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/* Copyright (c) 1993 Regents of the University of California */ |
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|
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#ifndef lint |
4 |
static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
6 |
|
7 |
/* |
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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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*/ |
12 |
|
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#include "ray.h" |
14 |
|
15 |
#include "octree.h" |
16 |
|
17 |
#include "otypes.h" |
18 |
|
19 |
#include "source.h" |
20 |
|
21 |
/* |
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* Structures used by direct() |
23 |
*/ |
24 |
|
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typedef struct { |
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int sno; /* source number */ |
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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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|
32 |
typedef struct { |
33 |
int sndx; /* source index (to CONTRIB array) */ |
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float brt; /* brightness (for comparison) */ |
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} CNTPTR; /* contribution pointer */ |
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|
37 |
static CONTRIB *srccnt; /* source contributions in direct() */ |
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static CNTPTR *cntord; /* source ordering in direct() */ |
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static int maxcntr = 0; /* size of contribution arrays */ |
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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 foundsource = 0; |
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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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|
55 |
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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|
60 |
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 (source[ns].sflags & SDISTANT) |
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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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if (!(source[ns].sflags & SSKIP)) |
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foundsource++; |
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} |
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if (!foundsource) { |
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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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/* allocate our contribution arrays */ |
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maxcntr = nsources + MAXSPART; /* start with this many */ |
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srccnt = (CONTRIB *)malloc(maxcntr*sizeof(CONTRIB)); |
108 |
cntord = (CNTPTR *)malloc(maxcntr*sizeof(CNTPTR)); |
109 |
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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srcray(sr, r, si) /* 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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SRCINDEX *si; /* source sample index */ |
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{ |
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double d; /* distance to source */ |
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register SRCREC *srcp; |
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|
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rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */ |
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|
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while ((d = nextssamp(sr, si)) != 0.0) { |
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sr->rsrc = si->sn; /* remember source */ |
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srcp = source + si->sn; |
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if (srcp->sflags & SDISTANT) { |
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if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s, 1)) |
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continue; |
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return(1); /* sample OK */ |
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} |
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/* local source */ |
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/* check proximity */ |
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if (srcp->sflags & SPROX && d > srcp->sl.prox) |
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continue; |
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/* check angle */ |
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if (srcp->sflags & SSPOT) { |
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if (spotout(sr, srcp->sl.s, 0)) |
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continue; |
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/* adjust solid angle */ |
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si->dom *= d*d; |
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d += srcp->sl.s->flen; |
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si->dom /= d*d; |
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} |
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return(1); /* sample OK */ |
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} |
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return(0); /* no more samples */ |
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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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register 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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if (!rayshade(r, r->ro->omod)) /* compute contribution */ |
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goto nomat; |
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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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if (!rayshade(r, r->ro->omod)) /* compute contribution */ |
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goto nomat; |
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return; |
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} |
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/* we missed our mark! */ |
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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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return; |
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nomat: |
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objerror(r->ro, USER, "material not found"); |
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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|SVIRTUAL)) == 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->rox = NULL; |
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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 int (*trace)(); |
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register int sn; |
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register CONTRIB *scp; |
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SRCINDEX si; |
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int nshadcheck, ncnts; |
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int nhits; |
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double 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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/* potential contributions */ |
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initsrcindex(&si); |
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for (sn = 0; srcray(&sr, r, &si); sn++) { |
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if (sn >= maxcntr) { |
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maxcntr = sn + MAXSPART; |
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srccnt = (CONTRIB *)realloc((char *)srccnt, |
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maxcntr*sizeof(CONTRIB)); |
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cntord = (CNTPTR *)realloc((char *)cntord, |
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maxcntr*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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} |
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cntord[sn].sndx = sn; |
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scp = srccnt + sn; |
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scp->sno = sr.rsrc; |
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/* compute coefficient */ |
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(*f)(scp->coef, p, sr.rdir, si.dom); |
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cntord[sn].brt = bright(scp->coef); |
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if (cntord[sn].brt <= 0.0) |
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continue; |
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VCOPY(scp->dir, sr.rdir); |
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/* compute potential */ |
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sr.revf = srcvalue; |
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rayvalue(&sr); |
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copycolor(scp->val, sr.rcol); |
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multcolor(scp->val, scp->coef); |
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cntord[sn].brt = bright(scp->val); |
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} |
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/* sort contributions */ |
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qsort(cntord, sn, 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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ncnts = l = sn; |
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sn = 0; |
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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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if (ncnts == 0) |
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return; /* no contributions! */ |
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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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/* compute number to check */ |
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nshadcheck = pow((double)ncnts, shadcert) + .5; |
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/* modify threshold */ |
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ourthresh = shadthresh / r->rweight; |
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/* test for shadows */ |
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for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts; |
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hwt += (double)source[scp->sno].nhits / |
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(double)source[scp->sno].ntests, |
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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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scp = srccnt + cntord[sn].sndx; |
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/* test for hit */ |
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rayorigin(&sr, r, SHADOW, 1.0); |
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VCOPY(sr.rdir, scp->dir); |
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sr.rsrc = scp->sno; |
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source[scp->sno].ntests++; /* keep statistics */ |
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if (localhit(&sr, &thescene) && |
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( sr.ro != source[scp->sno].so || |
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source[scp->sno].sflags & SFOLLOW )) { |
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/* follow entire path */ |
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if (!raycont(&sr)) |
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objerror(sr.ro, USER, "material not found"); |
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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(scp->val, sr.rcol); |
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multcolor(scp->val, scp->coef); |
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} |
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/* add contribution if hit */ |
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addcolor(r->rcol, scp->val); |
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nhits++; |
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source[scp->sno].nhits++; |
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} |
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/* source hit rate */ |
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if (hwt > FTINY) |
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hwt = (double)nhits / hwt; |
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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 conditional 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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scp = srccnt + cntord[sn].sndx; |
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prob = hwt * (double)source[scp->sno].nhits / |
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(double)source[scp->sno].ntests; |
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if (prob > 1.0) |
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prob = 1.0; |
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scalecolor(scp->val, prob); |
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addcolor(r->rcol, scp->val); |
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} |
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} |
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|
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|
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/**************************************************************** |
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* The following macros were separated from the m_light() routine |
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* because they are very nasty and difficult to understand. |
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*/ |
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|
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/* illumblock * |
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* |
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* We cannot allow an illum to pass to another illum, because that |
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* would almost certainly constitute overcounting. |
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* However, we do allow an illum to pass to another illum |
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* that is actually going to relay to a virtual light source. |
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* We also prevent an illum from passing to a glow; this provides a |
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* convenient mechanism for defining detailed light source |
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* geometry behind (or inside) an effective radiator. |
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*/ |
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|
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static int weaksrcmod(obj) int obj; /* efficiency booster function */ |
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{register OBJREC *o = objptr(obj); |
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return(o->otype==MAT_ILLUM|o->otype==MAT_GLOW);} |
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|
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#define illumblock(m, r) (!(source[r->rsrc].sflags&SVIRTUAL) && \ |
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r->rod > 0.0 && \ |
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weaksrcmod(source[r->rsrc].so->omod)) |
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|
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/* wrongsource * |
389 |
* |
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* This source is the wrong source (ie. overcounted) if we are |
391 |
* aimed to a different source than the one we hit and the one |
392 |
* we hit is not an illum that should be passed. |
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*/ |
394 |
|
395 |
#define wrongsource(m, r) (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \ |
396 |
(m->otype!=MAT_ILLUM || illumblock(m,r))) |
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|
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/* distglow * |
399 |
* |
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* A distant glow is an object that sometimes acts as a light source, |
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* but is too far away from the test point to be one in this case. |
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* (Glows with negative radii should NEVER participate in illumination.) |
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*/ |
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|
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#define distglow(m, r) (m->otype==MAT_GLOW && \ |
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m->oargs.farg[3] >= -FTINY && \ |
407 |
r->rot > m->oargs.farg[3]) |
408 |
|
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/* badcomponent * |
410 |
* |
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* We must avoid counting light sources in the ambient calculation, |
412 |
* since the direct component is handled separately. Therefore, any |
413 |
* ambient ray which hits an active light source must be discarded. |
414 |
* The same is true for stray specular samples, since the specular |
415 |
* contribution from light sources is calculated separately. |
416 |
*/ |
417 |
|
418 |
#define badcomponent(m, r) (r->crtype&(AMBIENT|SPECULAR) && \ |
419 |
!(r->crtype&SHADOW || r->rod < 0.0 || \ |
420 |
distglow(m, r))) |
421 |
|
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/* passillum * |
423 |
* |
424 |
* An illum passes to another material type when we didn't hit it |
425 |
* on purpose (as part of a direct calculation), or it is relaying |
426 |
* a virtual light source. |
427 |
*/ |
428 |
|
429 |
#define passillum(m, r) (m->otype==MAT_ILLUM && \ |
430 |
(r->rsrc<0 || source[r->rsrc].so!=r->ro || \ |
431 |
source[r->rsrc].sflags&SVIRTUAL)) |
432 |
|
433 |
/* srcignore * |
434 |
* |
435 |
* The -dv flag is normally on for sources to be visible. |
436 |
*/ |
437 |
|
438 |
#define srcignore(m, r) (!directvis && !(r->crtype&SHADOW) && \ |
439 |
!distglow(m, r)) |
440 |
|
441 |
|
442 |
m_light(m, r) /* ray hit a light source */ |
443 |
register OBJREC *m; |
444 |
register RAY *r; |
445 |
{ |
446 |
/* check for over-counting */ |
447 |
if (badcomponent(m, r)) |
448 |
return(1); |
449 |
if (wrongsource(m,r)) |
450 |
return(1); |
451 |
/* check for passed illum */ |
452 |
if (passillum(m, r)) { |
453 |
if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID)) |
454 |
return(rayshade(r, modifier(m->oargs.sarg[0]))); |
455 |
raytrans(r); |
456 |
return(1); |
457 |
} |
458 |
/* otherwise treat as source */ |
459 |
/* check for behind */ |
460 |
if (r->rod < 0.0) |
461 |
return(1); |
462 |
/* check for invisibility */ |
463 |
if (srcignore(m, r)) |
464 |
return(1); |
465 |
/* check for outside spot */ |
466 |
if (m->otype==MAT_SPOT && spotout(r, makespot(m), r->rot>=FHUGE)) |
467 |
return(1); |
468 |
/* get distribution pattern */ |
469 |
raytexture(r, m->omod); |
470 |
/* get source color */ |
471 |
setcolor(r->rcol, m->oargs.farg[0], |
472 |
m->oargs.farg[1], |
473 |
m->oargs.farg[2]); |
474 |
/* modify value */ |
475 |
multcolor(r->rcol, r->pcol); |
476 |
return(1); |
477 |
} |