src/rt/srcsupp.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#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          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 */


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 = 1/2 */
        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);
                                                /* 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);
}


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 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);
        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);
}


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) > .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);
}


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:	2.11
Committed:	Wed Apr 23 00:52:34 2003 UTC (21 years ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.10:	+1 -1 lines
Log Message:	Added (void *) cast to realloc calls
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.9	static const char RCSid[] = "$Id$";
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	1.14	#define SRCINC 4 /* 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			source[nsources].nhits = 1;
63			source[nsources].ntests = 2; /* initial hit probability = 1/2 */
64	greg	1.2	return(nsources++);
65	greg	1.1	}
66
67
68	greg	2.9	void
69	greg	1.14	setflatss(src) /* set sampling for a flat source */
70			register SRCREC *src;
71			{
72			double mult;
73			register int i;
74
75			src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
76			for (i = 0; i < 3; i++)
77			if (src->snorm[i] < 0.6 && src->snorm[i] > -0.6)
78			break;
79			src->ss[SV][i] = 1.0;
80			fcross(src->ss[SU], src->ss[SV], src->snorm);
81			mult = .5 * sqrt( src->ss2 / DOT(src->ss[SU],src->ss[SU]) );
82			for (i = 0; i < 3; i++)
83			src->ss[SU][i] *= mult;
84			fcross(src->ss[SV], src->snorm, src->ss[SU]);
85			}
86
87
88	greg	2.9	void
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	greg	2.9	void
133	greg	1.1	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	greg	2.9	void
160	greg	1.1	sphsetsrc(src, so) /* set a sphere as a source */
161			register SRCREC *src;
162			register OBJREC *so;
163			{
164	greg	1.14	register int i;
165
166	greg	1.1	src->sa.success = 2AIMREQT-1; / bitch on second failure */
167			src->so = so;
168			if (so->oargs.nfargs != 4)
169			objerror(so, USER, "bad # arguments");
170			if (so->oargs.farg[3] <= FTINY)
171			objerror(so, USER, "illegal radius");
172			VCOPY(src->sloc, so->oargs.farg);
173	greg	1.14	src->srad = so->oargs.farg[3];
174			src->ss2 = PI * src->srad * src->srad;
175			for (i = 0; i < 3; i++)
176			src->ss[SU][i] = src->ss[SV][i] = src->ss[SW][i] = 0.0;
177			for (i = 0; i < 3; i++)
178	greg	1.15	src->ss[i][i] = .7236 * so->oargs.farg[3];
179	greg	1.1	}
180
181
182	greg	2.9	void
183	greg	1.1	rsetsrc(src, so) /* set a ring (disk) as a source */
184			register SRCREC *src;
185			OBJREC *so;
186			{
187			register CONE *co;
188
189			src->sa.success = 2AIMREQT-1; / bitch on second failure */
190			src->so = so;
191			/* get the ring */
192			co = getcone(so, 0);
193			VCOPY(src->sloc, CO_P0(co));
194			if (CO_R0(co) > 0.0)
195			objerror(so, USER, "cannot hit center");
196			src->sflags \|= SFLAT;
197			VCOPY(src->snorm, co->ad);
198	greg	1.14	src->srad = CO_R1(co);
199			src->ss2 = PI * src->srad * src->srad;
200			setflatss(src);
201			}
202
203
204	greg	2.9	void
205	greg	1.14	cylsetsrc(src, so) /* set a cylinder as a source */
206			register SRCREC *src;
207			OBJREC *so;
208			{
209			register CONE *co;
210			register int i;
211
212			src->sa.success = 4AIMREQT-1; / bitch on fourth failure */
213			src->so = so;
214			/* get the cylinder */
215			co = getcone(so, 0);
216			if (CO_R0(co) > .2co->al) / heuristic constraint */
217			objerror(so, WARNING, "source aspect too small");
218	greg	1.15	src->sflags \|= SCYL;
219	greg	1.14	for (i = 0; i < 3; i++)
220			src->sloc[i] = .5 * (CO_P1(co)[i] + CO_P0(co)[i]);
221	greg	1.15	src->srad = .5*co->al;
222	greg	1.14	src->ss2 = 2.CO_R0(co)co->al;
223			/* set sampling vectors */
224			for (i = 0; i < 3; i++)
225			src->ss[SU][i] = .5 * co->al * co->ad[i];
226			src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
227			for (i = 0; i < 3; i++)
228			if (co->ad[i] < 0.6 && co->ad[i] > -0.6)
229			break;
230			src->ss[SV][i] = 1.0;
231			fcross(src->ss[SW], src->ss[SV], co->ad);
232			normalize(src->ss[SW]);
233			for (i = 0; i < 3; i++)
234	greg	1.15	src->ss[SW][i] = .8559 CO_R0(co);
235	greg	1.14	fcross(src->ss[SV], src->ss[SW], co->ad);
236	greg	1.1	}
237
238
239			SPOT *
240			makespot(m) /* make a spotlight */
241			register OBJREC *m;
242			{
243			register SPOT *ns;
244
245	greg	2.5	if ((ns = (SPOT *)m->os) != NULL)
246			return(ns);
247	greg	1.1	if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL)
248			return(NULL);
249			ns->siz = 2.0PI (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3]));
250			VCOPY(ns->aim, m->oargs.farg+4);
251			if ((ns->flen = normalize(ns->aim)) == 0.0)
252			objerror(m, USER, "zero focus vector");
253	greg	2.5	m->os = (char *)ns;
254	greg	1.1	return(ns);
255			}
256
257
258	greg	2.9	int
259	greg	2.8	spotout(r, s) /* check if we're outside spot region */
260	greg	2.5	register RAY *r;
261			register SPOT *s;
262			{
263			double d;
264			FVECT vd;
265
266			if (s == NULL)
267			return(0);
268	greg	2.8	if (s->flen < -FTINY) { /* distant source */
269	greg	2.5	vd[0] = s->aim[0] - r->rorg[0];
270			vd[1] = s->aim[1] - r->rorg[1];
271			vd[2] = s->aim[2] - r->rorg[2];
272			d = DOT(r->rdir,vd);
273			/* wrong side?
274			if (d <= FTINY)
275			return(1); */
276			d = DOT(vd,vd) - d*d;
277			if (PI*d > s->siz)
278			return(1); /* out */
279			return(0); /* OK */
280			}
281			/* local source */
282			if (s->siz < 2.0PI (1.0 + DOT(s->aim,r->rdir)))
283			return(1); /* out */
284			return(0); /* OK */
285			}
286
287
288	greg	1.1	double
289			fgetmaxdisk(ocent, op) /* get center and squared radius of face */
290			FVECT ocent;
291			OBJREC *op;
292			{
293			double maxrad2;
294	greg	1.5	double d;
295	greg	1.1	register int i, j;
296			register FACE *f;
297
298			f = getface(op);
299	greg	1.5	if (f->area == 0.)
300			return(0.);
301	greg	1.1	for (i = 0; i < 3; i++) {
302			ocent[i] = 0.;
303			for (j = 0; j < f->nv; j++)
304			ocent[i] += VERTEX(f,j)[i];
305			ocent[i] /= (double)f->nv;
306			}
307	greg	1.5	d = DOT(ocent,f->norm);
308			for (i = 0; i < 3; i++)
309			ocent[i] += (f->offset - d)*f->norm[i];
310	greg	1.1	maxrad2 = 0.;
311			for (j = 0; j < f->nv; j++) {
312	greg	1.5	d = dist2(VERTEX(f,j), ocent);
313			if (d > maxrad2)
314			maxrad2 = d;
315	greg	1.1	}
316			return(maxrad2);
317			}
318
319
320			double
321			rgetmaxdisk(ocent, op) /* get center and squared radius of ring */
322			FVECT ocent;
323			OBJREC *op;
324			{
325			register CONE *co;
326
327			co = getcone(op, 0);
328			VCOPY(ocent, CO_P0(co));
329			return(CO_R1(co)*CO_R1(co));
330			}
331
332
333			double
334			fgetplaneq(nvec, op) /* get plane equation for face */
335			FVECT nvec;
336			OBJREC *op;
337			{
338			register FACE *fo;
339
340			fo = getface(op);
341			VCOPY(nvec, fo->norm);
342			return(fo->offset);
343			}
344
345
346			double
347			rgetplaneq(nvec, op) /* get plane equation for ring */
348			FVECT nvec;
349			OBJREC *op;
350			{
351			register CONE *co;
352
353			co = getcone(op, 0);
354			VCOPY(nvec, co->ad);
355			return(DOT(nvec, CO_P0(co)));
356	greg	1.4	}
357
358
359	greg	2.9	int
360	greg	1.4	commonspot(sp1, sp2, org) /* set sp1 to intersection of sp1 and sp2 */
361			register SPOT sp1, sp2;
362			FVECT org;
363			{
364			FVECT cent;
365			double rad2, cos1, cos2;
366
367			cos1 = 1. - sp1->siz/(2.*PI);
368			cos2 = 1. - sp2->siz/(2.*PI);
369			if (sp2->siz >= 2.PI-FTINY) / BIG, just check overlap */
370			return(DOT(sp1->aim,sp2->aim) >= cos1*cos2 -
371			sqrt((1.-cos1cos1)(1.-cos2*cos2)));
372			/* compute and check disks */
373			rad2 = intercircle(cent, sp1->aim, sp2->aim,
374			1./(cos1cos1) - 1., 1./(cos2cos2) - 1.);
375			if (rad2 <= FTINY \|\| normalize(cent) == 0.)
376			return(0);
377			VCOPY(sp1->aim, cent);
378			sp1->siz = 2.PI(1. - 1./sqrt(1.+rad2));
379			return(1);
380			}
381
382
383	greg	2.9	int
384	greg	1.4	commonbeam(sp1, sp2, dir) /* set sp1 to intersection of sp1 and sp2 */
385			register SPOT sp1, sp2;
386			FVECT dir;
387			{
388			FVECT cent, c1, c2;
389			double rad2, d;
390			register int i;
391			/* move centers to common plane */
392			d = DOT(sp1->aim, dir);
393			for (i = 0; i < 3; i++)
394			c1[i] = sp1->aim[i] - d*dir[i];
395			d = DOT(sp2->aim, dir);
396			for (i = 0; i < 3; i++)
397			c2[i] = sp2->aim[i] - d*dir[i];
398			/* compute overlap */
399			rad2 = intercircle(cent, c1, c2, sp1->siz/PI, sp2->siz/PI);
400			if (rad2 <= FTINY)
401			return(0);
402			VCOPY(sp1->aim, cent);
403			sp1->siz = PI*rad2;
404			return(1);
405			}
406
407
408	greg	2.9	int
409	greg	1.4	checkspot(sp, nrm) /* check spotlight for behind source */
410			register SPOT sp; / spotlight */
411			FVECT nrm; /* source surface normal */
412			{
413			double d, d1;
414
415			d = DOT(sp->aim, nrm);
416			if (d > FTINY) /* center in front? */
417	greg	1.8	return(1);
418	greg	1.4	/* else check horizon */
419			d1 = 1. - sp->siz/(2.*PI);
420	greg	1.8	return(1.-FTINY-dd < d1d1);
421	greg	1.4	}
422
423
424			double
425	greg	1.6	spotdisk(oc, op, sp, pos) /* intersect spot with object op */
426			FVECT oc;
427			OBJREC *op;
428			register SPOT *sp;
429			FVECT pos;
430			{
431			FVECT onorm;
432			double offs, d, dist;
433			register int i;
434
435			offs = getplaneq(onorm, op);
436			d = -DOT(onorm, sp->aim);
437			if (d >= -FTINY && d <= FTINY)
438			return(0.);
439			dist = (DOT(pos, onorm) - offs)/d;
440			if (dist < 0.)
441			return(0.);
442			for (i = 0; i < 3; i++)
443			oc[i] = pos[i] + dist*sp->aim[i];
444			return(sp->sizdistdist/PI/(d*d));
445			}
446
447
448			double
449			beamdisk(oc, op, sp, dir) /* intersect beam with object op */
450			FVECT oc;
451			OBJREC *op;
452			register SPOT *sp;
453			FVECT dir;
454			{
455			FVECT onorm;
456			double offs, d, dist;
457			register int i;
458
459			offs = getplaneq(onorm, op);
460			d = -DOT(onorm, dir);
461			if (d >= -FTINY && d <= FTINY)
462			return(0.);
463			dist = (DOT(sp->aim, onorm) - offs)/d;
464			for (i = 0; i < 3; i++)
465			oc[i] = sp->aim[i] + dist*dir[i];
466			return(sp->siz/PI/(d*d));
467			}
468
469
470			double
471	greg	1.4	intercircle(cc, c1, c2, r1s, r2s) /* intersect two circles */
472			FVECT cc; /* midpoint (return value) */
473			FVECT c1, c2; /* circle centers */
474			double r1s, r2s; /* radii squared */
475			{
476			double a2, d2, l;
477			FVECT disp;
478			register int i;
479
480			for (i = 0; i < 3; i++)
481			disp[i] = c2[i] - c1[i];
482			d2 = DOT(disp,disp);
483			/* circle within overlap? */
484			if (r1s < r2s) {
485			if (r2s >= r1s + d2) {
486			VCOPY(cc, c1);
487			return(r1s);
488			}
489			} else {
490			if (r1s >= r2s + d2) {
491			VCOPY(cc, c2);
492			return(r2s);
493			}
494			}
495			a2 = .25(2.(r1s+r2s) - d2 - (r2s-r1s)*(r2s-r1s)/d2);
496			/* no overlap? */
497			if (a2 <= 0.)
498			return(0.);
499			/* overlap, compute center */
500			l = sqrt((r1s - a2)/d2);
501			for (i = 0; i < 3; i++)
502			cc[i] = c1[i] + l*disp[i];
503			return(a2);
504	greg	1.1	}