src/rt/srcsupp.c

/* Copyright (c) 1995 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)                         /* 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);
}


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)                   /* 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)));
}


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:	2.8
Committed:	Tue Nov 7 12:40:30 1995 UTC (28 years, 5 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.7:	+2 -3 lines
Log Message:	changed spotlight struct so flen<0 for distant sources
#	User	Rev	Content
1	greg	2.7	/* Copyright (c) 1995 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	greg	2.7	if (f->nv == 4) /* parallelogram case */
123	greg	1.14	for (j = 0; j < 3; j++) {
124			src->ss[SU][j] = .5*(VERTEX(f,1)[j]-VERTEX(f,0)[j]);
125			src->ss[SV][j] = .5*(VERTEX(f,3)[j]-VERTEX(f,0)[j]);
126			}
127			else
128			setflatss(src);
129	greg	1.1	}
130
131
132			ssetsrc(src, so) /* set a source as a source */
133			register SRCREC *src;
134			register OBJREC *so;
135			{
136			double theta;
137
138			src->sa.success = 2AIMREQT-1; / bitch on second failure */
139			src->so = so;
140			if (so->oargs.nfargs != 4)
141			objerror(so, USER, "bad arguments");
142			src->sflags \|= SDISTANT;
143			VCOPY(src->sloc, so->oargs.farg);
144			if (normalize(src->sloc) == 0.0)
145			objerror(so, USER, "zero direction");
146			theta = PI/180.0/2.0 * so->oargs.farg[3];
147			if (theta <= FTINY)
148			objerror(so, USER, "zero size");
149			src->ss2 = 2.0PI (1.0 - cos(theta));
150	greg	1.14	/* the following is approximate */
151			src->srad = sqrt(src->ss2/PI);
152			VCOPY(src->snorm, src->sloc);
153			setflatss(src); /* hey, whatever works */
154			src->ss[SW][0] = src->ss[SW][1] = src->ss[SW][2] = 0.0;
155	greg	1.1	}
156
157
158			sphsetsrc(src, so) /* set a sphere as a source */
159			register SRCREC *src;
160			register OBJREC *so;
161			{
162	greg	1.14	register int i;
163
164	greg	1.1	src->sa.success = 2AIMREQT-1; / bitch on second failure */
165			src->so = so;
166			if (so->oargs.nfargs != 4)
167			objerror(so, USER, "bad # arguments");
168			if (so->oargs.farg[3] <= FTINY)
169			objerror(so, USER, "illegal radius");
170			VCOPY(src->sloc, so->oargs.farg);
171	greg	1.14	src->srad = so->oargs.farg[3];
172			src->ss2 = PI * src->srad * src->srad;
173			for (i = 0; i < 3; i++)
174			src->ss[SU][i] = src->ss[SV][i] = src->ss[SW][i] = 0.0;
175			for (i = 0; i < 3; i++)
176	greg	1.15	src->ss[i][i] = .7236 * so->oargs.farg[3];
177	greg	1.1	}
178
179
180			rsetsrc(src, so) /* set a ring (disk) as a source */
181			register SRCREC *src;
182			OBJREC *so;
183			{
184			register CONE *co;
185
186			src->sa.success = 2AIMREQT-1; / bitch on second failure */
187			src->so = so;
188			/* get the ring */
189			co = getcone(so, 0);
190			VCOPY(src->sloc, CO_P0(co));
191			if (CO_R0(co) > 0.0)
192			objerror(so, USER, "cannot hit center");
193			src->sflags \|= SFLAT;
194			VCOPY(src->snorm, co->ad);
195	greg	1.14	src->srad = CO_R1(co);
196			src->ss2 = PI * src->srad * src->srad;
197			setflatss(src);
198			}
199
200
201			cylsetsrc(src, so) /* set a cylinder as a source */
202			register SRCREC *src;
203			OBJREC *so;
204			{
205			register CONE *co;
206			register int i;
207
208			src->sa.success = 4AIMREQT-1; / bitch on fourth failure */
209			src->so = so;
210			/* get the cylinder */
211			co = getcone(so, 0);
212			if (CO_R0(co) > .2co->al) / heuristic constraint */
213			objerror(so, WARNING, "source aspect too small");
214	greg	1.15	src->sflags \|= SCYL;
215	greg	1.14	for (i = 0; i < 3; i++)
216			src->sloc[i] = .5 * (CO_P1(co)[i] + CO_P0(co)[i]);
217	greg	1.15	src->srad = .5*co->al;
218	greg	1.14	src->ss2 = 2.CO_R0(co)co->al;
219			/* set sampling vectors */
220			for (i = 0; i < 3; i++)
221			src->ss[SU][i] = .5 * co->al * co->ad[i];
222			src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
223			for (i = 0; i < 3; i++)
224			if (co->ad[i] < 0.6 && co->ad[i] > -0.6)
225			break;
226			src->ss[SV][i] = 1.0;
227			fcross(src->ss[SW], src->ss[SV], co->ad);
228			normalize(src->ss[SW]);
229			for (i = 0; i < 3; i++)
230	greg	1.15	src->ss[SW][i] = .8559 CO_R0(co);
231	greg	1.14	fcross(src->ss[SV], src->ss[SW], co->ad);
232	greg	1.1	}
233
234
235			SPOT *
236			makespot(m) /* make a spotlight */
237			register OBJREC *m;
238			{
239			register SPOT *ns;
240
241	greg	2.5	if ((ns = (SPOT *)m->os) != NULL)
242			return(ns);
243	greg	1.1	if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL)
244			return(NULL);
245			ns->siz = 2.0PI (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3]));
246			VCOPY(ns->aim, m->oargs.farg+4);
247			if ((ns->flen = normalize(ns->aim)) == 0.0)
248			objerror(m, USER, "zero focus vector");
249	greg	2.5	m->os = (char *)ns;
250	greg	1.1	return(ns);
251			}
252
253
254	greg	2.8	spotout(r, s) /* check if we're outside spot region */
255	greg	2.5	register RAY *r;
256			register SPOT *s;
257			{
258			double d;
259			FVECT vd;
260
261			if (s == NULL)
262			return(0);
263	greg	2.8	if (s->flen < -FTINY) { /* distant source */
264	greg	2.5	vd[0] = s->aim[0] - r->rorg[0];
265			vd[1] = s->aim[1] - r->rorg[1];
266			vd[2] = s->aim[2] - r->rorg[2];
267			d = DOT(r->rdir,vd);
268			/* wrong side?
269			if (d <= FTINY)
270			return(1); */
271			d = DOT(vd,vd) - d*d;
272			if (PI*d > s->siz)
273			return(1); /* out */
274			return(0); /* OK */
275			}
276			/* local source */
277			if (s->siz < 2.0PI (1.0 + DOT(s->aim,r->rdir)))
278			return(1); /* out */
279			return(0); /* OK */
280			}
281
282
283	greg	1.1	double
284			fgetmaxdisk(ocent, op) /* get center and squared radius of face */
285			FVECT ocent;
286			OBJREC *op;
287			{
288			double maxrad2;
289	greg	1.5	double d;
290	greg	1.1	register int i, j;
291			register FACE *f;
292
293			f = getface(op);
294	greg	1.5	if (f->area == 0.)
295			return(0.);
296	greg	1.1	for (i = 0; i < 3; i++) {
297			ocent[i] = 0.;
298			for (j = 0; j < f->nv; j++)
299			ocent[i] += VERTEX(f,j)[i];
300			ocent[i] /= (double)f->nv;
301			}
302	greg	1.5	d = DOT(ocent,f->norm);
303			for (i = 0; i < 3; i++)
304			ocent[i] += (f->offset - d)*f->norm[i];
305	greg	1.1	maxrad2 = 0.;
306			for (j = 0; j < f->nv; j++) {
307	greg	1.5	d = dist2(VERTEX(f,j), ocent);
308			if (d > maxrad2)
309			maxrad2 = d;
310	greg	1.1	}
311			return(maxrad2);
312			}
313
314
315			double
316			rgetmaxdisk(ocent, op) /* get center and squared radius of ring */
317			FVECT ocent;
318			OBJREC *op;
319			{
320			register CONE *co;
321
322			co = getcone(op, 0);
323			VCOPY(ocent, CO_P0(co));
324			return(CO_R1(co)*CO_R1(co));
325			}
326
327
328			double
329			fgetplaneq(nvec, op) /* get plane equation for face */
330			FVECT nvec;
331			OBJREC *op;
332			{
333			register FACE *fo;
334
335			fo = getface(op);
336			VCOPY(nvec, fo->norm);
337			return(fo->offset);
338			}
339
340
341			double
342			rgetplaneq(nvec, op) /* get plane equation for ring */
343			FVECT nvec;
344			OBJREC *op;
345			{
346			register CONE *co;
347
348			co = getcone(op, 0);
349			VCOPY(nvec, co->ad);
350			return(DOT(nvec, CO_P0(co)));
351	greg	1.4	}
352
353
354			commonspot(sp1, sp2, org) /* set sp1 to intersection of sp1 and sp2 */
355			register SPOT sp1, sp2;
356			FVECT org;
357			{
358			FVECT cent;
359			double rad2, cos1, cos2;
360
361			cos1 = 1. - sp1->siz/(2.*PI);
362			cos2 = 1. - sp2->siz/(2.*PI);
363			if (sp2->siz >= 2.PI-FTINY) / BIG, just check overlap */
364			return(DOT(sp1->aim,sp2->aim) >= cos1*cos2 -
365			sqrt((1.-cos1cos1)(1.-cos2*cos2)));
366			/* compute and check disks */
367			rad2 = intercircle(cent, sp1->aim, sp2->aim,
368			1./(cos1cos1) - 1., 1./(cos2cos2) - 1.);
369			if (rad2 <= FTINY \|\| normalize(cent) == 0.)
370			return(0);
371			VCOPY(sp1->aim, cent);
372			sp1->siz = 2.PI(1. - 1./sqrt(1.+rad2));
373			return(1);
374			}
375
376
377			commonbeam(sp1, sp2, dir) /* set sp1 to intersection of sp1 and sp2 */
378			register SPOT sp1, sp2;
379			FVECT dir;
380			{
381			FVECT cent, c1, c2;
382			double rad2, d;
383			register int i;
384			/* move centers to common plane */
385			d = DOT(sp1->aim, dir);
386			for (i = 0; i < 3; i++)
387			c1[i] = sp1->aim[i] - d*dir[i];
388			d = DOT(sp2->aim, dir);
389			for (i = 0; i < 3; i++)
390			c2[i] = sp2->aim[i] - d*dir[i];
391			/* compute overlap */
392			rad2 = intercircle(cent, c1, c2, sp1->siz/PI, sp2->siz/PI);
393			if (rad2 <= FTINY)
394			return(0);
395			VCOPY(sp1->aim, cent);
396			sp1->siz = PI*rad2;
397			return(1);
398			}
399
400
401			checkspot(sp, nrm) /* check spotlight for behind source */
402			register SPOT sp; / spotlight */
403			FVECT nrm; /* source surface normal */
404			{
405			double d, d1;
406
407			d = DOT(sp->aim, nrm);
408			if (d > FTINY) /* center in front? */
409	greg	1.8	return(1);
410	greg	1.4	/* else check horizon */
411			d1 = 1. - sp->siz/(2.*PI);
412	greg	1.8	return(1.-FTINY-dd < d1d1);
413	greg	1.4	}
414
415
416			double
417	greg	1.6	spotdisk(oc, op, sp, pos) /* intersect spot with object op */
418			FVECT oc;
419			OBJREC *op;
420			register SPOT *sp;
421			FVECT pos;
422			{
423			FVECT onorm;
424			double offs, d, dist;
425			register int i;
426
427			offs = getplaneq(onorm, op);
428			d = -DOT(onorm, sp->aim);
429			if (d >= -FTINY && d <= FTINY)
430			return(0.);
431			dist = (DOT(pos, onorm) - offs)/d;
432			if (dist < 0.)
433			return(0.);
434			for (i = 0; i < 3; i++)
435			oc[i] = pos[i] + dist*sp->aim[i];
436			return(sp->sizdistdist/PI/(d*d));
437			}
438
439
440			double
441			beamdisk(oc, op, sp, dir) /* intersect beam with object op */
442			FVECT oc;
443			OBJREC *op;
444			register SPOT *sp;
445			FVECT dir;
446			{
447			FVECT onorm;
448			double offs, d, dist;
449			register int i;
450
451			offs = getplaneq(onorm, op);
452			d = -DOT(onorm, dir);
453			if (d >= -FTINY && d <= FTINY)
454			return(0.);
455			dist = (DOT(sp->aim, onorm) - offs)/d;
456			for (i = 0; i < 3; i++)
457			oc[i] = sp->aim[i] + dist*dir[i];
458			return(sp->siz/PI/(d*d));
459			}
460
461
462			double
463	greg	1.4	intercircle(cc, c1, c2, r1s, r2s) /* intersect two circles */
464			FVECT cc; /* midpoint (return value) */
465			FVECT c1, c2; /* circle centers */
466			double r1s, r2s; /* radii squared */
467			{
468			double a2, d2, l;
469			FVECT disp;
470			register int i;
471
472			for (i = 0; i < 3; i++)
473			disp[i] = c2[i] - c1[i];
474			d2 = DOT(disp,disp);
475			/* circle within overlap? */
476			if (r1s < r2s) {
477			if (r2s >= r1s + d2) {
478			VCOPY(cc, c1);
479			return(r1s);
480			}
481			} else {
482			if (r1s >= r2s + d2) {
483			VCOPY(cc, c2);
484			return(r2s);
485			}
486			}
487			a2 = .25(2.(r1s+r2s) - d2 - (r2s-r1s)*(r2s-r1s)/d2);
488			/* no overlap? */
489			if (a2 <= 0.)
490			return(0.);
491			/* overlap, compute center */
492			l = sqrt((r1s - a2)/d2);
493			for (i = 0; i < 3; i++)
494			cc[i] = c1[i] + l*disp[i];
495			return(a2);
496	greg	1.1	}