src/rt/srcsupp.c

#ifndef lint
static const char       RCSid[] = "$Id: srcsupp.c,v 2.15 2005/10/16 16:04:10 greg Exp $";
#endif
/*
 *  Support routines for source objects and materials
 *
 *  External symbols declared in source.h
 */

#include "copyright.h"

#include  "ray.h"

#include  "otypes.h"

#include  "source.h"

#include  "cone.h"

#include  "face.h"

#define SRCINC          8               /* realloc increment for array */

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

SRCFUNC  sfun[NUMOTYPE];                /* source dispatch table */


void
initstypes()                    /* initialize source dispatch table */
{
        extern VSMATERIAL  mirror_vs, direct1_vs, direct2_vs;
        static SOBJECT  fsobj = {fsetsrc, flatpart, fgetplaneq, fgetmaxdisk};
        static SOBJECT  ssobj = {ssetsrc, nopart};
        static SOBJECT  sphsobj = {sphsetsrc, nopart};
        static SOBJECT  cylsobj = {cylsetsrc, cylpart};
        static SOBJECT  rsobj = {rsetsrc, flatpart, rgetplaneq, rgetmaxdisk};

        sfun[MAT_MIRROR].mf = &mirror_vs;
        sfun[MAT_DIRECT1].mf = &direct1_vs;
        sfun[MAT_DIRECT2].mf = &direct2_vs;
        sfun[OBJ_FACE].of = &fsobj;
        sfun[OBJ_SOURCE].of = &ssobj;
        sfun[OBJ_SPHERE].of = &sphsobj;
        sfun[OBJ_CYLINDER].of = &cylsobj;
        sfun[OBJ_RING].of = &rsobj;
}


int
newsource()                     /* allocate new source in our array */
{
        if (nsources == 0)
                source = (SRCREC *)malloc(SRCINC*sizeof(SRCREC));
        else if (nsources%SRCINC == 0)
                source = (SRCREC *)realloc((void *)source,
                                (unsigned)(nsources+SRCINC)*sizeof(SRCREC));
        if (source == NULL)
                return(-1);
        source[nsources].sflags = 0;
        source[nsources].nhits = 1;
        source[nsources].ntests = 2;    /* initial hit probability = 50% */
#if SHADCACHE
        source[nsources].obscache = NULL;
#endif
        return(nsources++);
}


void
setflatss(src)                          /* set sampling for a flat source */
register SRCREC  *src;
{
        double  mult;
        register int  i;

        src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
        for (i = 0; i < 3; i++)
                if (src->snorm[i] < 0.6 && src->snorm[i] > -0.6)
                        break;
        src->ss[SV][i] = 1.0;
        fcross(src->ss[SU], src->ss[SV], src->snorm);
        mult = .5 * sqrt( src->ss2 / DOT(src->ss[SU],src->ss[SU]) );
        for (i = 0; i < 3; i++)
                src->ss[SU][i] *= mult;
        fcross(src->ss[SV], src->snorm, src->ss[SU]);
}


void
fsetsrc(src, so)                        /* set a face as a source */
register SRCREC  *src;
OBJREC  *so;
{
        register FACE  *f;
        register int  i, j;
        double  d;
        
        src->sa.success = 2*AIMREQT-1;          /* bitch on second failure */
        src->so = so;
                                                /* get the face */
        f = getface(so);
        if (f->area == 0.0)
                objerror(so, USER, "zero source area");
                                                /* find the center */
        for (j = 0; j < 3; j++) {
                src->sloc[j] = 0.0;
                for (i = 0; i < f->nv; i++)
                        src->sloc[j] += VERTEX(f,i)[j];
                src->sloc[j] /= (double)f->nv;
        }
        if (!inface(src->sloc, f))
                objerror(so, USER, "cannot hit source center");
        src->sflags |= SFLAT;
        VCOPY(src->snorm, f->norm);
        src->ss2 = f->area;
                                                /* find maximum radius */
        src->srad = 0.;
        for (i = 0; i < f->nv; i++) {
                d = dist2(VERTEX(f,i), src->sloc);
                if (d > src->srad)
                        src->srad = d;
        }
        src->srad = sqrt(src->srad);
                                                /* compute size vectors */
        if (f->nv == 4)                         /* parallelogram case */
                for (j = 0; j < 3; j++) {
                        src->ss[SU][j] = .5*(VERTEX(f,1)[j]-VERTEX(f,0)[j]);
                        src->ss[SV][j] = .5*(VERTEX(f,3)[j]-VERTEX(f,0)[j]);
                }
        else
                setflatss(src);
}


void
ssetsrc(src, so)                        /* set a source as a source */
register SRCREC  *src;
register OBJREC  *so;
{
        double  theta;
        
        src->sa.success = 2*AIMREQT-1;          /* bitch on second failure */
        src->so = so;
        if (so->oargs.nfargs != 4)
                objerror(so, USER, "bad arguments");
        src->sflags |= SDISTANT;
        VCOPY(src->sloc, so->oargs.farg);
        if (normalize(src->sloc) == 0.0)
                objerror(so, USER, "zero direction");
        theta = PI/180.0/2.0 * so->oargs.farg[3];
        if (theta <= FTINY)
                objerror(so, USER, "zero size");
        src->ss2 = 2.0*PI * (1.0 - cos(theta));
                                        /* the following is approximate */
        src->srad = sqrt(src->ss2/PI);
        VCOPY(src->snorm, src->sloc);
        setflatss(src);                 /* hey, whatever works */
        src->ss[SW][0] = src->ss[SW][1] = src->ss[SW][2] = 0.0;
}


void
sphsetsrc(src, so)                      /* set a sphere as a source */
register SRCREC  *src;
register OBJREC  *so;
{
        register int  i;

        src->sa.success = 2*AIMREQT-1;          /* bitch on second failure */
        src->so = so;
        if (so->oargs.nfargs != 4)
                objerror(so, USER, "bad # arguments");
        if (so->oargs.farg[3] <= FTINY)
                objerror(so, USER, "illegal source radius");
        VCOPY(src->sloc, so->oargs.farg);
        src->srad = so->oargs.farg[3];
        src->ss2 = PI * src->srad * src->srad;
        for (i = 0; i < 3; i++)
                src->ss[SU][i] = src->ss[SV][i] = src->ss[SW][i] = 0.0;
        for (i = 0; i < 3; i++)
                src->ss[i][i] = .7236 * so->oargs.farg[3];
}


void
rsetsrc(src, so)                        /* set a ring (disk) as a source */
register SRCREC  *src;
OBJREC  *so;
{
        register CONE  *co;
        
        src->sa.success = 2*AIMREQT-1;          /* bitch on second failure */
        src->so = so;
                                                /* get the ring */
        co = getcone(so, 0);
        if (CO_R1(co) <= FTINY)
                objerror(so, USER, "illegal source radius");
        VCOPY(src->sloc, CO_P0(co));
        if (CO_R0(co) > 0.0)
                objerror(so, USER, "cannot hit source center");
        src->sflags |= SFLAT;
        VCOPY(src->snorm, co->ad);
        src->srad = CO_R1(co);
        src->ss2 = PI * src->srad * src->srad;
        setflatss(src);
}


void
cylsetsrc(src, so)                      /* set a cylinder as a source */
register SRCREC  *src;
OBJREC  *so;
{
        register CONE  *co;
        register int  i;
        
        src->sa.success = 4*AIMREQT-1;          /* bitch on fourth failure */
        src->so = so;
                                                /* get the cylinder */
        co = getcone(so, 0);
        if (CO_R0(co) <= FTINY)
                objerror(so, USER, "illegal source radius");
        if (CO_R0(co) > .2*co->al)              /* heuristic constraint */
                objerror(so, WARNING, "source aspect too small");
        src->sflags |= SCYL;
        for (i = 0; i < 3; i++)
                src->sloc[i] = .5 * (CO_P1(co)[i] + CO_P0(co)[i]);
        src->srad = .5*co->al;
        src->ss2 = 2.*CO_R0(co)*co->al;
                                                /* set sampling vectors */
        for (i = 0; i < 3; i++)
                src->ss[SU][i] = .5 * co->al * co->ad[i];
        src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
        for (i = 0; i < 3; i++)
                if (co->ad[i] < 0.6 && co->ad[i] > -0.6)
                        break;
        src->ss[SV][i] = 1.0;
        fcross(src->ss[SW], src->ss[SV], co->ad);
        normalize(src->ss[SW]);
        for (i = 0; i < 3; i++)
                src->ss[SW][i] *= .8559 * CO_R0(co);
        fcross(src->ss[SV], src->ss[SW], co->ad);
}


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

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


int
spotout(r, s)                   /* check if we're outside spot region */
register RAY  *r;
register SPOT  *s;
{
        double  d;
        FVECT  vd;
        
        if (s == NULL)
                return(0);
        if (s->flen < -FTINY) {         /* distant source */
                vd[0] = s->aim[0] - r->rorg[0];
                vd[1] = s->aim[1] - r->rorg[1];
                vd[2] = s->aim[2] - r->rorg[2];
                d = DOT(r->rdir,vd);
                /*                      wrong side?
                if (d <= FTINY)
                        return(1);      */
                d = DOT(vd,vd) - d*d;
                if (PI*d > s->siz)
                        return(1);      /* out */
                return(0);      /* OK */
        }
                                        /* local source */
        if (s->siz < 2.0*PI * (1.0 + DOT(s->aim,r->rdir)))
                return(1);      /* out */
        return(0);      /* OK */
}


double
fgetmaxdisk(ocent, op)          /* get center and squared radius of face */
FVECT  ocent;
OBJREC  *op;
{
        double  maxrad2;
        double  d;
        register int  i, j;
        register FACE  *f;
        
        f = getface(op);
        if (f->area == 0.)
                return(0.);
        for (i = 0; i < 3; i++) {
                ocent[i] = 0.;
                for (j = 0; j < f->nv; j++)
                        ocent[i] += VERTEX(f,j)[i];
                ocent[i] /= (double)f->nv;
        }
        d = DOT(ocent,f->norm);
        for (i = 0; i < 3; i++)
                ocent[i] += (f->offset - d)*f->norm[i];
        maxrad2 = 0.;
        for (j = 0; j < f->nv; j++) {
                d = dist2(VERTEX(f,j), ocent);
                if (d > maxrad2)
                        maxrad2 = d;
        }
        return(maxrad2);
}


double
rgetmaxdisk(ocent, op)          /* get center and squared radius of ring */
FVECT  ocent;
OBJREC  *op;
{
        register CONE  *co;
        
        co = getcone(op, 0);
        VCOPY(ocent, CO_P0(co));
        return(CO_R1(co)*CO_R1(co));
}


double
fgetplaneq(nvec, op)                    /* get plane equation for face */
FVECT  nvec;
OBJREC  *op;
{
        register FACE  *fo;

        fo = getface(op);
        VCOPY(nvec, fo->norm);
        return(fo->offset);
}


double
rgetplaneq(nvec, op)                    /* get plane equation for ring */
FVECT  nvec;
OBJREC  *op;
{
        register CONE  *co;

        co = getcone(op, 0);
        VCOPY(nvec, co->ad);
        return(DOT(nvec, CO_P0(co)));
}


int
commonspot(sp1, sp2, org)       /* set sp1 to intersection of sp1 and sp2 */
register SPOT  *sp1, *sp2;
FVECT  org;
{
        FVECT  cent;
        double  rad2, cos1, cos2;

        cos1 = 1. - sp1->siz/(2.*PI);
        cos2 = 1. - sp2->siz/(2.*PI);
        if (sp2->siz >= 2.*PI-FTINY)            /* BIG, just check overlap */
                return(DOT(sp1->aim,sp2->aim) >= cos1*cos2 -
                                        sqrt((1.-cos1*cos1)*(1.-cos2*cos2)));
                                /* compute and check disks */
        rad2 = intercircle(cent, sp1->aim, sp2->aim,
                        1./(cos1*cos1) - 1.,  1./(cos2*cos2) - 1.);
        if (rad2 <= FTINY || normalize(cent) == 0.)
                return(0);
        VCOPY(sp1->aim, cent);
        sp1->siz = 2.*PI*(1. - 1./sqrt(1.+rad2));
        return(1);
}


int
commonbeam(sp1, sp2, dir)       /* set sp1 to intersection of sp1 and sp2 */
register SPOT  *sp1, *sp2;
FVECT  dir;
{
        FVECT  cent, c1, c2;
        double  rad2, d;
        register int  i;
                                        /* move centers to common plane */
        d = DOT(sp1->aim, dir);
        for (i = 0; i < 3; i++)
                c1[i] = sp1->aim[i] - d*dir[i];
        d = DOT(sp2->aim, dir);
        for (i = 0; i < 3; i++)
                c2[i] = sp2->aim[i] - d*dir[i];
                                        /* compute overlap */
        rad2 = intercircle(cent, c1, c2, sp1->siz/PI, sp2->siz/PI);
        if (rad2 <= FTINY)
                return(0);
        VCOPY(sp1->aim, cent);
        sp1->siz = PI*rad2;
        return(1);
}


int
checkspot(sp, nrm)              /* check spotlight for behind source */
register SPOT  *sp;     /* spotlight */
FVECT  nrm;             /* source surface normal */
{
        double  d, d1;

        d = DOT(sp->aim, nrm);
        if (d > FTINY)                  /* center in front? */
                return(1);
                                        /* else check horizon */
        d1 = 1. - sp->siz/(2.*PI);
        return(1.-FTINY-d*d < d1*d1);
}


double
spotdisk(oc, op, sp, pos)       /* intersect spot with object op */
FVECT  oc;
OBJREC  *op;
register SPOT  *sp;
FVECT  pos;
{
        FVECT  onorm;
        double  offs, d, dist;
        register int  i;

        offs = getplaneq(onorm, op);
        d = -DOT(onorm, sp->aim);
        if (d >= -FTINY && d <= FTINY)
                return(0.);
        dist = (DOT(pos, onorm) - offs)/d;
        if (dist < 0.)
                return(0.);
        for (i = 0; i < 3; i++)
                oc[i] = pos[i] + dist*sp->aim[i];
        return(sp->siz*dist*dist/PI/(d*d));
}


double
beamdisk(oc, op, sp, dir)       /* intersect beam with object op */
FVECT  oc;
OBJREC  *op;
register SPOT  *sp;
FVECT  dir;
{
        FVECT  onorm;
        double  offs, d, dist;
        register int  i;

        offs = getplaneq(onorm, op);
        d = -DOT(onorm, dir);
        if (d >= -FTINY && d <= FTINY)
                return(0.);
        dist = (DOT(sp->aim, onorm) - offs)/d;
        for (i = 0; i < 3; i++)
                oc[i] = sp->aim[i] + dist*dir[i];
        return(sp->siz/PI/(d*d));
}


double
intercircle(cc, c1, c2, r1s, r2s)       /* intersect two circles */
FVECT  cc;                      /* midpoint (return value) */
FVECT  c1, c2;                  /* circle centers */
double  r1s, r2s;               /* radii squared */
{
        double  a2, d2, l;
        FVECT  disp;
        register int  i;

        for (i = 0; i < 3; i++)
                disp[i] = c2[i] - c1[i];
        d2 = DOT(disp,disp);
                                        /* circle within overlap? */
        if (r1s < r2s) {
                if (r2s >= r1s + d2) {
                        VCOPY(cc, c1);
                        return(r1s);
                }
        } else {
                if (r1s >= r2s + d2) {
                        VCOPY(cc, c2);
                        return(r2s);
                }
        }
        a2 = .25*(2.*(r1s+r2s) - d2 - (r2s-r1s)*(r2s-r1s)/d2);
                                        /* no overlap? */
        if (a2 <= 0.)
                return(0.);
                                        /* overlap, compute center */
        l = sqrt((r1s - a2)/d2);
        for (i = 0; i < 3; i++)
                cc[i] = c1[i] + l*disp[i];
        return(a2);
}
Revision:	2.16
Committed:	Mon Feb 26 21:16:02 2007 UTC (17 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R9
Changes since 2.15:	+12 -4 lines
Log Message:	Added checks for source surfaces, including zero-area polygons
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.16	static const char RCSid[] = "$Id: srcsupp.c,v 2.15 2005/10/16 16:04:10 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* Support routines for source objects and materials
6	greg	2.9	*
7			* External symbols declared in source.h
8			*/
9
10	greg	2.10	#include "copyright.h"
11	greg	1.1
12			#include "ray.h"
13
14			#include "otypes.h"
15
16			#include "source.h"
17
18			#include "cone.h"
19
20			#include "face.h"
21
22	greg	2.12	#define SRCINC 8 /* realloc increment for array */
23	greg	1.1
24			SRCREC source = NULL; / our list of sources */
25			int nsources = 0; /* the number of sources */
26
27			SRCFUNC sfun[NUMOTYPE]; /* source dispatch table */
28
29
30	greg	2.9	void
31	greg	1.1	initstypes() /* initialize source dispatch table */
32			{
33	greg	1.9	extern VSMATERIAL mirror_vs, direct1_vs, direct2_vs;
34	greg	1.14	static SOBJECT fsobj = {fsetsrc, flatpart, fgetplaneq, fgetmaxdisk};
35			static SOBJECT ssobj = {ssetsrc, nopart};
36			static SOBJECT sphsobj = {sphsetsrc, nopart};
37			static SOBJECT cylsobj = {cylsetsrc, cylpart};
38			static SOBJECT rsobj = {rsetsrc, flatpart, rgetplaneq, rgetmaxdisk};
39	greg	1.1
40			sfun[MAT_MIRROR].mf = &mirror_vs;
41	greg	1.9	sfun[MAT_DIRECT1].mf = &direct1_vs;
42			sfun[MAT_DIRECT2].mf = &direct2_vs;
43	greg	1.1	sfun[OBJ_FACE].of = &fsobj;
44			sfun[OBJ_SOURCE].of = &ssobj;
45			sfun[OBJ_SPHERE].of = &sphsobj;
46	greg	1.14	sfun[OBJ_CYLINDER].of = &cylsobj;
47	greg	1.1	sfun[OBJ_RING].of = &rsobj;
48			}
49
50
51	greg	1.2	int
52	greg	1.1	newsource() /* allocate new source in our array */
53			{
54			if (nsources == 0)
55	greg	1.13	source = (SRCREC )malloc(SRCINCsizeof(SRCREC));
56			else if (nsources%SRCINC == 0)
57	greg	2.11	source = (SRCREC )realloc((void )source,
58	greg	1.13	(unsigned)(nsources+SRCINC)*sizeof(SRCREC));
59	greg	1.1	if (source == NULL)
60	greg	1.2	return(-1);
61	greg	1.1	source[nsources].sflags = 0;
62	greg	2.14	source[nsources].nhits = 1;
63			source[nsources].ntests = 2; /* initial hit probability = 50% */
64	greg	2.12	#if SHADCACHE
65			source[nsources].obscache = NULL;
66			#endif
67	greg	1.2	return(nsources++);
68	greg	1.1	}
69
70
71	greg	2.9	void
72	greg	1.14	setflatss(src) /* set sampling for a flat source */
73			register SRCREC *src;
74			{
75			double mult;
76			register int i;
77
78			src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
79			for (i = 0; i < 3; i++)
80			if (src->snorm[i] < 0.6 && src->snorm[i] > -0.6)
81			break;
82			src->ss[SV][i] = 1.0;
83			fcross(src->ss[SU], src->ss[SV], src->snorm);
84			mult = .5 * sqrt( src->ss2 / DOT(src->ss[SU],src->ss[SU]) );
85			for (i = 0; i < 3; i++)
86			src->ss[SU][i] *= mult;
87			fcross(src->ss[SV], src->snorm, src->ss[SU]);
88			}
89
90
91	greg	2.9	void
92	greg	1.1	fsetsrc(src, so) /* set a face as a source */
93			register SRCREC *src;
94			OBJREC *so;
95			{
96			register FACE *f;
97			register int i, j;
98	greg	1.14	double d;
99	greg	1.1
100			src->sa.success = 2AIMREQT-1; / bitch on second failure */
101			src->so = so;
102			/* get the face */
103			f = getface(so);
104	greg	2.16	if (f->area == 0.0)
105			objerror(so, USER, "zero source area");
106	greg	1.1	/* find the center */
107			for (j = 0; j < 3; j++) {
108			src->sloc[j] = 0.0;
109			for (i = 0; i < f->nv; i++)
110			src->sloc[j] += VERTEX(f,i)[j];
111			src->sloc[j] /= (double)f->nv;
112			}
113			if (!inface(src->sloc, f))
114	greg	2.16	objerror(so, USER, "cannot hit source center");
115	greg	1.1	src->sflags \|= SFLAT;
116			VCOPY(src->snorm, f->norm);
117			src->ss2 = f->area;
118	greg	1.14	/* find maximum radius */
119			src->srad = 0.;
120			for (i = 0; i < f->nv; i++) {
121			d = dist2(VERTEX(f,i), src->sloc);
122			if (d > src->srad)
123			src->srad = d;
124			}
125			src->srad = sqrt(src->srad);
126			/* compute size vectors */
127	greg	2.7	if (f->nv == 4) /* parallelogram case */
128	greg	1.14	for (j = 0; j < 3; j++) {
129			src->ss[SU][j] = .5*(VERTEX(f,1)[j]-VERTEX(f,0)[j]);
130			src->ss[SV][j] = .5*(VERTEX(f,3)[j]-VERTEX(f,0)[j]);
131			}
132			else
133			setflatss(src);
134	greg	1.1	}
135
136
137	greg	2.9	void
138	greg	1.1	ssetsrc(src, so) /* set a source as a source */
139			register SRCREC *src;
140			register OBJREC *so;
141			{
142			double theta;
143
144			src->sa.success = 2AIMREQT-1; / bitch on second failure */
145			src->so = so;
146			if (so->oargs.nfargs != 4)
147			objerror(so, USER, "bad arguments");
148			src->sflags \|= SDISTANT;
149			VCOPY(src->sloc, so->oargs.farg);
150			if (normalize(src->sloc) == 0.0)
151			objerror(so, USER, "zero direction");
152			theta = PI/180.0/2.0 * so->oargs.farg[3];
153			if (theta <= FTINY)
154			objerror(so, USER, "zero size");
155			src->ss2 = 2.0PI (1.0 - cos(theta));
156	greg	1.14	/* the following is approximate */
157			src->srad = sqrt(src->ss2/PI);
158			VCOPY(src->snorm, src->sloc);
159			setflatss(src); /* hey, whatever works */
160			src->ss[SW][0] = src->ss[SW][1] = src->ss[SW][2] = 0.0;
161	greg	1.1	}
162
163
164	greg	2.9	void
165	greg	1.1	sphsetsrc(src, so) /* set a sphere as a source */
166			register SRCREC *src;
167			register OBJREC *so;
168			{
169	greg	1.14	register int i;
170
171	greg	1.1	src->sa.success = 2AIMREQT-1; / bitch on second failure */
172			src->so = so;
173			if (so->oargs.nfargs != 4)
174			objerror(so, USER, "bad # arguments");
175			if (so->oargs.farg[3] <= FTINY)
176	greg	2.16	objerror(so, USER, "illegal source radius");
177	greg	1.1	VCOPY(src->sloc, so->oargs.farg);
178	greg	1.14	src->srad = so->oargs.farg[3];
179			src->ss2 = PI * src->srad * src->srad;
180			for (i = 0; i < 3; i++)
181			src->ss[SU][i] = src->ss[SV][i] = src->ss[SW][i] = 0.0;
182			for (i = 0; i < 3; i++)
183	greg	1.15	src->ss[i][i] = .7236 * so->oargs.farg[3];
184	greg	1.1	}
185
186
187	greg	2.9	void
188	greg	1.1	rsetsrc(src, so) /* set a ring (disk) as a source */
189			register SRCREC *src;
190			OBJREC *so;
191			{
192			register CONE *co;
193
194			src->sa.success = 2AIMREQT-1; / bitch on second failure */
195			src->so = so;
196			/* get the ring */
197			co = getcone(so, 0);
198	greg	2.16	if (CO_R1(co) <= FTINY)
199			objerror(so, USER, "illegal source radius");
200	greg	1.1	VCOPY(src->sloc, CO_P0(co));
201			if (CO_R0(co) > 0.0)
202	greg	2.16	objerror(so, USER, "cannot hit source center");
203	greg	1.1	src->sflags \|= SFLAT;
204			VCOPY(src->snorm, co->ad);
205	greg	1.14	src->srad = CO_R1(co);
206			src->ss2 = PI * src->srad * src->srad;
207			setflatss(src);
208			}
209
210
211	greg	2.9	void
212	greg	1.14	cylsetsrc(src, so) /* set a cylinder as a source */
213			register SRCREC *src;
214			OBJREC *so;
215			{
216			register CONE *co;
217			register int i;
218
219			src->sa.success = 4AIMREQT-1; / bitch on fourth failure */
220			src->so = so;
221			/* get the cylinder */
222			co = getcone(so, 0);
223	greg	2.16	if (CO_R0(co) <= FTINY)
224			objerror(so, USER, "illegal source radius");
225	greg	1.14	if (CO_R0(co) > .2co->al) / heuristic constraint */
226			objerror(so, WARNING, "source aspect too small");
227	greg	1.15	src->sflags \|= SCYL;
228	greg	1.14	for (i = 0; i < 3; i++)
229			src->sloc[i] = .5 * (CO_P1(co)[i] + CO_P0(co)[i]);
230	greg	1.15	src->srad = .5*co->al;
231	greg	1.14	src->ss2 = 2.CO_R0(co)co->al;
232			/* set sampling vectors */
233			for (i = 0; i < 3; i++)
234			src->ss[SU][i] = .5 * co->al * co->ad[i];
235			src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
236			for (i = 0; i < 3; i++)
237			if (co->ad[i] < 0.6 && co->ad[i] > -0.6)
238			break;
239			src->ss[SV][i] = 1.0;
240			fcross(src->ss[SW], src->ss[SV], co->ad);
241			normalize(src->ss[SW]);
242			for (i = 0; i < 3; i++)
243	greg	1.15	src->ss[SW][i] = .8559 CO_R0(co);
244	greg	1.14	fcross(src->ss[SV], src->ss[SW], co->ad);
245	greg	1.1	}
246
247
248			SPOT *
249			makespot(m) /* make a spotlight */
250			register OBJREC *m;
251			{
252			register SPOT *ns;
253
254	greg	2.5	if ((ns = (SPOT *)m->os) != NULL)
255			return(ns);
256	greg	1.1	if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL)
257			return(NULL);
258	greg	2.16	if (m->oargs.farg[3] <= FTINY)
259			objerror(m, USER, "zero angle");
260	greg	1.1	ns->siz = 2.0PI (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3]));
261			VCOPY(ns->aim, m->oargs.farg+4);
262			if ((ns->flen = normalize(ns->aim)) == 0.0)
263			objerror(m, USER, "zero focus vector");
264	greg	2.5	m->os = (char *)ns;
265	greg	1.1	return(ns);
266			}
267
268
269	greg	2.9	int
270	greg	2.8	spotout(r, s) /* check if we're outside spot region */
271	greg	2.5	register RAY *r;
272			register SPOT *s;
273			{
274			double d;
275			FVECT vd;
276
277			if (s == NULL)
278			return(0);
279	greg	2.8	if (s->flen < -FTINY) { /* distant source */
280	greg	2.5	vd[0] = s->aim[0] - r->rorg[0];
281			vd[1] = s->aim[1] - r->rorg[1];
282			vd[2] = s->aim[2] - r->rorg[2];
283			d = DOT(r->rdir,vd);
284			/* wrong side?
285			if (d <= FTINY)
286			return(1); */
287			d = DOT(vd,vd) - d*d;
288			if (PI*d > s->siz)
289			return(1); /* out */
290			return(0); /* OK */
291			}
292			/* local source */
293			if (s->siz < 2.0PI (1.0 + DOT(s->aim,r->rdir)))
294			return(1); /* out */
295			return(0); /* OK */
296			}
297
298
299	greg	1.1	double
300			fgetmaxdisk(ocent, op) /* get center and squared radius of face */
301			FVECT ocent;
302			OBJREC *op;
303			{
304			double maxrad2;
305	greg	1.5	double d;
306	greg	1.1	register int i, j;
307			register FACE *f;
308
309			f = getface(op);
310	greg	1.5	if (f->area == 0.)
311			return(0.);
312	greg	1.1	for (i = 0; i < 3; i++) {
313			ocent[i] = 0.;
314			for (j = 0; j < f->nv; j++)
315			ocent[i] += VERTEX(f,j)[i];
316			ocent[i] /= (double)f->nv;
317			}
318	greg	1.5	d = DOT(ocent,f->norm);
319			for (i = 0; i < 3; i++)
320			ocent[i] += (f->offset - d)*f->norm[i];
321	greg	1.1	maxrad2 = 0.;
322			for (j = 0; j < f->nv; j++) {
323	greg	1.5	d = dist2(VERTEX(f,j), ocent);
324			if (d > maxrad2)
325			maxrad2 = d;
326	greg	1.1	}
327			return(maxrad2);
328			}
329
330
331			double
332			rgetmaxdisk(ocent, op) /* get center and squared radius of ring */
333			FVECT ocent;
334			OBJREC *op;
335			{
336			register CONE *co;
337
338			co = getcone(op, 0);
339			VCOPY(ocent, CO_P0(co));
340			return(CO_R1(co)*CO_R1(co));
341			}
342
343
344			double
345			fgetplaneq(nvec, op) /* get plane equation for face */
346			FVECT nvec;
347			OBJREC *op;
348			{
349			register FACE *fo;
350
351			fo = getface(op);
352			VCOPY(nvec, fo->norm);
353			return(fo->offset);
354			}
355
356
357			double
358			rgetplaneq(nvec, op) /* get plane equation for ring */
359			FVECT nvec;
360			OBJREC *op;
361			{
362			register CONE *co;
363
364			co = getcone(op, 0);
365			VCOPY(nvec, co->ad);
366			return(DOT(nvec, CO_P0(co)));
367	greg	1.4	}
368
369
370	greg	2.9	int
371	greg	1.4	commonspot(sp1, sp2, org) /* set sp1 to intersection of sp1 and sp2 */
372			register SPOT sp1, sp2;
373			FVECT org;
374			{
375			FVECT cent;
376			double rad2, cos1, cos2;
377
378			cos1 = 1. - sp1->siz/(2.*PI);
379			cos2 = 1. - sp2->siz/(2.*PI);
380			if (sp2->siz >= 2.PI-FTINY) / BIG, just check overlap */
381			return(DOT(sp1->aim,sp2->aim) >= cos1*cos2 -
382			sqrt((1.-cos1cos1)(1.-cos2*cos2)));
383			/* compute and check disks */
384			rad2 = intercircle(cent, sp1->aim, sp2->aim,
385			1./(cos1cos1) - 1., 1./(cos2cos2) - 1.);
386			if (rad2 <= FTINY \|\| normalize(cent) == 0.)
387			return(0);
388			VCOPY(sp1->aim, cent);
389			sp1->siz = 2.PI(1. - 1./sqrt(1.+rad2));
390			return(1);
391			}
392
393
394	greg	2.9	int
395	greg	1.4	commonbeam(sp1, sp2, dir) /* set sp1 to intersection of sp1 and sp2 */
396			register SPOT sp1, sp2;
397			FVECT dir;
398			{
399			FVECT cent, c1, c2;
400			double rad2, d;
401			register int i;
402			/* move centers to common plane */
403			d = DOT(sp1->aim, dir);
404			for (i = 0; i < 3; i++)
405			c1[i] = sp1->aim[i] - d*dir[i];
406			d = DOT(sp2->aim, dir);
407			for (i = 0; i < 3; i++)
408			c2[i] = sp2->aim[i] - d*dir[i];
409			/* compute overlap */
410			rad2 = intercircle(cent, c1, c2, sp1->siz/PI, sp2->siz/PI);
411			if (rad2 <= FTINY)
412			return(0);
413			VCOPY(sp1->aim, cent);
414			sp1->siz = PI*rad2;
415			return(1);
416			}
417
418
419	greg	2.9	int
420	greg	1.4	checkspot(sp, nrm) /* check spotlight for behind source */
421			register SPOT sp; / spotlight */
422			FVECT nrm; /* source surface normal */
423			{
424			double d, d1;
425
426			d = DOT(sp->aim, nrm);
427			if (d > FTINY) /* center in front? */
428	greg	1.8	return(1);
429	greg	1.4	/* else check horizon */
430			d1 = 1. - sp->siz/(2.*PI);
431	greg	1.8	return(1.-FTINY-dd < d1d1);
432	greg	1.4	}
433
434
435			double
436	greg	1.6	spotdisk(oc, op, sp, pos) /* intersect spot with object op */
437			FVECT oc;
438			OBJREC *op;
439			register SPOT *sp;
440			FVECT pos;
441			{
442			FVECT onorm;
443			double offs, d, dist;
444			register int i;
445
446			offs = getplaneq(onorm, op);
447			d = -DOT(onorm, sp->aim);
448			if (d >= -FTINY && d <= FTINY)
449			return(0.);
450			dist = (DOT(pos, onorm) - offs)/d;
451			if (dist < 0.)
452			return(0.);
453			for (i = 0; i < 3; i++)
454			oc[i] = pos[i] + dist*sp->aim[i];
455			return(sp->sizdistdist/PI/(d*d));
456			}
457
458
459			double
460			beamdisk(oc, op, sp, dir) /* intersect beam with object op */
461			FVECT oc;
462			OBJREC *op;
463			register SPOT *sp;
464			FVECT dir;
465			{
466			FVECT onorm;
467			double offs, d, dist;
468			register int i;
469
470			offs = getplaneq(onorm, op);
471			d = -DOT(onorm, dir);
472			if (d >= -FTINY && d <= FTINY)
473			return(0.);
474			dist = (DOT(sp->aim, onorm) - offs)/d;
475			for (i = 0; i < 3; i++)
476			oc[i] = sp->aim[i] + dist*dir[i];
477			return(sp->siz/PI/(d*d));
478			}
479
480
481			double
482	greg	1.4	intercircle(cc, c1, c2, r1s, r2s) /* intersect two circles */
483			FVECT cc; /* midpoint (return value) */
484			FVECT c1, c2; /* circle centers */
485			double r1s, r2s; /* radii squared */
486			{
487			double a2, d2, l;
488			FVECT disp;
489			register int i;
490
491			for (i = 0; i < 3; i++)
492			disp[i] = c2[i] - c1[i];
493			d2 = DOT(disp,disp);
494			/* circle within overlap? */
495			if (r1s < r2s) {
496			if (r2s >= r1s + d2) {
497			VCOPY(cc, c1);
498			return(r1s);
499			}
500			} else {
501			if (r1s >= r2s + d2) {
502			VCOPY(cc, c2);
503			return(r2s);
504			}
505			}
506			a2 = .25(2.(r1s+r2s) - d2 - (r2s-r1s)*(r2s-r1s)/d2);
507			/* no overlap? */
508			if (a2 <= 0.)
509			return(0.);
510			/* overlap, compute center */
511			l = sqrt((r1s - a2)/d2);
512			for (i = 0; i < 3; i++)
513			cc[i] = c1[i] + l*disp[i];
514			return(a2);
515	greg	1.1	}