src/rt/source.c

#ifndef lint
static const char RCSid[] = "$Id: source.c,v 2.36 2003/08/26 16:09:44 greg Exp $";
#endif
/*
 *  source.c - routines dealing with illumination sources.
 *
 *  External symbols declared in source.h
 */

#include "copyright.h"

#include  "ray.h"

#include  "otypes.h"

#include  "source.h"

#include  "random.h"

extern double  ssampdist;               /* scatter sampling distance */

#ifndef MAXSSAMP
#define MAXSSAMP        16              /* maximum samples per ray */
#endif

/*
 * Structures used by direct()
 */

typedef struct {
        int  sno;               /* source number */
        FVECT  dir;             /* source direction */
        COLOR  coef;            /* material coefficient */
        COLOR  val;             /* contribution */
}  CONTRIB;             /* direct contribution */

typedef struct {
        int  sndx;              /* source index (to CONTRIB array) */
        float  brt;             /* brightness (for comparison) */
}  CNTPTR;              /* contribution pointer */

static CONTRIB  *srccnt;                /* source contributions in direct() */
static CNTPTR  *cntord;                 /* source ordering in direct() */
static int  maxcntr = 0;                /* size of contribution arrays */


void
marksources()                   /* find and mark source objects */
{
        int  foundsource = 0;
        int  i;
        register OBJREC  *o, *m;
        register int  ns;
                                        /* initialize dispatch table */
        initstypes();
                                        /* find direct sources */
        for (i = 0; i < nsceneobjs; i++) {
        
                o = objptr(i);

                if (!issurface(o->otype) || o->omod == OVOID)
                        continue;
                                        /* find material */
                m = objptr(o->omod);
                while (!ismaterial(m->otype))
                        if (ismixture(m->otype) || m->omod == OVOID) {
                                m = NULL;
                                break;
                        } else
                                m = objptr(m->omod);
                if (m == NULL || !islight(m->otype))
                        continue;       /* not source modifier */
        
                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 (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY &&
                                m->oargs.farg[2] <= FTINY)
                        continue;                       /* don't bother */

                if (sfun[o->otype].of == NULL ||
                                sfun[o->otype].of->setsrc == NULL)
                        objerror(o, USER, "illegal material");

                if ((ns = newsource()) < 0)
                        goto memerr;

                setsource(&source[ns], o);

                if (m->otype == MAT_GLOW) {
                        source[ns].sflags |= SPROX;
                        source[ns].sl.prox = m->oargs.farg[3];
                        if (source[ns].sflags & SDISTANT)
                                source[ns].sflags |= SSKIP;
                } else if (m->otype == MAT_SPOT) {
                        source[ns].sflags |= SSPOT;
                        if ((source[ns].sl.s = makespot(m)) == NULL)
                                goto memerr;
                        if (source[ns].sflags & SFLAT &&
                                !checkspot(source[ns].sl.s,source[ns].snorm)) {
                                objerror(o, WARNING,
                                        "invalid spotlight direction");
                                source[ns].sflags |= SSKIP;
                        }
                }
                if (!(source[ns].sflags & SSKIP))
                        foundsource++;
        }
        if (!foundsource) {
                error(WARNING, "no light sources found");
                return;
        }
        markvirtuals();                 /* find and add virtual sources */
                                /* allocate our contribution arrays */
        maxcntr = nsources + MAXSPART;  /* start with this many */
        srccnt = (CONTRIB *)malloc(maxcntr*sizeof(CONTRIB));
        cntord = (CNTPTR *)malloc(maxcntr*sizeof(CNTPTR));
        if ((srccnt == NULL) | (cntord == NULL))
                goto memerr;
        return;
memerr:
        error(SYSTEM, "out of memory in marksources");
}


void
freesources()                   /* free all source structures */
{
        if (nsources > 0) {
                free((void *)source);
                source = NULL;
                nsources = 0;
        }
        if (maxcntr <= 0)
                return;
        free((void *)srccnt);
        srccnt = NULL;
        free((void *)cntord);
        cntord = NULL;
        maxcntr = 0;
}


int
srcray(sr, r, si)               /* send a ray to a source, return domega */
register RAY  *sr;              /* returned source ray */
RAY  *r;                        /* ray which hit object */
SRCINDEX  *si;                  /* source sample index */
{
    double  d;                          /* distance to source */
    register SRCREC  *srcp;

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

    while ((d = nextssamp(sr, si)) != 0.0) {
        sr->rsrc = si->sn;                      /* remember source */
        srcp = source + si->sn;
        if (srcp->sflags & SDISTANT) {
                if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s))
                        continue;
                return(1);              /* sample OK */
        }
                                /* local source */
                                                /* check proximity */
        if (srcp->sflags & SPROX && d > srcp->sl.prox)
                continue;
                                                /* check angle */
        if (srcp->sflags & SSPOT) {
                if (spotout(sr, srcp->sl.s))
                        continue;
                                        /* adjust solid angle */
                si->dom *= d*d;
                d += srcp->sl.s->flen;
                si->dom /= d*d;
        }
        return(1);                      /* sample OK */
    }
    return(0);                  /* no more samples */
}


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

        sp = &source[r->rsrc];
        if (sp->sflags & SVIRTUAL) {    /* virtual source */
                                        /* check intersection */
                if (!(*ofun[sp->so->otype].funp)(sp->so, r))
                        return;
                if (!rayshade(r, r->ro->omod))  /* compute contribution */
                        goto nomat;
                rayparticipate(r);
                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++;
                if (!rayshade(r, r->ro->omod))  /* compute contribution */
                        goto nomat;
                rayparticipate(r);
                return;
        }
                                        /* we missed our mark! */
        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 */
        return;
nomat:
        objerror(r->ro, USER, "material not found");
}


int
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|SVIRTUAL)) == 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) {
                r->robj = objndx(r->ro);
                for (i = 0; i < 3; i++)
                        r->ron[i] = -r->rdir[i];
                r->rod = 1.0;
                r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
                r->uv[0] = r->uv[1] = 0.0;
                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);
}


void
direct(r, f, p)                         /* add direct component */
RAY  *r;                        /* ray that hit surface */
void  (*f)();                   /* direct component coefficient function */
char  *p;                       /* data for f */
{
        extern void  (*trace)();
        register int  sn;
        register CONTRIB  *scp;
        SRCINDEX  si;
        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?! */
                                                /* potential contributions */
        initsrcindex(&si);
        for (sn = 0; srcray(&sr, r, &si); sn++) {
                if (sn >= maxcntr) {
                        maxcntr = sn + MAXSPART;
                        srccnt = (CONTRIB *)realloc((void *)srccnt,
                                        maxcntr*sizeof(CONTRIB));
                        cntord = (CNTPTR *)realloc((void *)cntord,
                                        maxcntr*sizeof(CNTPTR));
                        if ((srccnt == NULL) | (cntord == NULL))
                                error(SYSTEM, "out of memory in direct");
                }
                cntord[sn].sndx = sn;
                scp = srccnt + sn;
                scp->sno = sr.rsrc;
                                                /* compute coefficient */
                (*f)(scp->coef, p, sr.rdir, si.dom);
                cntord[sn].brt = bright(scp->coef);
                if (cntord[sn].brt <= 0.0)
                        continue;
                VCOPY(scp->dir, sr.rdir);
                                                /* compute potential */
                sr.revf = srcvalue;
                rayvalue(&sr);
                copycolor(scp->val, sr.rcol);
                multcolor(scp->val, scp->coef);
                cntord[sn].brt = bright(scp->val);
        }
                                                /* sort contributions */
        qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
        {                                       /* find last */
                register int  l, m;

                ncnts = l = sn;
                sn = 0;
                while ((m = (sn + ncnts) >> 1) != l) {
                        if (cntord[m].brt > 0.0)
                                sn = m;
                        else
                                ncnts = m;
                        l = m;
                }
        }
        if (ncnts == 0)
                return;         /* no contributions! */
                                                /* accumulate tail */
        for (sn = ncnts-1; sn > 0; sn--)
                cntord[sn-1].brt += cntord[sn].brt;
                                                /* compute number to check */
        nshadcheck = pow((double)ncnts, shadcert) + .5;
                                                /* modify threshold */
        ourthresh = shadthresh / r->rweight;
                                                /* test for shadows */
        for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
                        hwt += (double)source[scp->sno].nhits /
                                (double)source[scp->sno].ntests,
                        sn++) {
                                                /* check threshold */
                if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
                                cntord[sn].brt-cntord[sn+nshadcheck].brt)
                                < ourthresh*bright(r->rcol))
                        break;
                scp = srccnt + cntord[sn].sndx;
                                                /* test for hit */
                rayorigin(&sr, r, SHADOW, 1.0);
                VCOPY(sr.rdir, scp->dir);
                sr.rsrc = scp->sno;
                                                /* keep statistics */
                if (source[scp->sno].ntests++ > 0xfffffff0) {
                        source[scp->sno].ntests >>= 1;
                        source[scp->sno].nhits >>= 1;
                }
                if (localhit(&sr, &thescene) &&
                                ( sr.ro != source[scp->sno].so ||
                                source[scp->sno].sflags & SFOLLOW )) {
                                                /* follow entire path */
                        raycont(&sr);
                        rayparticipate(&sr);
                        if (trace != NULL)
                                (*trace)(&sr);  /* trace execution */
                        if (bright(sr.rcol) <= FTINY)
                                continue;       /* missed! */
                        copycolor(scp->val, sr.rcol);
                        multcolor(scp->val, scp->coef);
                }
                                                /* add contribution if hit */
                addcolor(r->rcol, scp->val);
                nhits++;
                source[scp->sno].nhits++;
        }
                                        /* source hit rate */
        if (hwt > FTINY)
                hwt = (double)nhits / hwt;
        else
                hwt = 0.5;
#ifdef DEBUG
        sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
                        sn, ncnts-sn, hwt);
        eputs(errmsg);
#endif
                                        /* add in untested sources */
        for ( ; sn < ncnts; sn++) {
                scp = srccnt + cntord[sn].sndx;
                prob = hwt * (double)source[scp->sno].nhits /
                                (double)source[scp->sno].ntests;
                if (prob > 1.0)
                        prob = 1.0;
                scalecolor(scp->val, prob);
                addcolor(r->rcol, scp->val);
        }
}


void
srcscatter(r)                   /* compute source scattering into ray */
register RAY  *r;
{
        int  oldsampndx;
        int  nsamps;
        RAY  sr;
        SRCINDEX  si;
        double  t, d;
        double  re, ge, be;
        COLOR  cvext;
        int  i, j;

        if (r->slights == NULL || r->slights[0] == 0
                        || r->gecc >= 1.-FTINY || r->rot >= FHUGE)
                return;
        if (ssampdist <= FTINY || (nsamps = r->rot/ssampdist + .5) < 1)
                nsamps = 1;
#if MAXSSAMP
        else if (nsamps > MAXSSAMP)
                nsamps = MAXSSAMP;
#endif
        oldsampndx = samplendx;
        samplendx = random()&0x7fff;            /* randomize */
        for (i = r->slights[0]; i > 0; i--) {   /* for each source */
                for (j = 0; j < nsamps; j++) {  /* for each sample position */
                        samplendx++;
                        t = r->rot * (j+frandom())/nsamps;
                                                        /* extinction */
                        re = t*colval(r->cext,RED);
                        ge = t*colval(r->cext,GRN);
                        be = t*colval(r->cext,BLU);
                        setcolor(cvext, re > 92. ? 0. : exp(-re),
                                        ge > 92. ? 0. : exp(-ge),
                                        be > 92. ? 0. : exp(-be));
                        if (intens(cvext) <= FTINY)
                                break;                  /* too far away */
                        sr.rorg[0] = r->rorg[0] + r->rdir[0]*t;
                        sr.rorg[1] = r->rorg[1] + r->rdir[1]*t;
                        sr.rorg[2] = r->rorg[2] + r->rdir[2]*t;
                        sr.rmax = 0.;
                        initsrcindex(&si);      /* sample ray to this source */
                        si.sn = r->slights[i];
                        nopart(&si, &sr);
                        if (!srcray(&sr, NULL, &si) ||
                                        sr.rsrc != r->slights[i])
                                continue;               /* no path */
                        copycolor(sr.cext, r->cext);
                        copycolor(sr.albedo, r->albedo);
                        sr.gecc = r->gecc;
                        sr.slights = r->slights;
                        rayvalue(&sr);                  /* eval. source ray */
                        if (bright(sr.rcol) <= FTINY)
                                continue;
                        if (r->gecc <= FTINY)           /* compute P(theta) */
                                d = 1.;
                        else {
                                d = DOT(r->rdir, sr.rdir);
                                d = 1. + r->gecc*r->gecc - 2.*r->gecc*d;
                                d = (1. - r->gecc*r->gecc) / (d*sqrt(d));
                        }
                                                        /* other factors */
                        d *= si.dom * r->rot / (4.*PI*nsamps);
                        multcolor(sr.rcol, r->cext);
                        multcolor(sr.rcol, r->albedo);
                        scalecolor(sr.rcol, d);
                        multcolor(sr.rcol, cvext);
                        addcolor(r->rcol, sr.rcol);     /* add it in */
                }
        }
        samplendx = oldsampndx;
}


/****************************************************************
 * The following macros were separated from the m_light() routine
 * because they are very nasty and difficult to understand.
 */

/* illumblock *
 *
 * We cannot allow an illum to pass to another illum, because that
 * would almost certainly constitute overcounting.
 * However, we do allow an illum to pass to another illum
 * that is actually going to relay to a virtual light source.
 * We also prevent an illum from passing to a glow; this provides a
 * convenient mechanism for defining detailed light source
 * geometry behind (or inside) an effective radiator.
 */

static int
weaksrcmat(int obj)             /* identify material */
{
        register OBJREC *o = objptr(obj);
        
        while (!ismaterial(o->otype))   /* find material */
                o = objptr(o->omod);
        return((o->otype==MAT_ILLUM)|(o->otype==MAT_GLOW));
}

#define  illumblock(m, r)       (!(source[r->rsrc].sflags&SVIRTUAL) && \
                                r->rod > 0.0 && \
                                weaksrcmat(source[r->rsrc].so->omod))

/* wrongsource *
 *
 * This source is the wrong source (ie. overcounted) if we are
 * aimed to a different source than the one we hit and the one
 * we hit is not an illum that should be passed.
 */

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

/* distglow *
 *
 * A distant glow is an object that sometimes acts as a light source,
 * but is too far away from the test point to be one in this case.
 * (Glows with negative radii should NEVER participate in illumination.)
 */

#define  distglow(m, r, d)      (m->otype==MAT_GLOW && \
                                m->oargs.farg[3] >= -FTINY && \
                                d > m->oargs.farg[3])

/* badcomponent *
 *
 * We must avoid counting light sources in the ambient calculation,
 * since the direct component is handled separately.  Therefore, any
 * ambient ray which hits an active light source must be discarded.
 * The same is true for stray specular samples, since the specular
 * contribution from light sources is calculated separately.
 */

#define  badcomponent(m, r)     (r->crtype&(AMBIENT|SPECULAR) && \
                                !(r->crtype&SHADOW || r->rod < 0.0 || \
                /* not 100% correct */  distglow(m, r, r->rot)))

/* passillum *
 *
 * An illum passes to another material type when we didn't hit it
 * on purpose (as part of a direct calculation), or it is relaying
 * a virtual light source.
 */

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

/* srcignore *
 *
 * The -dv flag is normally on for sources to be visible.
 */

#define  srcignore(m, r)        !(directvis || r->crtype&SHADOW || \
                                distglow(m, r, raydist(r,PRIMARY)))


int
m_light(m, r)                   /* ray hit a light source */
register OBJREC  *m;
register RAY  *r;
{
                                                /* check for over-counting */
        if (badcomponent(m, r))
                return(1);
        if (wrongsource(m, r))
                return(1);
                                                /* check for passed illum */
        if (passillum(m, r)) {
                if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
                        return(rayshade(r,lastmod(objndx(m),m->oargs.sarg[0])));
                raytrans(r);
                return(1);
        }
                                        /* otherwise treat as source */
                                                /* check for behind */
        if (r->rod < 0.0)
                return(1);
                                                /* check for invisibility */
        if (srcignore(m, r))
                return(1);
                                                /* check for outside spot */
        if (m->otype==MAT_SPOT && spotout(r, makespot(m)))
                return(1);
                                                /* 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);
        return(1);
}
Revision:	2.37
Committed:	Fri Sep 12 22:35:54 2003 UTC (20 years, 7 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.36:	+11 -5 lines
Log Message:	Fixed potential bug associated with last change allowing pretextured sources
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.37	static const char RCSid[] = "$Id: source.c,v 2.36 2003/08/26 16:09:44 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* source.c - routines dealing with illumination sources.
6			*
7	greg	2.29	* External symbols declared in source.h
8			*/
9
10	greg	2.30	#include "copyright.h"
11	greg	1.1
12			#include "ray.h"
13
14			#include "otypes.h"
15
16	greg	1.35	#include "source.h"
17	greg	1.1
18	greg	2.19	#include "random.h"
19
20			extern double ssampdist; /* scatter sampling distance */
21
22	greg	2.22	#ifndef MAXSSAMP
23			#define MAXSSAMP 16 /* maximum samples per ray */
24			#endif
25
26	greg	1.35	/*
27			* Structures used by direct()
28			*/
29	greg	1.1
30	greg	1.35	typedef struct {
31	greg	1.45	int sno; /* source number */
32	greg	1.35	FVECT dir; /* source direction */
33			COLOR coef; /* material coefficient */
34			COLOR val; /* contribution */
35			} CONTRIB; /* direct contribution */
36	greg	1.1
37	greg	1.35	typedef struct {
38	greg	1.45	int sndx; /* source index (to CONTRIB array) */
39	greg	1.35	float brt; /* brightness (for comparison) */
40			} CNTPTR; /* contribution pointer */
41	greg	1.1
42	greg	1.25	static CONTRIB srccnt; / source contributions in direct() */
43			static CNTPTR cntord; / source ordering in direct() */
44	greg	1.45	static int maxcntr = 0; /* size of contribution arrays */
45	greg	1.1
46	greg	1.25
47	greg	2.29	void
48	greg	1.1	marksources() /* find and mark source objects */
49			{
50	greg	2.3	int foundsource = 0;
51	greg	1.33	int i;
52	greg	1.1	register OBJREC o, m;
53	greg	1.36	register int ns;
54	greg	1.35	/* initialize dispatch table */
55			initstypes();
56			/* find direct sources */
57	greg	2.33	for (i = 0; i < nsceneobjs; i++) {
58	greg	1.1
59			o = objptr(i);
60
61	greg	1.35	if (!issurface(o->otype) \|\| o->omod == OVOID)
62	greg	1.1	continue;
63	greg	2.36	/* find material */
64	greg	1.1	m = objptr(o->omod);
65	greg	2.36	while (!ismaterial(m->otype))
66			if (ismixture(m->otype) \|\| m->omod == OVOID) {
67			m = NULL;
68			break;
69			} else
70			m = objptr(m->omod);
71			if (m == NULL \|\| !islight(m->otype))
72			continue; /* not source modifier */
73	greg	1.1
74	greg	1.6	if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
75			m->otype == MAT_SPOT ? 7 : 3))
76	greg	1.1	objerror(m, USER, "bad # arguments");
77
78	greg	1.6	if (m->otype == MAT_GLOW &&
79			o->otype != OBJ_SOURCE &&
80			m->oargs.farg[3] <= FTINY)
81	greg	1.1	continue; /* don't bother */
82	greg	2.16	if (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY &&
83			m->oargs.farg[2] <= FTINY)
84			continue; /* don't bother */
85	greg	1.1
86	greg	1.35	if (sfun[o->otype].of == NULL \|\|
87			sfun[o->otype].of->setsrc == NULL)
88			objerror(o, USER, "illegal material");
89
90	greg	1.36	if ((ns = newsource()) < 0)
91	greg	1.25	goto memerr;
92	greg	1.1
93	greg	1.37	setsource(&source[ns], o);
94	greg	1.1
95	greg	1.6	if (m->otype == MAT_GLOW) {
96	greg	1.36	source[ns].sflags \|= SPROX;
97			source[ns].sl.prox = m->oargs.farg[3];
98	greg	2.8	if (source[ns].sflags & SDISTANT)
99	greg	1.36	source[ns].sflags \|= SSKIP;
100	greg	1.6	} else if (m->otype == MAT_SPOT) {
101	greg	1.36	source[ns].sflags \|= SSPOT;
102			if ((source[ns].sl.s = makespot(m)) == NULL)
103	greg	1.33	goto memerr;
104	greg	1.38	if (source[ns].sflags & SFLAT &&
105			!checkspot(source[ns].sl.s,source[ns].snorm)) {
106			objerror(o, WARNING,
107			"invalid spotlight direction");
108			source[ns].sflags \|= SSKIP;
109			}
110	greg	1.6	}
111	greg	2.3	if (!(source[ns].sflags & SSKIP))
112			foundsource++;
113	greg	1.1	}
114	greg	2.3	if (!foundsource) {
115	greg	1.25	error(WARNING, "no light sources found");
116			return;
117			}
118	greg	1.33	markvirtuals(); /* find and add virtual sources */
119	greg	1.45	/* allocate our contribution arrays */
120	greg	1.48	maxcntr = nsources + MAXSPART; /* start with this many */
121	greg	1.45	srccnt = (CONTRIB )malloc(maxcntrsizeof(CONTRIB));
122			cntord = (CNTPTR )malloc(maxcntrsizeof(CNTPTR));
123	schorsch	2.35	if ((srccnt == NULL) \| (cntord == NULL))
124	greg	1.33	goto memerr;
125			return;
126	greg	1.25	memerr:
127			error(SYSTEM, "out of memory in marksources");
128	greg	1.1	}
129
130
131	greg	2.29	void
132			freesources() /* free all source structures */
133			{
134			if (nsources > 0) {
135			free((void *)source);
136			source = NULL;
137			nsources = 0;
138			}
139			if (maxcntr <= 0)
140			return;
141			free((void *)srccnt);
142			srccnt = NULL;
143			free((void *)cntord);
144			cntord = NULL;
145			maxcntr = 0;
146			}
147
148
149			int
150	greg	1.45	srcray(sr, r, si) /* send a ray to a source, return domega */
151	greg	1.1	register RAY sr; / returned source ray */
152			RAY r; / ray which hit object */
153	greg	1.45	SRCINDEX si; / source sample index */
154	greg	1.1	{
155	greg	1.45	double d; /* distance to source */
156			register SRCREC *srcp;
157	greg	1.1
158	greg	1.45	rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */
159	greg	1.1
160	greg	1.47	while ((d = nextssamp(sr, si)) != 0.0) {
161	greg	1.45	sr->rsrc = si->sn; /* remember source */
162			srcp = source + si->sn;
163			if (srcp->sflags & SDISTANT) {
164	greg	2.18	if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s))
165	greg	2.4	continue;
166	greg	1.45	return(1); /* sample OK */
167	greg	1.40	}
168	greg	1.45	/* local source */
169	greg	1.6	/* check proximity */
170	greg	1.45	if (srcp->sflags & SPROX && d > srcp->sl.prox)
171			continue;
172	greg	1.6	/* check angle */
173	greg	1.45	if (srcp->sflags & SSPOT) {
174	greg	2.18	if (spotout(sr, srcp->sl.s))
175	greg	1.45	continue;
176			/* adjust solid angle */
177			si->dom = dd;
178			d += srcp->sl.s->flen;
179			si->dom /= d*d;
180	greg	1.1	}
181	greg	1.45	return(1); /* sample OK */
182			}
183			return(0); /* no more samples */
184	greg	1.1	}
185
186
187	greg	2.29	void
188	greg	1.35	srcvalue(r) /* punch ray to source and compute value */
189	greg	2.15	register RAY *r;
190	greg	1.1	{
191	greg	1.35	register SRCREC *sp;
192	greg	1.1
193	greg	1.35	sp = &source[r->rsrc];
194			if (sp->sflags & SVIRTUAL) { /* virtual source */
195			/* check intersection */
196			if (!(*ofun[sp->so->otype].funp)(sp->so, r))
197			return;
198	greg	2.15	if (!rayshade(r, r->ro->omod)) /* compute contribution */
199			goto nomat;
200	greg	2.19	rayparticipate(r);
201	greg	1.35	return;
202	greg	1.1	}
203	greg	1.35	/* compute intersection */
204			if (sp->sflags & SDISTANT ? sourcehit(r) :
205			(*ofun[sp->so->otype].funp)(sp->so, r)) {
206			if (sp->sa.success >= 0)
207			sp->sa.success++;
208	greg	2.15	if (!rayshade(r, r->ro->omod)) /* compute contribution */
209			goto nomat;
210	greg	2.19	rayparticipate(r);
211	greg	1.35	return;
212	greg	1.1	}
213	greg	2.15	/* we missed our mark! */
214	greg	1.35	if (sp->sa.success < 0)
215			return; /* bitched already */
216			sp->sa.success -= AIMREQT;
217			if (sp->sa.success >= 0)
218			return; /* leniency */
219			sprintf(errmsg, "aiming failure for light source \"%s\"",
220			sp->so->oname);
221			error(WARNING, errmsg); /* issue warning */
222	greg	2.15	return;
223			nomat:
224			objerror(r->ro, USER, "material not found");
225	greg	1.1	}
226
227
228	greg	2.29	int
229	greg	2.5	sourcehit(r) /* check to see if ray hit distant source */
230			register RAY *r;
231			{
232			int first, last;
233			register int i;
234
235			if (r->rsrc >= 0) { /* check only one if aimed */
236			first = last = r->rsrc;
237			} else { /* otherwise check all */
238			first = 0; last = nsources-1;
239			}
240			for (i = first; i <= last; i++)
241			if ((source[i].sflags & (SDISTANT\|SVIRTUAL)) == SDISTANT)
242			/*
243			* Check to see if ray is within
244			* solid angle of source.
245			*/
246			if (2.0PI (1.0 - DOT(source[i].sloc,r->rdir))
247			<= source[i].ss2) {
248			r->ro = source[i].so;
249			if (!(source[i].sflags & SSKIP))
250			break;
251			}
252
253			if (r->ro != NULL) {
254	gregl	2.27	r->robj = objndx(r->ro);
255	greg	2.5	for (i = 0; i < 3; i++)
256			r->ron[i] = -r->rdir[i];
257			r->rod = 1.0;
258	greg	2.31	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
259			r->uv[0] = r->uv[1] = 0.0;
260	greg	2.5	r->rox = NULL;
261			return(1);
262			}
263			return(0);
264			}
265
266
267	greg	1.4	static int
268			cntcmp(sc1, sc2) /* contribution compare (descending) */
269	greg	1.9	register CNTPTR sc1, sc2;
270	greg	1.4	{
271			if (sc1->brt > sc2->brt)
272			return(-1);
273			if (sc1->brt < sc2->brt)
274			return(1);
275			return(0);
276			}
277
278
279	greg	2.29	void
280	greg	1.4	direct(r, f, p) /* add direct component */
281			RAY r; / ray that hit surface */
282	greg	2.29	void (f)(); / direct component coefficient function */
283	greg	1.4	char p; / data for f */
284			{
285	greg	2.29	extern void (*trace)();
286	greg	1.4	register int sn;
287	greg	2.7	register CONTRIB *scp;
288	greg	1.45	SRCINDEX si;
289	greg	1.12	int nshadcheck, ncnts;
290	greg	1.29	int nhits;
291	greg	1.45	double prob, ourthresh, hwt;
292	greg	1.4	RAY sr;
293	greg	1.25	/* NOTE: srccnt and cntord global so no recursion */
294	greg	1.22	if (nsources <= 0)
295	greg	1.25	return; /* no sources?! */
296	greg	1.4	/* potential contributions */
297	greg	1.45	initsrcindex(&si);
298			for (sn = 0; srcray(&sr, r, &si); sn++) {
299			if (sn >= maxcntr) {
300			maxcntr = sn + MAXSPART;
301	greg	2.32	srccnt = (CONTRIB )realloc((void )srccnt,
302	greg	1.45	maxcntr*sizeof(CONTRIB));
303	greg	2.32	cntord = (CNTPTR )realloc((void )cntord,
304	greg	1.45	maxcntr*sizeof(CNTPTR));
305	schorsch	2.35	if ((srccnt == NULL) \| (cntord == NULL))
306	greg	1.45	error(SYSTEM, "out of memory in direct");
307			}
308			cntord[sn].sndx = sn;
309	greg	2.7	scp = srccnt + sn;
310			scp->sno = sr.rsrc;
311	greg	1.4	/* compute coefficient */
312	greg	2.7	(*f)(scp->coef, p, sr.rdir, si.dom);
313			cntord[sn].brt = bright(scp->coef);
314	greg	1.15	if (cntord[sn].brt <= 0.0)
315	greg	1.4	continue;
316	greg	2.7	VCOPY(scp->dir, sr.rdir);
317	greg	1.35	/* compute potential */
318			sr.revf = srcvalue;
319			rayvalue(&sr);
320	greg	2.7	copycolor(scp->val, sr.rcol);
321			multcolor(scp->val, scp->coef);
322			cntord[sn].brt = bright(scp->val);
323	greg	1.4	}
324			/* sort contributions */
325	greg	1.45	qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
326	greg	1.13	{ /* find last */
327			register int l, m;
328
329	greg	1.45	ncnts = l = sn;
330			sn = 0;
331	greg	1.13	while ((m = (sn + ncnts) >> 1) != l) {
332			if (cntord[m].brt > 0.0)
333			sn = m;
334			else
335			ncnts = m;
336			l = m;
337			}
338			}
339	greg	2.2	if (ncnts == 0)
340			return; /* no contributions! */
341	greg	1.12	/* accumulate tail */
342			for (sn = ncnts-1; sn > 0; sn--)
343			cntord[sn-1].brt += cntord[sn].brt;
344	greg	1.45	/* compute number to check */
345			nshadcheck = pow((double)ncnts, shadcert) + .5;
346			/* modify threshold */
347			ourthresh = shadthresh / r->rweight;
348	greg	1.10	/* test for shadows */
349	greg	2.13	for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
350			hwt += (double)source[scp->sno].nhits /
351			(double)source[scp->sno].ntests,
352			sn++) {
353	greg	1.10	/* check threshold */
354	greg	1.12	if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
355	greg	1.27	cntord[sn].brt-cntord[sn+nshadcheck].brt)
356			< ourthresh*bright(r->rcol))
357	greg	1.4	break;
358	greg	2.7	scp = srccnt + cntord[sn].sndx;
359	greg	1.4	/* test for hit */
360			rayorigin(&sr, r, SHADOW, 1.0);
361	greg	2.7	VCOPY(sr.rdir, scp->dir);
362			sr.rsrc = scp->sno;
363	greg	2.34	/* keep statistics */
364			if (source[scp->sno].ntests++ > 0xfffffff0) {
365			source[scp->sno].ntests >>= 1;
366			source[scp->sno].nhits >>= 1;
367			}
368	greg	1.4	if (localhit(&sr, &thescene) &&
369	greg	2.7	( sr.ro != source[scp->sno].so \|\|
370			source[scp->sno].sflags & SFOLLOW )) {
371	greg	1.33	/* follow entire path */
372	greg	2.23	raycont(&sr);
373	greg	2.19	rayparticipate(&sr);
374	greg	1.42	if (trace != NULL)
375			(trace)(&sr); / trace execution */
376	greg	1.5	if (bright(sr.rcol) <= FTINY)
377	greg	1.4	continue; /* missed! */
378	greg	2.7	copycolor(scp->val, sr.rcol);
379			multcolor(scp->val, scp->coef);
380	greg	1.4	}
381			/* add contribution if hit */
382	greg	2.7	addcolor(r->rcol, scp->val);
383	greg	1.29	nhits++;
384	greg	2.7	source[scp->sno].nhits++;
385	greg	1.4	}
386	greg	2.13	/* source hit rate */
387			if (hwt > FTINY)
388			hwt = (double)nhits / hwt;
389	greg	1.29	else
390			hwt = 0.5;
391	greg	1.20	#ifdef DEBUG
392	greg	2.13	sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
393	greg	1.12	sn, ncnts-sn, hwt);
394			eputs(errmsg);
395	greg	1.4	#endif
396			/* add in untested sources */
397	greg	1.12	for ( ; sn < ncnts; sn++) {
398	greg	2.7	scp = srccnt + cntord[sn].sndx;
399			prob = hwt * (double)source[scp->sno].nhits /
400			(double)source[scp->sno].ntests;
401	greg	2.13	if (prob > 1.0)
402			prob = 1.0;
403	greg	2.7	scalecolor(scp->val, prob);
404			addcolor(r->rcol, scp->val);
405	greg	2.19	}
406			}
407
408
409	greg	2.29	void
410	greg	2.19	srcscatter(r) /* compute source scattering into ray */
411			register RAY *r;
412			{
413	greg	2.20	int oldsampndx;
414	greg	2.19	int nsamps;
415			RAY sr;
416			SRCINDEX si;
417	greg	2.25	double t, d;
418			double re, ge, be;
419			COLOR cvext;
420	greg	2.19	int i, j;
421
422	greg	2.22	if (r->slights == NULL \|\| r->slights[0] == 0
423			\|\| r->gecc >= 1.-FTINY \|\| r->rot >= FHUGE)
424	greg	2.19	return;
425			if (ssampdist <= FTINY \|\| (nsamps = r->rot/ssampdist + .5) < 1)
426			nsamps = 1;
427	greg	2.22	#if MAXSSAMP
428			else if (nsamps > MAXSSAMP)
429			nsamps = MAXSSAMP;
430			#endif
431	greg	2.20	oldsampndx = samplendx;
432			samplendx = random()&0x7fff; /* randomize */
433	greg	2.19	for (i = r->slights[0]; i > 0; i--) { /* for each source */
434	greg	2.25	for (j = 0; j < nsamps; j++) { /* for each sample position */
435	greg	2.19	samplendx++;
436			t = r->rot * (j+frandom())/nsamps;
437	greg	2.25	/* extinction */
438			re = t*colval(r->cext,RED);
439			ge = t*colval(r->cext,GRN);
440			be = t*colval(r->cext,BLU);
441			setcolor(cvext, re > 92. ? 0. : exp(-re),
442			ge > 92. ? 0. : exp(-ge),
443			be > 92. ? 0. : exp(-be));
444			if (intens(cvext) <= FTINY)
445			break; /* too far away */
446	greg	2.19	sr.rorg[0] = r->rorg[0] + r->rdir[0]*t;
447			sr.rorg[1] = r->rorg[1] + r->rdir[1]*t;
448			sr.rorg[2] = r->rorg[2] + r->rdir[2]*t;
449			sr.rmax = 0.;
450	greg	2.21	initsrcindex(&si); /* sample ray to this source */
451			si.sn = r->slights[i];
452			nopart(&si, &sr);
453			if (!srcray(&sr, NULL, &si) \|\|
454			sr.rsrc != r->slights[i])
455			continue; /* no path */
456	greg	2.19	copycolor(sr.cext, r->cext);
457	greg	2.24	copycolor(sr.albedo, r->albedo);
458	greg	2.19	sr.gecc = r->gecc;
459	gregl	2.26	sr.slights = r->slights;
460	greg	2.19	rayvalue(&sr); /* eval. source ray */
461			if (bright(sr.rcol) <= FTINY)
462			continue;
463			if (r->gecc <= FTINY) /* compute P(theta) */
464			d = 1.;
465			else {
466			d = DOT(r->rdir, sr.rdir);
467	greg	2.25	d = 1. + r->geccr->gecc - 2.r->gecc*d;
468			d = (1. - r->geccr->gecc) / (dsqrt(d));
469	greg	2.19	}
470			/* other factors */
471	greg	2.24	d = si.dom r->rot / (4.PInsamps);
472	greg	2.19	multcolor(sr.rcol, r->cext);
473	greg	2.24	multcolor(sr.rcol, r->albedo);
474	greg	2.19	scalecolor(sr.rcol, d);
475	greg	2.25	multcolor(sr.rcol, cvext);
476			addcolor(r->rcol, sr.rcol); /* add it in */
477	greg	2.19	}
478	greg	1.1	}
479	greg	2.20	samplendx = oldsampndx;
480	greg	2.4	}
481
482
483			/****************************************************************
484			* The following macros were separated from the m_light() routine
485			* because they are very nasty and difficult to understand.
486			*/
487
488	greg	2.11	/* illumblock *
489	greg	2.4	*
490			* We cannot allow an illum to pass to another illum, because that
491			* would almost certainly constitute overcounting.
492			* However, we do allow an illum to pass to another illum
493			* that is actually going to relay to a virtual light source.
494	greg	2.11	* We also prevent an illum from passing to a glow; this provides a
495			* convenient mechanism for defining detailed light source
496			* geometry behind (or inside) an effective radiator.
497	greg	2.4	*/
498
499	greg	2.37	static int
500			weaksrcmat(int obj) /* identify material */
501			{
502			register OBJREC *o = objptr(obj);
503
504			while (!ismaterial(o->otype)) /* find material */
505			o = objptr(o->omod);
506			return((o->otype==MAT_ILLUM)\|(o->otype==MAT_GLOW));
507			}
508	greg	2.4
509	greg	2.11	#define illumblock(m, r) (!(source[r->rsrc].sflags&SVIRTUAL) && \
510	greg	2.12	r->rod > 0.0 && \
511	greg	2.37	weaksrcmat(source[r->rsrc].so->omod))
512	greg	2.11
513	greg	2.4	/* wrongsource *
514			*
515			* This source is the wrong source (ie. overcounted) if we are
516			* aimed to a different source than the one we hit and the one
517	greg	2.11	* we hit is not an illum that should be passed.
518	greg	2.4	*/
519
520			#define wrongsource(m, r) (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
521	greg	2.11	(m->otype!=MAT_ILLUM \|\| illumblock(m,r)))
522	greg	2.4
523			/* distglow *
524			*
525			* A distant glow is an object that sometimes acts as a light source,
526			* but is too far away from the test point to be one in this case.
527	greg	2.11	* (Glows with negative radii should NEVER participate in illumination.)
528	greg	2.4	*/
529
530	greg	2.17	#define distglow(m, r, d) (m->otype==MAT_GLOW && \
531	greg	2.10	m->oargs.farg[3] >= -FTINY && \
532	greg	2.17	d > m->oargs.farg[3])
533	greg	2.4
534			/* badcomponent *
535			*
536			* We must avoid counting light sources in the ambient calculation,
537			* since the direct component is handled separately. Therefore, any
538			* ambient ray which hits an active light source must be discarded.
539			* The same is true for stray specular samples, since the specular
540			* contribution from light sources is calculated separately.
541			*/
542
543			#define badcomponent(m, r) (r->crtype&(AMBIENT\|SPECULAR) && \
544			!(r->crtype&SHADOW \|\| r->rod < 0.0 \|\| \
545	greg	2.17	/* not 100% correct */ distglow(m, r, r->rot)))
546	greg	2.4
547			/* passillum *
548			*
549			* An illum passes to another material type when we didn't hit it
550			* on purpose (as part of a direct calculation), or it is relaying
551			* a virtual light source.
552			*/
553
554			#define passillum(m, r) (m->otype==MAT_ILLUM && \
555			(r->rsrc<0 \|\| source[r->rsrc].so!=r->ro \|\| \
556			source[r->rsrc].sflags&SVIRTUAL))
557
558			/* srcignore *
559			*
560	greg	2.10	* The -dv flag is normally on for sources to be visible.
561	greg	2.4	*/
562
563	greg	2.17	#define srcignore(m, r) !(directvis \|\| r->crtype&SHADOW \|\| \
564			distglow(m, r, raydist(r,PRIMARY)))
565	greg	2.4
566
567	greg	2.29	int
568	greg	2.4	m_light(m, r) /* ray hit a light source */
569			register OBJREC *m;
570			register RAY *r;
571			{
572			/* check for over-counting */
573	greg	2.12	if (badcomponent(m, r))
574	greg	2.14	return(1);
575	greg	2.17	if (wrongsource(m, r))
576	greg	2.14	return(1);
577	greg	2.4	/* check for passed illum */
578			if (passillum(m, r)) {
579	greg	2.14	if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
580	gwlarson	2.28	return(rayshade(r,lastmod(objndx(m),m->oargs.sarg[0])));
581	greg	2.14	raytrans(r);
582			return(1);
583	greg	2.4	}
584			/* otherwise treat as source */
585			/* check for behind */
586			if (r->rod < 0.0)
587	greg	2.14	return(1);
588	greg	2.4	/* check for invisibility */
589			if (srcignore(m, r))
590	greg	2.14	return(1);
591	greg	2.4	/* check for outside spot */
592	greg	2.18	if (m->otype==MAT_SPOT && spotout(r, makespot(m)))
593	greg	2.14	return(1);
594	greg	2.4	/* get distribution pattern */
595			raytexture(r, m->omod);
596			/* get source color */
597			setcolor(r->rcol, m->oargs.farg[0],
598			m->oargs.farg[1],
599			m->oargs.farg[2]);
600			/* modify value */
601			multcolor(r->rcol, r->pcol);
602	greg	2.14	return(1);
603	greg	1.1	}