summaryrefslogtreecommitdiff
path: root/src/strife/r_segs.c
blob: 29ed32a53f080bb88d6f83c6093de31f6ea7a8f3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
// 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:
//	All the clipping: columns, horizontal spans, sky columns.
//
//-----------------------------------------------------------------------------






#include <stdio.h>
#include <stdlib.h>

#include "i_system.h"

#include "doomdef.h"
#include "doomstat.h"

#include "r_local.h"
#include "r_sky.h"


// OPTIMIZE: closed two sided lines as single sided

// True if any of the segs textures might be visible.
boolean		segtextured;	

// False if the back side is the same plane.
boolean		markfloor;	
boolean		markceiling;

boolean		maskedtexture;
int		toptexture;
int		bottomtexture;
int		midtexture;


angle_t		rw_normalangle;
// angle to line origin
int		rw_angle1;	

//
// regular wall
//
int		rw_x;
int		rw_stopx;
angle_t		rw_centerangle;
fixed_t		rw_offset;
fixed_t		rw_distance;
fixed_t		rw_scale;
fixed_t		rw_scalestep;
fixed_t		rw_midtexturemid;
fixed_t		rw_toptexturemid;
fixed_t		rw_bottomtexturemid;

int		worldtop;
int		worldbottom;
int		worldhigh;
int		worldlow;

fixed_t		pixhigh;
fixed_t		pixlow;
fixed_t		pixhighstep;
fixed_t		pixlowstep;

fixed_t		topfrac;
fixed_t		topstep;

fixed_t		bottomfrac;
fixed_t		bottomstep;


lighttable_t**	walllights;

short*		maskedtexturecol;



//
// R_RenderMaskedSegRange
//
void
R_RenderMaskedSegRange
( drawseg_t*	ds,
  int		x1,
  int		x2 )
{
    unsigned	index;
    column_t*	col;
    int		lightnum;
    int		texnum;
    
    // Calculate light table.
    // Use different light tables
    //   for horizontal / vertical / diagonal. Diagonal?
    // OPTIMIZE: get rid of LIGHTSEGSHIFT globally
    curline = ds->curline;
    frontsector = curline->frontsector;
    backsector = curline->backsector;
    texnum = texturetranslation[curline->sidedef->midtexture];
	
    lightnum = (frontsector->lightlevel >> LIGHTSEGSHIFT)+extralight;

    if (curline->v1->y == curline->v2->y)
	lightnum--;
    else if (curline->v1->x == curline->v2->x)
	lightnum++;

    if (lightnum < 0)		
	walllights = scalelight[0];
    else if (lightnum >= LIGHTLEVELS)
	walllights = scalelight[LIGHTLEVELS-1];
    else
	walllights = scalelight[lightnum];

    maskedtexturecol = ds->maskedtexturecol;

    rw_scalestep = ds->scalestep;		
    spryscale = ds->scale1 + (x1 - ds->x1)*rw_scalestep;
    mfloorclip = ds->sprbottomclip;
    mceilingclip = ds->sprtopclip;
    
    // find positioning
    if (curline->linedef->flags & ML_DONTPEGBOTTOM)
    {
	dc_texturemid = frontsector->floorheight > backsector->floorheight
	    ? frontsector->floorheight : backsector->floorheight;
	dc_texturemid = dc_texturemid + textureheight[texnum] - viewz;
    }
    else
    {
	dc_texturemid =frontsector->ceilingheight<backsector->ceilingheight
	    ? frontsector->ceilingheight : backsector->ceilingheight;
	dc_texturemid = dc_texturemid - viewz;
    }
    dc_texturemid += curline->sidedef->rowoffset;
			
    if (fixedcolormap)
	dc_colormap = fixedcolormap;
    
    // draw the columns
    for (dc_x = x1 ; dc_x <= x2 ; dc_x++)
    {
	// calculate lighting
	if (maskedtexturecol[dc_x] != SHRT_MAX)
	{
	    if (!fixedcolormap)
	    {
		index = spryscale>>LIGHTSCALESHIFT;

		if (index >=  MAXLIGHTSCALE )
		    index = MAXLIGHTSCALE-1;

		dc_colormap = walllights[index];
	    }
			
	    sprtopscreen = centeryfrac - FixedMul(dc_texturemid, spryscale);
	    dc_iscale = 0xffffffffu / (unsigned)spryscale;
	    
	    // draw the texture
	    col = (column_t *)( 
		(byte *)R_GetColumn(texnum,maskedtexturecol[dc_x]) -3);
			
	    R_DrawMaskedColumn (col);
	    maskedtexturecol[dc_x] = SHRT_MAX;
	}
	spryscale += rw_scalestep;
    }
	
}




//
// R_RenderSegLoop
// Draws zero, one, or two textures (and possibly a masked
//  texture) for walls.
// Can draw or mark the starting pixel of floor and ceiling
//  textures.
// CALLED: CORE LOOPING ROUTINE.
//
#define HEIGHTBITS		12
#define HEIGHTUNIT		(1<<HEIGHTBITS)

void R_RenderSegLoop (void)
{
    angle_t		angle;
    unsigned		index;
    int			yl;
    int			yh;
    int			mid;
    fixed_t		texturecolumn;
    int			top;
    int			bottom;

    for ( ; rw_x < rw_stopx ; rw_x++)
    {
	// mark floor / ceiling areas
	yl = (topfrac+HEIGHTUNIT-1)>>HEIGHTBITS;

	// no space above wall?
	if (yl < ceilingclip[rw_x]+1)
	    yl = ceilingclip[rw_x]+1;
	
	if (markceiling)
	{
	    top = ceilingclip[rw_x]+1;
	    bottom = yl-1;

	    if (bottom >= floorclip[rw_x])
		bottom = floorclip[rw_x]-1;

	    if (top <= bottom)
	    {
		ceilingplane->top[rw_x] = top;
		ceilingplane->bottom[rw_x] = bottom;
	    }
	}
		
	yh = bottomfrac>>HEIGHTBITS;

	if (yh >= floorclip[rw_x])
	    yh = floorclip[rw_x]-1;

	if (markfloor)
	{
	    top = yh+1;
	    bottom = floorclip[rw_x]-1;
	    if (top <= ceilingclip[rw_x])
		top = ceilingclip[rw_x]+1;
	    if (top <= bottom)
	    {
		floorplane->top[rw_x] = top;
		floorplane->bottom[rw_x] = bottom;
	    }
	}
	
	// texturecolumn and lighting are independent of wall tiers
	if (segtextured)
	{
	    // calculate texture offset
	    angle = (rw_centerangle + xtoviewangle[rw_x])>>ANGLETOFINESHIFT;
	    texturecolumn = rw_offset-FixedMul(finetangent[angle],rw_distance);
	    texturecolumn >>= FRACBITS;
	    // calculate lighting
	    index = rw_scale>>LIGHTSCALESHIFT;

	    if (index >=  MAXLIGHTSCALE )
		index = MAXLIGHTSCALE-1;

	    dc_colormap = walllights[index];
	    dc_x = rw_x;
	    dc_iscale = 0xffffffffu / (unsigned)rw_scale;
	}
        else
        {
            // purely to shut up the compiler

            texturecolumn = 0;
        }
	
	// draw the wall tiers
	if (midtexture)
	{
	    // single sided line
	    dc_yl = yl;
	    dc_yh = yh;
	    dc_texturemid = rw_midtexturemid;
	    dc_source = R_GetColumn(midtexture,texturecolumn);
	    colfunc ();
	    ceilingclip[rw_x] = viewheight;
	    floorclip[rw_x] = -1;
	}
	else
	{
	    // two sided line
	    if (toptexture)
	    {
		// top wall
		mid = pixhigh>>HEIGHTBITS;
		pixhigh += pixhighstep;

		if (mid >= floorclip[rw_x])
		    mid = floorclip[rw_x]-1;

		if (mid >= yl)
		{
		    dc_yl = yl;
		    dc_yh = mid;
		    dc_texturemid = rw_toptexturemid;
		    dc_source = R_GetColumn(toptexture,texturecolumn);
		    colfunc ();
		    ceilingclip[rw_x] = mid;
		}
		else
		    ceilingclip[rw_x] = yl-1;
	    }
	    else
	    {
		// no top wall
		if (markceiling)
		    ceilingclip[rw_x] = yl-1;
	    }
			
	    if (bottomtexture)
	    {
		// bottom wall
		mid = (pixlow+HEIGHTUNIT-1)>>HEIGHTBITS;
		pixlow += pixlowstep;

		// no space above wall?
		if (mid <= ceilingclip[rw_x])
		    mid = ceilingclip[rw_x]+1;
		
		if (mid <= yh)
		{
		    dc_yl = mid;
		    dc_yh = yh;
		    dc_texturemid = rw_bottomtexturemid;
		    dc_source = R_GetColumn(bottomtexture,
					    texturecolumn);
		    colfunc ();
		    floorclip[rw_x] = mid;
		}
		else
		    floorclip[rw_x] = yh+1;
	    }
	    else
	    {
		// no bottom wall
		if (markfloor)
		    floorclip[rw_x] = yh+1;
	    }
			
	    if (maskedtexture)
	    {
		// save texturecol
		//  for backdrawing of masked mid texture
		maskedtexturecol[rw_x] = texturecolumn;
	    }
	}
		
	rw_scale += rw_scalestep;
	topfrac += topstep;
	bottomfrac += bottomstep;
    }
}




//
// R_StoreWallRange
// A wall segment will be drawn
//  between start and stop pixels (inclusive).
//
void
R_StoreWallRange
( int	start,
  int	stop )
{
    fixed_t		hyp;
    fixed_t		sineval;
    angle_t		distangle, offsetangle;
    fixed_t		vtop;
    int			lightnum;

    // don't overflow and crash
    if (ds_p == &drawsegs[MAXDRAWSEGS])
	return;		
		
#ifdef RANGECHECK
    if (start >=viewwidth || start > stop)
	I_Error ("Bad R_RenderWallRange: %i to %i", start , stop);
#endif
    
    sidedef = curline->sidedef;
    linedef = curline->linedef;

    // mark the segment as visible for auto map
    linedef->flags |= ML_MAPPED;
    
    // calculate rw_distance for scale calculation
    rw_normalangle = curline->angle + ANG90;
    offsetangle = abs(rw_normalangle-rw_angle1);
    
    if (offsetangle > ANG90)
	offsetangle = ANG90;

    distangle = ANG90 - offsetangle;
    hyp = R_PointToDist (curline->v1->x, curline->v1->y);
    sineval = finesine[distangle>>ANGLETOFINESHIFT];
    rw_distance = FixedMul (hyp, sineval);
		
	
    ds_p->x1 = rw_x = start;
    ds_p->x2 = stop;
    ds_p->curline = curline;
    rw_stopx = stop+1;
    
    // calculate scale at both ends and step
    ds_p->scale1 = rw_scale = 
	R_ScaleFromGlobalAngle (viewangle + xtoviewangle[start]);
    
    if (stop > start )
    {
	ds_p->scale2 = R_ScaleFromGlobalAngle (viewangle + xtoviewangle[stop]);
	ds_p->scalestep = rw_scalestep = 
	    (ds_p->scale2 - rw_scale) / (stop-start);
    }
    else
    {
	// UNUSED: try to fix the stretched line bug
#if 0
	if (rw_distance < FRACUNIT/2)
	{
	    fixed_t		trx,try;
	    fixed_t		gxt,gyt;

	    trx = curline->v1->x - viewx;
	    try = curline->v1->y - viewy;
			
	    gxt = FixedMul(trx,viewcos); 
	    gyt = -FixedMul(try,viewsin); 
	    ds_p->scale1 = FixedDiv(projection, gxt-gyt)<<detailshift;
	}
#endif
	ds_p->scale2 = ds_p->scale1;
    }
    
    // calculate texture boundaries
    //  and decide if floor / ceiling marks are needed
    worldtop = frontsector->ceilingheight - viewz;
    worldbottom = frontsector->floorheight - viewz;
	
    midtexture = toptexture = bottomtexture = maskedtexture = 0;
    ds_p->maskedtexturecol = NULL;
	
    if (!backsector)
    {
	// single sided line
	midtexture = texturetranslation[sidedef->midtexture];
	// a single sided line is terminal, so it must mark ends
	markfloor = markceiling = true;
	if (linedef->flags & ML_DONTPEGBOTTOM)
	{
	    vtop = frontsector->floorheight +
		textureheight[sidedef->midtexture];
	    // bottom of texture at bottom
	    rw_midtexturemid = vtop - viewz;	
	}
	else
	{
	    // top of texture at top
	    rw_midtexturemid = worldtop;
	}
	rw_midtexturemid += sidedef->rowoffset;

	ds_p->silhouette = SIL_BOTH;
	ds_p->sprtopclip = screenheightarray;
	ds_p->sprbottomclip = negonearray;
	ds_p->bsilheight = INT_MAX;
	ds_p->tsilheight = INT_MIN;
    }
    else
    {
	// two sided line
	ds_p->sprtopclip = ds_p->sprbottomclip = NULL;
	ds_p->silhouette = 0;
	
	if (frontsector->floorheight > backsector->floorheight)
	{
	    ds_p->silhouette = SIL_BOTTOM;
	    ds_p->bsilheight = frontsector->floorheight;
	}
	else if (backsector->floorheight > viewz)
	{
	    ds_p->silhouette = SIL_BOTTOM;
	    ds_p->bsilheight = INT_MAX;
	    // ds_p->sprbottomclip = negonearray;
	}
	
	if (frontsector->ceilingheight < backsector->ceilingheight)
	{
	    ds_p->silhouette |= SIL_TOP;
	    ds_p->tsilheight = frontsector->ceilingheight;
	}
	else if (backsector->ceilingheight < viewz)
	{
	    ds_p->silhouette |= SIL_TOP;
	    ds_p->tsilheight = INT_MIN;
	    // ds_p->sprtopclip = screenheightarray;
	}
		
	if (backsector->ceilingheight <= frontsector->floorheight)
	{
	    ds_p->sprbottomclip = negonearray;
	    ds_p->bsilheight = INT_MAX;
	    ds_p->silhouette |= SIL_BOTTOM;
	}
	
	if (backsector->floorheight >= frontsector->ceilingheight)
	{
	    ds_p->sprtopclip = screenheightarray;
	    ds_p->tsilheight = INT_MIN;
	    ds_p->silhouette |= SIL_TOP;
	}
	
	worldhigh = backsector->ceilingheight - viewz;
	worldlow = backsector->floorheight - viewz;
		
	// hack to allow height changes in outdoor areas
	if (frontsector->ceilingpic == skyflatnum 
	    && backsector->ceilingpic == skyflatnum)
	{
	    worldtop = worldhigh;
	}
	
			
	if (worldlow != worldbottom 
	    || backsector->floorpic != frontsector->floorpic
	    || backsector->lightlevel != frontsector->lightlevel)
	{
	    markfloor = true;
	}
	else
	{
	    // same plane on both sides
	    markfloor = false;
	}
	
			
	if (worldhigh != worldtop 
	    || backsector->ceilingpic != frontsector->ceilingpic
	    || backsector->lightlevel != frontsector->lightlevel)
	{
	    markceiling = true;
	}
	else
	{
	    // same plane on both sides
	    markceiling = false;
	}
	
	if (backsector->ceilingheight <= frontsector->floorheight
	    || backsector->floorheight >= frontsector->ceilingheight)
	{
	    // closed door
	    markceiling = markfloor = true;
	}
	

	if (worldhigh < worldtop)
	{
	    // top texture
	    toptexture = texturetranslation[sidedef->toptexture];
	    if (linedef->flags & ML_DONTPEGTOP)
	    {
		// top of texture at top
		rw_toptexturemid = worldtop;
	    }
	    else
	    {
		vtop =
		    backsector->ceilingheight
		    + textureheight[sidedef->toptexture];
		
		// bottom of texture
		rw_toptexturemid = vtop - viewz;	
	    }
	}
	if (worldlow > worldbottom)
	{
	    // bottom texture
	    bottomtexture = texturetranslation[sidedef->bottomtexture];

	    if (linedef->flags & ML_DONTPEGBOTTOM )
	    {
		// bottom of texture at bottom
		// top of texture at top
		rw_bottomtexturemid = worldtop;
	    }
	    else	// top of texture at top
		rw_bottomtexturemid = worldlow;
	}
	rw_toptexturemid += sidedef->rowoffset;
	rw_bottomtexturemid += sidedef->rowoffset;
	
	// allocate space for masked texture tables
	if (sidedef->midtexture)
	{
	    // masked midtexture
	    maskedtexture = true;
	    ds_p->maskedtexturecol = maskedtexturecol = lastopening - rw_x;
	    lastopening += rw_stopx - rw_x;
	}
    }
    
    // calculate rw_offset (only needed for textured lines)
    segtextured = midtexture | toptexture | bottomtexture | maskedtexture;

    if (segtextured)
    {
	offsetangle = rw_normalangle-rw_angle1;
	
	if (offsetangle > ANG180)
	    offsetangle = -offsetangle;

	if (offsetangle > ANG90)
	    offsetangle = ANG90;

	sineval = finesine[offsetangle >>ANGLETOFINESHIFT];
	rw_offset = FixedMul (hyp, sineval);

	if (rw_normalangle-rw_angle1 < ANG180)
	    rw_offset = -rw_offset;

	rw_offset += sidedef->textureoffset + curline->offset;
	rw_centerangle = ANG90 + viewangle - rw_normalangle;
	
	// calculate light table
	//  use different light tables
	//  for horizontal / vertical / diagonal
	// OPTIMIZE: get rid of LIGHTSEGSHIFT globally
	if (!fixedcolormap)
	{
	    lightnum = (frontsector->lightlevel >> LIGHTSEGSHIFT)+extralight;

	    if (curline->v1->y == curline->v2->y)
		lightnum--;
	    else if (curline->v1->x == curline->v2->x)
		lightnum++;

	    if (lightnum < 0)		
		walllights = scalelight[0];
	    else if (lightnum >= LIGHTLEVELS)
		walllights = scalelight[LIGHTLEVELS-1];
	    else
		walllights = scalelight[lightnum];
	}
    }
    
    // if a floor / ceiling plane is on the wrong side
    //  of the view plane, it is definitely invisible
    //  and doesn't need to be marked.
    
  
    if (frontsector->floorheight >= viewz)
    {
	// above view plane
	markfloor = false;
    }
    
    if (frontsector->ceilingheight <= viewz 
	&& frontsector->ceilingpic != skyflatnum)
    {
	// below view plane
	markceiling = false;
    }

    
    // calculate incremental stepping values for texture edges
    worldtop >>= 4;
    worldbottom >>= 4;
	
    topstep = -FixedMul (rw_scalestep, worldtop);
    topfrac = (centeryfrac>>4) - FixedMul (worldtop, rw_scale);

    bottomstep = -FixedMul (rw_scalestep,worldbottom);
    bottomfrac = (centeryfrac>>4) - FixedMul (worldbottom, rw_scale);
	
    if (backsector)
    {	
	worldhigh >>= 4;
	worldlow >>= 4;

	if (worldhigh < worldtop)
	{
	    pixhigh = (centeryfrac>>4) - FixedMul (worldhigh, rw_scale);
	    pixhighstep = -FixedMul (rw_scalestep,worldhigh);
	}
	
	if (worldlow > worldbottom)
	{
	    pixlow = (centeryfrac>>4) - FixedMul (worldlow, rw_scale);
	    pixlowstep = -FixedMul (rw_scalestep,worldlow);
	}
    }
    
    // render it
    if (markceiling)
	ceilingplane = R_CheckPlane (ceilingplane, rw_x, rw_stopx-1);
    
    if (markfloor)
	floorplane = R_CheckPlane (floorplane, rw_x, rw_stopx-1);

    R_RenderSegLoop ();

    
    // save sprite clipping info
    if ( ((ds_p->silhouette & SIL_TOP) || maskedtexture)
	 && !ds_p->sprtopclip)
    {
	memcpy (lastopening, ceilingclip+start, 2*(rw_stopx-start));
	ds_p->sprtopclip = lastopening - start;
	lastopening += rw_stopx - start;
    }
    
    if ( ((ds_p->silhouette & SIL_BOTTOM) || maskedtexture)
	 && !ds_p->sprbottomclip)
    {
	memcpy (lastopening, floorclip+start, 2*(rw_stopx-start));
	ds_p->sprbottomclip = lastopening - start;
	lastopening += rw_stopx - start;	
    }

    if (maskedtexture && !(ds_p->silhouette&SIL_TOP))
    {
	ds_p->silhouette |= SIL_TOP;
	ds_p->tsilheight = INT_MIN;
    }
    if (maskedtexture && !(ds_p->silhouette&SIL_BOTTOM))
    {
	ds_p->silhouette |= SIL_BOTTOM;
	ds_p->bsilheight = INT_MAX;
    }
    ds_p++;
}