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root/radiance/ray/src/rt/virtuals.c
Revision: 1.2
Committed: Thu Jun 20 09:37:38 1991 UTC (32 years, 10 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.1: +13 -24 lines
Log Message:
minor fixes

File Contents

# User Rev Content
1 greg 1.1 /* Copyright (c) 1991 Regents of the University of California */
2    
3     #ifndef lint
4     static char SCCSid[] = "$SunId$ LBL";
5     #endif
6    
7     /*
8     * Routines for simulating virtual light sources
9     * Thus far, we only support planar mirrors.
10     */
11    
12     #include "ray.h"
13    
14     #include "source.h"
15    
16     #include "otypes.h"
17    
18     #include "cone.h"
19    
20     #include "face.h"
21    
22     extern int directrelay; /* maximum number of source relays */
23    
24     double getplaneq();
25     double getmaxdisk();
26     double intercircle();
27     SRCREC *makevsrc();
28    
29     static OBJECT *vobject; /* virtual source objects */
30     static int nvobjects = 0; /* number of virtual source objects */
31    
32    
33     markvirtuals() /* find and mark virtual sources */
34     {
35     register OBJREC *o;
36     register int i;
37     /* check number of direct relays */
38     if (directrelay <= 0)
39     return;
40     /* find virtual source objects */
41     for (i = 0; i < nobjects; i++) {
42     o = objptr(i);
43     if (o->omod == OVOID)
44     continue;
45     if (!isvlight(objptr(o->omod)->otype))
46     continue;
47     if (nvobjects == 0)
48     vobject = (OBJECT *)malloc(sizeof(OBJECT));
49     else
50     vobject = (OBJECT *)realloc((char *)vobject,
51     (unsigned)(nvobjects+1)*sizeof(OBJECT));
52     if (vobject == NULL)
53     error(SYSTEM, "out of memory in addvirtuals");
54     vobject[nvobjects++] = i;
55     }
56     if (nvobjects == 0)
57     return;
58     /* append virtual sources */
59     for (i = nsources; i-- > 0; )
60     if (!(source[i].sflags & SSKIP))
61     addvirtuals(&source[i], directrelay);
62     /* done with our object list */
63     free((char *)vobject);
64     nvobjects = 0;
65     }
66    
67    
68     addvirtuals(sr, nr) /* add virtual sources associated with sr */
69     SRCREC *sr;
70     int nr;
71     {
72     register int i;
73     /* check relay limit first */
74     if (nr <= 0)
75     return;
76     /* check each virtual object for projection */
77     for (i = 0; i < nvobjects; i++)
78     vproject(objptr(i), sr, nr-1); /* calls us recursively */
79     }
80    
81    
82     SRCREC *
83     makevsrc(op, sp, pm) /* make virtual source if reasonable */
84     OBJREC *op;
85     register SRCREC *sp;
86     MAT4 pm;
87     {
88     register SRCREC *newsrc;
89     FVECT nsloc, ocent, nsnorm;
90     double maxrad2;
91     double d1, d2;
92     SPOT theirspot, ourspot;
93     register int i;
94     /* get object center and max. radius */
95     maxrad2 = getmaxdisk(ocent, op);
96     if (maxrad2 <= FTINY) /* too small? */
97     return(NULL);
98     /* get location and spot */
99     if (sp->sflags & SDISTANT) { /* distant source */
100     if (sp->sflags & SPROX)
101     return(NULL); /* should never get here! */
102     multv3(nsloc, sp->sloc, pm);
103     VCOPY(ourspot.aim, ocent);
104     ourspot.siz = PI*maxrad2;
105     ourspot.flen = 0.;
106     if (sp->sflags & SSPOT) {
107     copystruct(&theirspot, sp->sl.s);
108     multp3(theirspot.aim, sp->sl.s->aim, pm);
109     if (!commonbeam(&ourspot, &theirspot, nsloc))
110     return(NULL); /* no overlap */
111     }
112     } else { /* local source */
113     multp3(nsloc, sp->sloc, pm);
114     for (i = 0; i < 3; i++)
115     ourspot.aim[i] = ocent[i] - nsloc[i];
116     if ((d1 = normalize(ourspot.aim)) == 0.)
117     return(NULL); /* at source!! */
118 greg 1.2 if (sp->sflags & SPROX && d1 > sp->sl.prox)
119     return(NULL); /* too far away */
120 greg 1.1 ourspot.siz = 2.*PI*(1. - d1/sqrt(d1*d1+maxrad2));
121     ourspot.flen = 0.;
122     if (sp->sflags & SSPOT) {
123     copystruct(&theirspot, sp->sl.s);
124     multv3(theirspot.aim, sp->sl.s->aim, pm);
125     if (!commonspot(&ourspot, &theirspot, nsloc))
126     return(NULL); /* no overlap */
127     ourspot.flen = theirspot.flen;
128     }
129     if (sp->sflags & SFLAT) { /* check for behind source */
130     multv3(nsnorm, sp->snorm, pm);
131     if (checkspot(&ourspot, nsnorm) < 0)
132     return(NULL);
133     }
134     }
135     /* everything is OK, make source */
136     if ((newsrc = newsource()) == NULL)
137     goto memerr;
138     newsrc->sflags = sp->sflags | (SVIRTUAL|SSPOT|SFOLLOW);
139     VCOPY(newsrc->sloc, nsloc);
140     if (newsrc->sflags & SFLAT)
141     VCOPY(newsrc->snorm, nsnorm);
142     newsrc->ss = sp->ss; newsrc->ss2 = sp->ss2;
143     if ((newsrc->sl.s = (SPOT *)malloc(sizeof(SPOT))) == NULL)
144     goto memerr;
145     copystruct(newsrc->sl.s, &ourspot);
146     if (newsrc->sflags & SPROX)
147     newsrc->sl.prox = sp->sl.prox;
148     newsrc->sa.svnext = sp - source;
149     return(newsrc);
150     memerr:
151     error(SYSTEM, "out of memory in makevsrc");
152     }
153    
154    
155     commonspot(sp1, sp2, org) /* set sp1 to intersection of sp1 and sp2 */
156     register SPOT *sp1, *sp2;
157     FVECT org;
158     {
159     FVECT cent;
160 greg 1.2 double rad2, cos1, cos2;
161 greg 1.1
162 greg 1.2 cos1 = 1. - sp1->siz/(2.*PI);
163     cos2 = 1. - sp2->siz/(2.*PI);
164 greg 1.1 if (sp2->siz >= 2.*PI-FTINY) /* BIG, just check overlap */
165 greg 1.2 return(DOT(sp1->aim,sp2->aim) >= cos1*cos2 -
166     sqrt((1.-cos1*cos1)*(1.-cos2*cos2)));
167 greg 1.1 /* compute and check disks */
168 greg 1.2 rad2 = intercircle(cent, sp1->aim, sp2->aim,
169     1./(cos1*cos1) - 1., 1./(cos2*cos2) - 1.);
170 greg 1.1 if (rad2 <= FTINY || normalize(cent) == 0.)
171     return(0);
172     VCOPY(sp1->aim, cent);
173     sp1->siz = 2.*PI*(1. - 1./sqrt(1.+rad2));
174     return(1);
175     }
176    
177    
178     commonbeam(sp1, sp2, dir) /* set sp1 to intersection of sp1 and sp2 */
179     register SPOT *sp1, *sp2;
180     FVECT dir;
181     {
182     FVECT cent, c1, c2;
183     double rad2, d;
184     register int i;
185     /* move centers to common plane */
186     d = DOT(sp1->aim, dir);
187     for (i = 0; i < 3; i++)
188 greg 1.2 c1[i] = sp1->aim[i] - d*dir[i];
189 greg 1.1 d = DOT(sp2->aim, dir);
190     for (i = 0; i < 3; i++)
191     c2[i] = sp2->aim[i] - d*dir[i];
192     /* compute overlap */
193     rad2 = intercircle(cent, c1, c2, sp1->siz/PI, sp2->siz/PI);
194     if (rad2 <= FTINY)
195     return(0);
196     VCOPY(sp1->aim, cent);
197     sp1->siz = PI*rad2;
198     return(1);
199     }
200    
201    
202     checkspot(sp, nrm) /* check spotlight for behind source */
203     register SPOT *sp;
204     FVECT nrm;
205     {
206     double d, d1;
207    
208     d = DOT(sp->aim, nrm);
209     if (d > FTINY) /* center in front? */
210     return(0);
211     /* else check horizon */
212     d1 = 1. - sp->siz/(2.*PI);
213     return(1.-FTINY-d*d > d1*d1);
214     }
215    
216    
217     mirrorproj(m, nv, offs) /* get mirror projection for surface */
218     register MAT4 m;
219     FVECT nv;
220     double offs;
221     {
222     register int i, j;
223     /* assign matrix */
224     setident4(m);
225     for (i = 0; i < 3; i++)
226     for (j = 0; j < 3; j++)
227     m[i][j] -= 2.*nv[i]*nv[j];
228     for (j = 0; j < 3; j++)
229     m[3][j] = 2.*offs*nv[j];
230     }
231    
232    
233     double
234     intercircle(cc, c1, c2, r1s, r2s) /* intersect two circles */
235     FVECT cc; /* midpoint (return value) */
236     FVECT c1, c2; /* circle centers */
237     double r1s, r2s; /* radii squared */
238     {
239     double a2, d2, l;
240     FVECT disp;
241     register int i;
242    
243     for (i = 0; i < 3; i++)
244     disp[i] = c2[i] - c1[i];
245     d2 = DOT(disp,disp);
246     /* circle within overlap? */
247     if (r1s < r2s) {
248     if (r2s >= r1s + d2) {
249     VCOPY(cc, c1);
250     return(r1s);
251     }
252     } else {
253     if (r1s >= r2s + d2) {
254     VCOPY(cc, c2);
255     return(r2s);
256     }
257     }
258     a2 = .25*(2.*(r1s+r2s) - d2 - (r2s-r1s)*(r2s-r1s)/d2);
259     /* no overlap? */
260     if (a2 <= 0.)
261     return(0.);
262 greg 1.2 /* overlap, compute center */
263 greg 1.1 l = sqrt((r1s - a2)/d2);
264     for (i = 0; i < 3; i++)
265     cc[i] = c1[i] + l*disp[i];
266     return(a2);
267     }
268    
269    
270     /*
271     * The following routines depend on the supported OBJECTS:
272     */
273    
274    
275     double
276     getmaxdisk(ocent, op) /* get object center and squared radius */
277     FVECT ocent;
278     register OBJREC *op;
279     {
280     double maxrad2;
281    
282     switch (op->otype) {
283     case OBJ_FACE:
284     {
285 greg 1.2 double d2;
286 greg 1.1 register int i, j;
287     register FACE *f = getface(op);
288    
289     for (i = 0; i < 3; i++) {
290     ocent[i] = 0.;
291     for (j = 0; j < f->nv; j++)
292     ocent[i] += VERTEX(f,j)[i];
293     ocent[i] /= (double)f->nv;
294     }
295     maxrad2 = 0.;
296     for (j = 0; j < f->nv; j++) {
297 greg 1.2 d2 = dist2(VERTEX(f,j), ocent);
298 greg 1.1 if (d2 > maxrad2)
299     maxrad2 = d2;
300     }
301     }
302     return(maxrad2);
303     case OBJ_RING:
304     {
305     register CONE *co = getcone(op, 0);
306    
307     VCOPY(ocent, CO_P0(co));
308     maxrad2 = CO_R1(co);
309     maxrad2 *= maxrad2;
310     }
311     return(maxrad2);
312     }
313     objerror(op, USER, "illegal material");
314     }
315    
316    
317     double
318     getplaneq(nvec, op) /* get plane equation for object */
319     FVECT nvec;
320     OBJREC *op;
321     {
322     register FACE *fo;
323     register CONE *co;
324    
325     switch (op->otype) {
326     case OBJ_FACE:
327     fo = getface(op);
328     VCOPY(nvec, fo->norm);
329     return(fo->offset);
330     case OBJ_RING:
331     co = getcone(op, 0);
332     VCOPY(nvec, co->ad);
333     return(DOT(nvec, CO_P0(co)));
334     }
335     objerror(op, USER, "illegal material");
336     }
337    
338    
339     /*
340     * The following routines depend on the supported MATERIALS:
341     */
342    
343    
344     vproject(o, s, n) /* create projected source(s) if they exist */
345     OBJREC *o;
346     SRCREC *s;
347     int n;
348     {
349     SRCREC *ns;
350     FVECT norm;
351     double offset;
352     MAT4 proj;
353     /* get surface normal and offset */
354     offset = getplaneq(norm, o);
355     switch (objptr(o->omod)->otype) {
356     case MAT_MIRROR: /* mirror source */
357     if (DOT(s->sloc, norm) <= (s->sflags & SDISTANT ?
358     FTINY : offset+FTINY))
359     return; /* behind mirror */
360     mirrorproj(proj, norm, offset);
361     if ((ns = makevsrc(o, s, proj)) != NULL)
362     addvirtuals(ns, n);
363     break;
364     }
365     }
366    
367    
368     vsrcrelay(rn, rv) /* relay virtual source ray */
369     register RAY *rn, *rv;
370     {
371     int snext;
372     register int i;
373     /* source we're aiming for here */
374     snext = source[rv->rsrc].sa.svnext;
375     /* compute relayed ray direction */
376     switch (objptr(rv->ro->omod)->otype) {
377     case MAT_MIRROR: /* mirror: singular reflection */
378     rayorigin(rn, rv, REFLECTED, 1.);
379     /* ignore textures */
380     for (i = 0; i < 3; i++)
381     rn->rdir[i] = rv->rdir[i] + 2.*rv->rod*rv->ron[i];
382     break;
383     #ifdef DEBUG
384     default:
385     error(CONSISTENCY, "inappropriate material in vsrcrelay");
386     #endif
387     }
388     rn->rsrc = snext;
389     }
390    
391    
392     m_mirror(m, r) /* shade mirrored ray */
393     register OBJREC *m;
394     register RAY *r;
395     {
396     COLOR mcolor;
397     RAY nr;
398     register int i;
399    
400     if (m->oargs.nfargs != 3 || m->oargs.nsargs > 1)
401     objerror(m, USER, "bad number of arguments");
402     if (r->rsrc >= 0) { /* aiming for somebody */
403     if (source[r->rsrc].so != r->ro)
404     return; /* but not us */
405     } else if (m->oargs.nsargs > 0) { /* else call substitute? */
406     rayshade(r, modifier(m->oargs.sarg[0]));
407     return;
408     }
409     if (r->rod < 0.) /* back is black */
410     return;
411     /* get modifiers */
412     raytexture(r, m->omod);
413     /* assign material color */
414     setcolor(mcolor, m->oargs.farg[0],
415     m->oargs.farg[1],
416     m->oargs.farg[2]);
417     multcolor(mcolor, r->pcol);
418     /* compute reflected ray */
419     if (r->rsrc >= 0) /* relayed light source */
420     vsrcrelay(&nr, r);
421     else { /* ordinary reflection */
422     FVECT pnorm;
423     double pdot;
424    
425     if (rayorigin(&nr, r, REFLECTED, bright(mcolor)) < 0)
426     return;
427     pdot = raynormal(pnorm, r); /* use textures */
428     for (i = 0; i < 3; i++)
429     nr.rdir[i] = r->rdir[i] + 2.*pdot*pnorm[i];
430     }
431     rayvalue(&nr);
432     multcolor(nr.rcol, mcolor);
433     addcolor(r->rcol, nr.rcol);
434     }