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root/radiance/ray/src/rt/ambient.c
Revision: 1.8
Committed: Fri Jan 12 11:30:59 1990 UTC (34 years, 10 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.7: +20 -14 lines
Log Message:
changed recording of ambient include/exclude set so instances work

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     OBJECT obj;
80     AMBVAL amb;
81 greg 1.8
82 greg 1.1 maxarad = thescene.cusize / 2.0; /* maximum radius */
83     /* minimum radius */
84     minarad = ambres > 0 ? thescene.cusize/ambres : 0.0;
85    
86     /* open ambient file */
87     if (afile != NULL)
88     if ((ambfp = fopen(afile, "r+")) != NULL) {
89     while (fread(&amb, sizeof(AMBVAL), 1, ambfp) == 1)
90     avinsert(&amb, &atrunk, thescene.cuorg,
91     thescene.cusize);
92     /* align */
93     fseek(ambfp, -(ftell(ambfp)%sizeof(AMBVAL)), 1);
94     } else if ((ambfp = fopen(afile, "w")) == NULL) {
95     sprintf(errmsg, "cannot open ambient file \"%s\"",
96     afile);
97     error(SYSTEM, errmsg);
98 greg 1.8 }
99     }
100    
101    
102     ambnotify(obj) /* record new modifier */
103     OBJECT obj;
104     {
105     register OBJREC *o = objptr(obj);
106     register char **amblp;
107    
108     if (!ismodifier(o->otype))
109     return;
110     for (amblp = amblist; *amblp != NULL; amblp++)
111     if (!strcmp(o->oname, *amblp)) {
112     insertelem(ambset, obj);
113     return;
114 greg 1.1 }
115     }
116    
117    
118     ambient(acol, r) /* compute ambient component for ray */
119     COLOR acol;
120     register RAY *r;
121     {
122     static int rdepth = 0; /* ambient recursion */
123     double wsum;
124    
125     rdepth++; /* increment level */
126    
127     if (ambdiv <= 0) /* no ambient calculation */
128     goto dumbamb;
129     /* check number of bounces */
130     if (rdepth > ambounce)
131     goto dumbamb;
132     /* check ambient list */
133     if (ambincl != -1 && r->ro != NULL &&
134     ambincl != inset(ambset, r->ro->omod))
135     goto dumbamb;
136    
137     if (ambacc <= FTINY) { /* no ambient storage */
138     if (doambient(acol, r) == 0.0)
139     goto dumbamb;
140     goto done;
141     }
142     /* get ambient value */
143     setcolor(acol, 0.0, 0.0, 0.0);
144     wsum = sumambient(acol, r, &atrunk, thescene.cuorg, thescene.cusize);
145     if (wsum > FTINY)
146     scalecolor(acol, 1.0/wsum);
147     else if (makeambient(acol, r) == 0.0)
148     goto dumbamb;
149     goto done;
150    
151     dumbamb: /* return global value */
152     copycolor(acol, ambval);
153     done: /* must finish here! */
154     rdepth--;
155     }
156    
157    
158     double
159     sumambient(acol, r, at, c0, s) /* get interpolated ambient value */
160     COLOR acol;
161     register RAY *r;
162     AMBTREE *at;
163     FVECT c0;
164     double s;
165     {
166     extern double sqrt();
167     double d, e1, e2, wt, wsum;
168     COLOR ct;
169     FVECT ck0;
170     int i;
171     register int j;
172     register AMBVAL *av;
173 greg 1.7 /* do this node */
174 greg 1.1 wsum = 0.0;
175     for (av = at->alist; av != NULL; av = av->next) {
176     /*
177     * Ray strength test.
178     */
179     if (av->lvl > r->rlvl || av->weight < r->rweight-FTINY)
180     continue;
181     /*
182     * Ambient radius test.
183     */
184     e1 = 0.0;
185     for (j = 0; j < 3; j++) {
186     d = av->pos[j] - r->rop[j];
187     e1 += d * d;
188     }
189     e1 /= av->rad * av->rad;
190     if (e1 > ambacc*ambacc*1.21)
191     continue;
192     /*
193     * Normal direction test.
194     */
195     e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight;
196     if (e2 < 0.0) e2 = 0.0;
197     if (e1 + e2 > ambacc*ambacc*1.21)
198     continue;
199     /*
200     * Ray behind test.
201     */
202     d = 0.0;
203     for (j = 0; j < 3; j++)
204     d += (r->rop[j] - av->pos[j]) *
205     (av->dir[j] + r->ron[j]);
206     if (d < -minarad)
207     continue;
208     /*
209     * Jittering final test reduces image artifacts.
210     */
211     wt = sqrt(e1) + sqrt(e2);
212 greg 1.7 wt *= .9 + .2*frandom();
213 greg 1.6 if (wt > ambacc)
214 greg 1.1 continue;
215     if (wt <= 1e-3)
216     wt = 1e3;
217     else
218     wt = 1.0 / wt;
219     wsum += wt;
220     copycolor(ct, av->val);
221     scalecolor(ct, wt);
222     addcolor(acol, ct);
223 greg 1.7 }
224     if (at->kid == NULL)
225     return(wsum);
226     /* do children */
227     s *= 0.5;
228     for (i = 0; i < 8; i++) {
229     for (j = 0; j < 3; j++) {
230     ck0[j] = c0[j];
231     if (1<<j & i)
232     ck0[j] += s;
233     if (r->rop[j] < ck0[j] - OCTSCALE*s)
234     break;
235     if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
236     break;
237     }
238     if (j == 3)
239     wsum += sumambient(acol, r, at->kid+i, ck0, s);
240 greg 1.1 }
241     return(wsum);
242     }
243    
244    
245     double
246     makeambient(acol, r) /* make a new ambient value */
247     COLOR acol;
248     register RAY *r;
249     {
250     AMBVAL amb;
251    
252     amb.rad = doambient(acol, r); /* compute ambient */
253     if (amb.rad == 0.0)
254     return(0.0);
255     /* store it */
256     VCOPY(amb.pos, r->rop);
257     VCOPY(amb.dir, r->ron);
258     amb.lvl = r->rlvl;
259     amb.weight = r->rweight;
260     copycolor(amb.val, acol);
261     /* insert into tree */
262     avinsert(&amb, &atrunk, thescene.cuorg, thescene.cusize);
263     avsave(&amb); /* write to file */
264     return(amb.rad);
265     }
266    
267    
268     double
269     doambient(acol, r) /* compute ambient component */
270     COLOR acol;
271     register RAY *r;
272     {
273     extern int ambcmp();
274     extern double sin(), cos(), sqrt();
275     double phi, xd, yd, zd;
276 greg 1.3 double b, b2;
277 greg 1.1 register AMBSAMP *div;
278     AMBSAMP dnew;
279     RAY ar;
280     FVECT ux, uy;
281     double arad;
282     int ndivs, nt, np, ns, ne, i, j;
283     register int k;
284    
285     setcolor(acol, 0.0, 0.0, 0.0);
286     /* set number of divisions */
287     nt = sqrt(ambdiv * r->rweight * 0.5) + 0.5;
288     np = 2 * nt;
289     ndivs = nt * np;
290     /* check first */
291     if (ndivs == 0 || rayorigin(&ar, r, AMBIENT, 0.5) < 0)
292     return(0.0);
293     /* set number of super-samples */
294     ns = ambssamp * r->rweight + 0.5;
295     if (ns > 0) {
296     div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP));
297     if (div == NULL)
298     error(SYSTEM, "out of memory in doambient");
299     }
300     /* make axes */
301     uy[0] = uy[1] = uy[2] = 0.0;
302     for (k = 0; k < 3; k++)
303     if (r->ron[k] < 0.6 && r->ron[k] > -0.6)
304     break;
305     uy[k] = 1.0;
306     fcross(ux, r->ron, uy);
307     normalize(ux);
308     fcross(uy, ux, r->ron);
309     /* sample divisions */
310     arad = 0.0;
311     ne = 0;
312     for (i = 0; i < nt; i++)
313     for (j = 0; j < np; j++) {
314     rayorigin(&ar, r, AMBIENT, 0.5); /* pretested */
315     zd = sqrt((i+frandom())/nt);
316     phi = 2.0*PI * (j+frandom())/np;
317     xd = cos(phi) * zd;
318     yd = sin(phi) * zd;
319     zd = sqrt(1.0 - zd*zd);
320     for (k = 0; k < 3; k++)
321     ar.rdir[k] = xd*ux[k]+yd*uy[k]+zd*r->ron[k];
322     rayvalue(&ar);
323     if (ar.rot < FHUGE)
324     arad += 1.0 / ar.rot;
325     if (ns > 0) { /* save division */
326     div[ne].k = 0.0;
327     copycolor(div[ne].v, ar.rcol);
328     div[ne].n = 0;
329     div[ne].t = i; div[ne].p = j;
330     /* sum errors */
331 greg 1.3 b = bright(ar.rcol);
332 greg 1.1 if (i > 0) { /* from above */
333 greg 1.3 b2 = bright(div[ne-np].v) - b;
334     b2 *= b2 * 0.25;
335     div[ne].k += b2;
336 greg 1.1 div[ne].n++;
337 greg 1.3 div[ne-np].k += b2;
338 greg 1.1 div[ne-np].n++;
339     }
340     if (j > 0) { /* from behind */
341 greg 1.3 b2 = bright(div[ne-1].v) - b;
342     b2 *= b2 * 0.25;
343     div[ne].k += b2;
344 greg 1.1 div[ne].n++;
345 greg 1.3 div[ne-1].k += b2;
346 greg 1.1 div[ne-1].n++;
347     }
348     if (j == np-1) { /* around */
349 greg 1.3 b2 = bright(div[ne-(np-1)].v) - b;
350     b2 *= b2 * 0.25;
351     div[ne].k += b2;
352 greg 1.1 div[ne].n++;
353 greg 1.3 div[ne-(np-1)].k += b2;
354 greg 1.1 div[ne-(np-1)].n++;
355     }
356     ne++;
357     } else
358     addcolor(acol, ar.rcol);
359     }
360     for (k = 0; k < ne; k++) { /* compute errors */
361     if (div[k].n > 1)
362     div[k].k /= div[k].n;
363     div[k].n = 1;
364     }
365     /* sort the divisions */
366     qsort(div, ne, sizeof(AMBSAMP), ambcmp);
367     /* skim excess */
368     while (ne > ns) {
369     ne--;
370     addcolor(acol, div[ne].v);
371     }
372     /* super-sample */
373     for (i = ns; i > 0; i--) {
374     rayorigin(&ar, r, AMBIENT, 0.5); /* pretested */
375     zd = sqrt((div[0].t+frandom())/nt);
376     phi = 2.0*PI * (div[0].p+frandom())/np;
377     xd = cos(phi) * zd;
378     yd = sin(phi) * zd;
379     zd = sqrt(1.0 - zd*zd);
380     for (k = 0; k < 3; k++)
381     ar.rdir[k] = xd*ux[k]+yd*uy[k]+zd*r->ron[k];
382     rayvalue(&ar);
383     if (ar.rot < FHUGE)
384     arad += 1.0 / ar.rot;
385     /* recompute error */
386     copycolor(dnew.v, div[0].v);
387     addcolor(dnew.v, ar.rcol);
388     dnew.n = div[0].n + 1;
389     dnew.t = div[0].t; dnew.p = div[0].p;
390 greg 1.3 b2 = bright(dnew.v)/dnew.n - bright(ar.rcol);
391 greg 1.5 b2 = b2*b2 + div[0].k*(div[0].n*div[0].n);
392     dnew.k = b2/(dnew.n*dnew.n);
393 greg 1.1 /* reinsert */
394     for (k = 0; k < ne-1 && dnew.k < div[k+1].k; k++)
395     bcopy(&div[k+1], &div[k], sizeof(AMBSAMP));
396     bcopy(&dnew, &div[k], sizeof(AMBSAMP));
397    
398     if (ne >= i) { /* extract darkest division */
399     ne--;
400     if (div[ne].n > 1)
401     scalecolor(div[ne].v, 1.0/div[ne].n);
402     addcolor(acol, div[ne].v);
403     }
404     }
405     scalecolor(acol, 1.0/ndivs);
406     if (arad <= FTINY)
407     arad = FHUGE;
408     else
409     arad = (ndivs+ns) / arad / sqrt(r->rweight);
410     if (arad > maxarad)
411     arad = maxarad;
412     else if (arad < minarad)
413     arad = minarad;
414     if (ns > 0)
415     free((char *)div);
416     return(arad);
417     }
418    
419    
420     static int
421     ambcmp(d1, d2) /* decreasing order */
422     AMBSAMP *d1, *d2;
423     {
424     if (d1->k < d2->k)
425     return(1);
426     if (d1->k > d2->k)
427     return(-1);
428     return(0);
429     }
430    
431    
432     static
433     avsave(av) /* save an ambient value */
434     AMBVAL *av;
435     {
436     #ifdef AMBFLUSH
437     static int nunflshed = 0;
438     #endif
439     if (ambfp == NULL)
440     return;
441     if (fwrite(av, sizeof(AMBVAL), 1, ambfp) != 1)
442     goto writerr;
443     #ifdef AMBFLUSH
444     if (++nunflshed >= AMBFLUSH) {
445     if (fflush(ambfp) == EOF)
446     goto writerr;
447     nunflshed = 0;
448     }
449     #endif
450     return;
451     writerr:
452     error(SYSTEM, "error writing ambient file");
453     }
454    
455    
456     static
457     avinsert(aval, at, c0, s) /* insert ambient value in a tree */
458     AMBVAL *aval;
459     register AMBTREE *at;
460     FVECT c0;
461     double s;
462     {
463     FVECT ck0;
464     int branch;
465     register AMBVAL *av;
466     register int i;
467    
468     if ((av = newambval()) == NULL)
469     goto memerr;
470     bcopy(aval, av, sizeof(AMBVAL));
471     VCOPY(ck0, c0);
472     while (s*(OCTSCALE/2) > av->rad*ambacc) {
473     if (at->kid == NULL)
474     if ((at->kid = newambtree()) == NULL)
475     goto memerr;
476     s *= 0.5;
477     branch = 0;
478     for (i = 0; i < 3; i++)
479     if (av->pos[i] > ck0[i] + s) {
480     ck0[i] += s;
481     branch |= 1 << i;
482     }
483     at = at->kid + branch;
484     }
485     av->next = at->alist;
486     at->alist = av;
487     return;
488     memerr:
489     error(SYSTEM, "out of memory in avinsert");
490     }