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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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extern double shadcert; /* shadow testing certainty */ |
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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 (!islight(m->otype)) |
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continue; |
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|
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if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 : |
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m->otype == MAT_SPOT ? 7 : 3)) |
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objerror(m, USER, "bad # arguments"); |
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|
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if (m->otype == MAT_GLOW && |
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o->otype != OBJ_SOURCE && |
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m->oargs.farg[3] <= FTINY) |
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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 |= SPROX; |
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source[nsources].sl.prox = m->oargs.farg[3]; |
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if (o->otype == OBJ_SOURCE) |
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source[nsources].sflags |= SSKIP; |
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} else if (m->otype == MAT_SPOT) { |
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source[nsources].sflags |= SSPOT; |
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source[nsources].sl.s = makespot(m); |
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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 = 1; src->ntests = 2; /* start probability = 1/2 */ |
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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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SPOT * |
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makespot(m) /* make a spotlight */ |
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register OBJREC *m; |
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{ |
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extern double cos(); |
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register SPOT *ns; |
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|
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if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL) |
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error(SYSTEM, "out of memory in makespot"); |
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ns->siz = 2.0*PI * (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3])); |
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VCOPY(ns->aim, m->oargs.farg+4); |
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if ((ns->flen = normalize(ns->aim)) == 0.0) |
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objerror(m, USER, "zero focus vector"); |
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return(ns); |
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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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/* check proximity */ |
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if (source[sn].sflags & SPROX && |
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d > source[sn].sl.prox) |
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return(0.0); |
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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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/* check angle */ |
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if (source[sn].sflags & SSPOT) { |
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if (source[sn].sl.s->siz < 2.0*PI * |
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(1.0 + DOT(source[sn].sl.s->aim,sr->rdir))) |
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return(0.0); |
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d += source[sn].sl.s->flen; |
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} |
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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 CNTPTR *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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extern double pow(); |
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register int sn; |
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register CONTRIB *srccnt; |
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register CNTPTR *cntord; |
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int nshadcheck, ncnts; |
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double prob, ourthresh, hwt, test2, hit2; |
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RAY sr; |
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|
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if (nsources <= 0) |
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return; |
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srccnt = (CONTRIB *)malloc(nsources*sizeof(CONTRIB)); |
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cntord = (CNTPTR *)malloc(nsources*sizeof(CNTPTR)); |
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if (srccnt == NULL || cntord == NULL) |
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error(SYSTEM, "out of memory in direct"); |
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/* compute number to check */ |
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nshadcheck = pow((double)nsources, shadcert) + .5; |
| 318 |
/* modify threshold */ |
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ourthresh = shadthresh / r->rweight; |
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/* potential contributions */ |
| 321 |
for (sn = 0; sn < nsources; sn++) { |
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cntord[sn].sno = sn; |
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cntord[sn].brt = 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); |
| 328 |
/* compute coefficient */ |
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(*f)(srccnt[sn].val, p, srccnt[sn].dir, srccnt[sn].dom); |
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cntord[sn].brt = bright(srccnt[sn].val); |
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if (cntord[sn].brt <= 0.0) |
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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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raycont(&sr); |
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multcolor(srccnt[sn].val, sr.rcol); |
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cntord[sn].brt = bright(srccnt[sn].val); |
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} |
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/* sort contributions */ |
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qsort(cntord, nsources, sizeof(CNTPTR), cntcmp); |
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{ /* find last */ |
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register int l, m; |
| 348 |
|
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sn = 0; ncnts = l = nsources; |
| 350 |
while ((m = (sn + ncnts) >> 1) != l) { |
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if (cntord[m].brt > 0.0) |
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sn = m; |
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else |
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ncnts = m; |
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l = m; |
| 356 |
} |
| 357 |
} |
| 358 |
/* accumulate tail */ |
| 359 |
for (sn = ncnts-1; sn > 0; sn--) |
| 360 |
cntord[sn-1].brt += cntord[sn].brt; |
| 361 |
/* start with prob=.5 */ |
| 362 |
hit2 = 0.5; test2 = 1.0; |
| 363 |
/* test for shadows */ |
| 364 |
for (sn = 0; sn < ncnts; sn++) { |
| 365 |
/* check threshold */ |
| 366 |
if ((sn+nshadcheck>=ncnts ? cntord[sn].brt : |
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cntord[sn].brt-cntord[sn+nshadcheck].brt) < |
| 368 |
ourthresh*bright(r->rcol)) |
| 369 |
break; |
| 370 |
/* get statistics */ |
| 371 |
hwt = (double)source[cntord[sn].sno].nhits / |
| 372 |
(double)source[cntord[sn].sno].ntests; |
| 373 |
test2 += hwt; |
| 374 |
source[cntord[sn].sno].ntests++; |
| 375 |
/* test for hit */ |
| 376 |
rayorigin(&sr, r, SHADOW, 1.0); |
| 377 |
VCOPY(sr.rdir, srccnt[cntord[sn].sno].dir); |
| 378 |
sr.rsrc = cntord[sn].sno; |
| 379 |
if (localhit(&sr, &thescene) && |
| 380 |
sr.ro != source[cntord[sn].sno].so) { |
| 381 |
/* check for transmission */ |
| 382 |
raycont(&sr); |
| 383 |
if (bright(sr.rcol) <= FTINY) |
| 384 |
continue; /* missed! */ |
| 385 |
(*f)(srccnt[cntord[sn].sno].val, p, |
| 386 |
srccnt[cntord[sn].sno].dir, |
| 387 |
srccnt[cntord[sn].sno].dom); |
| 388 |
multcolor(srccnt[cntord[sn].sno].val, sr.rcol); |
| 389 |
} |
| 390 |
/* add contribution if hit */ |
| 391 |
addcolor(r->rcol, srccnt[cntord[sn].sno].val); |
| 392 |
hit2 += hwt; |
| 393 |
source[cntord[sn].sno].nhits++; |
| 394 |
} |
| 395 |
/* weighted hit rate */ |
| 396 |
hwt = hit2 / test2; |
| 397 |
#ifdef DEBUG |
| 398 |
sprintf(errmsg, "%d tested, %d untested, %f hit rate\n", |
| 399 |
sn, ncnts-sn, hwt); |
| 400 |
eputs(errmsg); |
| 401 |
#endif |
| 402 |
/* add in untested sources */ |
| 403 |
for ( ; sn < ncnts; sn++) { |
| 404 |
prob = hwt * (double)source[cntord[sn].sno].nhits / |
| 405 |
(double)source[cntord[sn].sno].ntests; |
| 406 |
scalecolor(srccnt[cntord[sn].sno].val, prob); |
| 407 |
addcolor(r->rcol, srccnt[cntord[sn].sno].val); |
| 408 |
} |
| 409 |
|
| 410 |
free((char *)srccnt); |
| 411 |
free((char *)cntord); |
| 412 |
} |
| 413 |
|
| 414 |
|
| 415 |
#define wrongsource(m, r) (m->otype!=MAT_ILLUM && \ |
| 416 |
r->rsrc>=0 && \ |
| 417 |
source[r->rsrc].so!=r->ro) |
| 418 |
|
| 419 |
#define badambient(m, r) ((r->crtype&(AMBIENT|SHADOW))==AMBIENT && \ |
| 420 |
!(r->rtype&REFLECTED) && /* hack! */\ |
| 421 |
!(m->otype==MAT_GLOW&&r->rot>m->oargs.farg[3])) |
| 422 |
|
| 423 |
#define passillum(m, r) (m->otype==MAT_ILLUM && \ |
| 424 |
!(r->rsrc>=0&&source[r->rsrc].so==r->ro)) |
| 425 |
|
| 426 |
|
| 427 |
m_light(m, r) /* ray hit a light source */ |
| 428 |
register OBJREC *m; |
| 429 |
register RAY *r; |
| 430 |
{ |
| 431 |
/* check for over-counting */ |
| 432 |
if (wrongsource(m, r) || badambient(m, r)) |
| 433 |
return; |
| 434 |
/* check for passed illum */ |
| 435 |
if (passillum(m, r)) { |
| 436 |
|
| 437 |
if (m->oargs.nsargs < 1 || !strcmp(m->oargs.sarg[0], VOIDID)) |
| 438 |
raytrans(r); |
| 439 |
else |
| 440 |
rayshade(r, modifier(m->oargs.sarg[0])); |
| 441 |
|
| 442 |
/* otherwise treat as source */ |
| 443 |
} else { |
| 444 |
/* check for behind */ |
| 445 |
if (r->rod < 0.0) |
| 446 |
return; |
| 447 |
/* get distribution pattern */ |
| 448 |
raytexture(r, m->omod); |
| 449 |
/* get source color */ |
| 450 |
setcolor(r->rcol, m->oargs.farg[0], |
| 451 |
m->oargs.farg[1], |
| 452 |
m->oargs.farg[2]); |
| 453 |
/* modify value */ |
| 454 |
multcolor(r->rcol, r->pcol); |
| 455 |
/* assign distance */ |
| 456 |
r->rt = r->rot; |
| 457 |
} |
| 458 |
} |
