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ZoneBuilder/Source/Plugins/vpo_dll/r_main.cc

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// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005 Simon Howard
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA.
//
// DESCRIPTION:
// Rendering main loop and setup functions,
// utility functions (BSP, geometry, trigonometry).
// See tables.c, too.
//
//-----------------------------------------------------------------------------
#include "vpo_local.h"
// #include "r_sky.h"
namespace vpo
{
// Fineangles in the SCREENWIDTH wide window.
#define FIELDOFVIEW 2048
int viewangleoffset;
// increment every time a check is made
int validcount = 1;
int centerx;
int centery;
fixed_t centerxfrac;
fixed_t centeryfrac;
fixed_t projection;
// just for profiling purposes
int framecount;
int sscount;
int linecount;
int loopcount;
fixed_t viewx;
fixed_t viewy;
fixed_t viewz;
angle_t viewangle;
fixed_t viewcos;
fixed_t viewsin;
//
// precalculated math tables
//
angle_t clipangle;
// The viewangletox[viewangle + FINEANGLES/4] lookup
// maps the visible view angles to screen X coordinates,
// flattening the arc to a flat projection plane.
// There will be many angles mapped to the same X.
int viewangletox[FINEANGLES/2];
// The xtoviewangleangle[] table maps a screen pixel
// to the lowest viewangle that maps back to x ranges
// from clipangle to -clipangle.
angle_t xtoviewangle[SCREENWIDTH+1];
// UNUSED.
// The finetangentgent[angle+FINEANGLES/4] table
// holds the fixed_t tangent values for view angles,
// ranging from INT_MIN to 0 to INT_MAX.
// fixed_t finetangent[FINEANGLES/2];
// fixed_t finesine[5*FINEANGLES/4];
const fixed_t* finecosine = &finesine[FINEANGLES/4];
// bumped light from gun blasts
int extralight;
// from R_DRAW
int viewwidth;
int scaledviewwidth;
int viewheight;
int viewwindowx;
int viewwindowy;
// from R_THINGS
fixed_t pspritescale;
fixed_t pspriteiscale;
short screenheightarray[SCREENWIDTH];
short negonearray[SCREENWIDTH];
//
// R_AddPointToBox
// Expand a given bbox
// so that it encloses a given point.
//
void R_AddPointToBox ( int x, int y, fixed_t* box )
{
if (x< box[BOXLEFT])
box[BOXLEFT] = x;
if (x> box[BOXRIGHT])
box[BOXRIGHT] = x;
if (y< box[BOXBOTTOM])
box[BOXBOTTOM] = y;
if (y> box[BOXTOP])
box[BOXTOP] = y;
}
//
// R_PointOnSide
// Traverse BSP (sub) tree,
// check point against partition plane.
// Returns side 0 (front) or 1 (back).
//
int R_PointOnSide ( fixed_t x, fixed_t y, node_t* node )
{
fixed_t dx;
fixed_t dy;
fixed_t left;
fixed_t right;
if (!node->dx)
{
if (x <= node->x)
return node->dy > 0;
return node->dy < 0;
}
if (!node->dy)
{
if (y <= node->y)
return node->dx < 0;
return node->dx > 0;
}
dx = (x - node->x);
dy = (y - node->y);
// Try to quickly decide by looking at sign bits.
if ( (node->dy ^ node->dx ^ dx ^ dy)&0x80000000 )
{
if ( (node->dy ^ dx) & 0x80000000 )
{
// (left is negative)
return 1;
}
return 0;
}
left = FixedMul ( node->dy>>FRACBITS , dx );
right = FixedMul ( dy , node->dx>>FRACBITS );
if (right < left)
{
// front side
return 0;
}
// back side
return 1;
}
int R_PointOnSegSide ( fixed_t x, fixed_t y, seg_t* line )
{
fixed_t lx;
fixed_t ly;
fixed_t ldx;
fixed_t ldy;
fixed_t dx;
fixed_t dy;
fixed_t left;
fixed_t right;
lx = line->v1->x;
ly = line->v1->y;
ldx = line->v2->x - lx;
ldy = line->v2->y - ly;
if (!ldx)
{
if (x <= lx)
return ldy > 0;
return ldy < 0;
}
if (!ldy)
{
if (y <= ly)
return ldx < 0;
return ldx > 0;
}
dx = (x - lx);
dy = (y - ly);
// Try to quickly decide by looking at sign bits.
if ( (ldy ^ ldx ^ dx ^ dy)&0x80000000 )
{
if ( (ldy ^ dx) & 0x80000000 )
{
// (left is negative)
return 1;
}
return 0;
}
left = FixedMul ( ldy>>FRACBITS , dx );
right = FixedMul ( dy , ldx>>FRACBITS );
if (right < left)
{
// front side
return 0;
}
// back side
return 1;
}
//
// R_PointToAngle
// To get a global angle from cartesian coordinates,
// the coordinates are flipped until they are in
// the first octant of the coordinate system, then
// the y (<=x) is scaled and divided by x to get a
// tangent (slope) value which is looked up in the
// tantoangle[] table.
angle_t R_PointToAngle ( fixed_t x, fixed_t y )
{
x -= viewx;
y -= viewy;
if ( (!x) && (!y) )
return 0;
if (x>= 0)
{
// x >=0
if (y>= 0)
{
// y>= 0
if (x>y)
{
// octant 0
return tantoangle[ SlopeDiv(y,x)];
}
else
{
// octant 1
return ANG90-1-tantoangle[ SlopeDiv(x,y)];
}
}
else
{
// y<0
y = -y;
if (x>y)
{
// octant 8
return -tantoangle[SlopeDiv(y,x)];
}
else
{
// octant 7
return ANG270+tantoangle[ SlopeDiv(x,y)];
}
}
}
else
{
// x<0
x = -x;
if (y>= 0)
{
// y>= 0
if (x>y)
{
// octant 3
return ANG180-1-tantoangle[ SlopeDiv(y,x)];
}
else
{
// octant 2
return ANG90+ tantoangle[ SlopeDiv(x,y)];
}
}
else
{
// y<0
y = -y;
if (x>y)
{
// octant 4
return ANG180+tantoangle[ SlopeDiv(y,x)];
}
else
{
// octant 5
return ANG270-1-tantoangle[ SlopeDiv(x,y)];
}
}
}
return 0;
}
angle_t R_PointToAngle2 ( fixed_t x1, fixed_t y1, fixed_t x2, fixed_t y2 )
{
viewx = x1;
viewy = y1;
return R_PointToAngle (x2, y2);
}
fixed_t R_PointToDist ( fixed_t x, fixed_t y )
{
int angle;
fixed_t dx;
fixed_t dy;
fixed_t temp;
fixed_t dist;
fixed_t frac;
dx = abs(x - viewx);
dy = abs(y - viewy);
if (dy>dx)
{
temp = dx;
dx = dy;
dy = temp;
}
// Fix crashes in udm1.wad
if (dx != 0)
{
frac = FixedDiv(dy, dx);
}
else
{
frac = 0;
}
angle = (tantoangle[frac>>DBITS]+ANG90) >> ANGLETOFINESHIFT;
// use as cosine
dist = FixedDiv (dx, finesine[angle] );
return dist;
}
//
// R_ScaleFromGlobalAngle
// Returns the texture mapping scale
// for the current line (horizontal span)
// at the given angle.
// rw_distance must be calculated first.
//
fixed_t R_ScaleFromGlobalAngle (angle_t visangle)
{
fixed_t scale;
angle_t anglea;
angle_t angleb;
int sinea;
int sineb;
fixed_t num;
int den;
// UNUSED
#if 0
{
fixed_t dist;
fixed_t z;
fixed_t sinv;
fixed_t cosv;
sinv = finesine[(visangle-rw_normalangle)>>ANGLETOFINESHIFT];
dist = FixedDiv (rw_distance, sinv);
cosv = finecosine[(viewangle-visangle)>>ANGLETOFINESHIFT];
z = abs(FixedMul (dist, cosv));
scale = FixedDiv(projection, z);
return scale;
}
#endif
anglea = ANG90 + (visangle-viewangle);
angleb = ANG90 + (visangle-rw_normalangle);
// both sines are allways positive
sinea = finesine[anglea>>ANGLETOFINESHIFT];
sineb = finesine[angleb>>ANGLETOFINESHIFT];
num = FixedMul(projection,sineb)<<0;
den = FixedMul(rw_distance,sinea);
if (den > num>>16)
{
scale = FixedDiv (num, den);
if (scale > 64*FRACUNIT)
scale = 64*FRACUNIT;
else if (scale < 256)
scale = 256;
}
else
scale = 64*FRACUNIT;
return scale;
}
void R_InitBuffer ( int width, int height )
{
int i;
// Handle resize,
// e.g. smaller view windows
// with border and/or status bar.
viewwindowx = (SCREENWIDTH-width) >> 1;
viewwindowy = 0;
// this was from R_InitSprites
for (i=0 ; i<SCREENWIDTH ; i++)
{
negonearray[i] = -1;
}
#if 0
// Column offset. For windows.
for (i=0 ; i<width ; i++)
columnofs[i] = viewwindowx + i;
// Samw with base row offset.
if (width == SCREENWIDTH)
viewwindowy = 0;
else
viewwindowy = (SCREENHEIGHT-SBARHEIGHT-height) >> 1;
// Preclaculate all row offsets.
for (i=0 ; i<height ; i++)
ylookup[i] = screens[0] + (i+viewwindowy)*SCREENWIDTH;
#endif
}
//
// R_InitTextureMapping
//
void R_InitTextureMapping (void)
{
int i;
int x;
int t;
fixed_t focallength;
// Use tangent table to generate viewangletox:
// viewangletox will give the next greatest x
// after the view angle.
//
// Calc focallength
// so FIELDOFVIEW angles covers SCREENWIDTH.
focallength = FixedDiv (centerxfrac,
finetangent[FINEANGLES/4+FIELDOFVIEW/2] );
for (i=0 ; i<FINEANGLES/2 ; i++)
{
if (finetangent[i] > FRACUNIT*2)
t = -1;
else if (finetangent[i] < -FRACUNIT*2)
t = viewwidth+1;
else
{
t = FixedMul (finetangent[i], focallength);
t = (centerxfrac - t+FRACUNIT-1)>>FRACBITS;
if (t < -1)
t = -1;
else if (t>viewwidth+1)
t = viewwidth+1;
}
viewangletox[i] = t;
}
// Scan viewangletox[] to generate xtoviewangle[]:
// xtoviewangle will give the smallest view angle
// that maps to x.
for (x=0;x<=viewwidth;x++)
{
i = 0;
while (viewangletox[i]>x)
i++;
xtoviewangle[x] = (i<<ANGLETOFINESHIFT)-ANG90;
}
// Take out the fencepost cases from viewangletox.
for (i=0 ; i<FINEANGLES/2 ; i++)
{
t = FixedMul (finetangent[i], focallength);
t = centerx - t;
if (viewangletox[i] == -1)
viewangletox[i] = 0;
else if (viewangletox[i] == viewwidth+1)
viewangletox[i] = viewwidth;
}
clipangle = xtoviewangle[0];
}
//
// R_SetViewSize
//
void R_SetViewSize ( int blocks, int detail )
{
fixed_t cosadj;
fixed_t dy;
int i;
if (blocks == 11)
{
scaledviewwidth = SCREENWIDTH;
viewheight = SCREENHEIGHT;
}
else
{
scaledviewwidth = blocks*32;
viewheight = (blocks*168/10)&~7;
}
viewwidth = scaledviewwidth >> 0;
centery = viewheight/2;
centerx = viewwidth/2;
centerxfrac = centerx<<FRACBITS;
centeryfrac = centery<<FRACBITS;
projection = centerxfrac;
R_InitBuffer (scaledviewwidth, viewheight);
R_InitTextureMapping ();
// psprite scales
pspritescale = FRACUNIT*viewwidth/SCREENWIDTH;
pspriteiscale = FRACUNIT*SCREENWIDTH/viewwidth;
// thing clipping
for (i=0 ; i<viewwidth ; i++)
screenheightarray[i] = viewheight;
// planes
for (i=0 ; i<viewheight ; i++)
{
dy = ((i-viewheight/2)<<FRACBITS)+FRACUNIT/2;
dy = abs(dy);
yslope[i] = FixedDiv ( (viewwidth<<0)/2*FRACUNIT, dy);
}
for (i=0 ; i<viewwidth ; i++)
{
cosadj = abs(finecosine[xtoviewangle[i]>>ANGLETOFINESHIFT]);
distscale[i] = FixedDiv (FRACUNIT,cosadj);
}
}
//
// R_Init
//
void R_Init (void)
{
R_SetViewSize (11, 0);
framecount = 0;
}
//
// R_PointInSubsector
//
subsector_t* R_PointInSubsector ( fixed_t x, fixed_t y )
{
node_t* node;
int side;
int nodenum;
// single subsector is a special case
if (!numnodes)
return subsectors;
nodenum = numnodes-1;
while (! (nodenum & NF_SUBSECTOR) )
{
node = &nodes[nodenum];
side = R_PointOnSide (x, y, node);
nodenum = node->children[side];
}
return &subsectors[nodenum & ~NF_SUBSECTOR];
}
//
// R_SetupFrame
//
void R_SetupFrame (fixed_t x, fixed_t y, fixed_t z, angle_t angle)
{
viewx = x;
viewy = y;
viewz = z;
viewangle = angle;
viewsin = finesine[viewangle>>ANGLETOFINESHIFT];
viewcos = finecosine[viewangle>>ANGLETOFINESHIFT];
sscount = 0;
framecount++;
validcount++;
}
//
// R_RenderView
//
void R_RenderView (fixed_t x, fixed_t y, fixed_t z, angle_t angle)
{
R_SetupFrame (x, y, z, angle);
// Clear buffers.
R_ClearClipSegs ();
R_ClearDrawSegs ();
R_ClearPlanes ();
/// R_ClearSprites ();
// The head node is the last node output.
R_RenderBSPNode (numnodes - 1);
}
} // namespace vpo
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