src/rt/virtuals.c

#ifndef lint
static const char       RCSid[] = "$Id: virtuals.c,v 2.25 2021/02/12 00:41:19 greg Exp $";
#endif
/*
 * Routines for simulating virtual light sources
 *      Thus far, we only support planar mirrors.
 *
 *  External symbols declared in source.h
 */

#include "copyright.h"

#include  "ray.h"
#include  "otypes.h"
#include  "otspecial.h"
#include  "source.h"
#include  "random.h"

#define  MINSAMPLES     16              /* minimum number of pretest samples */
#define  STESTMAX       32              /* maximum seeks per sample */


static OBJECT  *vobject;                /* virtual source objects */
static int  nvobjects = 0;              /* number of virtual source objects */


static int
isident4(MAT4 m)
{
        int     i, j;

        for (i = 4; i--; )
                for (j = 4; j--; )
                        if (!FABSEQ(m[i][j], i==j))
                                return(0);
        return(1);
}


void
markvirtuals(void)                      /* find and mark virtual sources */
{
        OBJREC  *o;
        int  i;
                                        /* check number of direct relays */
        if (directrelay <= 0)
                return;
                                        /* find virtual source objects */
        for (i = 0; i < nsceneobjs; i++) {
                o = objptr(i);
                if (!issurface(o->otype) || o->omod == OVOID)
                        continue;
                if (!isvlight(vsmaterial(o)->otype))
                        continue;
                if (sfun[o->otype].of == NULL ||
                                sfun[o->otype].of->getpleq == NULL) {
                        objerror(o,WARNING,"secondary sources not supported");
                        continue;
                }
                if (nvobjects == 0)
                        vobject = (OBJECT *)malloc(sizeof(OBJECT));
                else
                        vobject = (OBJECT *)realloc((void *)vobject,
                                (unsigned)(nvobjects+1)*sizeof(OBJECT));
                if (vobject == NULL)
                        error(SYSTEM, "out of memory in addvirtuals");
                vobject[nvobjects++] = i;
        }
        if (nvobjects == 0)
                return;
#ifdef DEBUG
        fprintf(stderr, "found %d virtual source objects\n", nvobjects);
#endif
                                        /* append virtual sources */
        for (i = nsources; i-- > 0; )
                addvirtuals(i, directrelay);
                                        /* done with our object list */
        free((void *)vobject);
        nvobjects = 0;
}


void
addvirtuals(            /* add virtuals associated with source */
        int  sn,
        int  nr
)
{
        int  i;
                                /* check relay limit first */
        if (nr <= 0)
                return;
        if (source[sn].sflags & SSKIP)
                return;
                                /* check each virtual object for projection */
        for (i = 0; i < nvobjects; i++)
                                        /* vproject() calls us recursively */
                vproject(objptr(vobject[i]), sn, nr-1);
}


void
vproject(               /* create projected source(s) if they exist */
        OBJREC  *o,
        int  sn,
        int  n
)
{
        int  i;
        VSMATERIAL  *vsmat;
        MAT4  proj;
        int  ns;

        if (o == source[sn].so) /* objects cannot project themselves */
                return;
                                /* get virtual source material */
        vsmat = sfun[vsmaterial(o)->otype].mf;
                                /* project virtual sources */
        for (i = 0; i < vsmat->nproj; i++)
                if ((*vsmat->vproj)(proj, o, &source[sn], i))
                        if ((ns = makevsrc(o, sn, proj)) >= 0) {
                                source[ns].sa.sv.pn = i;
#ifdef DEBUG
                                virtverb(ns, stderr);
#endif
                                addvirtuals(ns, n);
                        }
}


OBJREC *
vsmaterial(                     /* get virtual source material pointer */
        OBJREC  *o
)
{
        int  i;
        OBJREC  *m;

        i = o->omod;
        m = findmaterial(o);
        if (m == NULL)
                return(objptr(i));
        if (m->otype != MAT_ILLUM || m->oargs.nsargs < 1 ||
                        !strcmp(m->oargs.sarg[0], VOIDID) ||
                        (i = lastmod(objndx(m), m->oargs.sarg[0])) == OVOID)
                return(m);              /* direct modifier */
        return(objptr(i));              /* illum alternate */
}


int
makevsrc(               /* make virtual source if reasonable */
        OBJREC  *op,
        int  sn,
        MAT4  pm
)
{
        FVECT  nsloc, nsnorm, ocent, v;
        double  maxrad2, d;
        int  nsflags;
        SPOT  theirspot, ourspot;
        int  i;
                                        /* check for no-op */
        if (isident4(pm))
                return(0);
        nsflags = source[sn].sflags | (SVIRTUAL|SSPOT|SFOLLOW);
                                        /* get object center and max. radius */
        maxrad2 = getdisk(ocent, op, sn);
        if (maxrad2 <= FTINY)                   /* too small? */
                return(-1);
                                        /* get location and spot */
        if (source[sn].sflags & SDISTANT) {             /* distant source */
                if (source[sn].sflags & SPROX)
                        return(-1);             /* should never get here! */
                multv3(nsloc, source[sn].sloc, pm);
                normalize(nsloc);
                VCOPY(ourspot.aim, ocent);
                ourspot.siz = PI*maxrad2;
                ourspot.flen = -1.;
                if (source[sn].sflags & SSPOT) {
                        multp3(theirspot.aim, source[sn].sl.s->aim, pm);
                                                /* adjust for source size */
                        d = sqrt(dist2(ourspot.aim, theirspot.aim));
                        d = sqrt(source[sn].sl.s->siz/PI) + d*source[sn].srad;
                        theirspot.siz = PI*d*d;
                        ourspot.flen = theirspot.flen = source[sn].sl.s->flen;
                        d = ourspot.siz;
                        if (!commonbeam(&ourspot, &theirspot, nsloc))
                                return(-1);     /* no overlap */
                        if (ourspot.siz < d-FTINY) {    /* it shrunk */
                                d = beamdisk(v, op, &ourspot, nsloc);
                                if (d <= FTINY)
                                        return(-1);
                                if (d < maxrad2) {
                                        maxrad2 = d;
                                        VCOPY(ocent, v);
                                }
                        }
                }
        } else {                                /* local source */
                multp3(nsloc, source[sn].sloc, pm);
                for (i = 0; i < 3; i++)
                        ourspot.aim[i] = ocent[i] - nsloc[i];
                if ((d = normalize(ourspot.aim)) == 0.)
                        return(-1);             /* at source!! */
                if (source[sn].sflags & SPROX && d > source[sn].sl.prox)
                        return(-1);             /* too far away */
                ourspot.flen = 0.;
                                                /* adjust for source size */
                d = (sqrt(maxrad2) + source[sn].srad) / d;
                if (d < 1.-FTINY)
                        ourspot.siz = 2.*PI*(1. - sqrt(1.-d*d));
                else
                        nsflags &= ~SSPOT;
                if (source[sn].sflags & SSPOT) {
                        theirspot = *(source[sn].sl.s);
                        multv3(theirspot.aim, source[sn].sl.s->aim, pm);
                        normalize(theirspot.aim);
                        if (nsflags & SSPOT) {
                                ourspot.flen = theirspot.flen;
                                d = ourspot.siz;
                                if (!commonspot(&ourspot, &theirspot, nsloc))
                                        return(-1);     /* no overlap */
                        } else {
                                nsflags |= SSPOT;
                                ourspot = theirspot;
                                d = 2.*ourspot.siz;
                        }
                        if (ourspot.siz < d-FTINY) {    /* it shrunk */
                                d = spotdisk(v, op, &ourspot, nsloc);
                                if (d <= FTINY)
                                        return(-1);
                                if (d < maxrad2) {
                                        maxrad2 = d;
                                        VCOPY(ocent, v);
                                }
                        }
                }
                if (source[sn].sflags & SFLAT) {        /* behind source? */
                        multv3(nsnorm, source[sn].snorm, pm);
                        normalize(nsnorm);
                        if (nsflags & SSPOT && !checkspot(&ourspot, nsnorm))
                                return(-1);
                }
        }
                                        /* pretest visibility */
        nsflags = vstestvis(nsflags, op, ocent, maxrad2, sn);
        if (nsflags & SSKIP)
                return(-1);     /* obstructed */
                                        /* it all checks out, so make it */
        if ((i = newsource()) < 0)
                goto memerr;
        source[i].sflags = nsflags;
        VCOPY(source[i].sloc, nsloc);
        multv3(source[i].ss[SU], source[sn].ss[SU], pm);
        multv3(source[i].ss[SV], source[sn].ss[SV], pm);
        if (nsflags & SFLAT)
                VCOPY(source[i].snorm, nsnorm);
        else
                multv3(source[i].ss[SW], source[sn].ss[SW], pm);
        source[i].srad = source[sn].srad;
        source[i].ss2 = source[sn].ss2;
        if (nsflags & SSPOT) {
                if ((source[i].sl.s = (SPOT *)malloc(sizeof(SPOT))) == NULL)
                        goto memerr;
                *(source[i].sl.s) = ourspot;
        }
        if (nsflags & SPROX)
                source[i].sl.prox = source[sn].sl.prox;
        source[i].sa.sv.sn = sn;
        source[i].so = op;
        return(i);
memerr:
        error(SYSTEM, "out of memory in makevsrc");
        return -1; /* pro forma return */
}


double
getdisk(                /* get visible object disk */
        FVECT  oc,
        OBJREC  *op,
        int  sn
)
{
        double  rad2, roffs, offs, d, rd, rdoto;
        FVECT  rnrm, nrm;
                                /* first, use object getdisk function */
        rad2 = getmaxdisk(oc, op);
        if (!(source[sn].sflags & SVIRTUAL))
                return(rad2);           /* all done for normal source */
                                /* check for correct side of relay surface */
        roffs = getplaneq(rnrm, source[sn].so);
        rd = DOT(rnrm, source[sn].sloc);        /* source projection */
        if (!(source[sn].sflags & SDISTANT))
                rd -= roffs;
        d = DOT(rnrm, oc) - roffs;      /* disk distance to relay plane */
        if ((d > 0.) ^ (rd > 0.))
                return(rad2);           /* OK if opposite sides */
        if (d*d >= rad2)
                return(0.);             /* no relay is possible */
                                /* we need a closer look */
        offs = getplaneq(nrm, op);
        rdoto = DOT(rnrm, nrm);
        if (d*d >= rad2*(1.-rdoto*rdoto))
                return(0.);             /* disk entirely on projection side */
                                /* should shrink disk but I'm lazy */
        return(rad2);
}


int
vstestvis(              /* pretest source visibility */
        int  f,                 /* virtual source flags */
        OBJREC  *o,             /* relay object */
        FVECT  oc,              /* relay object center */
        double  or2,            /* relay object radius squared */
        int  sn /* target source number */
)
{
        RAY  sr;
        FVECT  onorm;
        double  offsdir[3];
        SRCINDEX  si;
        double  or, d, d1;
        int  stestlim, ssn;
        int  nhit, nok;
        int  i, n;
                                /* return if pretesting disabled */
        if (vspretest <= 0)
                return(f);
                                /* get surface normal */
        getplaneq(onorm, o);
                                /* set number of rays to sample */
        if (source[sn].sflags & SDISTANT) {
                                        /* 32. == heuristic constant */
                n = 32.*or2/(thescene.cusize*thescene.cusize)*vspretest + .5;
        } else {
                VSUB(offsdir, source[sn].sloc, oc);
                d = DOT(offsdir,offsdir);
                if (d <= FTINY)
                        n = 2.*PI * vspretest + .5;
                else
                        n = 2.*PI * (1.-sqrt(1./(1.+or2/d)))*vspretest + .5;
        }
        if (n < MINSAMPLES) n = MINSAMPLES;
#ifdef DEBUG
        fprintf(stderr, "pretesting source %d in object %s with %d rays\n",
                        sn, o->oname, n);
#endif
                                /* sample */
        or = sqrt(or2);
        stestlim = n*STESTMAX;
        ssn = 0;
        nhit = nok = 0;
        initsrcindex(&si);
        while (n-- > 0) {
                                        /* get sample point */
                do {
                        if (ssn >= stestlim) {
#ifdef DEBUG
                                fprintf(stderr, "\ttoo hard to hit\n");
#endif
                                return(f);      /* too small a target! */
                        }
                        multisamp(offsdir, 3, urand(sn*931+5827+ssn));
                        for (i = 0; i < 3; i++)
                                offsdir[i] = or*(1. - 2.*offsdir[i]);
                        ssn++;
                        d = 1. - DOT(offsdir, onorm);
                        for (i = 0; i < 3; i++) {
                                sr.rorg[i] = oc[i] + offsdir[i] + d*onorm[i];
                                sr.rdir[i] = -onorm[i];
                        }
                        sr.rmax = 0.0;
                        rayorigin(&sr, PRIMARY, NULL, NULL);
                } while (!(*ofun[o->otype].funp)(o, &sr));
                                        /* check against source */
                VCOPY(sr.rorg, sr.rop); /* starting from intersection */
                samplendx++;
                if (si.sp >= si.np-1 ||
                                !srcray(&sr, NULL, &si) || sr.rsrc != sn) {
                        si.sn = sn-1;           /* reset index to our source */
                        si.np = 0;
                        if (!srcray(&sr, NULL, &si) || sr.rsrc != sn)
                                continue;       /* can't get there from here */
                }
                sr.revf = srcvalue;
                rayvalue(&sr);                  /* check sample validity */
                if ((d = scolor_mean(sr.rcol)) <= FTINY)
                        continue;
                nok++;                  /* got sample; check obstructions */
                rayclear(&sr);
                sr.revf = raytrace;
                rayvalue(&sr);
                if ((d1 = scolor_mean(sr.rcol)) > FTINY) {
                        if (d - d1 > FTINY) {
#ifdef DEBUG
                                fprintf(stderr, "\tpartially shadowed\n");
#endif
                                return(f);      /* intervening transmitter */
                        }
                        nhit++;
                }
                if (nhit > 0 && nhit < nok) {
#ifdef DEBUG
                        fprintf(stderr, "\tpartially occluded\n");
#endif
                        return(f);              /* need to shadow test */
                }
        }
        if (nhit == 0) {
#ifdef DEBUG
                fprintf(stderr, "\t0%% hit rate\n");
#endif
                return(f | SSKIP);      /* 0% hit rate:  totally occluded */
        }
#ifdef DEBUG
        fprintf(stderr, "\t100%% hit rate\n");
#endif
        return(f & ~SFOLLOW);           /* 100% hit rate:  no occlusion */
}
        

#ifdef DEBUG
void
virtverb(       /* print verbose description of virtual source */
        int  sn,
        FILE  *fp
)
{
        fprintf(fp, "%s virtual source %d in %s %s\n",
                        source[sn].sflags & SDISTANT ? "distant" : "local",
                        sn, ofun[source[sn].so->otype].funame,
                        source[sn].so->oname);
        fprintf(fp, "\tat (%f,%f,%f)\n",
                source[sn].sloc[0], source[sn].sloc[1], source[sn].sloc[2]);
        fprintf(fp, "\tlinked to source %d (%s)\n",
                source[sn].sa.sv.sn, source[source[sn].sa.sv.sn].so->oname);
        if (source[sn].sflags & SFOLLOW)
                fprintf(fp, "\talways followed\n");
        else
                fprintf(fp, "\tnever followed\n");
        if (!(source[sn].sflags & SSPOT))
                return;
        fprintf(fp, "\twith spot aim (%f,%f,%f) and size %f\n",
                        source[sn].sl.s->aim[0], source[sn].sl.s->aim[1],
                        source[sn].sl.s->aim[2], source[sn].sl.s->siz);
}
#endif
Revision:	2.26
Committed:	Wed Nov 15 18:02:53 2023 UTC (23 months, 2 weeks ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad6R0, HEAD
Changes since 2.25:	+3 -3 lines
Log Message:	feat(rpict,rtrace,rcontrib,rtpict): Hyperspectral rendering (except photon map)
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.26	static const char RCSid[] = "$Id: virtuals.c,v 2.25 2021/02/12 00:41:19 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* Routines for simulating virtual light sources
6			* Thus far, we only support planar mirrors.
7	greg	2.7	*
8			* External symbols declared in source.h
9			*/
10
11	greg	2.8	#include "copyright.h"
12	greg	1.1
13			#include "ray.h"
14	greg	1.3	#include "otypes.h"
15	greg	2.23	#include "otspecial.h"
16	greg	1.1	#include "source.h"
17	greg	1.7	#include "random.h"
18	greg	1.1
19	greg	1.22	#define MINSAMPLES 16 /* minimum number of pretest samples */
20			#define STESTMAX 32 /* maximum seeks per sample */
21	greg	1.1
22	greg	1.13
23	greg	1.1	static OBJECT vobject; / virtual source objects */
24			static int nvobjects = 0; /* number of virtual source objects */
25
26
27	greg	2.20	static int
28			isident4(MAT4 m)
29			{
30			int i, j;
31
32			for (i = 4; i--; )
33			for (j = 4; j--; )
34	greg	2.25	if (!FABSEQ(m[i][j], i==j))
35	greg	2.20	return(0);
36			return(1);
37			}
38
39
40			void
41	schorsch	2.14	markvirtuals(void) /* find and mark virtual sources */
42	greg	1.1	{
43	greg	2.20	OBJREC *o;
44			int i;
45	greg	1.1	/* check number of direct relays */
46			if (directrelay <= 0)
47			return;
48			/* find virtual source objects */
49	greg	2.10	for (i = 0; i < nsceneobjs; i++) {
50	greg	1.1	o = objptr(i);
51	greg	1.3	if (!issurface(o->otype) \|\| o->omod == OVOID)
52	greg	1.1	continue;
53	greg	1.31	if (!isvlight(vsmaterial(o)->otype))
54	greg	1.1	continue;
55	greg	1.3	if (sfun[o->otype].of == NULL \|\|
56	greg	1.21	sfun[o->otype].of->getpleq == NULL) {
57			objerror(o,WARNING,"secondary sources not supported");
58			continue;
59			}
60	greg	1.1	if (nvobjects == 0)
61			vobject = (OBJECT *)malloc(sizeof(OBJECT));
62			else
63	greg	2.9	vobject = (OBJECT )realloc((void )vobject,
64	greg	1.1	(unsigned)(nvobjects+1)*sizeof(OBJECT));
65			if (vobject == NULL)
66			error(SYSTEM, "out of memory in addvirtuals");
67			vobject[nvobjects++] = i;
68			}
69			if (nvobjects == 0)
70			return;
71	greg	1.4	#ifdef DEBUG
72			fprintf(stderr, "found %d virtual source objects\n", nvobjects);
73			#endif
74	greg	1.1	/* append virtual sources */
75			for (i = nsources; i-- > 0; )
76	greg	1.7	addvirtuals(i, directrelay);
77	greg	1.1	/* done with our object list */
78	greg	2.7	free((void *)vobject);
79	greg	1.1	nvobjects = 0;
80			}
81
82
83	greg	2.20	void
84	schorsch	2.14	addvirtuals( /* add virtuals associated with source */
85			int sn,
86			int nr
87			)
88	greg	1.1	{
89	greg	2.20	int i;
90	greg	1.1	/* check relay limit first */
91			if (nr <= 0)
92			return;
93	greg	1.7	if (source[sn].sflags & SSKIP)
94			return;
95	greg	1.1	/* check each virtual object for projection */
96			for (i = 0; i < nvobjects; i++)
97	greg	1.3	/* vproject() calls us recursively */
98	greg	1.4	vproject(objptr(vobject[i]), sn, nr-1);
99	greg	1.1	}
100
101
102	greg	2.20	void
103	schorsch	2.14	vproject( /* create projected source(s) if they exist */
104			OBJREC *o,
105			int sn,
106			int n
107			)
108	greg	1.3	{
109	greg	2.20	int i;
110			VSMATERIAL *vsmat;
111	greg	1.3	MAT4 proj;
112	greg	1.4	int ns;
113
114			if (o == source[sn].so) /* objects cannot project themselves */
115			return;
116	greg	1.3	/* get virtual source material */
117	greg	1.31	vsmat = sfun[vsmaterial(o)->otype].mf;
118	greg	1.3	/* project virtual sources */
119			for (i = 0; i < vsmat->nproj; i++)
120	greg	1.4	if ((*vsmat->vproj)(proj, o, &source[sn], i))
121			if ((ns = makevsrc(o, sn, proj)) >= 0) {
122	greg	1.17	source[ns].sa.sv.pn = i;
123	greg	1.4	#ifdef DEBUG
124	greg	1.6	virtverb(ns, stderr);
125	greg	1.4	#endif
126	greg	1.3	addvirtuals(ns, n);
127	greg	1.4	}
128	greg	1.31	}
129
130
131	greg	2.20	OBJREC *
132	schorsch	2.14	vsmaterial( /* get virtual source material pointer */
133			OBJREC *o
134			)
135	greg	1.31	{
136	greg	2.20	int i;
137			OBJREC *m;
138	greg	1.31
139			i = o->omod;
140	greg	2.24	m = findmaterial(o);
141	greg	2.13	if (m == NULL)
142			return(objptr(i));
143	greg	1.31	if (m->otype != MAT_ILLUM \|\| m->oargs.nsargs < 1 \|\|
144			!strcmp(m->oargs.sarg[0], VOIDID) \|\|
145	gwlarson	2.6	(i = lastmod(objndx(m), m->oargs.sarg[0])) == OVOID)
146	greg	1.31	return(m); /* direct modifier */
147			return(objptr(i)); /* illum alternate */
148	greg	1.3	}
149
150
151	greg	2.20	int
152	schorsch	2.14	makevsrc( /* make virtual source if reasonable */
153			OBJREC *op,
154	greg	2.20	int sn,
155	schorsch	2.14	MAT4 pm
156			)
157	greg	1.1	{
158	greg	1.9	FVECT nsloc, nsnorm, ocent, v;
159			double maxrad2, d;
160	greg	1.3	int nsflags;
161	greg	1.1	SPOT theirspot, ourspot;
162	greg	2.20	int i;
163			/* check for no-op */
164			if (isident4(pm))
165			return(0);
166	greg	1.6	nsflags = source[sn].sflags \| (SVIRTUAL\|SSPOT\|SFOLLOW);
167	greg	1.1	/* get object center and max. radius */
168	greg	1.6	maxrad2 = getdisk(ocent, op, sn);
169			if (maxrad2 <= FTINY) /* too small? */
170			return(-1);
171	greg	1.1	/* get location and spot */
172	greg	1.4	if (source[sn].sflags & SDISTANT) { /* distant source */
173			if (source[sn].sflags & SPROX)
174	greg	1.5	return(-1); /* should never get here! */
175	greg	1.4	multv3(nsloc, source[sn].sloc, pm);
176	greg	1.17	normalize(nsloc);
177	greg	1.6	VCOPY(ourspot.aim, ocent);
178			ourspot.siz = PI*maxrad2;
179	greg	2.5	ourspot.flen = -1.;
180	greg	1.4	if (source[sn].sflags & SSPOT) {
181			multp3(theirspot.aim, source[sn].sl.s->aim, pm);
182	greg	1.29	/* adjust for source size */
183	greg	1.19	d = sqrt(dist2(ourspot.aim, theirspot.aim));
184	greg	1.28	d = sqrt(source[sn].sl.s->siz/PI) + d*source[sn].srad;
185	greg	1.19	theirspot.siz = PIdd;
186			ourspot.flen = theirspot.flen = source[sn].sl.s->flen;
187	greg	1.9	d = ourspot.siz;
188	greg	1.6	if (!commonbeam(&ourspot, &theirspot, nsloc))
189	greg	1.9	return(-1); /* no overlap */
190			if (ourspot.siz < d-FTINY) { /* it shrunk */
191			d = beamdisk(v, op, &ourspot, nsloc);
192			if (d <= FTINY)
193			return(-1);
194			if (d < maxrad2) {
195			maxrad2 = d;
196			VCOPY(ocent, v);
197			}
198			}
199	greg	1.1	}
200			} else { /* local source */
201	greg	1.4	multp3(nsloc, source[sn].sloc, pm);
202	greg	1.6	for (i = 0; i < 3; i++)
203			ourspot.aim[i] = ocent[i] - nsloc[i];
204	greg	1.9	if ((d = normalize(ourspot.aim)) == 0.)
205	greg	1.6	return(-1); /* at source!! */
206	greg	1.9	if (source[sn].sflags & SPROX && d > source[sn].sl.prox)
207	greg	1.6	return(-1); /* too far away */
208			ourspot.flen = 0.;
209	greg	1.29	/* adjust for source size */
210	greg	1.28	d = (sqrt(maxrad2) + source[sn].srad) / d;
211	greg	1.19	if (d < 1.-FTINY)
212			ourspot.siz = 2.PI(1. - sqrt(1.-d*d));
213	greg	1.14	else
214			nsflags &= ~SSPOT;
215	greg	1.4	if (source[sn].sflags & SSPOT) {
216	schorsch	2.11	theirspot = *(source[sn].sl.s);
217	greg	1.4	multv3(theirspot.aim, source[sn].sl.s->aim, pm);
218	greg	1.17	normalize(theirspot.aim);
219	greg	1.14	if (nsflags & SSPOT) {
220			ourspot.flen = theirspot.flen;
221			d = ourspot.siz;
222			if (!commonspot(&ourspot, &theirspot, nsloc))
223			return(-1); /* no overlap */
224			} else {
225			nsflags \|= SSPOT;
226	schorsch	2.11	ourspot = theirspot;
227	greg	1.14	d = 2.*ourspot.siz;
228			}
229	greg	1.9	if (ourspot.siz < d-FTINY) { /* it shrunk */
230			d = spotdisk(v, op, &ourspot, nsloc);
231			if (d <= FTINY)
232			return(-1);
233			if (d < maxrad2) {
234			maxrad2 = d;
235			VCOPY(ocent, v);
236			}
237			}
238	greg	1.1	}
239	greg	1.4	if (source[sn].sflags & SFLAT) { /* behind source? */
240			multv3(nsnorm, source[sn].snorm, pm);
241	greg	1.17	normalize(nsnorm);
242	greg	1.20	if (nsflags & SSPOT && !checkspot(&ourspot, nsnorm))
243	greg	1.5	return(-1);
244	greg	1.1	}
245			}
246	greg	1.7	/* pretest visibility */
247			nsflags = vstestvis(nsflags, op, ocent, maxrad2, sn);
248			if (nsflags & SSKIP)
249			return(-1); /* obstructed */
250			/* it all checks out, so make it */
251	greg	1.6	if ((i = newsource()) < 0)
252	greg	1.1	goto memerr;
253	greg	1.6	source[i].sflags = nsflags;
254			VCOPY(source[i].sloc, nsloc);
255	greg	1.28	multv3(source[i].ss[SU], source[sn].ss[SU], pm);
256			multv3(source[i].ss[SV], source[sn].ss[SV], pm);
257	greg	1.3	if (nsflags & SFLAT)
258	greg	1.6	VCOPY(source[i].snorm, nsnorm);
259	greg	1.28	else
260			multv3(source[i].ss[SW], source[sn].ss[SW], pm);
261	greg	1.29	source[i].srad = source[sn].srad;
262	greg	1.28	source[i].ss2 = source[sn].ss2;
263	greg	1.14	if (nsflags & SSPOT) {
264			if ((source[i].sl.s = (SPOT *)malloc(sizeof(SPOT))) == NULL)
265			goto memerr;
266	schorsch	2.11	*(source[i].sl.s) = ourspot;
267	greg	1.14	}
268	greg	1.3	if (nsflags & SPROX)
269	greg	1.6	source[i].sl.prox = source[sn].sl.prox;
270	greg	1.17	source[i].sa.sv.sn = sn;
271	greg	1.6	source[i].so = op;
272			return(i);
273	greg	1.1	memerr:
274			error(SYSTEM, "out of memory in makevsrc");
275	schorsch	2.14	return -1; /* pro forma return */
276	greg	1.1	}
277
278
279	greg	2.20	double
280	schorsch	2.14	getdisk( /* get visible object disk */
281			FVECT oc,
282			OBJREC *op,
283	greg	2.20	int sn
284	schorsch	2.14	)
285	greg	1.6	{
286			double rad2, roffs, offs, d, rd, rdoto;
287			FVECT rnrm, nrm;
288			/* first, use object getdisk function */
289	greg	1.9	rad2 = getmaxdisk(oc, op);
290	greg	1.6	if (!(source[sn].sflags & SVIRTUAL))
291			return(rad2); /* all done for normal source */
292			/* check for correct side of relay surface */
293	greg	1.9	roffs = getplaneq(rnrm, source[sn].so);
294	greg	1.6	rd = DOT(rnrm, source[sn].sloc); /* source projection */
295			if (!(source[sn].sflags & SDISTANT))
296			rd -= roffs;
297			d = DOT(rnrm, oc) - roffs; /* disk distance to relay plane */
298			if ((d > 0.) ^ (rd > 0.))
299			return(rad2); /* OK if opposite sides */
300			if (d*d >= rad2)
301	greg	1.9	return(0.); /* no relay is possible */
302	greg	1.6	/* we need a closer look */
303	greg	1.9	offs = getplaneq(nrm, op);
304	greg	1.6	rdoto = DOT(rnrm, nrm);
305			if (dd >= rad2(1.-rdoto*rdoto))
306			return(0.); /* disk entirely on projection side */
307			/* should shrink disk but I'm lazy */
308			return(rad2);
309			}
310
311
312	greg	2.20	int
313	schorsch	2.14	vstestvis( /* pretest source visibility */
314			int f, /* virtual source flags */
315			OBJREC o, / relay object */
316			FVECT oc, /* relay object center */
317			double or2, /* relay object radius squared */
318	greg	2.20	int sn /* target source number */
319	schorsch	2.14	)
320	greg	1.1	{
321	greg	1.7	RAY sr;
322			FVECT onorm;
323	greg	2.21	double offsdir[3];
324	greg	1.28	SRCINDEX si;
325	greg	2.17	double or, d, d1;
326	greg	1.16	int stestlim, ssn;
327	greg	1.11	int nhit, nok;
328	greg	2.20	int i, n;
329	greg	1.7	/* return if pretesting disabled */
330			if (vspretest <= 0)
331			return(f);
332			/* get surface normal */
333	greg	1.9	getplaneq(onorm, o);
334	greg	1.7	/* set number of rays to sample */
335	greg	1.8	if (source[sn].sflags & SDISTANT) {
336	greg	1.26	/* 32. == heuristic constant */
337			n = 32.or2/(thescene.cusizethescene.cusize)*vspretest + .5;
338	greg	1.8	} else {
339	greg	2.21	VSUB(offsdir, source[sn].sloc, oc);
340	greg	1.20	d = DOT(offsdir,offsdir);
341			if (d <= FTINY)
342			n = 2.PI vspretest + .5;
343			else
344			n = 2.PI (1.-sqrt(1./(1.+or2/d)))*vspretest + .5;
345	greg	1.8	}
346	greg	1.13	if (n < MINSAMPLES) n = MINSAMPLES;
347	greg	1.9	#ifdef DEBUG
348			fprintf(stderr, "pretesting source %d in object %s with %d rays\n",
349			sn, o->oname, n);
350			#endif
351	greg	1.7	/* sample */
352	greg	1.8	or = sqrt(or2);
353	greg	1.16	stestlim = n*STESTMAX;
354			ssn = 0;
355	greg	1.11	nhit = nok = 0;
356	greg	2.4	initsrcindex(&si);
357	greg	1.7	while (n-- > 0) {
358	greg	1.8	/* get sample point */
359			do {
360	greg	1.16	if (ssn >= stestlim) {
361	greg	1.9	#ifdef DEBUG
362			fprintf(stderr, "\ttoo hard to hit\n");
363			#endif
364	greg	1.8	return(f); /* too small a target! */
365	greg	1.9	}
366	greg	1.25	multisamp(offsdir, 3, urand(sn*931+5827+ssn));
367	greg	1.8	for (i = 0; i < 3; i++)
368	greg	1.23	offsdir[i] = or(1. - 2.offsdir[i]);
369	greg	1.16	ssn++;
370	greg	2.4	d = 1. - DOT(offsdir, onorm);
371			for (i = 0; i < 3; i++) {
372			sr.rorg[i] = oc[i] + offsdir[i] + d*onorm[i];
373			sr.rdir[i] = -onorm[i];
374			}
375	greg	2.22	sr.rmax = 0.0;
376	greg	2.16	rayorigin(&sr, PRIMARY, NULL, NULL);
377	greg	1.8	} while (!(*ofun[o->otype].funp)(o, &sr));
378			/* check against source */
379	greg	2.4	VCOPY(sr.rorg, sr.rop); /* starting from intersection */
380	greg	1.7	samplendx++;
381	greg	2.4	if (si.sp >= si.np-1 \|\|
382			!srcray(&sr, NULL, &si) \|\| sr.rsrc != sn) {
383			si.sn = sn-1; /* reset index to our source */
384			si.np = 0;
385			if (!srcray(&sr, NULL, &si) \|\| sr.rsrc != sn)
386			continue; /* can't get there from here */
387			}
388	greg	2.17	sr.revf = srcvalue;
389			rayvalue(&sr); /* check sample validity */
390	greg	2.26	if ((d = scolor_mean(sr.rcol)) <= FTINY)
391	greg	1.7	continue;
392	greg	2.4	nok++; /* got sample; check obstructions */
393	greg	1.18	rayclear(&sr);
394	greg	2.17	sr.revf = raytrace;
395	greg	1.27	rayvalue(&sr);
396	greg	2.26	if ((d1 = scolor_mean(sr.rcol)) > FTINY) {
397	greg	2.17	if (d - d1 > FTINY) {
398			#ifdef DEBUG
399			fprintf(stderr, "\tpartially shadowed\n");
400			#endif
401			return(f); /* intervening transmitter */
402			}
403	greg	1.11	nhit++;
404	greg	2.17	}
405	greg	1.11	if (nhit > 0 && nhit < nok) {
406	greg	1.9	#ifdef DEBUG
407	greg	1.11	fprintf(stderr, "\tpartially occluded\n");
408	greg	1.9	#endif
409	greg	1.11	return(f); /* need to shadow test */
410			}
411	greg	1.1	}
412	greg	1.9	if (nhit == 0) {
413			#ifdef DEBUG
414			fprintf(stderr, "\t0%% hit rate\n");
415			#endif
416	greg	1.7	return(f \| SSKIP); /* 0% hit rate: totally occluded */
417	greg	1.9	}
418			#ifdef DEBUG
419			fprintf(stderr, "\t100%% hit rate\n");
420			#endif
421			return(f & ~SFOLLOW); /* 100% hit rate: no occlusion */
422	greg	1.1	}
423	greg	1.7
424	greg	1.4
425			#ifdef DEBUG
426	greg	2.20	void
427	schorsch	2.14	virtverb( /* print verbose description of virtual source */
428	greg	2.20	int sn,
429	schorsch	2.14	FILE *fp
430			)
431	greg	1.4	{
432			fprintf(fp, "%s virtual source %d in %s %s\n",
433	greg	1.6	source[sn].sflags & SDISTANT ? "distant" : "local",
434			sn, ofun[source[sn].so->otype].funame,
435			source[sn].so->oname);
436	greg	1.4	fprintf(fp, "\tat (%f,%f,%f)\n",
437	greg	1.6	source[sn].sloc[0], source[sn].sloc[1], source[sn].sloc[2]);
438	greg	1.4	fprintf(fp, "\tlinked to source %d (%s)\n",
439	greg	1.17	source[sn].sa.sv.sn, source[source[sn].sa.sv.sn].so->oname);
440	greg	1.6	if (source[sn].sflags & SFOLLOW)
441	greg	1.4	fprintf(fp, "\talways followed\n");
442			else
443			fprintf(fp, "\tnever followed\n");
444	greg	1.6	if (!(source[sn].sflags & SSPOT))
445	greg	1.4	return;
446			fprintf(fp, "\twith spot aim (%f,%f,%f) and size %f\n",
447	greg	1.6	source[sn].sl.s->aim[0], source[sn].sl.s->aim[1],
448			source[sn].sl.s->aim[2], source[sn].sl.s->siz);
449	greg	1.4	}
450			#endif