ref: 94e26e7576fabcaacd8fa8f75c4f87f9eb6e56f3
dir: /sys/src/games/doom/r_plane.c/
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// $Log:$
//
// 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.
//
//-----------------------------------------------------------------------------
static const char
rcsid[] = "$Id: r_plane.c,v 1.4 1997/02/03 16:47:55 b1 Exp $";
#include "i_system.h"
#include "z_zone.h"
#include "w_wad.h"
#include "doomdef.h"
#include "doomstat.h"
#include "r_local.h"
#include "r_sky.h"
planefunction_t floorfunc;
planefunction_t ceilingfunc;
//
// opening
//
// Here comes the obnoxious "visplane".
#define MAXVISPLANES 128
visplane_t visplanes[MAXVISPLANES];
visplane_t* lastvisplane;
visplane_t* floorplane;
visplane_t* ceilingplane;
// ?
#define MAXOPENINGS SCREENWIDTH*64
short openings[MAXOPENINGS];
short* lastopening;
//
// 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
//
lighttable_t** planezlight;
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];
//
// R_InitPlanes
// Only at game startup.
//
void R_InitPlanes (void)
{
// Doh!
}
//
// 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
|| (unsigned)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 ();
}
//
// 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;
}
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 (lastvisplane - visplanes == MAXVISPLANES)
I_Error ("R_FindPlane: no more 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;
pl = lastvisplane++;
pl->minx = start;
pl->maxx = stop;
memset (pl->top,0xff,sizeof(pl->top));
return pl;
}
//
// 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--;
}
}
//
// R_DrawPlanes
// At the end of each frame.
//
void R_DrawPlanes (void)
{
visplane_t* pl;
int light;
int x;
int stop;
int angle;
#ifdef RANGECHECK
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
for (pl = visplanes ; pl < lastvisplane ; pl++)
{
if (pl->minx > pl->maxx)
continue;
// sky flat
if (pl->picnum == skyflatnum)
{
dc_iscale = pspriteiscale>>detailshift;
// Sky is allways drawn full bright,
// i.e. colormaps[0] is used.
// Because of this hack, sky is not affected
// by INVUL inverse mapping.
dc_colormap = colormaps;
dc_texturemid = skytexturemid;
for (x=pl->minx ; x <= pl->maxx ; x++)
{
dc_yl = pl->top[x];
dc_yh = pl->bottom[x];
if (dc_yl <= dc_yh)
{
angle = (viewangle + xtoviewangle[x])>>ANGLETOSKYSHIFT;
dc_x = x;
dc_source = R_GetColumn(skytexture, angle);
colfunc ();
}
}
continue;
}
// regular flat
ds_source = W_CacheLumpNum(firstflat +
flattranslation[pl->picnum],
PU_STATIC);
planeheight = abs(pl->height-viewz);
light = (pl->lightlevel >> LIGHTSEGSHIFT)+extralight;
if (light >= LIGHTLEVELS)
light = LIGHTLEVELS-1;
if (light < 0)
light = 0;
planezlight = zlight[light];
pl->top[pl->maxx+1] = 0xff;
pl->top[pl->minx-1] = 0xff;
stop = pl->maxx + 1;
for (x=pl->minx ; x<= stop ; x++)
{
R_MakeSpans(x,pl->top[x-1],
pl->bottom[x-1],
pl->top[x],
pl->bottom[x]);
}
Z_ChangeTag (ds_source, PU_CACHE);
}
}