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root/radiance/ray/src/rt/ambient.c
Revision: 1.2
Committed: Tue Feb 21 14:34:08 1989 UTC (35 years, 2 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.1: +5 -6 lines
Log Message:
Fixed incorrect octree test in sumambient

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     /* do this node */
168     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     if (wt > ambacc*(0.9 + 0.2*frandom()))
207     continue;
208     if (wt <= 1e-3)
209     wt = 1e3;
210     else
211     wt = 1.0 / wt;
212     wsum += wt;
213     copycolor(ct, av->val);
214     scalecolor(ct, wt);
215     addcolor(acol, ct);
216     }
217     if (at->kid == NULL)
218     return(wsum);
219     /* do children */
220     s *= 0.5;
221     for (i = 0; i < 8; i++) {
222     for (j = 0; j < 3; j++) {
223     ck0[j] = c0[j];
224 greg 1.2 if (1<<j & i)
225 greg 1.1 ck0[j] += s;
226 greg 1.2 if (r->rop[j] < ck0[j] - OCTSCALE*s)
227     break;
228     if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
229     break;
230 greg 1.1 }
231     if (j == 3)
232     wsum += sumambient(acol, r, at->kid+i, ck0, s);
233     }
234     return(wsum);
235     }
236    
237    
238     double
239     makeambient(acol, r) /* make a new ambient value */
240     COLOR acol;
241     register RAY *r;
242     {
243     AMBVAL amb;
244    
245     amb.rad = doambient(acol, r); /* compute ambient */
246     if (amb.rad == 0.0)
247     return(0.0);
248     /* store it */
249     VCOPY(amb.pos, r->rop);
250     VCOPY(amb.dir, r->ron);
251     amb.lvl = r->rlvl;
252     amb.weight = r->rweight;
253     copycolor(amb.val, acol);
254     /* insert into tree */
255     avinsert(&amb, &atrunk, thescene.cuorg, thescene.cusize);
256     avsave(&amb); /* write to file */
257     return(amb.rad);
258     }
259    
260    
261     double
262     doambient(acol, r) /* compute ambient component */
263     COLOR acol;
264     register RAY *r;
265     {
266     extern int ambcmp();
267     extern double sin(), cos(), sqrt();
268     double phi, xd, yd, zd;
269     register AMBSAMP *div;
270     AMBSAMP dnew;
271     RAY ar;
272     FVECT ux, uy;
273     double arad;
274     int ndivs, nt, np, ns, ne, i, j;
275     register int k;
276    
277     setcolor(acol, 0.0, 0.0, 0.0);
278     /* set number of divisions */
279     nt = sqrt(ambdiv * r->rweight * 0.5) + 0.5;
280     np = 2 * nt;
281     ndivs = nt * np;
282     /* check first */
283     if (ndivs == 0 || rayorigin(&ar, r, AMBIENT, 0.5) < 0)
284     return(0.0);
285     /* set number of super-samples */
286     ns = ambssamp * r->rweight + 0.5;
287     if (ns > 0) {
288     div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP));
289     if (div == NULL)
290     error(SYSTEM, "out of memory in doambient");
291     }
292     /* make axes */
293     uy[0] = uy[1] = uy[2] = 0.0;
294     for (k = 0; k < 3; k++)
295     if (r->ron[k] < 0.6 && r->ron[k] > -0.6)
296     break;
297     uy[k] = 1.0;
298     fcross(ux, r->ron, uy);
299     normalize(ux);
300     fcross(uy, ux, r->ron);
301     /* sample divisions */
302     arad = 0.0;
303     ne = 0;
304     for (i = 0; i < nt; i++)
305     for (j = 0; j < np; j++) {
306     rayorigin(&ar, r, AMBIENT, 0.5); /* pretested */
307     zd = sqrt((i+frandom())/nt);
308     phi = 2.0*PI * (j+frandom())/np;
309     xd = cos(phi) * zd;
310     yd = sin(phi) * zd;
311     zd = sqrt(1.0 - zd*zd);
312     for (k = 0; k < 3; k++)
313     ar.rdir[k] = xd*ux[k]+yd*uy[k]+zd*r->ron[k];
314     rayvalue(&ar);
315     if (ar.rot < FHUGE)
316     arad += 1.0 / ar.rot;
317     if (ns > 0) { /* save division */
318     div[ne].k = 0.0;
319     copycolor(div[ne].v, ar.rcol);
320     div[ne].n = 0;
321     div[ne].t = i; div[ne].p = j;
322     /* sum errors */
323     xd = bright(ar.rcol);
324     if (i > 0) { /* from above */
325     yd = bright(div[ne-np].v) - xd;
326     yd *= yd * 0.25;
327     div[ne].k += yd;
328     div[ne].n++;
329     div[ne-np].k += yd;
330     div[ne-np].n++;
331     }
332     if (j > 0) { /* from behind */
333     yd = bright(div[ne-1].v) - xd;
334     yd *= yd * 0.25;
335     div[ne].k += yd;
336     div[ne].n++;
337     div[ne-1].k += yd;
338     div[ne-1].n++;
339     }
340     if (j == np-1) { /* around */
341     yd = bright(div[ne-(np-1)].v) - xd;
342     yd *= yd * 0.25;
343     div[ne].k += yd;
344     div[ne].n++;
345     div[ne-(np-1)].k += yd;
346     div[ne-(np-1)].n++;
347     }
348     ne++;
349     } else
350     addcolor(acol, ar.rcol);
351     }
352     for (k = 0; k < ne; k++) { /* compute errors */
353     if (div[k].n > 1)
354     div[k].k /= div[k].n;
355     div[k].n = 1;
356     }
357     /* sort the divisions */
358     qsort(div, ne, sizeof(AMBSAMP), ambcmp);
359     /* skim excess */
360     while (ne > ns) {
361     ne--;
362     addcolor(acol, div[ne].v);
363     }
364     /* super-sample */
365     for (i = ns; i > 0; i--) {
366     rayorigin(&ar, r, AMBIENT, 0.5); /* pretested */
367     zd = sqrt((div[0].t+frandom())/nt);
368     phi = 2.0*PI * (div[0].p+frandom())/np;
369     xd = cos(phi) * zd;
370     yd = sin(phi) * zd;
371     zd = sqrt(1.0 - zd*zd);
372     for (k = 0; k < 3; k++)
373     ar.rdir[k] = xd*ux[k]+yd*uy[k]+zd*r->ron[k];
374     rayvalue(&ar);
375     if (ar.rot < FHUGE)
376     arad += 1.0 / ar.rot;
377     /* recompute error */
378     copycolor(dnew.v, div[0].v);
379     addcolor(dnew.v, ar.rcol);
380     dnew.n = div[0].n + 1;
381     dnew.t = div[0].t; dnew.p = div[0].p;
382     yd = bright(dnew.v)/dnew.n - bright(ar.rcol);
383     yd = yd*yd + div[0].k*(div[0].n*div[0].n);
384     dnew.k = yd/(dnew.n*dnew.n);
385     /* reinsert */
386     for (k = 0; k < ne-1 && dnew.k < div[k+1].k; k++)
387     bcopy(&div[k+1], &div[k], sizeof(AMBSAMP));
388     bcopy(&dnew, &div[k], sizeof(AMBSAMP));
389    
390     if (ne >= i) { /* extract darkest division */
391     ne--;
392     if (div[ne].n > 1)
393     scalecolor(div[ne].v, 1.0/div[ne].n);
394     addcolor(acol, div[ne].v);
395     }
396     }
397     scalecolor(acol, 1.0/ndivs);
398     if (arad <= FTINY)
399     arad = FHUGE;
400     else
401     arad = (ndivs+ns) / arad / sqrt(r->rweight);
402     if (arad > maxarad)
403     arad = maxarad;
404     else if (arad < minarad)
405     arad = minarad;
406     if (ns > 0)
407     free((char *)div);
408     return(arad);
409     }
410    
411    
412     static int
413     ambcmp(d1, d2) /* decreasing order */
414     AMBSAMP *d1, *d2;
415     {
416     if (d1->k < d2->k)
417     return(1);
418     if (d1->k > d2->k)
419     return(-1);
420     return(0);
421     }
422    
423    
424     static
425     avsave(av) /* save an ambient value */
426     AMBVAL *av;
427     {
428     #ifdef AMBFLUSH
429     static int nunflshed = 0;
430     #endif
431     if (ambfp == NULL)
432     return;
433     if (fwrite(av, sizeof(AMBVAL), 1, ambfp) != 1)
434     goto writerr;
435     #ifdef AMBFLUSH
436     if (++nunflshed >= AMBFLUSH) {
437     if (fflush(ambfp) == EOF)
438     goto writerr;
439     nunflshed = 0;
440     }
441     #endif
442     return;
443     writerr:
444     error(SYSTEM, "error writing ambient file");
445     }
446    
447    
448     static
449     avinsert(aval, at, c0, s) /* insert ambient value in a tree */
450     AMBVAL *aval;
451     register AMBTREE *at;
452     FVECT c0;
453     double s;
454     {
455     FVECT ck0;
456     int branch;
457     register AMBVAL *av;
458     register int i;
459    
460     if ((av = newambval()) == NULL)
461     goto memerr;
462     bcopy(aval, av, sizeof(AMBVAL));
463     VCOPY(ck0, c0);
464     while (s*(OCTSCALE/2) > av->rad*ambacc) {
465     if (at->kid == NULL)
466     if ((at->kid = newambtree()) == NULL)
467     goto memerr;
468     s *= 0.5;
469     branch = 0;
470     for (i = 0; i < 3; i++)
471     if (av->pos[i] > ck0[i] + s) {
472     ck0[i] += s;
473     branch |= 1 << i;
474     }
475     at = at->kid + branch;
476     }
477     av->next = at->alist;
478     at->alist = av;
479     return;
480     memerr:
481     error(SYSTEM, "out of memory in avinsert");
482     }