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-rw-r--r--src/doom/r_plane.c454
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diff --git a/src/doom/r_plane.c b/src/doom/r_plane.c
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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:
+// 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 <stdio.h>
+#include <stdlib.h>
+
+#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
+ || 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;
+ int lumpnum;
+
+#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
+ lumpnum = firstflat + flattranslation[pl->picnum];
+ ds_source = W_CacheLumpNum(lumpnum, 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]);
+ }
+
+ W_ReleaseLumpNum(lumpnum);
+ }
+}