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root/radiance/ray/src/rt/ambient.c
Revision: 1.7
Committed: Tue Sep 5 09:46:17 1989 UTC (34 years, 7 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.6: +19 -24 lines
Log Message:
undid last change, which didn't do much but make artifacts

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