src/rt/source.c

/* Copyright (c) 1990 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  source.c - routines dealing with illumination sources.
 *
 *     8/20/85
 */

#include  "ray.h"

#include  "octree.h"

#include  "source.h"

#include  "otypes.h"

#include  "cone.h"

#include  "face.h"

#include  "random.h"


extern double  dstrsrc;                 /* source distribution amount */
extern double  shadthresh;              /* relative shadow threshold */
extern double  shadcert;                /* shadow testing certainty */

SRCREC  *source = NULL;                 /* our list of sources */
int  nsources = 0;                      /* the number of sources */

static CONTRIB  *srccnt;                /* source contributions in direct() */
static CNTPTR  *cntord;                 /* source ordering in direct() */


marksources()                   /* find and mark source objects */
{
        int  i;
        register OBJREC  *o, *m;
        register SRCREC  *ns;

        for (i = 0; i < nobjects; i++) {
        
                o = objptr(i);

                if (o->omod == OVOID)
                        continue;

                m = objptr(o->omod);

                if (!islight(m->otype))
                        continue;
        
                if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
                                m->otype == MAT_SPOT ? 7 : 3))
                        objerror(m, USER, "bad # arguments");

                if (m->otype == MAT_GLOW &&
                                o->otype != OBJ_SOURCE &&
                                m->oargs.farg[3] <= FTINY)
                        continue;                       /* don't bother */

                if ((ns = newsource()) == NULL)
                        goto memerr;

                setsource(ns, o);

                if (m->otype == MAT_GLOW) {
                        ns->sflags |= SPROX;
                        ns->sl.prox = m->oargs.farg[3];
                        if (o->otype == OBJ_SOURCE)
                                ns->sflags |= SSKIP;
                } else if (m->otype == MAT_SPOT) {
                        ns->sflags |= SSPOT;
                        if ((ns->sl.s = makespot(m)) == NULL)
                                goto memerr;
                }
        }
        if (nsources <= 0) {
                error(WARNING, "no light sources found");
                return;
        }
        markvirtuals();                 /* find and add virtual sources */
        srccnt = (CONTRIB *)malloc(nsources*sizeof(CONTRIB));
        cntord = (CNTPTR *)malloc(nsources*sizeof(CNTPTR));
        if (srccnt != NULL && cntord != NULL)
                goto memerr;
        return;
memerr:
        error(SYSTEM, "out of memory in marksources");
}


SRCREC *
newsource()                     /* allocate new source in our array */
{
        if (nsources == 0)
                source = (SRCREC *)malloc(sizeof(SRCREC));
        else
                source = (SRCREC *)realloc((char *)source,
                                (unsigned)(nsources+1)*sizeof(SRCREC));
        if (source == NULL)
                return(NULL);
        source[nsources].sflags = 0;
        source[nsources].nhits = 1;
        source[nsources].ntests = 2;    /* initial hit probability = 1/2 */
        return(&source[nsources++]);
}


setsource(src, so)                      /* add a source to the array */
register SRCREC  *src;
register OBJREC  *so;
{
        double  cos(), tan(), sqrt();
        double  theta;
        FACE  *f;
        CONE  *co;
        int  j;
        register int  i;
        
        src->sa.success = 2*AIMREQT-1;          /* bitch on second failure */
        src->so = so;

        switch (so->otype) {
        case OBJ_SOURCE:
                if (so->oargs.nfargs != 4)
                        objerror(so, USER, "bad arguments");
                src->sflags |= SDISTANT;
                VCOPY(src->sloc, so->oargs.farg);
                if (normalize(src->sloc) == 0.0)
                        objerror(so, USER, "zero direction");
                theta = PI/180.0/2.0 * so->oargs.farg[3];
                if (theta <= FTINY)
                        objerror(so, USER, "zero size");
                src->ss = theta >= PI/4 ? 1.0 : tan(theta);
                src->ss2 = 2.0*PI * (1.0 - cos(theta));
                break;
        case OBJ_SPHERE:
                VCOPY(src->sloc, so->oargs.farg);
                src->ss = so->oargs.farg[3];
                src->ss2 = PI * src->ss * src->ss;
                break;
        case OBJ_FACE:
                                                /* get the face */
                f = getface(so);
                                                /* find the center */
                for (j = 0; j < 3; j++) {
                        src->sloc[j] = 0.0;
                        for (i = 0; i < f->nv; i++)
                                src->sloc[j] += VERTEX(f,i)[j];
                        src->sloc[j] /= (double)f->nv;
                }
                if (!inface(src->sloc, f))
                        objerror(so, USER, "cannot hit center");
                src->sflags |= SFLAT;
                VCOPY(src->snorm, f->norm);
                src->ss = sqrt(f->area / PI);
                src->ss2 = f->area;
                break;
        case OBJ_RING:
                                                /* get the ring */
                co = getcone(so, 0);
                VCOPY(src->sloc, CO_P0(co));
                if (CO_R0(co) > 0.0)
                        objerror(so, USER, "cannot hit center");
                src->sflags |= SFLAT;
                VCOPY(src->snorm, co->ad);
                src->ss = CO_R1(co);
                src->ss2 = PI * src->ss * src->ss;
                break;
        default:
                objerror(so, USER, "illegal material");
        }
}


SPOT *
makespot(m)                     /* make a spotlight */
register OBJREC  *m;
{
        extern double  cos();
        register SPOT  *ns;

        if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL)
                return(NULL);
        ns->siz = 2.0*PI * (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3]));
        VCOPY(ns->aim, m->oargs.farg+4);
        if ((ns->flen = normalize(ns->aim)) == 0.0)
                objerror(m, USER, "zero focus vector");
        return(ns);
}


double
srcray(sr, r, sn)               /* send a ray to a source, return domega */
register RAY  *sr;              /* returned source ray */
RAY  *r;                        /* ray which hit object */
register int  sn;               /* source number */
{
        double  ddot;                   /* (distance times) cosine */
        FVECT  vd;
        double  d;
        register int  i;

        if (source[sn].sflags & SSKIP)
                return(0.0);                    /* skip this source */

        rayorigin(sr, r, SHADOW, 1.0);          /* ignore limits */

        sr->rsrc = sn;                          /* remember source */
                                                /* get source direction */
        if (source[sn].sflags & SDISTANT) {
                if (source[sn].sflags & SSPOT) {        /* check location */
                        for (i = 0; i < 3; i++)
                                vd[i] = sr->rorg[i] - source[sn].sl.s->aim[i];
                        d = DOT(source[sn].sloc,vd);
                        d = DOT(vd,vd) - d*d;
                        if (PI*d > source[sn].sl.s->siz)
                                return(0.0);
                }
                                                /* constant direction */
                VCOPY(sr->rdir, source[sn].sloc);
        } else {                                /* compute direction */
                for (i = 0; i < 3; i++)
                        sr->rdir[i] = source[sn].sloc[i] - sr->rorg[i];

                if (source[sn].sflags & SFLAT &&
                        (ddot = -DOT(sr->rdir, source[sn].snorm)) <= FTINY)
                        return(0.0);            /* behind surface! */
        }
        if (dstrsrc > FTINY) {
                                        /* distribute source direction */
                dimlist[ndims++] = sn;
                for (i = 0; i < 3; i++) {
                        dimlist[ndims] = i + 8831;
                        vd[i] = dstrsrc * source[sn].ss *
                (1.0 - 2.0*urand(ilhash(dimlist,ndims+1)+samplendx));
                }
                ndims--;
                if (source[sn].sflags & SFLAT) {        /* project offset */
                        d = DOT(vd, source[sn].snorm);
                        for (i = 0; i < 3; i++)
                                vd[i] -= d * source[sn].snorm[i];
                }
                for (i = 0; i < 3; i++)         /* offset source direction */
                        sr->rdir[i] += vd[i];

        } else if (source[sn].sflags & SDISTANT)
                                                /* already normalized */
                return(source[sn].ss2);

        if ((d = normalize(sr->rdir)) == 0.0)
                                                /* at source! */
                return(0.0);
        
        if (source[sn].sflags & SDISTANT)
                                                /* domega constant */
                return(source[sn].ss2);

                                                /* check proximity */
        if (source[sn].sflags & SPROX &&
                        d > source[sn].sl.prox)
                return(0.0);
                                                /* compute dot product */
        if (source[sn].sflags & SFLAT)
                ddot /= d;
        else
                ddot = 1.0;
                                                /* check angle */
        if (source[sn].sflags & SSPOT) {
                if (source[sn].sl.s->siz < 2.0*PI *
                                (1.0 + DOT(source[sn].sl.s->aim,sr->rdir)))
                        return(0.0);
                d += source[sn].sl.s->flen;     /* adjust length */
        }
                                                /* compute domega */
        return(ddot*source[sn].ss2/(d*d));
}


sourcehit(r)                    /* check to see if ray hit distant source */
register RAY  *r;
{
        int  first, last;
        register int  i;

        if (r->rsrc >= 0) {             /* check only one if aimed */
                first = last = r->rsrc;
        } else {                        /* otherwise check all */
                first = 0; last = nsources-1;
        }
        for (i = first; i <= last; i++)
                if (source[i].sflags & SDISTANT)
                        /*
                         * Check to see if ray is within
                         * solid angle of source.
                         */
                        if (2.0*PI * (1.0 - DOT(source[i].sloc,r->rdir))
                                        <= source[i].ss2) {
                                r->ro = source[i].so;
                                if (!(source[i].sflags & SSKIP))
                                        break;
                        }

        if (r->ro != NULL) {
                for (i = 0; i < 3; i++)
                        r->ron[i] = -r->rdir[i];
                r->rod = 1.0;
                r->rox = NULL;
                return(1);
        }
        return(0);
}


static int
cntcmp(sc1, sc2)                        /* contribution compare (descending) */
register CNTPTR  *sc1, *sc2;
{
        if (sc1->brt > sc2->brt)
                return(-1);
        if (sc1->brt < sc2->brt)
                return(1);
        return(0);
}


direct(r, f, p)                         /* add direct component */
RAY  *r;                        /* ray that hit surface */
int  (*f)();                    /* direct component coefficient function */
char  *p;                       /* data for f */
{
        extern double  pow();
        register int  sn;
        int  nshadcheck, ncnts;
        int  nhits;
        double  prob, ourthresh, hwt;
        RAY  sr;
                        /* NOTE: srccnt and cntord global so no recursion */
        if (nsources <= 0)
                return;         /* no sources?! */
                                                /* compute number to check */
        nshadcheck = pow((double)nsources, shadcert) + .5;
                                                /* modify threshold */
        ourthresh = shadthresh / r->rweight;
                                                /* potential contributions */
        for (sn = 0; sn < nsources; sn++) {
                cntord[sn].sno = sn;
                cntord[sn].brt = 0.0;
                                                /* get source ray */
                if ((srccnt[sn].dom = srcray(&sr, r, sn)) == 0.0)
                        continue;
                VCOPY(srccnt[sn].dir, sr.rdir);
                                                /* compute coefficient */
                (*f)(srccnt[sn].val, p, srccnt[sn].dir, srccnt[sn].dom);
                cntord[sn].brt = bright(srccnt[sn].val);
                if (cntord[sn].brt <= 0.0)
                        continue;
                                                /* compute contribution */
                srcvalue(&sr);
                multcolor(srccnt[sn].val, sr.rcol);
                cntord[sn].brt = bright(srccnt[sn].val);
        }
                                                /* sort contributions */
        qsort(cntord, nsources, sizeof(CNTPTR), cntcmp);
        {                                       /* find last */
                register int  l, m;

                sn = 0; ncnts = l = nsources;
                while ((m = (sn + ncnts) >> 1) != l) {
                        if (cntord[m].brt > 0.0)
                                sn = m;
                        else
                                ncnts = m;
                        l = m;
                }
        }
                                                /* accumulate tail */
        for (sn = ncnts-1; sn > 0; sn--)
                cntord[sn-1].brt += cntord[sn].brt;
                                                /* test for shadows */
        nhits = 0;
        for (sn = 0; sn < ncnts; sn++) {
                                                /* check threshold */
                if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
                                cntord[sn].brt-cntord[sn+nshadcheck].brt)
                                < ourthresh*bright(r->rcol))
                        break;
                                                /* get statistics */
                source[cntord[sn].sno].ntests++;
                                                /* test for hit */
                rayorigin(&sr, r, SHADOW, 1.0);
                VCOPY(sr.rdir, srccnt[cntord[sn].sno].dir);
                sr.rsrc = cntord[sn].sno;
                if (localhit(&sr, &thescene) &&
                                ( sr.ro != source[cntord[sn].sno].so ||
                                source[cntord[sn].sno].sflags & SFOLLOW )) {
                                                /* follow entire path */
                        raycont(&sr);
                        if (bright(sr.rcol) <= FTINY)
                                continue;       /* missed! */
                        (*f)(srccnt[cntord[sn].sno].val, p,
                                        srccnt[cntord[sn].sno].dir,
                                        srccnt[cntord[sn].sno].dom);
                        multcolor(srccnt[cntord[sn].sno].val, sr.rcol);
                }
                                                /* add contribution if hit */
                addcolor(r->rcol, srccnt[cntord[sn].sno].val);
                nhits++;
                source[cntord[sn].sno].nhits++;
        }
                                        /* surface hit rate */
        if (sn > 0)
                hwt = (double)nhits / (double)sn;
        else
                hwt = 0.5;
#ifdef DEBUG
        sprintf(errmsg, "%d tested, %d untested, %f hit rate\n",
                        sn, ncnts-sn, hwt);
        eputs(errmsg);
#endif
                                        /* add in untested sources */
        for ( ; sn < ncnts; sn++) {
                prob = hwt * (double)source[cntord[sn].sno].nhits /
                                (double)source[cntord[sn].sno].ntests;
                scalecolor(srccnt[cntord[sn].sno].val, prob);
                addcolor(r->rcol, srccnt[cntord[sn].sno].val);
        }
}


srcvalue(r)                     /* punch ray to source and compute value */
RAY  *r;
{
        register SRCREC  *sp;

        sp = &source[r->rsrc];
        if (sp->sflags & SVIRTUAL) {            /* virtual source */
                RAY  nr;
                                        /* check intersection */
                if (!(*ofun[sp->so->otype].funp)(sp->so, r))
                        return;
                                        /* relay ray to source */
                vsrcrelay(&nr, r);
                srcvalue(&nr);
                return;
        }
                                        /* compute intersection */
        if (sp->sflags & SDISTANT ? sourcehit(r) :
                        (*ofun[sp->so->otype].funp)(sp->so, r)) {
                if (sp->sa.success >= 0)
                        sp->sa.success++;
                raycont(r);             /* compute contribution */
                return;
        }
        if (sp->sa.success < 0)
                return;                 /* bitched already */
        sp->sa.success -= AIMREQT;
        if (sp->sa.success >= 0)
                return;                 /* leniency */
        sprintf(errmsg, "aiming failure for light source \"%s\"",
                        sp->so->oname);
        error(WARNING, errmsg);         /* issue warning */
}


#define  wrongsource(m, r)      (m->otype!=MAT_ILLUM && \
                                r->rsrc>=0 && \
                                source[r->rsrc].so!=r->ro)

#define  badambient(m, r)       ((r->crtype&(AMBIENT|SHADOW))==AMBIENT && \
                                !(m->otype==MAT_GLOW&&r->rot>m->oargs.farg[3]))

#define  passillum(m, r)        (m->otype==MAT_ILLUM && \
                                !(r->rsrc>=0&&source[r->rsrc].so==r->ro))


m_light(m, r)                   /* ray hit a light source */
register OBJREC  *m;
register RAY  *r;
{
                                                /* check for over-counting */
        if (wrongsource(m, r) || badambient(m, r))
                return;
                                                /* check for passed illum */
        if (passillum(m, r)) {

                if (m->oargs.nsargs < 1 || !strcmp(m->oargs.sarg[0], VOIDID))
                        raytrans(r);
                else
                        rayshade(r, modifier(m->oargs.sarg[0]));

                                                /* otherwise treat as source */
        } else {
                                                /* check for behind */
                if (r->rod < 0.0)
                        return;
                                                /* get distribution pattern */
                raytexture(r, m->omod);
                                                /* get source color */
                setcolor(r->rcol, m->oargs.farg[0],
                                  m->oargs.farg[1],
                                  m->oargs.farg[2]);
                                                /* modify value */
                multcolor(r->rcol, r->pcol);
        }
}
Revision:	1.33
Committed:	Wed Jun 19 16:36:44 1991 UTC (32 years, 10 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.32:	+93 -59 lines
Log Message:	added virtual sources
#	User	Rev	Content
1	greg	1.25	/* Copyright (c) 1990 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* source.c - routines dealing with illumination sources.
9			*
10			* 8/20/85
11			*/
12
13			#include "ray.h"
14
15	greg	1.4	#include "octree.h"
16
17	greg	1.1	#include "source.h"
18
19			#include "otypes.h"
20
21			#include "cone.h"
22
23			#include "face.h"
24
25			#include "random.h"
26
27
28			extern double dstrsrc; /* source distribution amount */
29	greg	1.4	extern double shadthresh; /* relative shadow threshold */
30	greg	1.12	extern double shadcert; /* shadow testing certainty */
31	greg	1.1
32	greg	1.4	SRCREC source = NULL; / our list of sources */
33	greg	1.1	int nsources = 0; /* the number of sources */
34
35	greg	1.25	static CONTRIB srccnt; / source contributions in direct() */
36			static CNTPTR cntord; / source ordering in direct() */
37	greg	1.1
38	greg	1.25
39	greg	1.1	marksources() /* find and mark source objects */
40			{
41	greg	1.33	int i;
42	greg	1.1	register OBJREC o, m;
43	greg	1.33	register SRCREC *ns;
44	greg	1.1
45			for (i = 0; i < nobjects; i++) {
46
47			o = objptr(i);
48
49			if (o->omod == OVOID)
50			continue;
51
52			m = objptr(o->omod);
53
54	greg	1.24	if (!islight(m->otype))
55	greg	1.1	continue;
56
57	greg	1.6	if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
58			m->otype == MAT_SPOT ? 7 : 3))
59	greg	1.1	objerror(m, USER, "bad # arguments");
60
61	greg	1.6	if (m->otype == MAT_GLOW &&
62			o->otype != OBJ_SOURCE &&
63			m->oargs.farg[3] <= FTINY)
64	greg	1.1	continue; /* don't bother */
65
66	greg	1.33	if ((ns = newsource()) == NULL)
67	greg	1.25	goto memerr;
68	greg	1.1
69	greg	1.33	setsource(ns, o);
70	greg	1.1
71	greg	1.6	if (m->otype == MAT_GLOW) {
72	greg	1.33	ns->sflags \|= SPROX;
73			ns->sl.prox = m->oargs.farg[3];
74	greg	1.6	if (o->otype == OBJ_SOURCE)
75	greg	1.33	ns->sflags \|= SSKIP;
76	greg	1.6	} else if (m->otype == MAT_SPOT) {
77	greg	1.33	ns->sflags \|= SSPOT;
78			if ((ns->sl.s = makespot(m)) == NULL)
79			goto memerr;
80	greg	1.6	}
81	greg	1.1	}
82	greg	1.25	if (nsources <= 0) {
83			error(WARNING, "no light sources found");
84			return;
85			}
86	greg	1.33	markvirtuals(); /* find and add virtual sources */
87	greg	1.25	srccnt = (CONTRIB )malloc(nsourcessizeof(CONTRIB));
88			cntord = (CNTPTR )malloc(nsourcessizeof(CNTPTR));
89			if (srccnt != NULL && cntord != NULL)
90	greg	1.33	goto memerr;
91			return;
92	greg	1.25	memerr:
93			error(SYSTEM, "out of memory in marksources");
94	greg	1.1	}
95
96
97	greg	1.33	SRCREC *
98			newsource() /* allocate new source in our array */
99			{
100			if (nsources == 0)
101			source = (SRCREC *)malloc(sizeof(SRCREC));
102			else
103			source = (SRCREC )realloc((char )source,
104			(unsigned)(nsources+1)*sizeof(SRCREC));
105			if (source == NULL)
106			return(NULL);
107			source[nsources].sflags = 0;
108			source[nsources].nhits = 1;
109			source[nsources].ntests = 2; /* initial hit probability = 1/2 */
110			return(&source[nsources++]);
111			}
112
113
114			setsource(src, so) /* add a source to the array */
115	greg	1.4	register SRCREC *src;
116	greg	1.1	register OBJREC *so;
117			{
118			double cos(), tan(), sqrt();
119			double theta;
120			FACE *f;
121			CONE *co;
122			int j;
123			register int i;
124
125	greg	1.33	src->sa.success = 2AIMREQT-1; / bitch on second failure */
126	greg	1.1	src->so = so;
127
128			switch (so->otype) {
129			case OBJ_SOURCE:
130			if (so->oargs.nfargs != 4)
131			objerror(so, USER, "bad arguments");
132			src->sflags \|= SDISTANT;
133			VCOPY(src->sloc, so->oargs.farg);
134			if (normalize(src->sloc) == 0.0)
135			objerror(so, USER, "zero direction");
136			theta = PI/180.0/2.0 * so->oargs.farg[3];
137			if (theta <= FTINY)
138			objerror(so, USER, "zero size");
139			src->ss = theta >= PI/4 ? 1.0 : tan(theta);
140			src->ss2 = 2.0PI (1.0 - cos(theta));
141			break;
142			case OBJ_SPHERE:
143			VCOPY(src->sloc, so->oargs.farg);
144			src->ss = so->oargs.farg[3];
145			src->ss2 = PI * src->ss * src->ss;
146			break;
147			case OBJ_FACE:
148			/* get the face */
149			f = getface(so);
150			/* find the center */
151			for (j = 0; j < 3; j++) {
152			src->sloc[j] = 0.0;
153			for (i = 0; i < f->nv; i++)
154			src->sloc[j] += VERTEX(f,i)[j];
155	greg	1.33	src->sloc[j] /= (double)f->nv;
156	greg	1.1	}
157			if (!inface(src->sloc, f))
158			objerror(so, USER, "cannot hit center");
159	greg	1.33	src->sflags \|= SFLAT;
160			VCOPY(src->snorm, f->norm);
161	greg	1.1	src->ss = sqrt(f->area / PI);
162			src->ss2 = f->area;
163			break;
164			case OBJ_RING:
165			/* get the ring */
166			co = getcone(so, 0);
167			VCOPY(src->sloc, CO_P0(co));
168			if (CO_R0(co) > 0.0)
169			objerror(so, USER, "cannot hit center");
170	greg	1.33	src->sflags \|= SFLAT;
171			VCOPY(src->snorm, co->ad);
172	greg	1.1	src->ss = CO_R1(co);
173			src->ss2 = PI * src->ss * src->ss;
174			break;
175			default:
176			objerror(so, USER, "illegal material");
177			}
178			}
179
180
181	greg	1.6	SPOT *
182			makespot(m) /* make a spotlight */
183			register OBJREC *m;
184			{
185			extern double cos();
186			register SPOT *ns;
187
188			if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL)
189	greg	1.33	return(NULL);
190	greg	1.6	ns->siz = 2.0PI (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3]));
191			VCOPY(ns->aim, m->oargs.farg+4);
192			if ((ns->flen = normalize(ns->aim)) == 0.0)
193			objerror(m, USER, "zero focus vector");
194			return(ns);
195			}
196
197
198	greg	1.1	double
199			srcray(sr, r, sn) /* send a ray to a source, return domega */
200			register RAY sr; / returned source ray */
201			RAY r; / ray which hit object */
202			register int sn; /* source number */
203			{
204			double ddot; /* (distance times) cosine */
205			FVECT vd;
206			double d;
207			register int i;
208
209	greg	1.4	if (source[sn].sflags & SSKIP)
210	greg	1.1	return(0.0); /* skip this source */
211
212			rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */
213
214			sr->rsrc = sn; /* remember source */
215			/* get source direction */
216	greg	1.33	if (source[sn].sflags & SDISTANT) {
217			if (source[sn].sflags & SSPOT) { /* check location */
218			for (i = 0; i < 3; i++)
219			vd[i] = sr->rorg[i] - source[sn].sl.s->aim[i];
220			d = DOT(source[sn].sloc,vd);
221			d = DOT(vd,vd) - d*d;
222			if (PI*d > source[sn].sl.s->siz)
223			return(0.0);
224			}
225	greg	1.1	/* constant direction */
226	greg	1.4	VCOPY(sr->rdir, source[sn].sloc);
227	greg	1.33	} else { /* compute direction */
228	greg	1.1	for (i = 0; i < 3; i++)
229	greg	1.4	sr->rdir[i] = source[sn].sloc[i] - sr->rorg[i];
230	greg	1.1
231	greg	1.33	if (source[sn].sflags & SFLAT &&
232			(ddot = -DOT(sr->rdir, source[sn].snorm)) <= FTINY)
233	greg	1.1	return(0.0); /* behind surface! */
234			}
235			if (dstrsrc > FTINY) {
236			/* distribute source direction */
237	greg	1.31	dimlist[ndims++] = sn;
238			for (i = 0; i < 3; i++) {
239			dimlist[ndims] = i + 8831;
240			vd[i] = dstrsrc * source[sn].ss *
241			(1.0 - 2.0*urand(ilhash(dimlist,ndims+1)+samplendx));
242			}
243			ndims--;
244	greg	1.33	if (source[sn].sflags & SFLAT) { /* project offset */
245			d = DOT(vd, source[sn].snorm);
246	greg	1.1	for (i = 0; i < 3; i++)
247	greg	1.33	vd[i] -= d * source[sn].snorm[i];
248	greg	1.1	}
249			for (i = 0; i < 3; i++) /* offset source direction */
250			sr->rdir[i] += vd[i];
251
252	greg	1.4	} else if (source[sn].sflags & SDISTANT)
253	greg	1.1	/* already normalized */
254	greg	1.4	return(source[sn].ss2);
255	greg	1.1
256			if ((d = normalize(sr->rdir)) == 0.0)
257			/* at source! */
258			return(0.0);
259
260	greg	1.4	if (source[sn].sflags & SDISTANT)
261	greg	1.1	/* domega constant */
262	greg	1.4	return(source[sn].ss2);
263	greg	1.1
264	greg	1.6	/* check proximity */
265	greg	1.27	if (source[sn].sflags & SPROX &&
266			d > source[sn].sl.prox)
267			return(0.0);
268			/* compute dot product */
269	greg	1.33	if (source[sn].sflags & SFLAT)
270	greg	1.27	ddot /= d;
271			else
272			ddot = 1.0;
273	greg	1.6	/* check angle */
274	greg	1.27	if (source[sn].sflags & SSPOT) {
275			if (source[sn].sl.s->siz < 2.0PI
276	greg	1.6	(1.0 + DOT(source[sn].sl.s->aim,sr->rdir)))
277	greg	1.27	return(0.0);
278			d += source[sn].sl.s->flen; /* adjust length */
279	greg	1.1	}
280	greg	1.27	/* compute domega */
281			return(ddotsource[sn].ss2/(dd));
282	greg	1.1	}
283
284
285			sourcehit(r) /* check to see if ray hit distant source */
286			register RAY *r;
287			{
288			int first, last;
289			register int i;
290
291			if (r->rsrc >= 0) { /* check only one if aimed */
292			first = last = r->rsrc;
293			} else { /* otherwise check all */
294			first = 0; last = nsources-1;
295			}
296			for (i = first; i <= last; i++)
297	greg	1.4	if (source[i].sflags & SDISTANT)
298	greg	1.1	/*
299			* Check to see if ray is within
300			* solid angle of source.
301			*/
302	greg	1.4	if (2.0PI (1.0 - DOT(source[i].sloc,r->rdir))
303			<= source[i].ss2) {
304			r->ro = source[i].so;
305			if (!(source[i].sflags & SSKIP))
306	greg	1.1	break;
307			}
308
309			if (r->ro != NULL) {
310			for (i = 0; i < 3; i++)
311			r->ron[i] = -r->rdir[i];
312			r->rod = 1.0;
313	greg	1.26	r->rox = NULL;
314	greg	1.1	return(1);
315			}
316			return(0);
317			}
318
319
320	greg	1.4	static int
321			cntcmp(sc1, sc2) /* contribution compare (descending) */
322	greg	1.9	register CNTPTR sc1, sc2;
323	greg	1.4	{
324			if (sc1->brt > sc2->brt)
325			return(-1);
326			if (sc1->brt < sc2->brt)
327			return(1);
328			return(0);
329			}
330
331
332			direct(r, f, p) /* add direct component */
333			RAY r; / ray that hit surface */
334			int (f)(); / direct component coefficient function */
335			char p; / data for f */
336			{
337	greg	1.12	extern double pow();
338	greg	1.4	register int sn;
339	greg	1.12	int nshadcheck, ncnts;
340	greg	1.29	int nhits;
341			double prob, ourthresh, hwt;
342	greg	1.4	RAY sr;
343	greg	1.25	/* NOTE: srccnt and cntord global so no recursion */
344	greg	1.22	if (nsources <= 0)
345	greg	1.25	return; /* no sources?! */
346	greg	1.12	/* compute number to check */
347			nshadcheck = pow((double)nsources, shadcert) + .5;
348	greg	1.8	/* modify threshold */
349			ourthresh = shadthresh / r->rweight;
350	greg	1.4	/* potential contributions */
351			for (sn = 0; sn < nsources; sn++) {
352	greg	1.9	cntord[sn].sno = sn;
353			cntord[sn].brt = 0.0;
354	greg	1.4	/* get source ray */
355			if ((srccnt[sn].dom = srcray(&sr, r, sn)) == 0.0)
356			continue;
357			VCOPY(srccnt[sn].dir, sr.rdir);
358			/* compute coefficient */
359			(*f)(srccnt[sn].val, p, srccnt[sn].dir, srccnt[sn].dom);
360	greg	1.9	cntord[sn].brt = bright(srccnt[sn].val);
361	greg	1.15	if (cntord[sn].brt <= 0.0)
362	greg	1.4	continue;
363			/* compute contribution */
364	greg	1.33	srcvalue(&sr);
365	greg	1.4	multcolor(srccnt[sn].val, sr.rcol);
366	greg	1.9	cntord[sn].brt = bright(srccnt[sn].val);
367	greg	1.4	}
368			/* sort contributions */
369	greg	1.9	qsort(cntord, nsources, sizeof(CNTPTR), cntcmp);
370	greg	1.13	{ /* find last */
371			register int l, m;
372
373			sn = 0; ncnts = l = nsources;
374			while ((m = (sn + ncnts) >> 1) != l) {
375			if (cntord[m].brt > 0.0)
376			sn = m;
377			else
378			ncnts = m;
379			l = m;
380			}
381			}
382	greg	1.12	/* accumulate tail */
383			for (sn = ncnts-1; sn > 0; sn--)
384			cntord[sn-1].brt += cntord[sn].brt;
385	greg	1.10	/* test for shadows */
386	greg	1.29	nhits = 0;
387	greg	1.12	for (sn = 0; sn < ncnts; sn++) {
388	greg	1.10	/* check threshold */
389	greg	1.12	if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
390	greg	1.27	cntord[sn].brt-cntord[sn+nshadcheck].brt)
391			< ourthresh*bright(r->rcol))
392	greg	1.4	break;
393			/* get statistics */
394	greg	1.9	source[cntord[sn].sno].ntests++;
395	greg	1.4	/* test for hit */
396			rayorigin(&sr, r, SHADOW, 1.0);
397	greg	1.9	VCOPY(sr.rdir, srccnt[cntord[sn].sno].dir);
398	greg	1.19	sr.rsrc = cntord[sn].sno;
399	greg	1.4	if (localhit(&sr, &thescene) &&
400	greg	1.33	( sr.ro != source[cntord[sn].sno].so \|\|
401			source[cntord[sn].sno].sflags & SFOLLOW )) {
402			/* follow entire path */
403	greg	1.19	raycont(&sr);
404	greg	1.5	if (bright(sr.rcol) <= FTINY)
405	greg	1.4	continue; /* missed! */
406	greg	1.9	(*f)(srccnt[cntord[sn].sno].val, p,
407			srccnt[cntord[sn].sno].dir,
408			srccnt[cntord[sn].sno].dom);
409			multcolor(srccnt[cntord[sn].sno].val, sr.rcol);
410	greg	1.4	}
411			/* add contribution if hit */
412	greg	1.9	addcolor(r->rcol, srccnt[cntord[sn].sno].val);
413	greg	1.29	nhits++;
414	greg	1.9	source[cntord[sn].sno].nhits++;
415	greg	1.4	}
416	greg	1.29	/* surface hit rate */
417			if (sn > 0)
418			hwt = (double)nhits / (double)sn;
419			else
420			hwt = 0.5;
421	greg	1.20	#ifdef DEBUG
422	greg	1.12	sprintf(errmsg, "%d tested, %d untested, %f hit rate\n",
423			sn, ncnts-sn, hwt);
424			eputs(errmsg);
425	greg	1.4	#endif
426			/* add in untested sources */
427	greg	1.12	for ( ; sn < ncnts; sn++) {
428	greg	1.9	prob = hwt * (double)source[cntord[sn].sno].nhits /
429			(double)source[cntord[sn].sno].ntests;
430			scalecolor(srccnt[cntord[sn].sno].val, prob);
431			addcolor(r->rcol, srccnt[cntord[sn].sno].val);
432	greg	1.4	}
433			}
434
435
436	greg	1.33	srcvalue(r) /* punch ray to source and compute value */
437			RAY *r;
438			{
439			register SRCREC *sp;
440
441			sp = &source[r->rsrc];
442			if (sp->sflags & SVIRTUAL) { /* virtual source */
443			RAY nr;
444			/* check intersection */
445			if (!(*ofun[sp->so->otype].funp)(sp->so, r))
446			return;
447			/* relay ray to source */
448			vsrcrelay(&nr, r);
449			srcvalue(&nr);
450			return;
451			}
452			/* compute intersection */
453			if (sp->sflags & SDISTANT ? sourcehit(r) :
454			(*ofun[sp->so->otype].funp)(sp->so, r)) {
455			if (sp->sa.success >= 0)
456			sp->sa.success++;
457			raycont(r); /* compute contribution */
458			return;
459			}
460			if (sp->sa.success < 0)
461			return; /* bitched already */
462			sp->sa.success -= AIMREQT;
463			if (sp->sa.success >= 0)
464			return; /* leniency */
465			sprintf(errmsg, "aiming failure for light source \"%s\"",
466			sp->so->oname);
467			error(WARNING, errmsg); /* issue warning */
468			}
469
470
471	greg	1.1	#define wrongsource(m, r) (m->otype!=MAT_ILLUM && \
472			r->rsrc>=0 && \
473	greg	1.4	source[r->rsrc].so!=r->ro)
474	greg	1.1
475			#define badambient(m, r) ((r->crtype&(AMBIENT\|SHADOW))==AMBIENT && \
476	greg	1.6	!(m->otype==MAT_GLOW&&r->rot>m->oargs.farg[3]))
477	greg	1.1
478			#define passillum(m, r) (m->otype==MAT_ILLUM && \
479	greg	1.4	!(r->rsrc>=0&&source[r->rsrc].so==r->ro))
480	greg	1.1
481
482			m_light(m, r) /* ray hit a light source */
483			register OBJREC *m;
484			register RAY *r;
485			{
486			/* check for over-counting */
487			if (wrongsource(m, r) \|\| badambient(m, r))
488			return;
489			/* check for passed illum */
490			if (passillum(m, r)) {
491
492			if (m->oargs.nsargs < 1 \|\| !strcmp(m->oargs.sarg[0], VOIDID))
493			raytrans(r);
494			else
495			rayshade(r, modifier(m->oargs.sarg[0]));
496
497			/* otherwise treat as source */
498			} else {
499	greg	1.16	/* check for behind */
500			if (r->rod < 0.0)
501			return;
502	greg	1.1	/* get distribution pattern */
503			raytexture(r, m->omod);
504			/* get source color */
505			setcolor(r->rcol, m->oargs.farg[0],
506			m->oargs.farg[1],
507			m->oargs.farg[2]);
508			/* modify value */
509			multcolor(r->rcol, r->pcol);
510			}
511			}