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root/radiance/ray/src/hd/rhd_odraw.c
Revision: 3.7
Committed: Wed Dec 23 21:49:43 1998 UTC (25 years, 4 months ago) by gwlarson
Content type: text/plain
Branch: MAIN
Changes since 3.6: +4 -4 lines
Log Message:
changed edge clipping to include boundary and avoid black edges

File Contents

# User Rev Content
1 gwlarson 3.1 /* Copyright (c) 1998 Silicon Graphics, Inc. */
2    
3     #ifndef lint
4     static char SCCSid[] = "$SunId$ SGI";
5     #endif
6    
7     /*
8     * Routines for drawing samples using depth buffer checks.
9     */
10    
11     #include "standard.h"
12    
13     #include <sys/types.h>
14     #include <GL/glx.h>
15     #include <GL/glu.h>
16    
17     #include "rhd_odraw.h"
18    
19     #ifndef DEPTHEPS
20     #define DEPTHEPS 0.02 /* depth epsilon */
21     #endif
22     #ifndef SAMPSPERBLOCK
23     #define SAMPSPERBLOCK 1024 /* target samples per image block */
24     #endif
25     #ifndef SFREEFRAC
26     #define SFREEFRAC 0.2 /* fraction to free at a time */
27     #endif
28     #ifndef MAXFAN
29     #define MAXFAN 32 /* maximum arms in a triangle fan */
30     #endif
31     #ifndef MINFAN
32     #define MINFAN 4 /* minimum arms in a triangle fan */
33     #endif
34     #ifndef FANSIZE
35     #define FANSIZE 3.5 /* fan sizing factor */
36     #endif
37    
38     #define NEWMAP 01 /* need to recompute mapping */
39     #define NEWRGB 02 /* need to remap RGB values */
40 gwlarson 3.2 #define NEWHIST 04 /* clear histogram as well */
41 gwlarson 3.1
42     struct ODview *odView; /* our view list */
43     int odNViews; /* number of views in our list */
44    
45     struct ODsamp odS; /* sample values */
46    
47     static int needmapping; /* what needs doing with tone map */
48    
49    
50     #define SAMP32 (32*(2*sizeof(short)+sizeof(union ODfunion)+sizeof(TMbright)+\
51     6*sizeof(BYTE))+sizeof(int4))
52    
53     int
54     odInit(n) /* initialize drawing routines */
55     int n;
56     {
57     int nbytes, i, j, k, nextsamp, count, blockdiv;
58     int res[2];
59    
60 gwlarson 3.3 if (odNViews > 0) { /* deallocate view structures */
61     for (i = odNViews; i--; ) {
62 gwlarson 3.1 free((char *)odView[i].bmap);
63 gwlarson 3.3 free((char *)odView[i].pmap);
64 gwlarson 3.1 if (odView[i].emap != NULL)
65     free((char *)odView[i].emap);
66     }
67     free((char *)odView);
68     odView = NULL;
69     odNViews = 0;
70     }
71     if (n && n != odS.nsamp) {
72     /* round space up to nearest power of 2 */
73     nbytes = (n+31)/32 * SAMP32;
74     for (i = 1024; nbytes > i-8; i <<= 1)
75     ;
76     n = (i-8)/SAMP32 * 32;
77 gwlarson 3.2 needmapping = NEWHIST;
78 gwlarson 3.1 }
79     if (n != odS.nsamp) { /* (re)allocate sample array */
80     if (odS.nsamp)
81     free(odS.base);
82     odS.nsamp = 0;
83     if (!n)
84     return(0);
85     nbytes = (n+31)/32 * SAMP32;
86     odS.base = (char *)malloc(nbytes);
87     if (odS.base == NULL)
88     return(0);
89     /* assign larger alignment types earlier */
90     odS.f = (union ODfunion *)odS.base;
91     odS.redraw = (int4 *)(odS.f + n);
92     odS.ip = (short (*)[2])(odS.redraw + n/32);
93     odS.brt = (TMbright *)(odS.ip + n);
94     odS.chr = (BYTE (*)[3])(odS.brt + n);
95     odS.rgb = (BYTE (*)[3])(odS.chr + n);
96     odS.nsamp = n;
97     }
98     if (!n)
99     return(0);
100     /* allocate view information */
101     count = 0; /* count pixels */
102     for (i = 0; dev_auxview(i, res) != NULL; i++)
103     count += res[0]*res[1];
104     odView = (struct ODview *)malloc(i*sizeof(struct ODview));
105     if (odView == NULL)
106     return(0);
107     odNViews = i;
108     blockdiv = sqrt(count/(n/SAMPSPERBLOCK)) + 0.5;
109     if (blockdiv < 8) blockdiv = 8;
110     nextsamp = 0; count /= blockdiv*blockdiv; /* # blocks */
111     while (i--) { /* initialize each view */
112     dev_auxview(i, res);
113     odView[i].hhi = res[0];
114     odView[i].hlow = (res[0] + blockdiv/2) / blockdiv;
115     if (odView[i].hlow < 1) odView[i].hlow = 1;
116     odView[i].vhi = res[1];
117     odView[i].vlow = (res[1] + blockdiv/2) / blockdiv;
118     if (odView[i].vlow < 1) odView[i].vlow = 1;
119 gwlarson 3.3 odView[i].emap = NULL;
120     odView[i].dmap = NULL;
121     odView[i].pmap = (int4 *)calloc(FL4NELS(res[0]*res[1]),
122     sizeof(int4));
123     if (odView[i].pmap == NULL)
124     return(0);
125 gwlarson 3.1 j = odView[i].hlow*odView[i].vlow;
126     odView[i].bmap = (struct ODblock *)malloc(
127     j * sizeof(struct ODblock));
128     if (odView[i].bmap == NULL)
129     return(0);
130     DCHECK(count<=0 | nextsamp>=n,
131     CONSISTENCY, "counter botch in odInit");
132     if (!i) count = j;
133 gwlarson 3.5 odView[i].sfirst = nextsamp;
134 gwlarson 3.2 while (j--) { /* initialize blocks & free lists */
135     odView[i].bmap[j].pthresh = FHUGE;
136 gwlarson 3.1 odView[i].bmap[j].first = k = nextsamp;
137     nextsamp += odView[i].bmap[j].nsamp =
138     (n - nextsamp)/count--;
139     odView[i].bmap[j].free = k;
140     while (++k < nextsamp)
141     odS.nextfree(k-1) = k;
142     odS.nextfree(k-1) = ENDFREE;
143     odView[i].bmap[j].nused = 0;
144     }
145 gwlarson 3.5 odView[i].snext = nextsamp;
146 gwlarson 3.1 }
147     CLR4ALL(odS.redraw, odS.nsamp); /* clear redraw flags */
148 gwlarson 3.2 for (i = odS.nsamp; i--; ) { /* clear values */
149 gwlarson 3.1 odS.ip[i][0] = odS.ip[i][1] = -1;
150 gwlarson 3.2 odS.brt[i] = TM_NOBRT;
151     }
152     needmapping |= NEWMAP; /* compute new map on update */
153 gwlarson 3.1 return(odS.nsamp); /* return number of samples */
154     }
155    
156     #undef SAMP32
157    
158    
159     int
160     sampcmp(s0, s1) /* sample order, descending proximity */
161     int *s0, *s1;
162     {
163     register double diff = odS.closeness(*s1) - odS.closeness(*s0);
164    
165     return (diff > FTINY ? 1 : diff < -FTINY ? -1 : 0);
166     }
167    
168    
169     int
170 gwlarson 3.2 odAllocBlockSamp(vn, hh, vh, prox) /* allocate sample from block */
171     int vn, hh, vh;
172     double prox;
173 gwlarson 3.1 {
174     int si[SAMPSPERBLOCK+SAMPSPERBLOCK/4];
175 gwlarson 3.2 int hl, vl;
176 gwlarson 3.1 VIEW *vw;
177     FVECT ro, rd;
178     int res[2];
179     register struct ODblock *bp;
180 gwlarson 3.2 register int i, j;
181     /* get block */
182     hl = hh*odView[vn].hlow/odView[vn].hhi;
183     vl = vh*odView[vn].vlow/odView[vn].vhi;
184 gwlarson 3.1 bp = odView[vn].bmap + vl*odView[vn].hlow + hl;
185 gwlarson 3.2 if (prox > bp->pthresh)
186     return(-1); /* worse than free list occupants */
187     /* check for duplicate pixel */
188 gwlarson 3.3 if (CHK4(odView[vn].pmap, vh*odView[vn].hhi + hh))
189     i = bp->first + bp->nsamp;
190     else
191     i = -1;
192     while (i-- > bp->first)
193 gwlarson 3.2 if (hh == odS.ip[i][0] && vh == odS.ip[i][1]) { /* found it! */
194     /* search free list for it */
195     if (i == bp->free)
196     break; /* special case */
197     if (bp->free != ENDFREE)
198     for (j = bp->free; odS.nextfree(j) != ENDFREE;
199     j = odS.nextfree(j))
200     if (odS.nextfree(j) == i) {
201     odS.nextfree(j) =
202     odS.nextfree(i);
203     bp->nused++;
204     goto gotit;
205     }
206     if (prox >= 0.999*odS.closeness(i))
207     return(-1); /* previous sample is fine */
208     goto gotit;
209     }
210 gwlarson 3.3 DCHECK(i>=-1, WARNING, "pixel in presence map not found in block");
211 gwlarson 3.2 if (bp->free != ENDFREE) { /* allocate from free list */
212 gwlarson 3.1 i = bp->free;
213 gwlarson 3.3 if (odS.ip[i][0] >= 0 & odS.ip[i][1] >= 0)
214     CLR4(odView[vn].pmap, odS.ip[i][1]*odView[vn].hhi +
215     odS.ip[i][0]);
216 gwlarson 3.1 bp->free = odS.nextfree(i);
217     bp->nused++;
218 gwlarson 3.2 goto gotit;
219 gwlarson 3.1 }
220     DCHECK(bp->nsamp<=0, CONSISTENCY,
221     "no available samples in odAllocBlockSamp");
222     DCHECK(bp->nsamp > sizeof(si)/sizeof(si[0]), CONSISTENCY,
223     "too many samples in odAllocBlockSamp");
224     /* free some samples */
225     if ((vw = dev_auxview(vn, res)) == NULL)
226     error(CONSISTENCY, "bad view number in odAllocBlockSamp");
227     for (i = bp->nsamp; i--; ) /* figure out which are worse */
228     si[i] = bp->first + i;
229     qsort((char *)si, bp->nsamp, sizeof(int), sampcmp);
230 gwlarson 3.2 i = bp->nsamp*SFREEFRAC + .5; /* put them into free list */
231     if (i >= bp->nsamp) i = bp->nsamp-1; /* paranoia */
232     bp->pthresh = odS.closeness(si[i]); /* new proximity threshold */
233 gwlarson 3.1 while (--i > 0) {
234     odS.nextfree(si[i]) = bp->free;
235     bp->free = si[i];
236     bp->nused--;
237     }
238 gwlarson 3.2 i = si[0]; /* use worst sample */
239 gwlarson 3.3 CLR4(odView[vn].pmap, odS.ip[i][1]*odView[vn].hhi + odS.ip[i][0]);
240 gwlarson 3.2 gotit:
241     odS.ip[i][0] = hh;
242     odS.ip[i][1] = vh;
243     odS.closeness(i) = prox;
244 gwlarson 3.3 SET4(odView[vn].pmap, vh*odView[vn].hhi + hh);
245 gwlarson 3.2 return(i);
246 gwlarson 3.1 }
247    
248    
249     odSample(c, d, p) /* add a sample value */
250     COLR c;
251     FVECT d, p;
252     {
253     FVECT disp;
254 gwlarson 3.2 double d0, d1, h, v, prox;
255 gwlarson 3.1 register VIEW *vw;
256 gwlarson 3.2 int hh, vh;
257 gwlarson 3.1 int res[2];
258     register int i, id;
259    
260     DCHECK(odS.nsamp<=0, CONSISTENCY, "no samples allocated in odSample");
261     /* add value to each view */
262     for (i = 0; (vw = dev_auxview(i, res)) != NULL; i++) {
263     DCHECK(i>=odNViews, CONSISTENCY, "too many views in odSample");
264     CHECK(vw->type!=VT_PER, INTERNAL,
265     "cannot handle non-perspective views");
266     if (p != NULL) { /* compute view position */
267     VSUB(disp, p, vw->vp);
268     d0 = DOT(disp, vw->vdir);
269     if (d0 <= vw->vfore+FTINY)
270     continue; /* too close */
271     } else {
272     VCOPY(disp, d);
273     d0 = DOT(disp, vw->vdir);
274     if (d0 <= FTINY) /* behind view */
275     continue;
276     }
277     h = DOT(disp,vw->hvec)/(d0*vw->hn2) + 0.5 - vw->hoff;
278     if (h < 0. || h >= 1.)
279     continue; /* left or right */
280     v = DOT(disp,vw->vvec)/(d0*vw->vn2) + 0.5 - vw->voff;
281     if (v < 0. || v >= 1.)
282     continue; /* above or below */
283     hh = h * res[0];
284     vh = v * res[1];
285     if (odView[i].dmap != NULL) { /* check depth */
286     d1 = odView[i].dmap[vh*res[0] + hh];
287     if (d1 < 0.99*FHUGE && (d0 > (1.+DEPTHEPS)*d1 ||
288     (1.+DEPTHEPS)*d0 < d1))
289     continue; /* occlusion error */
290     }
291     if (p != NULL) { /* compute closeness (sin^2) */
292     d1 = DOT(disp, d);
293 gwlarson 3.2 prox = 1. - d1*d1/DOT(disp,disp);
294 gwlarson 3.1 } else
295 gwlarson 3.2 prox = 0.;
296     /* allocate sample */
297     id = odAllocBlockSamp(i, hh, vh, prox);
298     if (id < 0)
299     continue; /* not good enough */
300 gwlarson 3.1 /* convert color */
301     tmCvColrs(&odS.brt[id], odS.chr[id], c, 1);
302     if (imm_mode | needmapping) /* if immediate mode */
303     needmapping |= NEWRGB; /* map it later */
304     else /* else map it now */
305     tmMapPixels(odS.rgb[id], &odS.brt[id], odS.chr[id], 1);
306     SET4(odS.redraw, id); /* mark for redraw */
307     }
308     }
309    
310    
311 gwlarson 3.2 odRemap(newhist) /* recompute tone mapping */
312     int newhist;
313 gwlarson 3.1 {
314     needmapping |= NEWMAP|NEWRGB;
315 gwlarson 3.2 if (newhist)
316     needmapping |= NEWHIST;
317 gwlarson 3.1 }
318    
319    
320 gwlarson 3.6 odRedrawAll() /* mark all samples for redraw */
321     {
322     register int i;
323    
324     if ((needmapping&(NEWMAP|NEWRGB)) == (NEWMAP|NEWRGB))
325     return; /* will be called later, anyway */
326     for (i = odS.nsamp; i--; )
327     if (odS.ip[i][0] >= 0)
328     SET4(odS.redraw, i);
329     }
330    
331    
332 gwlarson 3.1 odRedraw(vn, hmin, vmin, hmax, vmax) /* redraw view region */
333     int vn, hmin, vmin, hmax, vmax;
334     {
335     int i, j;
336     register struct ODblock *bp;
337     register int k;
338    
339     if (vn<0 | vn>=odNViews)
340     return;
341     /* check view limits */
342     if (hmin < 0) hmin = 0;
343     if (hmax >= odView[vn].hhi) hmax = odView[vn].hhi-1;
344     if (vmin < 0) vmin = 0;
345     if (vmax >= odView[vn].vhi) vmax = odView[vn].vhi-1;
346     if (hmax <= hmin | vmax <= vmin)
347     return;
348     /* convert to low resolution */
349     hmin = hmin * odView[vn].hlow / odView[vn].hhi;
350     hmax = hmax * odView[vn].hlow / odView[vn].hhi;
351     vmin = vmin * odView[vn].vlow / odView[vn].vhi;
352     vmax = vmax * odView[vn].vlow / odView[vn].vhi;
353     /* mark block samples for redraw, inclusive */
354     for (i = hmin; i <= hmax; i++)
355     for (j = vmin; j <= vmax; j++) {
356     bp = odView[vn].bmap + j*odView[vn].hlow + i;
357     for (k = bp->nsamp; k--; )
358     if (odS.ip[bp->first+k][0] >= 0)
359     SET4(odS.redraw, bp->first+k);
360     }
361     }
362    
363    
364     odDepthMap(vn, dm) /* assign depth map for view */
365     int vn;
366     GLfloat *dm;
367     {
368     double d0, d1;
369     int i, j, hmin, hmax, vmin, vmax;
370     register int k, l;
371    
372     if (dm == NULL) { /* free edge map */
373 gwlarson 3.2 if (vn<0 | vn>=odNViews)
374     return; /* too late -- they're gone! */
375 gwlarson 3.1 if (odView[vn].emap != NULL)
376     free((char *)odView[vn].emap);
377     odView[vn].emap = NULL;
378     odView[vn].dmap = NULL;
379     return;
380     }
381 gwlarson 3.2 DCHECK(vn<0 | vn>=odNViews, CONSISTENCY,
382     "bad view number in odDepthMap");
383 gwlarson 3.1 odView[vn].dmap = dm; /* initialize edge map */
384     if (odView[vn].emap == NULL) {
385     odView[vn].emap = (int4 *)malloc(
386     FL4NELS(odView[vn].hlow*odView[vn].vlow)*sizeof(int4));
387     if (odView[vn].emap == NULL)
388     error(SYSTEM, "out of memory in odDepthMap");
389     }
390     CLR4ALL(odView[vn].emap, odView[vn].hlow*odView[vn].vlow);
391     /* compute edge map */
392     vmin = odView[vn].vhi; /* enter loopsville */
393     for (j = odView[vn].vlow; j--; ) {
394     vmax = vmin;
395     vmin = j*odView[vn].vhi/odView[vn].vlow;
396     hmin = odView[vn].hhi;
397     for (i = odView[vn].hlow; i--; ) {
398     hmax = hmin;
399     hmin = i*odView[vn].hhi/odView[vn].hlow;
400     for (l = vmin; l < vmax; l++) { /* vertical edges */
401     d1 = dm[l*odView[vn].hhi+hmin];
402     for (k = hmin+1; k < hmax; k++) {
403     d0 = d1;
404     d1 = dm[l*odView[vn].hhi+k];
405     if (d0 > (1.+DEPTHEPS)*d1 ||
406     (1.+DEPTHEPS)*d0 < d1) {
407     SET4(odView[vn].emap,
408     j*odView[vn].hlow + i);
409     break;
410     }
411     }
412     if (k < hmax)
413     break;
414     }
415     if (l < vmax)
416     continue;
417     for (k = hmin; k < hmax; k++) { /* horizontal edges */
418     d1 = dm[vmin*odView[vn].hhi+k];
419     for (l = vmin+1; l < vmax; l++) {
420     d0 = d1;
421     d1 = dm[l*odView[vn].hhi+k];
422     if (d0 > (1.+DEPTHEPS)*d1 ||
423     (1.+DEPTHEPS)*d0 < d1) {
424     SET4(odView[vn].emap,
425     j*odView[vn].hlow + i);
426     break;
427     }
428     }
429     if (l < vmax)
430     break;
431     }
432     }
433     }
434     }
435    
436    
437     odUpdate(vn) /* update this view */
438     int vn;
439     {
440 gwlarson 3.4 register int i, j;
441 gwlarson 3.1
442     DCHECK(vn<0 | vn>=odNViews, CONSISTENCY,
443     "bad view number in odUpdate");
444     /* need to do some tone mapping? */
445     if (needmapping & NEWRGB) {
446     if (needmapping & NEWMAP) {
447 gwlarson 3.2 if (needmapping & NEWHIST)
448     tmClearHisto();
449 gwlarson 3.6 needmapping &= ~NEWHIST;
450 gwlarson 3.1 if (tmAddHisto(odS.brt,odS.nsamp,1) != TM_E_OK)
451     return;
452     if (tmComputeMapping(0.,0.,0.) != TM_E_OK)
453     return;
454 gwlarson 3.6 needmapping &= ~NEWMAP;
455     odRedrawAll(); /* redraw everything */
456 gwlarson 3.1 }
457     if (tmMapPixels(odS.rgb,odS.brt,odS.chr,odS.nsamp) != TM_E_OK)
458     return;
459 gwlarson 3.6 needmapping &= ~NEWRGB;
460 gwlarson 3.1 }
461 gwlarson 3.5 /* this code segment was too slow */
462     #if 0
463     for (i = odView[vn].sfirst; i < odView[vn].snext; i++)
464     if (CHK4(odS.redraw, i)) {
465     odDrawSamp(vn, i);
466     CLR4(odS.redraw, i);
467     }
468 gwlarson 3.6 #else
469 gwlarson 3.5 /* redraw samples at each end */
470     for (i = odView[vn].sfirst; i < odView[vn].sfirst+31; i++)
471     if (CHK4(odS.redraw, i)) {
472     odDrawSamp(vn, i);
473     CLR4(odS.redraw, i);
474     }
475     for (i = odView[vn].snext-31; i < odView[vn].snext; i++)
476     if (CHK4(odS.redraw, i)) {
477     odDrawSamp(vn, i);
478     CLR4(odS.redraw, i);
479     }
480     /* faster flag checks in middle */
481     for (j = odView[vn].snext>>5; j-- > (odView[vn].sfirst+0x1f)>>5; )
482 gwlarson 3.4 for (i = 0; odS.redraw[j]; i++) /* skips faster */
483     if (odS.redraw[j] & 1L<<i) {
484     odDrawSamp(vn, (j<<5)+i);
485     odS.redraw[j] &= ~(1L<<i);
486     }
487 gwlarson 3.6 #endif
488 gwlarson 3.1 }
489    
490    
491 gwlarson 3.5 /* this turned out to be unnecessary */
492 gwlarson 3.1 #if 0
493     static
494     clip_end(p, o, vp) /* clip line segment to view */
495     GLshort p[3];
496     short o[2];
497     register struct ODview *vp;
498     {
499     if (p[0] < 0) {
500     p[1] = -o[0]*(p[1]-o[1])/(p[0]-o[0]) + o[1];
501     p[2] = -o[0]*p[2]/(p[0]-o[0]);
502     p[0] = 0;
503     } else if (p[0] >= vp->hhi) {
504     p[1] = (vp->hhi-1-o[0])*(p[1]-o[1])/(p[0]-o[0]) + o[1];
505     p[2] = (vp->hhi-1-o[0])*p[2]/(p[0]-o[0]);
506     p[0] = vp->hhi-1;
507     }
508     if (p[1] < 0) {
509     p[0] = -o[1]*(p[0]-o[0])/(p[1]-o[1]) + o[0];
510     p[2] = -o[1]*p[2]/(p[1]-o[1]);
511     p[1] = 0;
512     } else if (p[1] >= vp->vhi) {
513     p[0] = (vp->vhi-1-o[1])*(p[0]-o[0])/(p[1]-o[1]) + o[0];
514     p[2] = (vp->vhi-1-o[1])*p[2]/(p[1]-o[1]);
515     p[1] = vp->vhi-1;
516     }
517     }
518     #endif
519    
520    
521     static int
522     make_arms(ar, cp, vp, sz) /* make arms for triangle fan */
523     GLshort ar[MAXFAN][3];
524     short cp[2];
525     register struct ODview *vp;
526     double sz;
527     {
528     int na, dv;
529 gwlarson 3.6 double hrad, vrad, phi;
530 gwlarson 3.1 register int i;
531    
532     DCHECK(sz > 1, CONSISTENCY, "super-unary size in make_arms");
533     na = MAXFAN*sz*sz + 0.5; /* keep area constant */
534     if (na < MINFAN) na = MINFAN;
535     hrad = FANSIZE*sz*vp->hhi/vp->hlow;
536     vrad = FANSIZE*sz*vp->vhi/vp->vlow;
537     if (hrad*vrad < 2.25)
538     hrad = vrad = 1.5;
539     dv = OMAXDEPTH*sz + 0.5;
540     for (i = 0; i < na; i++) {
541 gwlarson 3.6 phi = (2.*PI)*i/na;
542 gwlarson 3.1 ar[i][0] = cp[0] + tcos(phi)*hrad + 0.5;
543     ar[i][1] = cp[1] + tsin(phi)*vrad + 0.5;
544     ar[i][2] = dv;
545     /* clip_end(ar[i], cp, vp); */
546     }
547     return(na);
548     }
549    
550    
551     static int
552     depthchange(vp, x0, y0, x1, y1) /* check depth discontinuity */
553     register struct ODview *vp;
554     int x0, y0, x1, y1;
555     {
556     register double d0, d1;
557    
558     DCHECK(x0<0 | x0>=vp->hhi | y0<0 | y0>=vp->vhi,
559     CONSISTENCY, "coordinates off view in depthchange");
560    
561     if (x1<0 | x1>=vp->hhi | y1<0 | y1>=vp->vhi)
562     return(1);
563    
564     d0 = vp->dmap[y0*vp->hhi + x0];
565     d1 = vp->dmap[y1*vp->hhi + x1];
566    
567     return((1.+DEPTHEPS)*d0 < d1 || d0 > (1.+DEPTHEPS)*d1);
568     }
569    
570    
571     static
572     clip_edge(p, o, vp) /* clip line segment to depth edge */
573     GLshort p[3];
574     short o[2];
575     register struct ODview *vp;
576     {
577     int x, y, xstep, ystep, rise, rise2, run, run2, n;
578    
579     DCHECK(vp->dmap==NULL, CONSISTENCY,
580     "clip_edge called with no depth map");
581     x = o[0]; y = o[1];
582     run = p[0] - x;
583     xstep = run > 0 ? 1 : -1;
584     run *= xstep;
585     rise = p[1] - y;
586     ystep = rise > 0 ? 1 : -1;
587     rise *= ystep;
588     rise2 = run2 = 0;
589     if (rise > run) rise2 = 1;
590     else run2 = 1;
591     n = rise + run;
592     while (n--) /* run out arm, checking depth */
593     if (run2 > rise2) {
594     x += xstep;
595     rise2 += rise;
596 gwlarson 3.7 if (depthchange(vp, x-xstep, y, x, y))
597     break;
598 gwlarson 3.1 } else {
599     y += ystep;
600     run2 += run;
601 gwlarson 3.7 if (depthchange(vp, x, y-ystep, x, y))
602     break;
603 gwlarson 3.1 }
604     if (n < 0) /* found something? */
605     return;
606     if (run > rise)
607     p[2] = (x - o[0])*p[2]/(p[0] - o[0]);
608     else
609     p[2] = (y - o[1])*p[2]/(p[1] - o[1]);
610     p[0] = x;
611     p[1] = y;
612     }
613    
614    
615     static int
616     getblock(vp, h, v) /* get block index */
617     register struct ODview *vp;
618     register int h, v;
619     {
620     if (h<0 | h>=vp->hhi | v<0 | v>=vp->vhi)
621     return(-1);
622     return(h*vp->hlow/vp->hhi + v*vp->vlow/vp->vhi*vp->hlow);
623     }
624    
625    
626 gwlarson 3.6 static int
627     blockedge(vp, bi0, bi1) /* check for edge between blocks? */
628     register struct ODview *vp;
629     register int bi0, bi1;
630     {
631     if (bi1 < 0)
632     return(1); /* end off view */
633     if (CHK4(vp->emap, bi1))
634     return(1); /* end has edges */
635     if (bi1 == bi0+1 || bi1 == bi0-1 ||
636     bi1 == bi0+vp->hlow || bi1 == bi0-vp->hlow)
637     return(0); /* end in adjacent block -- no edges */
638     return(1); /* conservative for rarer case */
639     }
640    
641    
642 gwlarson 3.4 odDrawSamp(vn, id) /* draw view sample */
643     int vn;
644 gwlarson 3.1 register int id;
645     {
646     GLshort arm[MAXFAN][3];
647 gwlarson 3.6 int narms, blockindex;
648 gwlarson 3.1 register struct ODview *vp;
649     double size;
650     int home_edges;
651     register int i;
652    
653     vp = odView + vn;
654 gwlarson 3.4 blockindex = getblock(vp, odS.ip[id][0], odS.ip[id][1]);
655     DCHECK(blockindex<0, CONSISTENCY, "bad sample handed to odDrawSamp");
656 gwlarson 3.1 DCHECK(vp->bmap[blockindex].nused <= 0,
657 gwlarson 3.4 CONSISTENCY, "bad in-use count in odDrawSamp");
658 gwlarson 3.1 /* create triangle fan */
659     size = 1./sqrt((double)vp->bmap[blockindex].nused);
660     narms = make_arms(arm, odS.ip[id], vp, size);
661     if (vp->emap != NULL) { /* check for edge collisions */
662     home_edges = CHK4(vp->emap, blockindex);
663     for (i = 0; i < narms; i++)
664 gwlarson 3.6 if (home_edges || blockedge(vp, blockindex,
665     getblock(vp, arm[i][0], arm[i][1])))
666 gwlarson 3.1 clip_edge(arm[i], odS.ip[id], vp);
667     }
668     /* draw triangle fan */
669     glColor3ub(odS.rgb[id][0], odS.rgb[id][1], odS.rgb[id][2]);
670     glBegin(GL_TRIANGLE_FAN);
671     glVertex3s((GLshort)odS.ip[id][0], (GLshort)odS.ip[id][1], (GLshort)0);
672     for (i = 0; i < narms; i++)
673     glVertex3sv(arm[i]);
674     glVertex3sv(arm[0]); /* connect last to first */
675     glEnd();
676     }