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/* Copyright (c) 1986 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* source.c - routines dealing with illumination sources. |
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* |
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* 8/20/85 |
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*/ |
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|
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#include "ray.h" |
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|
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#include "octree.h" |
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|
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#include "source.h" |
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|
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#include "otypes.h" |
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|
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#include "cone.h" |
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|
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#include "face.h" |
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|
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#include "random.h" |
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|
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|
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extern double dstrsrc; /* source distribution amount */ |
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extern double shadthresh; /* relative shadow threshold */ |
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|
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SRCREC *source = NULL; /* our list of sources */ |
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int nsources = 0; /* the number of sources */ |
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|
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|
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marksources() /* find and mark source objects */ |
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{ |
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register OBJREC *o, *m; |
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register int i; |
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|
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for (i = 0; i < nobjects; i++) { |
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|
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o = objptr(i); |
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|
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if (o->omod == OVOID) |
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continue; |
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|
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m = objptr(o->omod); |
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|
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if (m->otype != MAT_LIGHT && |
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m->otype != MAT_ILLUM && |
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m->otype != MAT_GLOW) |
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continue; |
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|
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if (m->oargs.nfargs != 3) |
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objerror(m, USER, "bad # arguments"); |
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|
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if (m->otype == MAT_GLOW && o->otype != OBJ_SOURCE) |
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continue; /* don't bother */ |
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|
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if (source == NULL) |
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source = (SRCREC *)malloc(sizeof(SRCREC)); |
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else |
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source = (SRCREC *)realloc((char *)source, |
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(unsigned)(nsources+1)*sizeof(SRCREC)); |
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if (source == NULL) |
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error(SYSTEM, "out of memory in marksources"); |
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|
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newsource(&source[nsources], o); |
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|
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if (m->otype == MAT_GLOW) |
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source[nsources].sflags |= SSKIP; |
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|
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nsources++; |
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} |
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} |
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|
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|
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newsource(src, so) /* add a source to the array */ |
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register SRCREC *src; |
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register OBJREC *so; |
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{ |
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double cos(), tan(), sqrt(); |
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double theta; |
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FACE *f; |
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CONE *co; |
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int j; |
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register int i; |
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|
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src->sflags = 0; |
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src->nhits = src->ntests = 1; /* start with hit probability = 1 */ |
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src->so = so; |
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|
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switch (so->otype) { |
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case OBJ_SOURCE: |
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if (so->oargs.nfargs != 4) |
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objerror(so, USER, "bad arguments"); |
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src->sflags |= SDISTANT; |
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VCOPY(src->sloc, so->oargs.farg); |
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if (normalize(src->sloc) == 0.0) |
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objerror(so, USER, "zero direction"); |
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theta = PI/180.0/2.0 * so->oargs.farg[3]; |
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if (theta <= FTINY) |
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objerror(so, USER, "zero size"); |
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src->ss = theta >= PI/4 ? 1.0 : tan(theta); |
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src->ss2 = 2.0*PI * (1.0 - cos(theta)); |
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break; |
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case OBJ_SPHERE: |
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VCOPY(src->sloc, so->oargs.farg); |
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src->ss = so->oargs.farg[3]; |
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src->ss2 = PI * src->ss * src->ss; |
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break; |
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case OBJ_FACE: |
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/* get the face */ |
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f = getface(so); |
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/* find the center */ |
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for (j = 0; j < 3; j++) { |
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src->sloc[j] = 0.0; |
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for (i = 0; i < f->nv; i++) |
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src->sloc[j] += VERTEX(f,i)[j]; |
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src->sloc[j] /= f->nv; |
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} |
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if (!inface(src->sloc, f)) |
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objerror(so, USER, "cannot hit center"); |
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src->ss = sqrt(f->area / PI); |
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src->ss2 = f->area; |
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break; |
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case OBJ_RING: |
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/* get the ring */ |
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co = getcone(so, 0); |
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VCOPY(src->sloc, CO_P0(co)); |
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if (CO_R0(co) > 0.0) |
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objerror(so, USER, "cannot hit center"); |
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src->ss = CO_R1(co); |
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src->ss2 = PI * src->ss * src->ss; |
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break; |
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default: |
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objerror(so, USER, "illegal material"); |
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} |
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} |
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|
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|
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double |
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srcray(sr, r, sn) /* send a ray to a source, return domega */ |
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register RAY *sr; /* returned source ray */ |
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RAY *r; /* ray which hit object */ |
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register int sn; /* source number */ |
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{ |
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register double *norm = NULL; /* plane normal */ |
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double ddot; /* (distance times) cosine */ |
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FVECT vd; |
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double d; |
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register int i; |
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|
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if (source[sn].sflags & SSKIP) |
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return(0.0); /* skip this source */ |
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|
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rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */ |
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|
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sr->rsrc = sn; /* remember source */ |
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/* get source direction */ |
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if (source[sn].sflags & SDISTANT) |
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/* constant direction */ |
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VCOPY(sr->rdir, source[sn].sloc); |
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else { /* compute direction */ |
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for (i = 0; i < 3; i++) |
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sr->rdir[i] = source[sn].sloc[i] - sr->rorg[i]; |
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|
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if (source[sn].so->otype == OBJ_FACE) |
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norm = getface(source[sn].so)->norm; |
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else if (source[sn].so->otype == OBJ_RING) |
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norm = getcone(source[sn].so,0)->ad; |
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|
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if (norm != NULL && (ddot = -DOT(sr->rdir, norm)) <= FTINY) |
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return(0.0); /* behind surface! */ |
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} |
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if (dstrsrc > FTINY) { |
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/* distribute source direction */ |
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for (i = 0; i < 3; i++) |
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vd[i] = dstrsrc * source[sn].ss * (1.0 - 2.0*frandom()); |
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|
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if (norm != NULL) { /* project offset */ |
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d = DOT(vd, norm); |
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for (i = 0; i < 3; i++) |
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vd[i] -= d * norm[i]; |
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} |
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for (i = 0; i < 3; i++) /* offset source direction */ |
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sr->rdir[i] += vd[i]; |
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|
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} else if (source[sn].sflags & SDISTANT) |
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/* already normalized */ |
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return(source[sn].ss2); |
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|
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if ((d = normalize(sr->rdir)) == 0.0) |
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/* at source! */ |
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return(0.0); |
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|
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if (source[sn].sflags & SDISTANT) |
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/* domega constant */ |
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return(source[sn].ss2); |
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|
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else { |
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|
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if (norm != NULL) |
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ddot /= d; |
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else |
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ddot = 1.0; |
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/* return domega */ |
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return(ddot*source[sn].ss2/(d*d)); |
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} |
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} |
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|
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|
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sourcehit(r) /* check to see if ray hit distant source */ |
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register RAY *r; |
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{ |
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int first, last; |
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register int i; |
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|
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if (r->rsrc >= 0) { /* check only one if aimed */ |
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first = last = r->rsrc; |
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} else { /* otherwise check all */ |
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first = 0; last = nsources-1; |
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} |
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for (i = first; i <= last; i++) |
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if (source[i].sflags & SDISTANT) |
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/* |
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* Check to see if ray is within |
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* solid angle of source. |
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*/ |
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if (2.0*PI * (1.0 - DOT(source[i].sloc,r->rdir)) |
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<= source[i].ss2) { |
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r->ro = source[i].so; |
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if (!(source[i].sflags & SSKIP)) |
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break; |
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} |
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|
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if (r->ro != NULL) { |
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for (i = 0; i < 3; i++) |
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r->ron[i] = -r->rdir[i]; |
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r->rod = 1.0; |
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r->rofs = 1.0; setident4(r->rofx); |
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r->robs = 1.0; setident4(r->robx); |
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return(1); |
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} |
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return(0); |
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} |
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|
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|
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static int |
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cntcmp(sc1, sc2) /* contribution compare (descending) */ |
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register CONTRIB *sc1, *sc2; |
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{ |
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if (sc1->brt > sc2->brt) |
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return(-1); |
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if (sc1->brt < sc2->brt) |
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return(1); |
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return(0); |
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} |
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|
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|
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direct(r, f, p) /* add direct component */ |
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RAY *r; /* ray that hit surface */ |
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int (*f)(); /* direct component coefficient function */ |
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char *p; /* data for f */ |
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{ |
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register int sn; |
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register CONTRIB *srccnt; |
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double dtmp, hwt, test2, hit2; |
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RAY sr; |
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|
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if ((srccnt = (CONTRIB *)malloc(nsources*sizeof(CONTRIB))) == NULL) |
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error(SYSTEM, "out of memory in direct"); |
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/* potential contributions */ |
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for (sn = 0; sn < nsources; sn++) { |
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srccnt[sn].sno = sn; |
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setcolor(srccnt[sn].val, 0.0, 0.0, 0.0); |
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/* get source ray */ |
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if ((srccnt[sn].dom = srcray(&sr, r, sn)) == 0.0) |
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continue; |
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VCOPY(srccnt[sn].dir, sr.rdir); |
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/* compute coefficient */ |
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(*f)(srccnt[sn].val, p, srccnt[sn].dir, srccnt[sn].dom); |
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srccnt[sn].brt = intens(srccnt[sn].val); |
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if (srccnt[sn].brt <= FTINY) |
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continue; |
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/* compute intersection */ |
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if (!( source[sn].sflags & SDISTANT ? |
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sourcehit(&sr) : |
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(*ofun[source[sn].so->otype].funp) |
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(source[sn].so, &sr) )) |
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continue; |
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/* compute contribution */ |
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rayshade(&sr, sr.ro->omod); |
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multcolor(srccnt[sn].val, sr.rcol); |
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srccnt[sn].brt = intens(srccnt[sn].val); |
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} |
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/* sort contributions */ |
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qsort(srccnt, nsources, sizeof(CONTRIB), cntcmp); |
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hit2 = test2 = 0.0; |
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/* test for shadows */ |
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for (sn = 0; sn < nsources; sn++) { |
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/* check threshold */ |
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if (srccnt[sn].brt <= shadthresh*intens(r->rcol)/r->rweight) |
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break; |
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/* get statistics */ |
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hwt = (double)source[srccnt[sn].sno].nhits / |
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(double)source[srccnt[sn].sno].ntests; |
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test2 += hwt; |
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source[srccnt[sn].sno].ntests++; |
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/* test for hit */ |
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rayorigin(&sr, r, SHADOW, 1.0); |
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VCOPY(sr.rdir, srccnt[sn].dir); |
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if (localhit(&sr, &thescene) && |
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sr.ro != source[srccnt[sn].sno].so) { |
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/* check for transmission */ |
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if (sr.clipset != NULL && inset(sr.clipset,sr.ro->omod)) |
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raytrans(&sr); /* object is clipped */ |
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else |
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rayshade(&sr, sr.ro->omod); |
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if (intens(sr.rcol) <= FTINY) |
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continue; /* missed! */ |
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(*f)(srccnt[sn].val, p, srccnt[sn].dir, srccnt[sn].dom); |
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multcolor(srccnt[sn].val, sr.rcol); |
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} |
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/* add contribution if hit */ |
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addcolor(r->rcol, srccnt[sn].val); |
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hit2 += hwt; |
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source[srccnt[sn].sno].nhits++; |
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} |
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if (test2 > FTINY) /* weighted hit rate */ |
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hwt = hit2 / test2; |
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else |
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hwt = 0.0; |
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#ifdef DEBUG |
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fprintf(stderr, "%d tested, %f hit rate\n", sn, hwt); |
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#endif |
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/* add in untested sources */ |
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for ( ; sn < nsources; sn++) { |
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if (srccnt[sn].brt <= 0.0) |
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break; |
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dtmp = hwt * (double)source[srccnt[sn].sno].nhits / |
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(double)source[srccnt[sn].sno].ntests; |
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scalecolor(srccnt[sn].val, dtmp); |
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addcolor(r->rcol, srccnt[sn].val); |
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} |
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|
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free(srccnt); |
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} |
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|
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|
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#define wrongsource(m, r) (m->otype!=MAT_ILLUM && \ |
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r->rsrc>=0 && \ |
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source[r->rsrc].so!=r->ro) |
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|
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#define badambient(m, r) ((r->crtype&(AMBIENT|SHADOW))==AMBIENT && \ |
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!(r->rtype&REFLECTED)) /* hack! */ |
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|
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#define passillum(m, r) (m->otype==MAT_ILLUM && \ |
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!(r->rsrc>=0&&source[r->rsrc].so==r->ro)) |
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|
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|
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m_light(m, r) /* ray hit a light source */ |
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register OBJREC *m; |
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register RAY *r; |
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{ |
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/* check for behind */ |
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if (r->rod < 0.0) |
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return; |
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/* check for over-counting */ |
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if (wrongsource(m, r) || badambient(m, r)) |
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return; |
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/* check for passed illum */ |
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if (passillum(m, r)) { |
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|
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if (m->oargs.nsargs < 1 || !strcmp(m->oargs.sarg[0], VOIDID)) |
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raytrans(r); |
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else |
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rayshade(r, modifier(m->oargs.sarg[0])); |
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|
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/* otherwise treat as source */ |
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} else { |
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/* get distribution pattern */ |
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raytexture(r, m->omod); |
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/* get source color */ |
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setcolor(r->rcol, m->oargs.farg[0], |
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m->oargs.farg[1], |
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m->oargs.farg[2]); |
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/* modify value */ |
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multcolor(r->rcol, r->pcol); |
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} |
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} |
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|
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|
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o_source() {} /* intersection with a source is done elsewhere */ |
