src/rt/srcsupp.c

/* Copyright (c) 1992 Regents of the University of California */

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

/*
 *  Support routines for source objects and materials
 */

#include  "ray.h"

#include  "otypes.h"

#include  "source.h"

#include  "cone.h"

#include  "face.h"

#define SRCINC          4               /* realloc increment for array */

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

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


initstypes()                    /* initialize source dispatch table */
{
        extern VSMATERIAL  mirror_vs, direct1_vs, direct2_vs;
        extern int  fsetsrc(), ssetsrc(), sphsetsrc(), cylsetsrc(), rsetsrc();
        extern int  nopart(), flatpart(), cylpart();
        extern double  fgetplaneq(), rgetplaneq();
        extern double  fgetmaxdisk(), rgetmaxdisk();
        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((char *)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 = 1/2 */
        return(nsources++);
}


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]);
}


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);
                                                /* find the center */
        for (j = 0; j < 3; j++) {
                src->sloc[j] = 0.0;
                for (i = 0; i < f->nv; i++)
                        src->sloc[j] += VERTEX(f,i)[j];
                src->sloc[j] /= (double)f->nv;
        }
        if (!inface(src->sloc, f))
                objerror(so, USER, "cannot hit center");
        src->sflags |= SFLAT;
        VCOPY(src->snorm, f->norm);
        src->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 || (f->nv == 5 &&        /* parallelogram case */
                        dist2(VERTEX(f,0),VERTEX(f,4)) <= FTINY*FTINY))
                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);
}


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;
}


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 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];
}


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);
        VCOPY(src->sloc, CO_P0(co));
        if (CO_R0(co) > 0.0)
                objerror(so, USER, "cannot hit center");
        src->sflags |= SFLAT;
        VCOPY(src->snorm, co->ad);
        src->srad = CO_R1(co);
        src->ss2 = PI * src->srad * src->srad;
        setflatss(src);
}


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) > .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);
        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);
}


spotout(r, s, dist)             /* check if we're outside spot region */
register RAY  *r;
register SPOT  *s;
int  dist;
{
        double  d;
        FVECT  vd;
        
        if (s == NULL)
                return(0);
        if (dist) {                     /* 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)));
}


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);
}


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);
}


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:	2.6
Committed:	Fri Aug 28 15:10:47 1992 UTC (31 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.5:	+0 -35 lines
Log Message:	moved sourcehit() from srcsupp.c back to source.c
#	User	Rev	Content
1	greg	2.2	/* Copyright (c) 1992 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* Support routines for source objects and materials
9			*/
10
11			#include "ray.h"
12
13			#include "otypes.h"
14
15			#include "source.h"
16
17			#include "cone.h"
18
19			#include "face.h"
20
21	greg	1.14	#define SRCINC 4 /* realloc increment for array */
22	greg	1.1
23			SRCREC source = NULL; / our list of sources */
24			int nsources = 0; /* the number of sources */
25
26			SRCFUNC sfun[NUMOTYPE]; /* source dispatch table */
27
28
29			initstypes() /* initialize source dispatch table */
30			{
31	greg	1.9	extern VSMATERIAL mirror_vs, direct1_vs, direct2_vs;
32	greg	1.14	extern int fsetsrc(), ssetsrc(), sphsetsrc(), cylsetsrc(), rsetsrc();
33			extern int nopart(), flatpart(), cylpart();
34	greg	1.1	extern double fgetplaneq(), rgetplaneq();
35			extern double fgetmaxdisk(), rgetmaxdisk();
36	greg	1.14	static SOBJECT fsobj = {fsetsrc, flatpart, fgetplaneq, fgetmaxdisk};
37			static SOBJECT ssobj = {ssetsrc, nopart};
38			static SOBJECT sphsobj = {sphsetsrc, nopart};
39			static SOBJECT cylsobj = {cylsetsrc, cylpart};
40			static SOBJECT rsobj = {rsetsrc, flatpart, rgetplaneq, rgetmaxdisk};
41	greg	1.1
42			sfun[MAT_MIRROR].mf = &mirror_vs;
43	greg	1.9	sfun[MAT_DIRECT1].mf = &direct1_vs;
44			sfun[MAT_DIRECT2].mf = &direct2_vs;
45	greg	1.1	sfun[OBJ_FACE].of = &fsobj;
46			sfun[OBJ_SOURCE].of = &ssobj;
47			sfun[OBJ_SPHERE].of = &sphsobj;
48	greg	1.14	sfun[OBJ_CYLINDER].of = &cylsobj;
49	greg	1.1	sfun[OBJ_RING].of = &rsobj;
50			}
51
52
53	greg	1.2	int
54	greg	1.1	newsource() /* allocate new source in our array */
55			{
56			if (nsources == 0)
57	greg	1.13	source = (SRCREC )malloc(SRCINCsizeof(SRCREC));
58			else if (nsources%SRCINC == 0)
59	greg	1.1	source = (SRCREC )realloc((char )source,
60	greg	1.13	(unsigned)(nsources+SRCINC)*sizeof(SRCREC));
61	greg	1.1	if (source == NULL)
62	greg	1.2	return(-1);
63	greg	1.1	source[nsources].sflags = 0;
64			source[nsources].nhits = 1;
65			source[nsources].ntests = 2; /* initial hit probability = 1/2 */
66	greg	1.2	return(nsources++);
67	greg	1.1	}
68
69
70	greg	1.14	setflatss(src) /* set sampling for a flat source */
71			register SRCREC *src;
72			{
73			double mult;
74			register int i;
75
76			src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
77			for (i = 0; i < 3; i++)
78			if (src->snorm[i] < 0.6 && src->snorm[i] > -0.6)
79			break;
80			src->ss[SV][i] = 1.0;
81			fcross(src->ss[SU], src->ss[SV], src->snorm);
82			mult = .5 * sqrt( src->ss2 / DOT(src->ss[SU],src->ss[SU]) );
83			for (i = 0; i < 3; i++)
84			src->ss[SU][i] *= mult;
85			fcross(src->ss[SV], src->snorm, src->ss[SU]);
86			}
87
88
89	greg	1.1	fsetsrc(src, so) /* set a face as a source */
90			register SRCREC *src;
91			OBJREC *so;
92			{
93			register FACE *f;
94			register int i, j;
95	greg	1.14	double d;
96	greg	1.1
97			src->sa.success = 2AIMREQT-1; / bitch on second failure */
98			src->so = so;
99			/* get the face */
100			f = getface(so);
101			/* find the center */
102			for (j = 0; j < 3; j++) {
103			src->sloc[j] = 0.0;
104			for (i = 0; i < f->nv; i++)
105			src->sloc[j] += VERTEX(f,i)[j];
106			src->sloc[j] /= (double)f->nv;
107			}
108			if (!inface(src->sloc, f))
109			objerror(so, USER, "cannot hit center");
110			src->sflags \|= SFLAT;
111			VCOPY(src->snorm, f->norm);
112			src->ss2 = f->area;
113	greg	1.14	/* find maximum radius */
114			src->srad = 0.;
115			for (i = 0; i < f->nv; i++) {
116			d = dist2(VERTEX(f,i), src->sloc);
117			if (d > src->srad)
118			src->srad = d;
119			}
120			src->srad = sqrt(src->srad);
121			/* compute size vectors */
122			if (f->nv == 4 \|\| (f->nv == 5 && /* parallelogram case */
123			dist2(VERTEX(f,0),VERTEX(f,4)) <= FTINY*FTINY))
124			for (j = 0; j < 3; j++) {
125			src->ss[SU][j] = .5*(VERTEX(f,1)[j]-VERTEX(f,0)[j]);
126			src->ss[SV][j] = .5*(VERTEX(f,3)[j]-VERTEX(f,0)[j]);
127			}
128			else
129			setflatss(src);
130	greg	1.1	}
131
132
133			ssetsrc(src, so) /* set a source as a source */
134			register SRCREC *src;
135			register OBJREC *so;
136			{
137			double theta;
138
139			src->sa.success = 2AIMREQT-1; / bitch on second failure */
140			src->so = so;
141			if (so->oargs.nfargs != 4)
142			objerror(so, USER, "bad arguments");
143			src->sflags \|= SDISTANT;
144			VCOPY(src->sloc, so->oargs.farg);
145			if (normalize(src->sloc) == 0.0)
146			objerror(so, USER, "zero direction");
147			theta = PI/180.0/2.0 * so->oargs.farg[3];
148			if (theta <= FTINY)
149			objerror(so, USER, "zero size");
150			src->ss2 = 2.0PI (1.0 - cos(theta));
151	greg	1.14	/* the following is approximate */
152			src->srad = sqrt(src->ss2/PI);
153			VCOPY(src->snorm, src->sloc);
154			setflatss(src); /* hey, whatever works */
155			src->ss[SW][0] = src->ss[SW][1] = src->ss[SW][2] = 0.0;
156	greg	1.1	}
157
158
159			sphsetsrc(src, so) /* set a sphere as a source */
160			register SRCREC *src;
161			register OBJREC *so;
162			{
163	greg	1.14	register int i;
164
165	greg	1.1	src->sa.success = 2AIMREQT-1; / bitch on second failure */
166			src->so = so;
167			if (so->oargs.nfargs != 4)
168			objerror(so, USER, "bad # arguments");
169			if (so->oargs.farg[3] <= FTINY)
170			objerror(so, USER, "illegal radius");
171			VCOPY(src->sloc, so->oargs.farg);
172	greg	1.14	src->srad = so->oargs.farg[3];
173			src->ss2 = PI * src->srad * src->srad;
174			for (i = 0; i < 3; i++)
175			src->ss[SU][i] = src->ss[SV][i] = src->ss[SW][i] = 0.0;
176			for (i = 0; i < 3; i++)
177	greg	1.15	src->ss[i][i] = .7236 * so->oargs.farg[3];
178	greg	1.1	}
179
180
181			rsetsrc(src, so) /* set a ring (disk) as a source */
182			register SRCREC *src;
183			OBJREC *so;
184			{
185			register CONE *co;
186
187			src->sa.success = 2AIMREQT-1; / bitch on second failure */
188			src->so = so;
189			/* get the ring */
190			co = getcone(so, 0);
191			VCOPY(src->sloc, CO_P0(co));
192			if (CO_R0(co) > 0.0)
193			objerror(so, USER, "cannot hit center");
194			src->sflags \|= SFLAT;
195			VCOPY(src->snorm, co->ad);
196	greg	1.14	src->srad = CO_R1(co);
197			src->ss2 = PI * src->srad * src->srad;
198			setflatss(src);
199			}
200
201
202			cylsetsrc(src, so) /* set a cylinder as a source */
203			register SRCREC *src;
204			OBJREC *so;
205			{
206			register CONE *co;
207			register int i;
208
209			src->sa.success = 4AIMREQT-1; / bitch on fourth failure */
210			src->so = so;
211			/* get the cylinder */
212			co = getcone(so, 0);
213			if (CO_R0(co) > .2co->al) / heuristic constraint */
214			objerror(so, WARNING, "source aspect too small");
215	greg	1.15	src->sflags \|= SCYL;
216	greg	1.14	for (i = 0; i < 3; i++)
217			src->sloc[i] = .5 * (CO_P1(co)[i] + CO_P0(co)[i]);
218	greg	1.15	src->srad = .5*co->al;
219	greg	1.14	src->ss2 = 2.CO_R0(co)co->al;
220			/* set sampling vectors */
221			for (i = 0; i < 3; i++)
222			src->ss[SU][i] = .5 * co->al * co->ad[i];
223			src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
224			for (i = 0; i < 3; i++)
225			if (co->ad[i] < 0.6 && co->ad[i] > -0.6)
226			break;
227			src->ss[SV][i] = 1.0;
228			fcross(src->ss[SW], src->ss[SV], co->ad);
229			normalize(src->ss[SW]);
230			for (i = 0; i < 3; i++)
231	greg	1.15	src->ss[SW][i] = .8559 CO_R0(co);
232	greg	1.14	fcross(src->ss[SV], src->ss[SW], co->ad);
233	greg	1.1	}
234
235
236			SPOT *
237			makespot(m) /* make a spotlight */
238			register OBJREC *m;
239			{
240			register SPOT *ns;
241
242	greg	2.5	if ((ns = (SPOT *)m->os) != NULL)
243			return(ns);
244	greg	1.1	if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL)
245			return(NULL);
246			ns->siz = 2.0PI (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3]));
247			VCOPY(ns->aim, m->oargs.farg+4);
248			if ((ns->flen = normalize(ns->aim)) == 0.0)
249			objerror(m, USER, "zero focus vector");
250	greg	2.5	m->os = (char *)ns;
251	greg	1.1	return(ns);
252			}
253
254
255	greg	2.5	spotout(r, s, dist) /* check if we're outside spot region */
256			register RAY *r;
257			register SPOT *s;
258			int dist;
259			{
260			double d;
261			FVECT vd;
262
263			if (s == NULL)
264			return(0);
265			if (dist) { /* distant source */
266			vd[0] = s->aim[0] - r->rorg[0];
267			vd[1] = s->aim[1] - r->rorg[1];
268			vd[2] = s->aim[2] - r->rorg[2];
269			d = DOT(r->rdir,vd);
270			/* wrong side?
271			if (d <= FTINY)
272			return(1); */
273			d = DOT(vd,vd) - d*d;
274			if (PI*d > s->siz)
275			return(1); /* out */
276			return(0); /* OK */
277			}
278			/* local source */
279			if (s->siz < 2.0PI (1.0 + DOT(s->aim,r->rdir)))
280			return(1); /* out */
281			return(0); /* OK */
282			}
283
284
285	greg	1.1	double
286			fgetmaxdisk(ocent, op) /* get center and squared radius of face */
287			FVECT ocent;
288			OBJREC *op;
289			{
290			double maxrad2;
291	greg	1.5	double d;
292	greg	1.1	register int i, j;
293			register FACE *f;
294
295			f = getface(op);
296	greg	1.5	if (f->area == 0.)
297			return(0.);
298	greg	1.1	for (i = 0; i < 3; i++) {
299			ocent[i] = 0.;
300			for (j = 0; j < f->nv; j++)
301			ocent[i] += VERTEX(f,j)[i];
302			ocent[i] /= (double)f->nv;
303			}
304	greg	1.5	d = DOT(ocent,f->norm);
305			for (i = 0; i < 3; i++)
306			ocent[i] += (f->offset - d)*f->norm[i];
307	greg	1.1	maxrad2 = 0.;
308			for (j = 0; j < f->nv; j++) {
309	greg	1.5	d = dist2(VERTEX(f,j), ocent);
310			if (d > maxrad2)
311			maxrad2 = d;
312	greg	1.1	}
313			return(maxrad2);
314			}
315
316
317			double
318			rgetmaxdisk(ocent, op) /* get center and squared radius of ring */
319			FVECT ocent;
320			OBJREC *op;
321			{
322			register CONE *co;
323
324			co = getcone(op, 0);
325			VCOPY(ocent, CO_P0(co));
326			return(CO_R1(co)*CO_R1(co));
327			}
328
329
330			double
331			fgetplaneq(nvec, op) /* get plane equation for face */
332			FVECT nvec;
333			OBJREC *op;
334			{
335			register FACE *fo;
336
337			fo = getface(op);
338			VCOPY(nvec, fo->norm);
339			return(fo->offset);
340			}
341
342
343			double
344			rgetplaneq(nvec, op) /* get plane equation for ring */
345			FVECT nvec;
346			OBJREC *op;
347			{
348			register CONE *co;
349
350			co = getcone(op, 0);
351			VCOPY(nvec, co->ad);
352			return(DOT(nvec, CO_P0(co)));
353	greg	1.4	}
354
355
356			commonspot(sp1, sp2, org) /* set sp1 to intersection of sp1 and sp2 */
357			register SPOT sp1, sp2;
358			FVECT org;
359			{
360			FVECT cent;
361			double rad2, cos1, cos2;
362
363			cos1 = 1. - sp1->siz/(2.*PI);
364			cos2 = 1. - sp2->siz/(2.*PI);
365			if (sp2->siz >= 2.PI-FTINY) / BIG, just check overlap */
366			return(DOT(sp1->aim,sp2->aim) >= cos1*cos2 -
367			sqrt((1.-cos1cos1)(1.-cos2*cos2)));
368			/* compute and check disks */
369			rad2 = intercircle(cent, sp1->aim, sp2->aim,
370			1./(cos1cos1) - 1., 1./(cos2cos2) - 1.);
371			if (rad2 <= FTINY \|\| normalize(cent) == 0.)
372			return(0);
373			VCOPY(sp1->aim, cent);
374			sp1->siz = 2.PI(1. - 1./sqrt(1.+rad2));
375			return(1);
376			}
377
378
379			commonbeam(sp1, sp2, dir) /* set sp1 to intersection of sp1 and sp2 */
380			register SPOT sp1, sp2;
381			FVECT dir;
382			{
383			FVECT cent, c1, c2;
384			double rad2, d;
385			register int i;
386			/* move centers to common plane */
387			d = DOT(sp1->aim, dir);
388			for (i = 0; i < 3; i++)
389			c1[i] = sp1->aim[i] - d*dir[i];
390			d = DOT(sp2->aim, dir);
391			for (i = 0; i < 3; i++)
392			c2[i] = sp2->aim[i] - d*dir[i];
393			/* compute overlap */
394			rad2 = intercircle(cent, c1, c2, sp1->siz/PI, sp2->siz/PI);
395			if (rad2 <= FTINY)
396			return(0);
397			VCOPY(sp1->aim, cent);
398			sp1->siz = PI*rad2;
399			return(1);
400			}
401
402
403			checkspot(sp, nrm) /* check spotlight for behind source */
404			register SPOT sp; / spotlight */
405			FVECT nrm; /* source surface normal */
406			{
407			double d, d1;
408
409			d = DOT(sp->aim, nrm);
410			if (d > FTINY) /* center in front? */
411	greg	1.8	return(1);
412	greg	1.4	/* else check horizon */
413			d1 = 1. - sp->siz/(2.*PI);
414	greg	1.8	return(1.-FTINY-dd < d1d1);
415	greg	1.4	}
416
417
418			double
419	greg	1.6	spotdisk(oc, op, sp, pos) /* intersect spot with object op */
420			FVECT oc;
421			OBJREC *op;
422			register SPOT *sp;
423			FVECT pos;
424			{
425			FVECT onorm;
426			double offs, d, dist;
427			register int i;
428
429			offs = getplaneq(onorm, op);
430			d = -DOT(onorm, sp->aim);
431			if (d >= -FTINY && d <= FTINY)
432			return(0.);
433			dist = (DOT(pos, onorm) - offs)/d;
434			if (dist < 0.)
435			return(0.);
436			for (i = 0; i < 3; i++)
437			oc[i] = pos[i] + dist*sp->aim[i];
438			return(sp->sizdistdist/PI/(d*d));
439			}
440
441
442			double
443			beamdisk(oc, op, sp, dir) /* intersect beam with object op */
444			FVECT oc;
445			OBJREC *op;
446			register SPOT *sp;
447			FVECT dir;
448			{
449			FVECT onorm;
450			double offs, d, dist;
451			register int i;
452
453			offs = getplaneq(onorm, op);
454			d = -DOT(onorm, dir);
455			if (d >= -FTINY && d <= FTINY)
456			return(0.);
457			dist = (DOT(sp->aim, onorm) - offs)/d;
458			for (i = 0; i < 3; i++)
459			oc[i] = sp->aim[i] + dist*dir[i];
460			return(sp->siz/PI/(d*d));
461			}
462
463
464			double
465	greg	1.4	intercircle(cc, c1, c2, r1s, r2s) /* intersect two circles */
466			FVECT cc; /* midpoint (return value) */
467			FVECT c1, c2; /* circle centers */
468			double r1s, r2s; /* radii squared */
469			{
470			double a2, d2, l;
471			FVECT disp;
472			register int i;
473
474			for (i = 0; i < 3; i++)
475			disp[i] = c2[i] - c1[i];
476			d2 = DOT(disp,disp);
477			/* circle within overlap? */
478			if (r1s < r2s) {
479			if (r2s >= r1s + d2) {
480			VCOPY(cc, c1);
481			return(r1s);
482			}
483			} else {
484			if (r1s >= r2s + d2) {
485			VCOPY(cc, c2);
486			return(r2s);
487			}
488			}
489			a2 = .25(2.(r1s+r2s) - d2 - (r2s-r1s)*(r2s-r1s)/d2);
490			/* no overlap? */
491			if (a2 <= 0.)
492			return(0.);
493			/* overlap, compute center */
494			l = sqrt((r1s - a2)/d2);
495			for (i = 0; i < 3; i++)
496			cc[i] = c1[i] + l*disp[i];
497			return(a2);
498	greg	1.1	}