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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 "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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|
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SOURCE srcval[MAXSOURCE]; /* our array 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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m->otype != MAT_SPOT) |
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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 (nsources >= MAXSOURCE) |
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error(INTERNAL, "too many sources in marksources"); |
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|
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newsource(&srcval[nsources], o); |
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|
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if (m->otype == MAT_GLOW) { |
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srcval[nsources].sflags |= SPROX; |
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srcval[nsources].sl.prox = m->oargs.farg[3]; |
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if (o->otype == OBJ_SOURCE) |
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srcval[nsources].sflags |= SSKIP; |
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} else if (m->otype == MAT_SPOT) { |
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srcval[nsources].sflags |= SSPOT; |
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srcval[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 SOURCE *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->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 (srcval[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 (srcval[sn].sflags & SDISTANT) |
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/* constant direction */ |
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VCOPY(sr->rdir, srcval[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] = srcval[sn].sloc[i] - sr->rorg[i]; |
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|
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if (srcval[sn].so->otype == OBJ_FACE) |
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norm = getface(srcval[sn].so)->norm; |
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else if (srcval[sn].so->otype == OBJ_RING) |
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norm = getcone(srcval[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 * srcval[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 (srcval[sn].sflags & SDISTANT) |
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/* already normalized */ |
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return(srcval[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 (srcval[sn].sflags & SDISTANT) |
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/* domega constant */ |
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return(srcval[sn].ss2); |
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|
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else { |
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/* check proximity */ |
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if (srcval[sn].sflags & SPROX && |
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d > srcval[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 (srcval[sn].sflags & SSPOT) { |
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if (srcval[sn].sl.s->siz < 2.0*PI * |
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(1.0 + DOT(srcval[sn].sl.s->aim,sr->rdir))) |
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return(0.0); |
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d += srcval[sn].sl.s->flen; |
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} |
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/* return domega */ |
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return(ddot*srcval[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 (srcval[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(srcval[i].sloc,r->rdir)) |
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<= srcval[i].ss2) { |
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r->ro = srcval[i].so; |
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if (!(srcval[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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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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#define wrongsource(m, r) (m->otype!=MAT_ILLUM && \ |
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r->rsrc>=0 && \ |
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srcval[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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!(m->otype==MAT_GLOW&&r->rot>m->oargs.farg[3])) |
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|
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#define passillum(m, r) (m->otype==MAT_ILLUM && \ |
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!(r->rsrc>=0&&srcval[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 */ |
