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/* Copyright (c) 1991 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 "otypes.h" |
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|
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#include "source.h" |
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|
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#include "random.h" |
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|
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/* |
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* Structures used by direct() |
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*/ |
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|
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typedef struct { |
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FVECT dir; /* source direction */ |
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COLOR coef; /* material coefficient */ |
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COLOR val; /* contribution */ |
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} CONTRIB; /* direct contribution */ |
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|
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typedef struct { |
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int sno; /* source number */ |
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float brt; /* brightness (for comparison) */ |
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} CNTPTR; /* contribution pointer */ |
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|
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static CONTRIB *srccnt; /* source contributions in direct() */ |
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static CNTPTR *cntord; /* source ordering in direct() */ |
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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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int i; |
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register OBJREC *o, *m; |
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register int ns; |
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/* initialize dispatch table */ |
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initstypes(); |
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/* find direct sources */ |
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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 (!issurface(o->otype) || 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 (sfun[o->otype].of == NULL || |
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sfun[o->otype].of->setsrc == NULL) |
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objerror(o, USER, "illegal material"); |
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|
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if ((ns = newsource()) < 0) |
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goto memerr; |
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|
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setsource(&source[ns], o); |
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|
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if (m->otype == MAT_GLOW) { |
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source[ns].sflags |= SPROX; |
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source[ns].sl.prox = m->oargs.farg[3]; |
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if (o->otype == OBJ_SOURCE) |
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source[ns].sflags |= SSKIP; |
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} else if (m->otype == MAT_SPOT) { |
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source[ns].sflags |= SSPOT; |
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if ((source[ns].sl.s = makespot(m)) == NULL) |
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goto memerr; |
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if (source[ns].sflags & SFLAT && |
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!checkspot(source[ns].sl.s,source[ns].snorm)) { |
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objerror(o, WARNING, |
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"invalid spotlight direction"); |
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source[ns].sflags |= SSKIP; |
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} |
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} |
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} |
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if (nsources <= 0) { |
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error(WARNING, "no light sources found"); |
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return; |
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} |
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markvirtuals(); /* find and add virtual sources */ |
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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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goto memerr; |
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return; |
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memerr: |
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error(SYSTEM, "out of memory in marksources"); |
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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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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].sflags & SFLAT && |
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(ddot = -DOT(sr->rdir, source[sn].snorm)) <= 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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dimlist[ndims++] = sn; |
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for (i = 0; i < 3; i++) { |
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dimlist[ndims] = i + 8831; |
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vd[i] = dstrsrc * source[sn].ss * |
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(1.0 - 2.0*urand(urind(ilhash(dimlist,ndims+1),samplendx))); |
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} |
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ndims--; |
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if (source[sn].sflags & SFLAT) { /* project offset */ |
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d = DOT(vd, source[sn].snorm); |
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for (i = 0; i < 3; i++) |
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vd[i] -= d * source[sn].snorm[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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/* normalize */ |
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d = normalize(sr->rdir); |
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|
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} else if (!(source[sn].sflags & SDISTANT)) |
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/* normalize direction */ |
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d = normalize(sr->rdir); |
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|
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if (source[sn].sflags & SDISTANT) { |
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if (source[sn].sflags & SSPOT) { /* check location */ |
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for (i = 0; i < 3; i++) |
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vd[i] = source[sn].sl.s->aim[i] - sr->rorg[i]; |
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d = DOT(sr->rdir,vd); |
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if (d <= FTINY) |
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return(0.0); |
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d = DOT(vd,vd) - d*d; |
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if (PI*d > source[sn].sl.s->siz) |
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return(0.0); |
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} |
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return(source[sn].ss2); /* domega constant */ |
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} |
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/* check direction */ |
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if (d == 0.0) |
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return(0.0); |
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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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/* compute dot product */ |
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if (source[sn].sflags & SFLAT) |
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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; /* adjust length */ |
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} |
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/* compute 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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srcvalue(r) /* punch ray to source and compute value */ |
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RAY *r; |
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{ |
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register SRCREC *sp; |
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|
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sp = &source[r->rsrc]; |
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if (sp->sflags & SVIRTUAL) { /* virtual source */ |
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/* check intersection */ |
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if (!(*ofun[sp->so->otype].funp)(sp->so, r)) |
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return; |
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raycont(r); /* compute contribution */ |
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return; |
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} |
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/* compute intersection */ |
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if (sp->sflags & SDISTANT ? sourcehit(r) : |
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(*ofun[sp->so->otype].funp)(sp->so, r)) { |
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if (sp->sa.success >= 0) |
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sp->sa.success++; |
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raycont(r); /* compute contribution */ |
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return; |
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} |
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if (sp->sa.success < 0) |
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return; /* bitched already */ |
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sp->sa.success -= AIMREQT; |
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if (sp->sa.success >= 0) |
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return; /* leniency */ |
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sprintf(errmsg, "aiming failure for light source \"%s\"", |
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sp->so->oname); |
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error(WARNING, errmsg); /* issue warning */ |
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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 int (*trace)(); |
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extern double pow(); |
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register int sn; |
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int nshadcheck, ncnts; |
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int nhits; |
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double dom, prob, ourthresh, hwt; |
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RAY sr; |
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/* NOTE: srccnt and cntord global so no recursion */ |
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if (nsources <= 0) |
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return; /* no sources?! */ |
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/* compute number to check */ |
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nshadcheck = pow((double)nsources, shadcert) + .5; |
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/* modify threshold */ |
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ourthresh = shadthresh / r->rweight; |
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/* potential contributions */ |
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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 ((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].coef, p, srccnt[sn].dir, dom); |
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cntord[sn].brt = bright(srccnt[sn].coef); |
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if (cntord[sn].brt <= 0.0) |
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continue; |
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/* compute potential */ |
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sr.revf = srcvalue; |
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rayvalue(&sr); |
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copycolor(srccnt[sn].val, sr.rcol); |
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multcolor(srccnt[sn].val, srccnt[sn].coef); |
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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; |
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|
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sn = 0; ncnts = l = nsources; |
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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; |
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} |
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} |
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/* accumulate tail */ |
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for (sn = ncnts-1; sn > 0; sn--) |
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cntord[sn-1].brt += cntord[sn].brt; |
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/* test for shadows */ |
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nhits = 0; |
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for (sn = 0; sn < ncnts; sn++) { |
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/* check threshold */ |
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if ((sn+nshadcheck>=ncnts ? cntord[sn].brt : |
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cntord[sn].brt-cntord[sn+nshadcheck].brt) |
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< ourthresh*bright(r->rcol)) |
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break; |
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/* get statistics */ |
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source[cntord[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[cntord[sn].sno].dir); |
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sr.rsrc = cntord[sn].sno; |
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if (localhit(&sr, &thescene) && |
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( sr.ro != source[cntord[sn].sno].so || |
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source[cntord[sn].sno].sflags & SFOLLOW )) { |
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/* follow entire path */ |
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raycont(&sr); |
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if (trace != NULL) |
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(*trace)(&sr); /* trace execution */ |
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if (bright(sr.rcol) <= FTINY) |
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continue; /* missed! */ |
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copycolor(srccnt[cntord[sn].sno].val, sr.rcol); |
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multcolor(srccnt[cntord[sn].sno].val, |
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srccnt[cntord[sn].sno].coef); |
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} |
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/* add contribution if hit */ |
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addcolor(r->rcol, srccnt[cntord[sn].sno].val); |
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nhits++; |
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source[cntord[sn].sno].nhits++; |
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} |
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/* surface hit rate */ |
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if (sn > 0) |
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hwt = (double)nhits / (double)sn; |
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else |
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hwt = 0.5; |
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#ifdef DEBUG |
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sprintf(errmsg, "%d tested, %d untested, %f hit rate\n", |
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sn, ncnts-sn, hwt); |
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eputs(errmsg); |
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#endif |
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/* add in untested sources */ |
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for ( ; sn < ncnts; sn++) { |
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prob = hwt * (double)source[cntord[sn].sno].nhits / |
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(double)source[cntord[sn].sno].ntests; |
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scalecolor(srccnt[cntord[sn].sno].val, prob); |
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addcolor(r->rcol, srccnt[cntord[sn].sno].val); |
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} |
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} |
