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root/radiance/ray/src/rt/ambient.c
Revision: 1.10
Committed: Tue Jun 26 09:00:07 1990 UTC (33 years, 10 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.9: +0 -1 lines
Log Message:
Nit-picking for Stardent C-compiler

File Contents

# User Rev Content
1 greg 1.1 /* Copyright (c) 1986 Regents of the University of California */
2    
3     #ifndef lint
4     static char SCCSid[] = "$SunId$ LBL";
5     #endif
6    
7     /*
8     * ambient.c - routines dealing with ambient (inter-reflected) component.
9     *
10     * The macro AMBFLUSH (if defined) is the number of ambient values
11     * to wait before flushing to the ambient file.
12     *
13     * 5/9/86
14     */
15    
16     #include "ray.h"
17    
18     #include "octree.h"
19    
20 greg 1.8 #include "otypes.h"
21    
22 greg 1.1 #include "random.h"
23    
24     #define OCTSCALE 0.5 /* ceil((valid rad.)/(cube size)) */
25    
26     extern CUBE thescene; /* contains space boundaries */
27    
28     extern COLOR ambval; /* global ambient component */
29     extern double ambacc; /* ambient accuracy */
30     extern int ambres; /* ambient resolution */
31     extern int ambdiv; /* number of divisions for calculation */
32     extern int ambssamp; /* number of super-samples */
33     extern int ambounce; /* number of ambient bounces */
34     extern char *amblist[]; /* ambient include/exclude list */
35     extern int ambincl; /* include == 1, exclude == 0 */
36    
37 greg 1.8 OBJECT ambset[256]={0}; /* ambient include/exclude set */
38 greg 1.1
39     double maxarad; /* maximum ambient radius */
40     double minarad; /* minimum ambient radius */
41    
42     typedef struct ambval {
43     FVECT pos; /* position in space */
44     FVECT dir; /* normal direction */
45     int lvl; /* recursion level of parent ray */
46     float weight; /* weight of parent ray */
47     COLOR val; /* computed ambient value */
48     float rad; /* validity radius */
49     struct ambval *next; /* next in list */
50     } AMBVAL; /* ambient value */
51    
52     typedef struct ambtree {
53     AMBVAL *alist; /* ambient value list */
54     struct ambtree *kid; /* 8 child nodes */
55     } AMBTREE; /* ambient octree */
56    
57     typedef struct {
58     float k; /* error contribution per sample */
59     COLOR v; /* ray sum */
60     int n; /* number of samples */
61     short t, p; /* theta, phi indices */
62     } AMBSAMP; /* ambient sample */
63    
64     static AMBTREE atrunk; /* our ambient trunk node */
65    
66     static FILE *ambfp = NULL; /* ambient file pointer */
67    
68     #define newambval() (AMBVAL *)bmalloc(sizeof(AMBVAL))
69    
70     #define newambtree() (AMBTREE *)calloc(8, sizeof(AMBTREE))
71    
72     double sumambient(), doambient(), makeambient();
73    
74    
75     setambient(afile) /* initialize calculation */
76     char *afile;
77     {
78     long ftell();
79     AMBVAL amb;
80 greg 1.8
81 greg 1.1 maxarad = thescene.cusize / 2.0; /* maximum radius */
82     /* minimum radius */
83     minarad = ambres > 0 ? thescene.cusize/ambres : 0.0;
84    
85     /* open ambient file */
86     if (afile != NULL)
87     if ((ambfp = fopen(afile, "r+")) != NULL) {
88 greg 1.9 while (fread((char *)&amb,sizeof(AMBVAL),1,ambfp) == 1)
89 greg 1.1 avinsert(&amb, &atrunk, thescene.cuorg,
90     thescene.cusize);
91     /* align */
92     fseek(ambfp, -(ftell(ambfp)%sizeof(AMBVAL)), 1);
93     } else if ((ambfp = fopen(afile, "w")) == NULL) {
94     sprintf(errmsg, "cannot open ambient file \"%s\"",
95     afile);
96     error(SYSTEM, errmsg);
97 greg 1.8 }
98     }
99    
100    
101     ambnotify(obj) /* record new modifier */
102     OBJECT obj;
103     {
104     register OBJREC *o = objptr(obj);
105     register char **amblp;
106    
107     if (!ismodifier(o->otype))
108     return;
109     for (amblp = amblist; *amblp != NULL; amblp++)
110     if (!strcmp(o->oname, *amblp)) {
111     insertelem(ambset, obj);
112     return;
113 greg 1.1 }
114     }
115    
116    
117     ambient(acol, r) /* compute ambient component for ray */
118     COLOR acol;
119     register RAY *r;
120     {
121     static int rdepth = 0; /* ambient recursion */
122     double wsum;
123    
124     rdepth++; /* increment level */
125    
126     if (ambdiv <= 0) /* no ambient calculation */
127     goto dumbamb;
128     /* check number of bounces */
129     if (rdepth > ambounce)
130     goto dumbamb;
131     /* check ambient list */
132     if (ambincl != -1 && r->ro != NULL &&
133     ambincl != inset(ambset, r->ro->omod))
134     goto dumbamb;
135    
136     if (ambacc <= FTINY) { /* no ambient storage */
137     if (doambient(acol, r) == 0.0)
138     goto dumbamb;
139     goto done;
140     }
141     /* get ambient value */
142     setcolor(acol, 0.0, 0.0, 0.0);
143     wsum = sumambient(acol, r, &atrunk, thescene.cuorg, thescene.cusize);
144     if (wsum > FTINY)
145     scalecolor(acol, 1.0/wsum);
146     else if (makeambient(acol, r) == 0.0)
147     goto dumbamb;
148     goto done;
149    
150     dumbamb: /* return global value */
151     copycolor(acol, ambval);
152     done: /* must finish here! */
153     rdepth--;
154     }
155    
156    
157     double
158     sumambient(acol, r, at, c0, s) /* get interpolated ambient value */
159     COLOR acol;
160     register RAY *r;
161     AMBTREE *at;
162     FVECT c0;
163     double s;
164     {
165     extern double sqrt();
166     double d, e1, e2, wt, wsum;
167     COLOR ct;
168     FVECT ck0;
169     int i;
170     register int j;
171     register AMBVAL *av;
172 greg 1.7 /* do this node */
173 greg 1.1 wsum = 0.0;
174     for (av = at->alist; av != NULL; av = av->next) {
175     /*
176     * Ray strength test.
177     */
178     if (av->lvl > r->rlvl || av->weight < r->rweight-FTINY)
179     continue;
180     /*
181     * Ambient radius test.
182     */
183     e1 = 0.0;
184     for (j = 0; j < 3; j++) {
185     d = av->pos[j] - r->rop[j];
186     e1 += d * d;
187     }
188     e1 /= av->rad * av->rad;
189     if (e1 > ambacc*ambacc*1.21)
190     continue;
191     /*
192     * Normal direction test.
193     */
194     e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight;
195     if (e2 < 0.0) e2 = 0.0;
196     if (e1 + e2 > ambacc*ambacc*1.21)
197     continue;
198     /*
199     * Ray behind test.
200     */
201     d = 0.0;
202     for (j = 0; j < 3; j++)
203     d += (r->rop[j] - av->pos[j]) *
204     (av->dir[j] + r->ron[j]);
205     if (d < -minarad)
206     continue;
207     /*
208     * Jittering final test reduces image artifacts.
209     */
210     wt = sqrt(e1) + sqrt(e2);
211 greg 1.7 wt *= .9 + .2*frandom();
212 greg 1.6 if (wt > ambacc)
213 greg 1.1 continue;
214     if (wt <= 1e-3)
215     wt = 1e3;
216     else
217     wt = 1.0 / wt;
218     wsum += wt;
219     copycolor(ct, av->val);
220     scalecolor(ct, wt);
221     addcolor(acol, ct);
222 greg 1.7 }
223     if (at->kid == NULL)
224     return(wsum);
225     /* do children */
226     s *= 0.5;
227     for (i = 0; i < 8; i++) {
228     for (j = 0; j < 3; j++) {
229     ck0[j] = c0[j];
230     if (1<<j & i)
231     ck0[j] += s;
232     if (r->rop[j] < ck0[j] - OCTSCALE*s)
233     break;
234     if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
235     break;
236     }
237     if (j == 3)
238     wsum += sumambient(acol, r, at->kid+i, ck0, s);
239 greg 1.1 }
240     return(wsum);
241     }
242    
243    
244     double
245     makeambient(acol, r) /* make a new ambient value */
246     COLOR acol;
247     register RAY *r;
248     {
249     AMBVAL amb;
250    
251     amb.rad = doambient(acol, r); /* compute ambient */
252     if (amb.rad == 0.0)
253     return(0.0);
254     /* store it */
255     VCOPY(amb.pos, r->rop);
256     VCOPY(amb.dir, r->ron);
257     amb.lvl = r->rlvl;
258     amb.weight = r->rweight;
259     copycolor(amb.val, acol);
260     /* insert into tree */
261     avinsert(&amb, &atrunk, thescene.cuorg, thescene.cusize);
262     avsave(&amb); /* write to file */
263     return(amb.rad);
264     }
265    
266    
267     double
268     doambient(acol, r) /* compute ambient component */
269     COLOR acol;
270     register RAY *r;
271     {
272     extern int ambcmp();
273     extern double sin(), cos(), sqrt();
274     double phi, xd, yd, zd;
275 greg 1.3 double b, b2;
276 greg 1.1 register AMBSAMP *div;
277     AMBSAMP dnew;
278     RAY ar;
279     FVECT ux, uy;
280     double arad;
281     int ndivs, nt, np, ns, ne, i, j;
282     register int k;
283    
284     setcolor(acol, 0.0, 0.0, 0.0);
285     /* set number of divisions */
286     nt = sqrt(ambdiv * r->rweight * 0.5) + 0.5;
287     np = 2 * nt;
288     ndivs = nt * np;
289     /* check first */
290     if (ndivs == 0 || rayorigin(&ar, r, AMBIENT, 0.5) < 0)
291     return(0.0);
292     /* set number of super-samples */
293     ns = ambssamp * r->rweight + 0.5;
294     if (ns > 0) {
295     div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP));
296     if (div == NULL)
297     error(SYSTEM, "out of memory in doambient");
298     }
299     /* make axes */
300     uy[0] = uy[1] = uy[2] = 0.0;
301     for (k = 0; k < 3; k++)
302     if (r->ron[k] < 0.6 && r->ron[k] > -0.6)
303     break;
304     uy[k] = 1.0;
305     fcross(ux, r->ron, uy);
306     normalize(ux);
307     fcross(uy, ux, r->ron);
308     /* sample divisions */
309     arad = 0.0;
310     ne = 0;
311     for (i = 0; i < nt; i++)
312     for (j = 0; j < np; j++) {
313     rayorigin(&ar, r, AMBIENT, 0.5); /* pretested */
314     zd = sqrt((i+frandom())/nt);
315     phi = 2.0*PI * (j+frandom())/np;
316     xd = cos(phi) * zd;
317     yd = sin(phi) * zd;
318     zd = sqrt(1.0 - zd*zd);
319     for (k = 0; k < 3; k++)
320     ar.rdir[k] = xd*ux[k]+yd*uy[k]+zd*r->ron[k];
321     rayvalue(&ar);
322     if (ar.rot < FHUGE)
323     arad += 1.0 / ar.rot;
324     if (ns > 0) { /* save division */
325     div[ne].k = 0.0;
326     copycolor(div[ne].v, ar.rcol);
327     div[ne].n = 0;
328     div[ne].t = i; div[ne].p = j;
329     /* sum errors */
330 greg 1.3 b = bright(ar.rcol);
331 greg 1.1 if (i > 0) { /* from above */
332 greg 1.3 b2 = bright(div[ne-np].v) - b;
333     b2 *= b2 * 0.25;
334     div[ne].k += b2;
335 greg 1.1 div[ne].n++;
336 greg 1.3 div[ne-np].k += b2;
337 greg 1.1 div[ne-np].n++;
338     }
339     if (j > 0) { /* from behind */
340 greg 1.3 b2 = bright(div[ne-1].v) - b;
341     b2 *= b2 * 0.25;
342     div[ne].k += b2;
343 greg 1.1 div[ne].n++;
344 greg 1.3 div[ne-1].k += b2;
345 greg 1.1 div[ne-1].n++;
346     }
347     if (j == np-1) { /* around */
348 greg 1.3 b2 = bright(div[ne-(np-1)].v) - b;
349     b2 *= b2 * 0.25;
350     div[ne].k += b2;
351 greg 1.1 div[ne].n++;
352 greg 1.3 div[ne-(np-1)].k += b2;
353 greg 1.1 div[ne-(np-1)].n++;
354     }
355     ne++;
356     } else
357     addcolor(acol, ar.rcol);
358     }
359     for (k = 0; k < ne; k++) { /* compute errors */
360     if (div[k].n > 1)
361     div[k].k /= div[k].n;
362     div[k].n = 1;
363     }
364     /* sort the divisions */
365     qsort(div, ne, sizeof(AMBSAMP), ambcmp);
366     /* skim excess */
367     while (ne > ns) {
368     ne--;
369     addcolor(acol, div[ne].v);
370     }
371     /* super-sample */
372     for (i = ns; i > 0; i--) {
373     rayorigin(&ar, r, AMBIENT, 0.5); /* pretested */
374     zd = sqrt((div[0].t+frandom())/nt);
375     phi = 2.0*PI * (div[0].p+frandom())/np;
376     xd = cos(phi) * zd;
377     yd = sin(phi) * zd;
378     zd = sqrt(1.0 - zd*zd);
379     for (k = 0; k < 3; k++)
380     ar.rdir[k] = xd*ux[k]+yd*uy[k]+zd*r->ron[k];
381     rayvalue(&ar);
382     if (ar.rot < FHUGE)
383     arad += 1.0 / ar.rot;
384     /* recompute error */
385     copycolor(dnew.v, div[0].v);
386     addcolor(dnew.v, ar.rcol);
387     dnew.n = div[0].n + 1;
388     dnew.t = div[0].t; dnew.p = div[0].p;
389 greg 1.3 b2 = bright(dnew.v)/dnew.n - bright(ar.rcol);
390 greg 1.5 b2 = b2*b2 + div[0].k*(div[0].n*div[0].n);
391     dnew.k = b2/(dnew.n*dnew.n);
392 greg 1.1 /* reinsert */
393     for (k = 0; k < ne-1 && dnew.k < div[k+1].k; k++)
394 greg 1.9 copystruct(&div[k], &div[k+1]);
395     copystruct(&div[k], &dnew);
396 greg 1.1
397     if (ne >= i) { /* extract darkest division */
398     ne--;
399     if (div[ne].n > 1)
400     scalecolor(div[ne].v, 1.0/div[ne].n);
401     addcolor(acol, div[ne].v);
402     }
403     }
404     scalecolor(acol, 1.0/ndivs);
405     if (arad <= FTINY)
406     arad = FHUGE;
407     else
408     arad = (ndivs+ns) / arad / sqrt(r->rweight);
409     if (arad > maxarad)
410     arad = maxarad;
411     else if (arad < minarad)
412     arad = minarad;
413     if (ns > 0)
414     free((char *)div);
415     return(arad);
416     }
417    
418    
419     static int
420     ambcmp(d1, d2) /* decreasing order */
421     AMBSAMP *d1, *d2;
422     {
423     if (d1->k < d2->k)
424     return(1);
425     if (d1->k > d2->k)
426     return(-1);
427     return(0);
428     }
429    
430    
431     static
432     avsave(av) /* save an ambient value */
433     AMBVAL *av;
434     {
435     #ifdef AMBFLUSH
436     static int nunflshed = 0;
437     #endif
438     if (ambfp == NULL)
439     return;
440 greg 1.9 if (fwrite((char *)av, sizeof(AMBVAL), 1, ambfp) != 1)
441 greg 1.1 goto writerr;
442     #ifdef AMBFLUSH
443     if (++nunflshed >= AMBFLUSH) {
444     if (fflush(ambfp) == EOF)
445     goto writerr;
446     nunflshed = 0;
447     }
448     #endif
449     return;
450     writerr:
451     error(SYSTEM, "error writing ambient file");
452     }
453    
454    
455     static
456     avinsert(aval, at, c0, s) /* insert ambient value in a tree */
457     AMBVAL *aval;
458     register AMBTREE *at;
459     FVECT c0;
460     double s;
461     {
462     FVECT ck0;
463     int branch;
464     register AMBVAL *av;
465     register int i;
466    
467     if ((av = newambval()) == NULL)
468     goto memerr;
469 greg 1.9 copystruct(av, aval);
470 greg 1.1 VCOPY(ck0, c0);
471     while (s*(OCTSCALE/2) > av->rad*ambacc) {
472     if (at->kid == NULL)
473     if ((at->kid = newambtree()) == NULL)
474     goto memerr;
475     s *= 0.5;
476     branch = 0;
477     for (i = 0; i < 3; i++)
478     if (av->pos[i] > ck0[i] + s) {
479     ck0[i] += s;
480     branch |= 1 << i;
481     }
482     at = at->kid + branch;
483     }
484     av->next = at->alist;
485     at->alist = av;
486     return;
487     memerr:
488     error(SYSTEM, "out of memory in avinsert");
489     }