src/rt/source.c

#ifndef lint
static const char RCSid[] = "$Id: source.c,v 2.43 2004/03/01 18:11:20 greg Exp $";
#endif
/*
 *  source.c - routines dealing with illumination sources.
 *
 *  External symbols declared in source.h
 */

#include  "ray.h"
#include  "otypes.h"
#include  "rtotypes.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 */

static int cntcmp(const void *p1, const void *p2);


extern OBJREC *                 /* find an object's actual material */
findmaterial(register OBJREC *o)
{
        while (!ismaterial(o->otype)) {
                if (ismixture(o->otype))
                        return(NULL);   /* reject mixed materials */
                if (o->otype == MOD_ALIAS && o->oargs.nsargs) {
                        OBJECT  aobj;
                        OBJREC  *ao;
                        aobj = lastmod(objndx(o), o->oargs.sarg[0]);
                        if (aobj < 0)
                                objerror(o, USER, "bad reference");
                        ao = objptr(aobj);
                        if (ismaterial(ao->otype))
                                return(ao);
                }
                if (o->omod == OVOID)
                        return(NULL);
                o = objptr(o->omod);
        }
        return(o);
}


extern void
marksources(void)                       /* 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 = findmaterial(objptr(o->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  SHADCACHE
                source[ns].obscache = NULL;
#endif
                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");
}


extern void
freesources(void)                       /* free all source structures */
{
        if (nsources > 0) {
#if SHADCACHE
                while (nsources--)
                        freeobscache(&source[nsources]);
#endif
                free((void *)source);
                source = NULL;
                nsources = 0;
        }
        if (maxcntr <= 0)
                return;
        free((void *)srccnt);
        srccnt = NULL;
        free((void *)cntord);
        cntord = NULL;
        maxcntr = 0;
}


extern int
srcray(                         /* 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 */
}


extern void
srcvalue(                       /* 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");
}


extern int
sourcehit(                      /* 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(                         /* contribution compare (descending) */
        const void *p1,
        const void *p2
)
{
        register const CNTPTR  *sc1 = (const CNTPTR *)p1;
        register const CNTPTR  *sc2 = (const CNTPTR *)p2;

        if (sc1->brt > sc2->brt)
                return(-1);
        if (sc1->brt < sc2->brt)
                return(1);
        return(0);
}


extern void
direct(                                 /* add direct component */
        RAY  *r,                        /* ray that hit surface */
        srcdirf_t *f,                   /* direct component coefficient function */
        void  *p                        /* data for f */
)
{
        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;
#if SHADCACHE
                                                /* check shadow cache */
                if (si.np == 1 && srcblocked(&sr)) {
                        cntord[sn].brt = 0.0;
                        continue;
                }
#endif
                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) {
#if SHADCACHE
                                if ((scp <= srccnt || scp[-1].sno != scp->sno)
                                                && (scp >= srccnt+ncnts-1 ||
                                                    scp[1].sno != scp->sno))
                                        srcblocker(&sr);
#endif
                                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);
        }
}


extern void
srcscatter(                     /* 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(OBJECT obj)          /* identify material */
{
        OBJREC *o = findmaterial(objptr(obj));
        
        if (o == NULL) return 0;
        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)))


extern int
m_light(                                /* 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:	2.44
Committed:	Tue Mar 30 16:13:01 2004 UTC (20 years, 1 month ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.43:	+28 -29 lines
Log Message:	Continued ANSIfication. There are only bits and pieces left now.
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	schorsch	2.44	static const char RCSid[] = "$Id: source.c,v 2.43 2004/03/01 18:11:20 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	1.1	#include "ray.h"
11			#include "otypes.h"
12	schorsch	2.44	#include "rtotypes.h"
13	greg	1.35	#include "source.h"
14	greg	2.19	#include "random.h"
15
16			extern double ssampdist; /* scatter sampling distance */
17
18	greg	2.22	#ifndef MAXSSAMP
19			#define MAXSSAMP 16 /* maximum samples per ray */
20			#endif
21
22	greg	1.35	/*
23			* Structures used by direct()
24			*/
25	greg	1.1
26	greg	1.35	typedef struct {
27	greg	1.45	int sno; /* source number */
28	greg	1.35	FVECT dir; /* source direction */
29			COLOR coef; /* material coefficient */
30			COLOR val; /* contribution */
31			} CONTRIB; /* direct contribution */
32	greg	1.1
33	greg	1.35	typedef struct {
34	greg	1.45	int sndx; /* source index (to CONTRIB array) */
35	greg	1.35	float brt; /* brightness (for comparison) */
36			} CNTPTR; /* contribution pointer */
37	greg	1.1
38	greg	1.25	static CONTRIB srccnt; / source contributions in direct() */
39			static CNTPTR cntord; / source ordering in direct() */
40	greg	1.45	static int maxcntr = 0; /* size of contribution arrays */
41	greg	1.1
42	schorsch	2.44	static int cntcmp(const void p1, const void p2);
43
44	greg	1.25
45	schorsch	2.44	extern OBJREC * /* find an object's actual material */
46	greg	2.38	findmaterial(register OBJREC *o)
47			{
48			while (!ismaterial(o->otype)) {
49			if (ismixture(o->otype))
50			return(NULL); /* reject mixed materials */
51			if (o->otype == MOD_ALIAS && o->oargs.nsargs) {
52			OBJECT aobj;
53			OBJREC *ao;
54			aobj = lastmod(objndx(o), o->oargs.sarg[0]);
55			if (aobj < 0)
56			objerror(o, USER, "bad reference");
57			ao = objptr(aobj);
58			if (ismaterial(ao->otype))
59			return(ao);
60			}
61			if (o->omod == OVOID)
62			return(NULL);
63			o = objptr(o->omod);
64			}
65			return(o);
66			}
67
68
69	schorsch	2.44	extern void
70			marksources(void) /* find and mark source objects */
71	greg	1.1	{
72	greg	2.3	int foundsource = 0;
73	greg	1.33	int i;
74	greg	1.1	register OBJREC o, m;
75	greg	1.36	register int ns;
76	greg	1.35	/* initialize dispatch table */
77			initstypes();
78			/* find direct sources */
79	greg	2.33	for (i = 0; i < nsceneobjs; i++) {
80	greg	1.1
81			o = objptr(i);
82
83	greg	1.35	if (!issurface(o->otype) \|\| o->omod == OVOID)
84	greg	1.1	continue;
85	greg	2.36	/* find material */
86	greg	2.43	m = findmaterial(objptr(o->omod));
87	greg	2.36	if (m == NULL \|\| !islight(m->otype))
88			continue; /* not source modifier */
89	greg	1.1
90	greg	1.6	if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
91			m->otype == MAT_SPOT ? 7 : 3))
92	greg	1.1	objerror(m, USER, "bad # arguments");
93
94	greg	1.6	if (m->otype == MAT_GLOW &&
95			o->otype != OBJ_SOURCE &&
96			m->oargs.farg[3] <= FTINY)
97	greg	1.1	continue; /* don't bother */
98	greg	2.16	if (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY &&
99			m->oargs.farg[2] <= FTINY)
100			continue; /* don't bother */
101	greg	1.1
102	greg	1.35	if (sfun[o->otype].of == NULL \|\|
103			sfun[o->otype].of->setsrc == NULL)
104			objerror(o, USER, "illegal material");
105
106	greg	1.36	if ((ns = newsource()) < 0)
107	greg	1.25	goto memerr;
108	greg	1.1
109	greg	1.37	setsource(&source[ns], o);
110	greg	1.1
111	greg	1.6	if (m->otype == MAT_GLOW) {
112	greg	1.36	source[ns].sflags \|= SPROX;
113			source[ns].sl.prox = m->oargs.farg[3];
114	greg	2.8	if (source[ns].sflags & SDISTANT)
115	greg	1.36	source[ns].sflags \|= SSKIP;
116	greg	1.6	} else if (m->otype == MAT_SPOT) {
117	greg	1.36	source[ns].sflags \|= SSPOT;
118			if ((source[ns].sl.s = makespot(m)) == NULL)
119	greg	1.33	goto memerr;
120	greg	1.38	if (source[ns].sflags & SFLAT &&
121			!checkspot(source[ns].sl.s,source[ns].snorm)) {
122			objerror(o, WARNING,
123			"invalid spotlight direction");
124			source[ns].sflags \|= SSKIP;
125			}
126	greg	1.6	}
127	greg	2.38	#if SHADCACHE
128			source[ns].obscache = NULL;
129			#endif
130	greg	2.3	if (!(source[ns].sflags & SSKIP))
131			foundsource++;
132	greg	1.1	}
133	greg	2.3	if (!foundsource) {
134	greg	1.25	error(WARNING, "no light sources found");
135			return;
136			}
137	greg	1.33	markvirtuals(); /* find and add virtual sources */
138	greg	1.45	/* allocate our contribution arrays */
139	greg	1.48	maxcntr = nsources + MAXSPART; /* start with this many */
140	greg	1.45	srccnt = (CONTRIB )malloc(maxcntrsizeof(CONTRIB));
141			cntord = (CNTPTR )malloc(maxcntrsizeof(CNTPTR));
142	schorsch	2.35	if ((srccnt == NULL) \| (cntord == NULL))
143	greg	1.33	goto memerr;
144			return;
145	greg	1.25	memerr:
146			error(SYSTEM, "out of memory in marksources");
147	greg	1.1	}
148
149
150	schorsch	2.44	extern void
151			freesources(void) /* free all source structures */
152	greg	2.29	{
153			if (nsources > 0) {
154	greg	2.38	#if SHADCACHE
155			while (nsources--)
156			freeobscache(&source[nsources]);
157			#endif
158	greg	2.29	free((void *)source);
159			source = NULL;
160			nsources = 0;
161			}
162			if (maxcntr <= 0)
163			return;
164			free((void *)srccnt);
165			srccnt = NULL;
166			free((void *)cntord);
167			cntord = NULL;
168			maxcntr = 0;
169			}
170
171
172	schorsch	2.44	extern int
173	greg	2.38	srcray( /* send a ray to a source, return domega */
174	schorsch	2.44	register RAY sr, / returned source ray */
175			RAY r, / ray which hit object */
176			SRCINDEX si / source sample index */
177	greg	2.38	)
178	greg	1.1	{
179	greg	1.45	double d; /* distance to source */
180			register SRCREC *srcp;
181	greg	1.1
182	greg	1.45	rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */
183	greg	1.1
184	greg	1.47	while ((d = nextssamp(sr, si)) != 0.0) {
185	greg	1.45	sr->rsrc = si->sn; /* remember source */
186			srcp = source + si->sn;
187			if (srcp->sflags & SDISTANT) {
188	greg	2.18	if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s))
189	greg	2.4	continue;
190	greg	1.45	return(1); /* sample OK */
191	greg	1.40	}
192	greg	1.45	/* local source */
193	greg	1.6	/* check proximity */
194	greg	1.45	if (srcp->sflags & SPROX && d > srcp->sl.prox)
195			continue;
196	greg	1.6	/* check angle */
197	greg	1.45	if (srcp->sflags & SSPOT) {
198	greg	2.18	if (spotout(sr, srcp->sl.s))
199	greg	1.45	continue;
200			/* adjust solid angle */
201			si->dom = dd;
202			d += srcp->sl.s->flen;
203			si->dom /= d*d;
204	greg	1.1	}
205	greg	1.45	return(1); /* sample OK */
206			}
207			return(0); /* no more samples */
208	greg	1.1	}
209
210
211	schorsch	2.44	extern void
212	greg	2.38	srcvalue( /* punch ray to source and compute value */
213	schorsch	2.44	register RAY *r
214	greg	2.38	)
215	greg	1.1	{
216	greg	1.35	register SRCREC *sp;
217	greg	1.1
218	greg	1.35	sp = &source[r->rsrc];
219			if (sp->sflags & SVIRTUAL) { /* virtual source */
220			/* check intersection */
221			if (!(*ofun[sp->so->otype].funp)(sp->so, r))
222			return;
223	greg	2.15	if (!rayshade(r, r->ro->omod)) /* compute contribution */
224			goto nomat;
225	greg	2.19	rayparticipate(r);
226	greg	1.35	return;
227	greg	1.1	}
228	greg	1.35	/* compute intersection */
229			if (sp->sflags & SDISTANT ? sourcehit(r) :
230			(*ofun[sp->so->otype].funp)(sp->so, r)) {
231			if (sp->sa.success >= 0)
232			sp->sa.success++;
233	greg	2.15	if (!rayshade(r, r->ro->omod)) /* compute contribution */
234			goto nomat;
235	greg	2.19	rayparticipate(r);
236	greg	1.35	return;
237	greg	1.1	}
238	greg	2.15	/* we missed our mark! */
239	greg	1.35	if (sp->sa.success < 0)
240			return; /* bitched already */
241			sp->sa.success -= AIMREQT;
242			if (sp->sa.success >= 0)
243			return; /* leniency */
244			sprintf(errmsg, "aiming failure for light source \"%s\"",
245			sp->so->oname);
246			error(WARNING, errmsg); /* issue warning */
247	greg	2.15	return;
248			nomat:
249			objerror(r->ro, USER, "material not found");
250	greg	1.1	}
251
252
253	schorsch	2.44	extern int
254	greg	2.38	sourcehit( /* check to see if ray hit distant source */
255	schorsch	2.44	register RAY *r
256	greg	2.38	)
257	greg	2.5	{
258			int first, last;
259			register int i;
260
261			if (r->rsrc >= 0) { /* check only one if aimed */
262			first = last = r->rsrc;
263			} else { /* otherwise check all */
264			first = 0; last = nsources-1;
265			}
266			for (i = first; i <= last; i++)
267			if ((source[i].sflags & (SDISTANT\|SVIRTUAL)) == SDISTANT)
268			/*
269			* Check to see if ray is within
270			* solid angle of source.
271			*/
272			if (2.0PI (1.0 - DOT(source[i].sloc,r->rdir))
273			<= source[i].ss2) {
274			r->ro = source[i].so;
275			if (!(source[i].sflags & SSKIP))
276			break;
277			}
278
279			if (r->ro != NULL) {
280	gregl	2.27	r->robj = objndx(r->ro);
281	greg	2.5	for (i = 0; i < 3; i++)
282			r->ron[i] = -r->rdir[i];
283			r->rod = 1.0;
284	greg	2.31	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
285			r->uv[0] = r->uv[1] = 0.0;
286	greg	2.5	r->rox = NULL;
287			return(1);
288			}
289			return(0);
290			}
291	greg	2.38
292
293	greg	1.4	static int
294	greg	2.38	cntcmp( /* contribution compare (descending) */
295	schorsch	2.44	const void *p1,
296			const void *p2
297	greg	2.38	)
298	greg	1.4	{
299	greg	2.38	register const CNTPTR sc1 = (const CNTPTR )p1;
300			register const CNTPTR sc2 = (const CNTPTR )p2;
301
302	greg	1.4	if (sc1->brt > sc2->brt)
303			return(-1);
304			if (sc1->brt < sc2->brt)
305			return(1);
306			return(0);
307			}
308
309
310	schorsch	2.44	extern void
311	greg	2.38	direct( /* add direct component */
312	schorsch	2.44	RAY r, / ray that hit surface */
313			srcdirf_t f, / direct component coefficient function */
314			void p / data for f */
315	greg	2.38	)
316	greg	1.4	{
317			register int sn;
318	greg	2.7	register CONTRIB *scp;
319	greg	1.45	SRCINDEX si;
320	greg	1.12	int nshadcheck, ncnts;
321	greg	1.29	int nhits;
322	greg	1.45	double prob, ourthresh, hwt;
323	greg	1.4	RAY sr;
324	greg	1.25	/* NOTE: srccnt and cntord global so no recursion */
325	greg	1.22	if (nsources <= 0)
326	greg	1.25	return; /* no sources?! */
327	greg	1.4	/* potential contributions */
328	greg	1.45	initsrcindex(&si);
329			for (sn = 0; srcray(&sr, r, &si); sn++) {
330			if (sn >= maxcntr) {
331			maxcntr = sn + MAXSPART;
332	greg	2.32	srccnt = (CONTRIB )realloc((void )srccnt,
333	greg	1.45	maxcntr*sizeof(CONTRIB));
334	greg	2.32	cntord = (CNTPTR )realloc((void )cntord,
335	greg	1.45	maxcntr*sizeof(CNTPTR));
336	schorsch	2.35	if ((srccnt == NULL) \| (cntord == NULL))
337	greg	1.45	error(SYSTEM, "out of memory in direct");
338			}
339			cntord[sn].sndx = sn;
340	greg	2.7	scp = srccnt + sn;
341			scp->sno = sr.rsrc;
342	greg	1.4	/* compute coefficient */
343	greg	2.7	(*f)(scp->coef, p, sr.rdir, si.dom);
344			cntord[sn].brt = bright(scp->coef);
345	greg	1.15	if (cntord[sn].brt <= 0.0)
346	greg	1.4	continue;
347	greg	2.38	#if SHADCACHE
348			/* check shadow cache */
349			if (si.np == 1 && srcblocked(&sr)) {
350			cntord[sn].brt = 0.0;
351			continue;
352			}
353			#endif
354	greg	2.7	VCOPY(scp->dir, sr.rdir);
355	greg	1.35	/* compute potential */
356			sr.revf = srcvalue;
357			rayvalue(&sr);
358	greg	2.7	copycolor(scp->val, sr.rcol);
359			multcolor(scp->val, scp->coef);
360			cntord[sn].brt = bright(scp->val);
361	greg	1.4	}
362			/* sort contributions */
363	greg	1.45	qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
364	greg	1.13	{ /* find last */
365			register int l, m;
366
367	greg	1.45	ncnts = l = sn;
368			sn = 0;
369	greg	1.13	while ((m = (sn + ncnts) >> 1) != l) {
370			if (cntord[m].brt > 0.0)
371			sn = m;
372			else
373			ncnts = m;
374			l = m;
375			}
376			}
377	greg	2.2	if (ncnts == 0)
378			return; /* no contributions! */
379	greg	1.12	/* accumulate tail */
380			for (sn = ncnts-1; sn > 0; sn--)
381			cntord[sn-1].brt += cntord[sn].brt;
382	greg	1.45	/* compute number to check */
383			nshadcheck = pow((double)ncnts, shadcert) + .5;
384			/* modify threshold */
385			ourthresh = shadthresh / r->rweight;
386	greg	1.10	/* test for shadows */
387	greg	2.13	for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
388			hwt += (double)source[scp->sno].nhits /
389			(double)source[scp->sno].ntests,
390			sn++) {
391	greg	1.10	/* check threshold */
392	greg	1.12	if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
393	greg	1.27	cntord[sn].brt-cntord[sn+nshadcheck].brt)
394			< ourthresh*bright(r->rcol))
395	greg	1.4	break;
396	greg	2.7	scp = srccnt + cntord[sn].sndx;
397	greg	1.4	/* test for hit */
398			rayorigin(&sr, r, SHADOW, 1.0);
399	greg	2.7	VCOPY(sr.rdir, scp->dir);
400			sr.rsrc = scp->sno;
401	greg	2.34	/* keep statistics */
402			if (source[scp->sno].ntests++ > 0xfffffff0) {
403			source[scp->sno].ntests >>= 1;
404			source[scp->sno].nhits >>= 1;
405			}
406	greg	1.4	if (localhit(&sr, &thescene) &&
407	greg	2.7	( sr.ro != source[scp->sno].so \|\|
408			source[scp->sno].sflags & SFOLLOW )) {
409	greg	1.33	/* follow entire path */
410	greg	2.23	raycont(&sr);
411	greg	2.19	rayparticipate(&sr);
412	greg	1.42	if (trace != NULL)
413			(trace)(&sr); / trace execution */
414	greg	2.38	if (bright(sr.rcol) <= FTINY) {
415			#if SHADCACHE
416			if ((scp <= srccnt \|\| scp[-1].sno != scp->sno)
417	greg	2.41	&& (scp >= srccnt+ncnts-1 \|\|
418	greg	2.38	scp[1].sno != scp->sno))
419			srcblocker(&sr);
420			#endif
421	greg	1.4	continue; /* missed! */
422	greg	2.38	}
423	greg	2.7	copycolor(scp->val, sr.rcol);
424			multcolor(scp->val, scp->coef);
425	greg	1.4	}
426			/* add contribution if hit */
427	greg	2.7	addcolor(r->rcol, scp->val);
428	greg	1.29	nhits++;
429	greg	2.7	source[scp->sno].nhits++;
430	greg	1.4	}
431	greg	2.13	/* source hit rate */
432			if (hwt > FTINY)
433			hwt = (double)nhits / hwt;
434	greg	1.29	else
435			hwt = 0.5;
436	greg	1.20	#ifdef DEBUG
437	greg	2.13	sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
438	greg	1.12	sn, ncnts-sn, hwt);
439			eputs(errmsg);
440	greg	1.4	#endif
441			/* add in untested sources */
442	greg	1.12	for ( ; sn < ncnts; sn++) {
443	greg	2.7	scp = srccnt + cntord[sn].sndx;
444			prob = hwt * (double)source[scp->sno].nhits /
445			(double)source[scp->sno].ntests;
446	greg	2.13	if (prob > 1.0)
447			prob = 1.0;
448	greg	2.7	scalecolor(scp->val, prob);
449			addcolor(r->rcol, scp->val);
450	greg	2.19	}
451			}
452
453
454	schorsch	2.44	extern void
455	greg	2.38	srcscatter( /* compute source scattering into ray */
456	schorsch	2.44	register RAY *r
457	greg	2.38	)
458	greg	2.19	{
459	greg	2.20	int oldsampndx;
460	greg	2.19	int nsamps;
461			RAY sr;
462			SRCINDEX si;
463	greg	2.25	double t, d;
464			double re, ge, be;
465			COLOR cvext;
466	greg	2.19	int i, j;
467
468	greg	2.22	if (r->slights == NULL \|\| r->slights[0] == 0
469			\|\| r->gecc >= 1.-FTINY \|\| r->rot >= FHUGE)
470	greg	2.19	return;
471			if (ssampdist <= FTINY \|\| (nsamps = r->rot/ssampdist + .5) < 1)
472			nsamps = 1;
473	greg	2.22	#if MAXSSAMP
474			else if (nsamps > MAXSSAMP)
475			nsamps = MAXSSAMP;
476			#endif
477	greg	2.20	oldsampndx = samplendx;
478			samplendx = random()&0x7fff; /* randomize */
479	greg	2.19	for (i = r->slights[0]; i > 0; i--) { /* for each source */
480	greg	2.25	for (j = 0; j < nsamps; j++) { /* for each sample position */
481	greg	2.19	samplendx++;
482			t = r->rot * (j+frandom())/nsamps;
483	greg	2.25	/* extinction */
484			re = t*colval(r->cext,RED);
485			ge = t*colval(r->cext,GRN);
486			be = t*colval(r->cext,BLU);
487			setcolor(cvext, re > 92. ? 0. : exp(-re),
488			ge > 92. ? 0. : exp(-ge),
489			be > 92. ? 0. : exp(-be));
490			if (intens(cvext) <= FTINY)
491			break; /* too far away */
492	greg	2.19	sr.rorg[0] = r->rorg[0] + r->rdir[0]*t;
493			sr.rorg[1] = r->rorg[1] + r->rdir[1]*t;
494			sr.rorg[2] = r->rorg[2] + r->rdir[2]*t;
495			sr.rmax = 0.;
496	greg	2.21	initsrcindex(&si); /* sample ray to this source */
497			si.sn = r->slights[i];
498			nopart(&si, &sr);
499			if (!srcray(&sr, NULL, &si) \|\|
500			sr.rsrc != r->slights[i])
501			continue; /* no path */
502	greg	2.19	copycolor(sr.cext, r->cext);
503	greg	2.24	copycolor(sr.albedo, r->albedo);
504	greg	2.19	sr.gecc = r->gecc;
505	gregl	2.26	sr.slights = r->slights;
506	greg	2.19	rayvalue(&sr); /* eval. source ray */
507			if (bright(sr.rcol) <= FTINY)
508			continue;
509			if (r->gecc <= FTINY) /* compute P(theta) */
510			d = 1.;
511			else {
512			d = DOT(r->rdir, sr.rdir);
513	greg	2.25	d = 1. + r->geccr->gecc - 2.r->gecc*d;
514			d = (1. - r->geccr->gecc) / (dsqrt(d));
515	greg	2.19	}
516			/* other factors */
517	greg	2.24	d = si.dom r->rot / (4.PInsamps);
518	greg	2.19	multcolor(sr.rcol, r->cext);
519	greg	2.24	multcolor(sr.rcol, r->albedo);
520	greg	2.19	scalecolor(sr.rcol, d);
521	greg	2.25	multcolor(sr.rcol, cvext);
522			addcolor(r->rcol, sr.rcol); /* add it in */
523	greg	2.19	}
524	greg	1.1	}
525	greg	2.20	samplendx = oldsampndx;
526	greg	2.4	}
527
528
529			/****************************************************************
530			* The following macros were separated from the m_light() routine
531			* because they are very nasty and difficult to understand.
532			*/
533
534	greg	2.11	/* illumblock *
535	greg	2.4	*
536			* We cannot allow an illum to pass to another illum, because that
537			* would almost certainly constitute overcounting.
538			* However, we do allow an illum to pass to another illum
539			* that is actually going to relay to a virtual light source.
540	greg	2.11	* We also prevent an illum from passing to a glow; this provides a
541			* convenient mechanism for defining detailed light source
542			* geometry behind (or inside) an effective radiator.
543	greg	2.4	*/
544
545	greg	2.37	static int
546	greg	2.42	weaksrcmat(OBJECT obj) /* identify material */
547	greg	2.37	{
548	greg	2.42	OBJREC *o = findmaterial(objptr(obj));
549	greg	2.37
550	greg	2.42	if (o == NULL) return 0;
551	greg	2.37	return((o->otype==MAT_ILLUM)\|(o->otype==MAT_GLOW));
552			}
553	greg	2.4
554	greg	2.11	#define illumblock(m, r) (!(source[r->rsrc].sflags&SVIRTUAL) && \
555	greg	2.12	r->rod > 0.0 && \
556	greg	2.37	weaksrcmat(source[r->rsrc].so->omod))
557	greg	2.11
558	greg	2.4	/* wrongsource *
559			*
560			* This source is the wrong source (ie. overcounted) if we are
561			* aimed to a different source than the one we hit and the one
562	greg	2.11	* we hit is not an illum that should be passed.
563	greg	2.4	*/
564
565			#define wrongsource(m, r) (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
566	greg	2.11	(m->otype!=MAT_ILLUM \|\| illumblock(m,r)))
567	greg	2.4
568			/* distglow *
569			*
570			* A distant glow is an object that sometimes acts as a light source,
571			* but is too far away from the test point to be one in this case.
572	greg	2.11	* (Glows with negative radii should NEVER participate in illumination.)
573	greg	2.4	*/
574
575	greg	2.17	#define distglow(m, r, d) (m->otype==MAT_GLOW && \
576	greg	2.10	m->oargs.farg[3] >= -FTINY && \
577	greg	2.17	d > m->oargs.farg[3])
578	greg	2.4
579			/* badcomponent *
580			*
581			* We must avoid counting light sources in the ambient calculation,
582			* since the direct component is handled separately. Therefore, any
583			* ambient ray which hits an active light source must be discarded.
584			* The same is true for stray specular samples, since the specular
585			* contribution from light sources is calculated separately.
586			*/
587
588			#define badcomponent(m, r) (r->crtype&(AMBIENT\|SPECULAR) && \
589			!(r->crtype&SHADOW \|\| r->rod < 0.0 \|\| \
590	greg	2.17	/* not 100% correct */ distglow(m, r, r->rot)))
591	greg	2.4
592			/* passillum *
593			*
594			* An illum passes to another material type when we didn't hit it
595			* on purpose (as part of a direct calculation), or it is relaying
596			* a virtual light source.
597			*/
598
599			#define passillum(m, r) (m->otype==MAT_ILLUM && \
600			(r->rsrc<0 \|\| source[r->rsrc].so!=r->ro \|\| \
601			source[r->rsrc].sflags&SVIRTUAL))
602
603			/* srcignore *
604			*
605	greg	2.10	* The -dv flag is normally on for sources to be visible.
606	greg	2.4	*/
607
608	greg	2.17	#define srcignore(m, r) !(directvis \|\| r->crtype&SHADOW \|\| \
609			distglow(m, r, raydist(r,PRIMARY)))
610	greg	2.4
611
612	schorsch	2.44	extern int
613	greg	2.38	m_light( /* ray hit a light source */
614	schorsch	2.44	register OBJREC *m,
615			register RAY *r
616	greg	2.38	)
617	greg	2.4	{
618			/* check for over-counting */
619	greg	2.12	if (badcomponent(m, r))
620	greg	2.14	return(1);
621	greg	2.17	if (wrongsource(m, r))
622	greg	2.14	return(1);
623	greg	2.4	/* check for passed illum */
624			if (passillum(m, r)) {
625	greg	2.14	if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
626	gwlarson	2.28	return(rayshade(r,lastmod(objndx(m),m->oargs.sarg[0])));
627	greg	2.14	raytrans(r);
628			return(1);
629	greg	2.4	}
630			/* otherwise treat as source */
631			/* check for behind */
632			if (r->rod < 0.0)
633	greg	2.14	return(1);
634	greg	2.4	/* check for invisibility */
635			if (srcignore(m, r))
636	greg	2.14	return(1);
637	greg	2.4	/* check for outside spot */
638	greg	2.18	if (m->otype==MAT_SPOT && spotout(r, makespot(m)))
639	greg	2.14	return(1);
640	greg	2.4	/* get distribution pattern */
641			raytexture(r, m->omod);
642			/* get source color */
643			setcolor(r->rcol, m->oargs.farg[0],
644			m->oargs.farg[1],
645			m->oargs.farg[2]);
646			/* modify value */
647			multcolor(r->rcol, r->pcol);
648	greg	2.14	return(1);
649	greg	1.1	}