ZoneBuilder/Source/Plugins/vpo_dll/r_plane.cc

// 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:
//	Here is a core component: drawing the floors and ceilings,
//	 while maintaining a per column clipping list only.
//	Moreover, the sky areas have to be determined.
//
//-----------------------------------------------------------------------------

#include "vpo_local.h"

namespace vpo
{


//
// opening
//

// Here comes the obnoxious "visplane".
visplane_t		visplanes[MAXVISPLANES+10];
visplane_t*		lastvisplane;
visplane_t*		floorplane;
visplane_t*		ceilingplane;

int total_visplanes;

short			openings[MAXOPENINGS+400];
short*			lastopening;

int total_openings;


//
// Clip values are the solid pixel bounding the range.
//  floorclip starts out SCREENHEIGHT
//  ceilingclip starts out -1
//
short			floorclip[SCREENWIDTH];
short			ceilingclip[SCREENWIDTH];

//
// spanstart holds the start of a plane span
// initialized to 0 at start
//
int			spanstart[SCREENHEIGHT];
int			spanstop[SCREENHEIGHT];

//
// texture mapping
//
fixed_t			planeheight;

fixed_t			yslope[SCREENHEIGHT];
fixed_t			distscale[SCREENWIDTH];
fixed_t			basexscale;
fixed_t			baseyscale;

fixed_t			cachedheight[SCREENHEIGHT];
fixed_t			cacheddistance[SCREENHEIGHT];
fixed_t			cachedxstep[SCREENHEIGHT];
fixed_t			cachedystep[SCREENHEIGHT];



#if 0
//
// R_MapPlane
//
// Uses global vars:
//  planeheight
//  ds_source
//  basexscale
//  baseyscale
//  viewx
//  viewy
//
// BASIC PRIMITIVE
//
void R_MapPlane ( int  y, int  x1, int  x2 )
{
    angle_t	angle;
    fixed_t	distance;
    fixed_t	length;
    unsigned	index;
	
#ifdef RANGECHECK
    if (x2 < x1
     || x1 < 0
     || x2 >= viewwidth
     || y > viewheight)
    {
	I_Error ("R_MapPlane: %i, %i at %i",x1,x2,y);
    }
#endif

    if (planeheight != cachedheight[y])
    {
	cachedheight[y] = planeheight;
	distance = cacheddistance[y] = FixedMul (planeheight, yslope[y]);
	ds_xstep = cachedxstep[y] = FixedMul (distance,basexscale);
	ds_ystep = cachedystep[y] = FixedMul (distance,baseyscale);
    }
    else
    {
	distance = cacheddistance[y];
	ds_xstep = cachedxstep[y];
	ds_ystep = cachedystep[y];
    }
	
    length = FixedMul (distance,distscale[x1]);
    angle = (viewangle + xtoviewangle[x1])>>ANGLETOFINESHIFT;
    ds_xfrac = viewx + FixedMul(finecosine[angle], length);
    ds_yfrac = -viewy - FixedMul(finesine[angle], length);

    if (fixedcolormap)
	ds_colormap = fixedcolormap;
    else
    {
	index = distance >> LIGHTZSHIFT;
	
	if (index >= MAXLIGHTZ )
	    index = MAXLIGHTZ-1;

	ds_colormap = planezlight[index];
    }
	
    ds_y = y;
    ds_x1 = x1;
    ds_x2 = x2;

    // high or low detail
    spanfunc ();	
}
#endif


//
// R_ClearPlanes
// At begining of frame.
//
void R_ClearPlanes (void)
{
    int		i;
    angle_t	angle;
    
    // opening / clipping determination
    for (i=0 ; i<viewwidth ; i++)
    {
	floorclip[i] = viewheight;
	ceilingclip[i] = -1;
    }

    total_visplanes = 0;
    total_openings  = 0;

    lastvisplane = visplanes;
    lastopening = openings;

    // texture calculation
    memset (cachedheight, 0, sizeof(cachedheight));

    // left to right mapping
    angle = (viewangle-ANG90)>>ANGLETOFINESHIFT;
	
    // scale will be unit scale at SCREENWIDTH/2 distance
    basexscale = FixedDiv (finecosine[angle],centerxfrac);
    baseyscale = -FixedDiv (finesine[angle],centerxfrac);
}




//
// R_FindPlane
//
visplane_t* R_FindPlane ( fixed_t height, int  picnum, int  lightlevel )
{
    visplane_t*	check;
	
    if (picnum == skyflatnum)
    {
	height = 0;			// all skys map together
	lightlevel = 0;
    }
	
    for (check=visplanes; check<lastvisplane; check++)
    {
	if (height == check->height
	    && picnum == check->picnum
	    && lightlevel == check->lightlevel)
	{
	    break;
	}
    }
    
			
    if (check < lastvisplane)
	return check;
		
    if (total_visplanes >= MAXVISPLANES)
      throw overflow_exception(); // I_Error ("R_FindPlane: no more visplanes");
		
    total_visplanes++;
    lastvisplane++;

    check->height = height;
    check->picnum = picnum;
    check->lightlevel = lightlevel;
    check->minx = SCREENWIDTH;
    check->maxx = -1;
    
    memset (check->top,0xff,sizeof(check->top));
		
    return check;
}


//
// R_CheckPlane
//
visplane_t* R_CheckPlane ( visplane_t* pl, int  start, int  stop )
{
    int		intrl;
    int		intrh;
    int		unionl;
    int		unionh;
    int		x;
	
    if (start < pl->minx)
    {
	intrl = pl->minx;
	unionl = start;
    }
    else
    {
	unionl = pl->minx;
	intrl = start;
    }
	
    if (stop > pl->maxx)
    {
	intrh = pl->maxx;
	unionh = stop;
    }
    else
    {
	unionh = pl->maxx;
	intrh = stop;
    }

    for (x=intrl ; x<= intrh ; x++)
	if (pl->top[x] != 0xff)
	    break;

    if (x > intrh)
    {
	pl->minx = unionl;
	pl->maxx = unionh;

	// use the same one
	return pl;		
    }
	
    // make a new visplane
    lastvisplane->height = pl->height;
    lastvisplane->picnum = pl->picnum;
    lastvisplane->lightlevel = pl->lightlevel;
    
    if (total_visplanes >= MAXVISPLANES)
      throw overflow_exception(); // I_Error ("R_FindPlane: no more visplanes");

    total_visplanes++;

    pl = lastvisplane++;
    pl->minx = start;
    pl->maxx = stop;

    memset (pl->top,0xff,sizeof(pl->top));

    return pl;
}


#if 0
//
// R_MakeSpans
//
void R_MakeSpans ( int  x, int  t1, int  b1, int  t2, int  b2 )
{
    while (t1 < t2 && t1<=b1)
    {
	R_MapPlane (t1,spanstart[t1],x-1);
	t1++;
    }
    while (b1 > b2 && b1>=t1)
    {
	R_MapPlane (b1,spanstart[b1],x-1);
	b1--;
    }
	
    while (t2 < t1 && t2<=b2)
    {
	spanstart[t2] = x;
	t2++;
    }
    while (b2 > b1 && b2>=t2)
    {
	spanstart[b2] = x;
	b2--;
    }
}
#endif



#if 0
    was: R_DrawPlanes()

				
    if (ds_p - drawsegs > MAXDRAWSEGS)
	I_Error ("R_DrawPlanes: drawsegs overflow (%i)",
		 ds_p - drawsegs);
    
    if (lastvisplane - visplanes > MAXVISPLANES)
	I_Error ("R_DrawPlanes: visplane overflow (%i)",
		 lastvisplane - visplanes);
    
    if (lastopening - openings > MAXOPENINGS)
	I_Error ("R_DrawPlanes: opening overflow (%i)",
		 lastopening - openings);
#endif


} // namespace vpo