ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/src/rt/virtuals.c
Revision: 1.1
Committed: Wed Jun 19 16:36:14 1991 UTC (32 years, 10 months ago) by greg
Content type: text/plain
Branch: MAIN
Log Message:
Initial revision

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     if (sp->sflags & SPROX) {
115     d2 = 0.;
116     for (i = 0; i < 3; i++) {
117     d1 = ocent[i] - nsloc[i];
118     d2 += d1*d1;
119     }
120     if (d2 > sp->sl.prox*sp->sl.prox)
121     return(NULL); /* too far away */
122     }
123     for (i = 0; i < 3; i++)
124     ourspot.aim[i] = ocent[i] - nsloc[i];
125     if ((d1 = normalize(ourspot.aim)) == 0.)
126     return(NULL); /* at source!! */
127     ourspot.siz = 2.*PI*(1. - d1/sqrt(d1*d1+maxrad2));
128     ourspot.flen = 0.;
129     if (sp->sflags & SSPOT) {
130     copystruct(&theirspot, sp->sl.s);
131     multv3(theirspot.aim, sp->sl.s->aim, pm);
132     if (!commonspot(&ourspot, &theirspot, nsloc))
133     return(NULL); /* no overlap */
134     ourspot.flen = theirspot.flen;
135     }
136     if (sp->sflags & SFLAT) { /* check for behind source */
137     multv3(nsnorm, sp->snorm, pm);
138     if (checkspot(&ourspot, nsnorm) < 0)
139     return(NULL);
140     }
141     }
142     /* everything is OK, make source */
143     if ((newsrc = newsource()) == NULL)
144     goto memerr;
145     newsrc->sflags = sp->sflags | (SVIRTUAL|SSPOT|SFOLLOW);
146     VCOPY(newsrc->sloc, nsloc);
147     if (newsrc->sflags & SFLAT)
148     VCOPY(newsrc->snorm, nsnorm);
149     newsrc->ss = sp->ss; newsrc->ss2 = sp->ss2;
150     if ((newsrc->sl.s = (SPOT *)malloc(sizeof(SPOT))) == NULL)
151     goto memerr;
152     copystruct(newsrc->sl.s, &ourspot);
153     if (newsrc->sflags & SPROX)
154     newsrc->sl.prox = sp->sl.prox;
155     newsrc->sa.svnext = sp - source;
156     return(newsrc);
157     memerr:
158     error(SYSTEM, "out of memory in makevsrc");
159     }
160    
161    
162     commonspot(sp1, sp2, org) /* set sp1 to intersection of sp1 and sp2 */
163     register SPOT *sp1, *sp2;
164     FVECT org;
165     {
166     FVECT cent;
167     double rad2, d1r2, d2r2;
168    
169     d1r2 = 1. - sp1->siz/(2.*PI);
170     d2r2 = 1. - sp2->siz/(2.*PI);
171     if (sp2->siz >= 2.*PI-FTINY) /* BIG, just check overlap */
172     return(DOT(sp1->aim,sp2->aim) >= d1r2*d2r2 -
173     sqrt((1.-d1r2*d1r2)*(1.-d2r2*d2r2)));
174     /* compute and check disks */
175     d1r2 = 1./(d1r2*d1r2) - 1.;
176     d2r2 = 1./(d2r2*d2r2) - 1.;
177     rad2 = intercircle(cent, sp1->aim, sp2->aim, d1r2, d2r2);
178     if (rad2 <= FTINY || normalize(cent) == 0.)
179     return(0);
180     VCOPY(sp1->aim, cent);
181     sp1->siz = 2.*PI*(1. - 1./sqrt(1.+rad2));
182     return(1);
183     }
184    
185    
186     commonbeam(sp1, sp2, dir) /* set sp1 to intersection of sp1 and sp2 */
187     register SPOT *sp1, *sp2;
188     FVECT dir;
189     {
190     FVECT cent, c1, c2;
191     double rad2, d;
192     register int i;
193     /* move centers to common plane */
194     d = DOT(sp1->aim, dir);
195     for (i = 0; i < 3; i++)
196     c1[i] = sp2->aim[i] - d*dir[i];
197     d = DOT(sp2->aim, dir);
198     for (i = 0; i < 3; i++)
199     c2[i] = sp2->aim[i] - d*dir[i];
200     /* compute overlap */
201     rad2 = intercircle(cent, c1, c2, sp1->siz/PI, sp2->siz/PI);
202     if (rad2 <= FTINY)
203     return(0);
204     VCOPY(sp1->aim, cent);
205     sp1->siz = PI*rad2;
206     return(1);
207     }
208    
209    
210     checkspot(sp, nrm) /* check spotlight for behind source */
211     register SPOT *sp;
212     FVECT nrm;
213     {
214     double d, d1;
215    
216     d = DOT(sp->aim, nrm);
217     if (d > FTINY) /* center in front? */
218     return(0);
219     /* else check horizon */
220     d1 = 1. - sp->siz/(2.*PI);
221     return(1.-FTINY-d*d > d1*d1);
222     }
223    
224    
225     mirrorproj(m, nv, offs) /* get mirror projection for surface */
226     register MAT4 m;
227     FVECT nv;
228     double offs;
229     {
230     register int i, j;
231     /* assign matrix */
232     setident4(m);
233     for (i = 0; i < 3; i++)
234     for (j = 0; j < 3; j++)
235     m[i][j] -= 2.*nv[i]*nv[j];
236     for (j = 0; j < 3; j++)
237     m[3][j] = 2.*offs*nv[j];
238     }
239    
240    
241     double
242     intercircle(cc, c1, c2, r1s, r2s) /* intersect two circles */
243     FVECT cc; /* midpoint (return value) */
244     FVECT c1, c2; /* circle centers */
245     double r1s, r2s; /* radii squared */
246     {
247     double a2, d2, l;
248     FVECT disp;
249     register int i;
250    
251     for (i = 0; i < 3; i++)
252     disp[i] = c2[i] - c1[i];
253     d2 = DOT(disp,disp);
254     /* circle within overlap? */
255     if (r1s < r2s) {
256     if (r2s >= r1s + d2) {
257     VCOPY(cc, c1);
258     return(r1s);
259     }
260     } else {
261     if (r1s >= r2s + d2) {
262     VCOPY(cc, c2);
263     return(r2s);
264     }
265     }
266     a2 = .25*(2.*(r1s+r2s) - d2 - (r2s-r1s)*(r2s-r1s)/d2);
267     /* no overlap? */
268     if (a2 <= 0.)
269     return(0.);
270     l = sqrt((r1s - a2)/d2);
271     for (i = 0; i < 3; i++)
272     cc[i] = c1[i] + l*disp[i];
273     return(a2);
274     }
275    
276    
277     /*
278     * The following routines depend on the supported OBJECTS:
279     */
280    
281    
282     double
283     getmaxdisk(ocent, op) /* get object center and squared radius */
284     FVECT ocent;
285     register OBJREC *op;
286     {
287     double maxrad2;
288    
289     switch (op->otype) {
290     case OBJ_FACE:
291     {
292     double d1, d2;
293     register int i, j;
294     register FACE *f = getface(op);
295    
296     for (i = 0; i < 3; i++) {
297     ocent[i] = 0.;
298     for (j = 0; j < f->nv; j++)
299     ocent[i] += VERTEX(f,j)[i];
300     ocent[i] /= (double)f->nv;
301     }
302     maxrad2 = 0.;
303     for (j = 0; j < f->nv; j++) {
304     d2 = 0.;
305     for (i = 0; i < 3; i++) {
306     d1 = VERTEX(f,j)[i] - ocent[i];
307     d2 += d1*d1;
308     }
309     if (d2 > maxrad2)
310     maxrad2 = d2;
311     }
312     }
313     return(maxrad2);
314     case OBJ_RING:
315     {
316     register CONE *co = getcone(op, 0);
317    
318     VCOPY(ocent, CO_P0(co));
319     maxrad2 = CO_R1(co);
320     maxrad2 *= maxrad2;
321     }
322     return(maxrad2);
323     }
324     objerror(op, USER, "illegal material");
325     }
326    
327    
328     double
329     getplaneq(nvec, op) /* get plane equation for object */
330     FVECT nvec;
331     OBJREC *op;
332     {
333     register FACE *fo;
334     register CONE *co;
335    
336     switch (op->otype) {
337     case OBJ_FACE:
338     fo = getface(op);
339     VCOPY(nvec, fo->norm);
340     return(fo->offset);
341     case OBJ_RING:
342     co = getcone(op, 0);
343     VCOPY(nvec, co->ad);
344     return(DOT(nvec, CO_P0(co)));
345     }
346     objerror(op, USER, "illegal material");
347     }
348    
349    
350     /*
351     * The following routines depend on the supported MATERIALS:
352     */
353    
354    
355     vproject(o, s, n) /* create projected source(s) if they exist */
356     OBJREC *o;
357     SRCREC *s;
358     int n;
359     {
360     SRCREC *ns;
361     FVECT norm;
362     double offset;
363     MAT4 proj;
364     /* get surface normal and offset */
365     offset = getplaneq(norm, o);
366     switch (objptr(o->omod)->otype) {
367     case MAT_MIRROR: /* mirror source */
368     if (DOT(s->sloc, norm) <= (s->sflags & SDISTANT ?
369     FTINY : offset+FTINY))
370     return; /* behind mirror */
371     mirrorproj(proj, norm, offset);
372     if ((ns = makevsrc(o, s, proj)) != NULL)
373     addvirtuals(ns, n);
374     break;
375     }
376     }
377    
378    
379     vsrcrelay(rn, rv) /* relay virtual source ray */
380     register RAY *rn, *rv;
381     {
382     int snext;
383     register int i;
384     /* source we're aiming for here */
385     snext = source[rv->rsrc].sa.svnext;
386     /* compute relayed ray direction */
387     switch (objptr(rv->ro->omod)->otype) {
388     case MAT_MIRROR: /* mirror: singular reflection */
389     rayorigin(rn, rv, REFLECTED, 1.);
390     /* ignore textures */
391     for (i = 0; i < 3; i++)
392     rn->rdir[i] = rv->rdir[i] + 2.*rv->rod*rv->ron[i];
393     break;
394     #ifdef DEBUG
395     default:
396     error(CONSISTENCY, "inappropriate material in vsrcrelay");
397     #endif
398     }
399     rn->rsrc = snext;
400     }
401    
402    
403     m_mirror(m, r) /* shade mirrored ray */
404     register OBJREC *m;
405     register RAY *r;
406     {
407     COLOR mcolor;
408     RAY nr;
409     register int i;
410    
411     if (m->oargs.nfargs != 3 || m->oargs.nsargs > 1)
412     objerror(m, USER, "bad number of arguments");
413     if (r->rsrc >= 0) { /* aiming for somebody */
414     if (source[r->rsrc].so != r->ro)
415     return; /* but not us */
416     } else if (m->oargs.nsargs > 0) { /* else call substitute? */
417     rayshade(r, modifier(m->oargs.sarg[0]));
418     return;
419     }
420     if (r->rod < 0.) /* back is black */
421     return;
422     /* get modifiers */
423     raytexture(r, m->omod);
424     /* assign material color */
425     setcolor(mcolor, m->oargs.farg[0],
426     m->oargs.farg[1],
427     m->oargs.farg[2]);
428     multcolor(mcolor, r->pcol);
429     /* compute reflected ray */
430     if (r->rsrc >= 0) /* relayed light source */
431     vsrcrelay(&nr, r);
432     else { /* ordinary reflection */
433     FVECT pnorm;
434     double pdot;
435    
436     if (rayorigin(&nr, r, REFLECTED, bright(mcolor)) < 0)
437     return;
438     pdot = raynormal(pnorm, r); /* use textures */
439     for (i = 0; i < 3; i++)
440     nr.rdir[i] = r->rdir[i] + 2.*pdot*pnorm[i];
441     }
442     rayvalue(&nr);
443     multcolor(nr.rcol, mcolor);
444     addcolor(r->rcol, nr.rcol);
445     }