
    {
        if (showval) { OSD_Printf("r_vertexarrays is %d\n", r_vertexarrays); }
        else r_vertexarrays = (val != 0);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_vbos"))
    {
        if (showval) { OSD_Printf("r_vbos is %d\n", r_vbos); }
        else
        {
            if (!glinfo.vbos)
            {
                OSD_Printf("Your OpenGL implementation doesn't support Vertex Buffer Objects.\n");
                r_vbos = 0;
                return OSDCMD_OK;
            }
            r_vbos = (val != 0);
        }
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_vbocount"))
    {
        if (showval) { OSD_Printf("r_vbocount is %d\n", r_vbocount); }
        else if (val < 1) { OSD_Printf("Value out of range.\n"); }
        else r_vbocount = val;
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_animsmoothing"))
    {
        if (showval) { OSD_Printf("r_animsmoothing is %d\n", r_animsmoothing); }
        else r_animsmoothing = (val != 0);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_parallaxskyclamping"))
    {
        if (showval) { OSD_Printf("r_parallaxskyclamping is %d\n", r_parallaxskyclamping); }
        else r_parallaxskyclamping = (val != 0);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_parallaxskypanning"))
    {
        if (showval) { OSD_Printf("r_parallaxskypanning is %d\n", r_parallaxskypanning); }
        else r_parallaxskypanning = (val != 0);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "glpolygonmode"))
    {
        if (showval) { OSD_Printf("glpolygonmode is %d\n", glpolygonmode); }
        else glpolygonmode = val;
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "glusetexcache"))
    {
        if (showval) { OSD_Printf("glusetexcache is %d\n", glusetexcache); }
        else glusetexcache = (val != 0);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "glusetexcachecompression"))
    {
        if (showval) { OSD_Printf("glusetexcachecompression is %d\n", glusetexcachecompression); }
        else glusetexcachecompression = (val != 0);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "glmultisample"))
    {
        if (showval) { OSD_Printf("glmultisample is %d\n", glmultisample); }
        else glmultisample = max(0,val);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "glnvmultisamplehint"))
    {
        if (showval) { OSD_Printf("glnvmultisamplehint is %d\n", glnvmultisamplehint); }
        else glnvmultisamplehint = (val != 0);
        return OSDCMD_OK;
    }
    else if (!Bstrcasecmp(parm->name, "r_shadescale"))
    {
        if (showval) { OSD_Printf("r_shadescale is %g\n", shadescale); }
        else
        {
            float fval = atof(parm->parms[0]);
            shadescale = fval;
        }
        return OSDCMD_OK;
    }
#endif
    return OSDCMD_SHOWHELP;
}

#if 0
// because I'm lazy
static int dumptexturedefs(const osdfuncparm_t *parm)
{
    hicreplctyp *hr;
    int i;

    if (!hicfirstinit) return OSDCMD_OK;

    initprintf("// Begin Texture Dump\n");
    for (i=0;i<MAXTILES;i++)
    {
        hr = hicreplc[i];
        if (!hr) continue;
        initprintf("texture %d {\n", i);
        for (; hr; hr = hr->next)
        {
            if (!hr->filename) continue;
            initprintf("    pal %d { name \"%s\" ", hr->palnum, hr->filename);
            if (hr->alphacut >= 0.0) initprintf("alphacut %g ", hr->alphacut);
            initprintf("}\n");
        }
        initprintf("}\n");
    }
    initprintf("// End Texture Dump\n");

    return OSDCMD_OK;	// no replacement found
}
#endif

void polymost_initosdfuncs(void)
{
#ifdef USE_OPENGL
    OSD_RegisterFunction("glusetexcompr","glusetexcompr: enable/disable OpenGL texture compression",osdcmd_polymostvars);
    OSD_RegisterFunction("glredbluemode","glredbluemode: enable/disable experimental OpenGL red-blue glasses mode",osdcmd_polymostvars);
    OSD_RegisterFunction("gltexturemode", "gltexturemode: changes the texture filtering settings", gltexturemode);
    OSD_RegisterFunction("gltextureanisotropy", "gltextureanisotropy: changes the OpenGL texture anisotropy setting", gltextureanisotropy);
    OSD_RegisterFunction("gltexturemaxsize","gltexturemaxsize: changes the maximum OpenGL texture size limit",osdcmd_polymostvars);
    OSD_RegisterFunction("gltexturemiplevel","gltexturemiplevel: changes the highest OpenGL mipmap level used",osdcmd_polymostvars);
    OSD_RegisterFunction("glpolygonmode","glpolygonmode: debugging feature",osdcmd_polymostvars); //FUK
    OSD_RegisterFunction("glusetexcache","glusetexcache: enable/disable OpenGL compressed texture cache",osdcmd_polymostvars);
    OSD_RegisterFunction("glusetexcachecompression","usetexcachecompression: enable/disable compression of files in the OpenGL compressed texture cache",osdcmd_polymostvars);
    OSD_RegisterFunction("glmultisample","glmultisample: sets the number of samples used for antialiasing (0 = off)",osdcmd_polymostvars);
    OSD_RegisterFunction("glnvmultisamplehint","glnvmultisamplehint: enable/disable Nvidia multisampling hinting",osdcmd_polymostvars);
    OSD_RegisterFunction("r_shadescale","r_shadescale: multiplier for lighting",osdcmd_polymostvars);
    OSD_RegisterFunction("r_depthpeeling","r_depthpeeling: enable/disable order-independant transparency",osdcmd_polymostvars);
    OSD_RegisterFunction("r_peelscount","r_peelscount: sets the number of depth layers for depth peeling",osdcmd_polymostvars);
    OSD_RegisterFunction("r_curpeel","r_curpeel: allows to display one depth layer at a time (for development purposes)",osdcmd_polymostvars);
    OSD_RegisterFunction("r_detailmapping","r_detailmapping: enable/disable detail mapping",osdcmd_polymostvars);
    OSD_RegisterFunction("r_glowmapping","r_glowmapping: enable/disable glow mapping",osdcmd_polymostvars);
    OSD_RegisterFunction("r_vertexarrays","r_vertexarrays: enable/disable using vertex arrays when drawing models",osdcmd_polymostvars);
    OSD_RegisterFunction("r_vbos","r_vbos: enable/disable using Vertex Buffer Objects when drawing models",osdcmd_polymostvars);
    OSD_RegisterFunction("r_vbocount","r_vbocount: sets the number of Vertex Buffer Objects to use when drawing models",osdcmd_polymostvars);
    OSD_RegisterFunction("r_animsmoothing","r_animsmoothing: enable/disable model animation smoothing",osdcmd_polymostvars);
    OSD_RegisterFunction("r_parallaxskyclamping","r_parallaxskyclamping: enable/disable parallaxed floor/ceiling sky texture clamping",osdcmd_polymostvars);
    OSD_RegisterFunction("r_parallaxskypanning","r_parallaxskypanning: enable/disable parallaxed floor/ceiling panning when drawing a parallaxed sky",osdcmd_polymostvars);
#endif
    OSD_RegisterFunction("usemodels","usemodels: enable/disable model rendering in >8-bit mode",osdcmd_polymostvars);
    OSD_RegisterFunction("usehightile","usehightile: enable/disable hightile texture rendering in >8-bit mode",osdcmd_polymostvars);
    //OSD_RegisterFunction("dumptexturedefs","dumptexturedefs: dumps all texture definitions in the new style",dumptexturedefs);
}

void polymost_precache(int dapicnum, int dapalnum, int datype)
{
#ifdef USE_OPENGL
    // dapicnum and dapalnum are like you'd expect
    // datype is 0 for a wall/floor/ceiling and 1 for a sprite
    //    basically this just means walls are repeating
    //    while sprites are clamped
    int mid;
    int pal1;

    if (rendmode < 3) return;

    if ((palookup[dapalnum] == NULL) && (dapalnum < (MAXPALOOKUPS - RESERVEDPALS))) return;//dapalnum = 0;

    //OSD_Printf("precached %d %d type %d\n", dapicnum, dapalnum, datype);
    hicprecaching = 1;
    for (pal1=SPECPAL;pal1<=REDPAL;pal1++)
        if (hicfindsubst(globalpicnum, pal1, 0))
            gltexcache(globalpicnum, pal1, (datype & 1) << 2);

    gltexcache(dapicnum, dapalnum, (datype & 1) << 2);
    hicprecaching = 0;

    if (datype == 0) return;

    mid = md_tilehasmodel(dapicnum,dapalnum);
    if (mid < 0 || models[mid]->mdnum < 2) return;

    {
        int i,j=0;

        if (models[mid]->mdnum == 3)
            j = ((md3model *)models[mid])->head.numsurfs;

        for (i=0;i<=j;i++)
        {
            int pal1;
            for (pal1=SPECPAL;pal1<=REDPAL;pal1++)mdloadskin((md2model*)models[mid],0,pal1,i);
            mdloadskin((md2model*)models[mid], 0, dapalnum, i);
        }
    }
#endif
}

static unsigned short hicosub(unsigned short c)
{
    int r, g, b;
    g = ((c>> 5)&63);
    r = ((c>>11)-(g>>1))&31;
    b = ((c>> 0)-(g>>1))&31;
    return((r<<11)+(g<<5)+b);
}

static unsigned short hicoadd(unsigned short c)
{
    int r, g, b;
    g = ((c>> 5)&63);
    r = ((c>>11)+(g>>1))&31;
    b = ((c>> 0)+(g>>1))&31;
    return((r<<11)+(g<<5)+b);
}

/*
Description of Ken's filter to improve LZW compression of DXT1 format by ~15%: (as tested with the HRP)

 To increase LZW patterns, I store each field of the DXT block structure separately.
 Here are the 3 DXT fields:
 1.  __int64 alpha_4x4; //DXT3 only (16 byte structure size when included)
 2.  short rgb0, rgb1;
 3.  int index_4x4;

 Each field is then stored with its own specialized algorithm.
 1. I haven't done much testing with this field - I just copy it raw without any transform for now.

 2. For rgb0 and rgb1, I use a "green" filter like this:
 g = g;
 r = r-g;
 b = b-g;
 For grayscale, this makes the stream: x,0,0,x,0,0,x,0,0,... instead of x,x,x,x,x,x,x,x,...
 Q:what was the significance of choosing green? A:largest/most dominant component
 Believe it or not, this gave 1% better compression :P
 I tried subtracting each componenet with the previous pixel, but strangely it hurt compression.
 Oh, the joy of trial & error. :)

 3. For index_4x4, I transform the ordering of 2-bit indices in the DXT blocks from this:
 0123 0123 0123  ---- ---- ----
 4567 4567 4567  ---- ---- ----
 89ab 89ab 89ab  ---- ---- ----
 cdef cdef cdef  ---- ---- ----
 To this: (I swap x & y axes)
 048c 048c 048c  |||| |||| ||||
 159d 159d 159d  |||| |||| ||||
 26ae 26ae 26ae  |||| |||| ||||
 37bf 37bf 37bf  |||| |||| ||||
 The trick is: going from the bottom of the 4th line to the top of the 5th line
 is the exact same jump (geometrically) as from 5th to 6th, etc.. This is not true in the top case.
 These silly tricks will increase patterns and therefore make LZW compress better.
 I think this improved compression by a few % :)
 */

#if defined(POLYMOST) && defined(USE_OPENGL)
int dxtfilter(int fil, texcachepicture *pict, char *pic, void *midbuf, char *packbuf, unsigned int miplen)
{
    void *writebuf;
#if (USEKENFILTER == 0)
    unsigned int cleng,j;
    if (glusetexcachecompression)
    {
#ifdef USELZF
        cleng = lzf_compress(pic, miplen, packbuf, miplen-1);
        if (cleng == 0)
        {
            // failed to compress
            cleng = miplen;
            writebuf = pic;
        }
        else writebuf = packbuf;
#else
        cleng = lzwcompress(pic,miplen,packbuf);
        writebuf = packbuf;
#endif
    }
    else
    {
        cleng = miplen;
        writebuf = pic;
    }
    if (cleng < 0) return -1; j = B_LITTLE32(cleng);
    if (Bwrite(fil, &j, sizeof(unsigned int)) != sizeof(unsigned int)) return -1;
    if (Bwrite(fil, writebuf, cleng) != cleng) return -1;
#else
    unsigned int j, k, offs, stride, cleng;
    char *cptr;

    if ((pict->format == B_LITTLE32(GL_COMPRESSED_RGB_S3TC_DXT1_EXT)) ||
            (pict->format == B_LITTLE32(GL_COMPRESSED_RGBA_S3TC_DXT1_EXT))) { offs = 0; stride = 8; }
    else if ((pict->format == B_LITTLE32(GL_COMPRESSED_RGBA_S3TC_DXT3_EXT)) ||
             (pict->format == B_LITTLE32(GL_COMPRESSED_RGBA_S3TC_DXT5_EXT))) { offs = 8; stride = 16; }
    else { offs = 0; stride = 8; }

    if (stride == 16) //If DXT3...
    {
        //alpha_4x4
        cptr = midbuf;
        for (k=0;k<8;k++) *cptr++ = pic[k];
        for (j=stride;(unsigned)j<miplen;j+=stride)
            for (k=0;k<8;k++) *cptr++ = pic[j+k];
        if (glusetexcachecompression)
        {
#ifdef USELZF
            j = (miplen/stride)*8;
            cleng = lzf_compress(midbuf,j,packbuf,j-1);
            if (cleng == 0)
            {
                cleng = j;
                writebuf = midbuf;
            }
            else writebuf = packbuf;
#else
    cleng = lzwcompress(midbuf,(miplen/stride)*8,packbuf);
    writebuf = packbuf;
#endif
        }
        else
        {
            cleng = (miplen/stride)*8;
            writebuf = midbuf;
        }
        j = B_LITTLE32(cleng);
        Bwrite(fil,&j,4);
        Bwrite(fil,writebuf,cleng);
    }

    //rgb0,rgb1
    cptr = midbuf;
    for (k=0;k<=2;k+=2)
        for (j=0;(unsigned)j<miplen;j+=stride)
            { *(short *)cptr = hicosub(*(short *)(&pic[offs+j+k])); cptr += 2; }
    if (glusetexcachecompression)
    {
#ifdef USELZF
        j = (miplen/stride)*4;
        cleng = lzf_compress(midbuf,j,packbuf,j-1);
        if (cleng == 0)
        {
            cleng = j;
            writebuf = midbuf;
        }
        else writebuf = packbuf;
#else
    cleng = lzwcompress(midbuf,(miplen/stride)*4,packbuf);
    writebuf = packbuf;
#endif
    }
    else
    {
        cleng = (miplen/stride)*4;
        writebuf = midbuf;
    }
    j = B_LITTLE32(cleng);
    Bwrite(fil,&j,4);
    Bwrite(fil,writebuf,cleng);

    //index_4x4
    cptr = midbuf;
    for (j=0;(unsigned)j<miplen;j+=stride)
    {
        char *c2 = &pic[j+offs+4];
        cptr[0] = ((c2[0]>>0)&3) + (((c2[1]>>0)&3)<<2) + (((c2[2]>>0)&3)<<4) + (((c2[3]>>0)&3)<<6);
        cptr[1] = ((c2[0]>>2)&3) + (((c2[1]>>2)&3)<<2) + (((c2[2]>>2)&3)<<4) + (((c2[3]>>2)&3)<<6);
        cptr[2] = ((c2[0]>>4)&3) + (((c2[1]>>4)&3)<<2) + (((c2[2]>>4)&3)<<4) + (((c2[3]>>4)&3)<<6);
        cptr[3] = ((c2[0]>>6)&3) + (((c2[1]>>6)&3)<<2) + (((c2[2]>>6)&3)<<4) + (((c2[3]>>6)&3)<<6);
        cptr += 4;
    }
    if (glusetexcachecompression)
    {
#ifdef USELZF
        j = (miplen/stride)*4;
        cleng = lzf_compress(midbuf,j,packbuf,j-1);
        if (cleng == 0)
        {
            cleng = j;
            writebuf = midbuf;
        }
        else writebuf = packbuf;
#else
    cleng = lzwcompress(midbuf,(miplen/stride)*4,packbuf);
    writebuf = packbuf;
#endif
    }
    else
    {
        cleng = (miplen/stride)*4;
        writebuf = midbuf;
    }
    j = B_LITTLE32(cleng);
    Bwrite(fil,&j,4);
    Bwrite(fil,writebuf,cleng);
#endif
    return 0;
}

int dedxtfilter(int fil, texcachepicture *pict, char *pic, void *midbuf, char *packbuf, int ispacked)
{
    void *inbuf;
#if (USEKENFILTER == 0)
    unsigned int cleng;
    if (kread(fil, &cleng, sizeof(unsigned int)) != sizeof(unsigned int)) return -1; cleng = B_LITTLE32(cleng);
#ifdef USELZF
    if (ispacked && cleng < pict->size) inbuf = packbuf; else inbuf = pic;
    if (kread(fil, inbuf, cleng) != cleng) return -1;
    if (ispacked && cleng < pict->size)
        if (lzf_decompress(packbuf, cleng, pic, pict->size) == 0) return -1;
#else
    if (ispacked) inbuf = packbuf; else inbuf = pic;
    if (kread(fil, inbuf, cleng) != cleng) return -1;
    if (ispacked && lzwuncompress(packbuf, cleng, pic, pict->size) != pict->size) return -1;
#endif
#else
    int j, k, offs, stride, cleng;
    char *cptr;

    if (ispacked) inbuf = packbuf; else inbuf = midbuf;

    if ((pict->format == GL_COMPRESSED_RGB_S3TC_DXT1_EXT) ||
            (pict->format == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT)) { offs = 0; stride = 8; }
    else if ((pict->format == GL_COMPRESSED_RGBA_S3TC_DXT3_EXT) ||
             (pict->format == GL_COMPRESSED_RGBA_S3TC_DXT5_EXT)) { offs = 8; stride = 16; }
    else { offs = 0; stride = 8; }

    if (stride == 16) //If DXT3...
    {
        //alpha_4x4
        if (kread(fil,&cleng,4) < 4) return -1; cleng = B_LITTLE32(cleng);
        j = (pict->size/stride)*8;
#ifdef USELZF
        if (ispacked && cleng < j) inbuf = packbuf; else inbuf = midbuf;
        if (kread(fil,inbuf,cleng) < cleng) return -1;
        if (ispacked && cleng < j)
            if (lzf_decompress(packbuf,cleng,midbuf,j) == 0) return -1;
#else
    if (kread(fil,inbuf,cleng) < cleng) return -1;
    if (ispacked && lzwuncompress(packbuf,cleng,midbuf,j) != j) return -1;
#endif
        cptr = midbuf;
        for (k=0;k<8;k++) pic[k] = *cptr++;
        for (j=stride;j<pict->size;j+=stride)
            for (k=0;k<8;k++) pic[j+k] = (*cptr++);
    }

    //rgb0,rgb1
    if (kread(fil,&cleng,4) < 4) return -1; cleng = B_LITTLE32(cleng);
    j = (pict->size/stride)*4;
#ifdef USELZF
    if (ispacked && cleng < j) inbuf = packbuf; else inbuf = midbuf;
    if (kread(fil,inbuf,cleng) < cleng) return -1;
    if (ispacked && cleng < j)
        if (lzf_decompress(packbuf,cleng,midbuf,j) == 0) return -1;
#else
    if (kread(fil,inbuf,cleng) < cleng) return -1;
    if (ispacked && lzwuncompress(packbuf,cleng,midbuf,j) != j) return -1;
#endif
    cptr = midbuf;
    for (k=0;k<=2;k+=2)
        for (j=0;j<pict->size;j+=stride)
        {
            *(short *)(&pic[offs+j+k]) = hicoadd(*(short *)cptr);
            cptr += 2;
        }

    //index_4x4:
    if (kread(fil,&cleng,4) < 4) return -1; cleng = B_LITTLE32(cleng);
    j = (pict->size/stride)*4;
#ifdef USELZF
    if (ispacked && cleng < j) inbuf = packbuf; else inbuf = midbuf;
    if (kread(fil,inbuf,cleng) < cleng) return -1;
    if (ispacked && cleng < j)
        if (lzf_decompress(packbuf,cleng,midbuf,j) == 0) return -1;
#else
    if (kread(fil,inbuf,cleng) < cleng) return -1;
    if (ispacked && lzwuncompress(packbuf,cleng,midbuf,j) != j) return -1;
#endif
    cptr = midbuf;
    for (j=0;j<pict->size;j+=stride)
    {
        pic[j+offs+4] = ((cptr[0]>>0)&3) + (((cptr[1]>>0)&3)<<2) + (((cptr[2]>>0)&3)<<4) + (((cptr[3]>>0)&3)<<6);
        pic[j+offs+5] = ((cptr[0]>>2)&3) + (((cptr[1]>>2)&3)<<2) + (((cptr[2]>>2)&3)<<4) + (((cptr[3]>>2)&3)<<6);
        pic[j+offs+6] = ((cptr[0]>>4)&3) + (((cptr[1]>>4)&3)<<2) + (((cptr[2]>>4)&3)<<4) + (((cptr[3]>>4)&3)<<6);
        pic[j+offs+7] = ((cptr[0]>>6)&3) + (((cptr[1]>>6)&3)<<2) + (((cptr[2]>>6)&3)<<4) + (((cptr[3]>>6)&3)<<6);
        cptr += 4;
    }
#endif
    return 0;
}
#endif
// vim:ts=4:sw=4: