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
 */

/* ====================================================================
 * The Radiance Software License, Version 1.0
 *
 * Copyright (c) 1990 - 2002 The Regents of the University of California,
 * through Lawrence Berkeley National Laboratory.   All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *           if any, must include the following acknowledgment:
 *             "This product includes Radiance software
 *                 (http://radsite.lbl.gov/)
 *                 developed by the Lawrence Berkeley National Laboratory
 *               (http://www.lbl.gov/)."
 *       Alternately, this acknowledgment may appear in the software itself,
 *       if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
 *       and "The Regents of the University of California" must
 *       not be used to endorse or promote products derived from this
 *       software without prior written permission. For written
 *       permission, please contact [email protected].
 *
 * 5. Products derived from this software may not be called "Radiance",
 *       nor may "Radiance" appear in their name, without prior written
 *       permission of Lawrence Berkeley National Laboratory.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.   IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Lawrence Berkeley National Laboratory.   For more
 * information on Lawrence Berkeley National Laboratory, please see
 * <http://www.lbl.gov/>.
 */

#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((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++);
}


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:	2.9
Committed:	Sat Feb 22 02:07:29 2003 UTC (21 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.8:	+71 -8 lines
Log Message:	Changes and check-in for 3.5 release Includes new source files and modifications not recorded for many years See ray/doc/notes/ReleaseNotes for notes between 3.1 and 3.5 release
#	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			/* ====================================================================
11			* The Radiance Software License, Version 1.0
12			*
13			* Copyright (c) 1990 - 2002 The Regents of the University of California,
14			* through Lawrence Berkeley National Laboratory. All rights reserved.
15			*
16			* Redistribution and use in source and binary forms, with or without
17			* modification, are permitted provided that the following conditions
18			* are met:
19			*
20			* 1. Redistributions of source code must retain the above copyright
21			* notice, this list of conditions and the following disclaimer.
22			*
23			* 2. Redistributions in binary form must reproduce the above copyright
24			* notice, this list of conditions and the following disclaimer in
25			* the documentation and/or other materials provided with the
26			* distribution.
27			*
28			* 3. The end-user documentation included with the redistribution,
29			* if any, must include the following acknowledgment:
30			* "This product includes Radiance software
31			* (http://radsite.lbl.gov/)
32			* developed by the Lawrence Berkeley National Laboratory
33			* (http://www.lbl.gov/)."
34			* Alternately, this acknowledgment may appear in the software itself,
35			* if and wherever such third-party acknowledgments normally appear.
36			*
37			* 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
38			* and "The Regents of the University of California" must
39			* not be used to endorse or promote products derived from this
40			* software without prior written permission. For written
41			* permission, please contact [email protected].
42			*
43			* 5. Products derived from this software may not be called "Radiance",
44			* nor may "Radiance" appear in their name, without prior written
45			* permission of Lawrence Berkeley National Laboratory.
46			*
47			* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
48			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
49			* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
50			* DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
51			* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
52			* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
53			* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
54			* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
55			* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
56			* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
57			* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58			* SUCH DAMAGE.
59			* ====================================================================
60			*
61			* This software consists of voluntary contributions made by many
62			* individuals on behalf of Lawrence Berkeley National Laboratory. For more
63			* information on Lawrence Berkeley National Laboratory, please see
64			* <http://www.lbl.gov/>.
65	greg	1.1	*/
66
67			#include "ray.h"
68
69			#include "otypes.h"
70
71			#include "source.h"
72
73			#include "cone.h"
74
75			#include "face.h"
76
77	greg	1.14	#define SRCINC 4 /* realloc increment for array */
78	greg	1.1
79			SRCREC source = NULL; / our list of sources */
80			int nsources = 0; /* the number of sources */
81
82			SRCFUNC sfun[NUMOTYPE]; /* source dispatch table */
83
84
85	greg	2.9	void
86	greg	1.1	initstypes() /* initialize source dispatch table */
87			{
88	greg	1.9	extern VSMATERIAL mirror_vs, direct1_vs, direct2_vs;
89	greg	1.14	static SOBJECT fsobj = {fsetsrc, flatpart, fgetplaneq, fgetmaxdisk};
90			static SOBJECT ssobj = {ssetsrc, nopart};
91			static SOBJECT sphsobj = {sphsetsrc, nopart};
92			static SOBJECT cylsobj = {cylsetsrc, cylpart};
93			static SOBJECT rsobj = {rsetsrc, flatpart, rgetplaneq, rgetmaxdisk};
94	greg	1.1
95			sfun[MAT_MIRROR].mf = &mirror_vs;
96	greg	1.9	sfun[MAT_DIRECT1].mf = &direct1_vs;
97			sfun[MAT_DIRECT2].mf = &direct2_vs;
98	greg	1.1	sfun[OBJ_FACE].of = &fsobj;
99			sfun[OBJ_SOURCE].of = &ssobj;
100			sfun[OBJ_SPHERE].of = &sphsobj;
101	greg	1.14	sfun[OBJ_CYLINDER].of = &cylsobj;
102	greg	1.1	sfun[OBJ_RING].of = &rsobj;
103			}
104
105
106	greg	1.2	int
107	greg	1.1	newsource() /* allocate new source in our array */
108			{
109			if (nsources == 0)
110	greg	1.13	source = (SRCREC )malloc(SRCINCsizeof(SRCREC));
111			else if (nsources%SRCINC == 0)
112	greg	1.1	source = (SRCREC )realloc((char )source,
113	greg	1.13	(unsigned)(nsources+SRCINC)*sizeof(SRCREC));
114	greg	1.1	if (source == NULL)
115	greg	1.2	return(-1);
116	greg	1.1	source[nsources].sflags = 0;
117			source[nsources].nhits = 1;
118			source[nsources].ntests = 2; /* initial hit probability = 1/2 */
119	greg	1.2	return(nsources++);
120	greg	1.1	}
121
122
123	greg	2.9	void
124	greg	1.14	setflatss(src) /* set sampling for a flat source */
125			register SRCREC *src;
126			{
127			double mult;
128			register int i;
129
130			src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
131			for (i = 0; i < 3; i++)
132			if (src->snorm[i] < 0.6 && src->snorm[i] > -0.6)
133			break;
134			src->ss[SV][i] = 1.0;
135			fcross(src->ss[SU], src->ss[SV], src->snorm);
136			mult = .5 * sqrt( src->ss2 / DOT(src->ss[SU],src->ss[SU]) );
137			for (i = 0; i < 3; i++)
138			src->ss[SU][i] *= mult;
139			fcross(src->ss[SV], src->snorm, src->ss[SU]);
140			}
141
142
143	greg	2.9	void
144	greg	1.1	fsetsrc(src, so) /* set a face as a source */
145			register SRCREC *src;
146			OBJREC *so;
147			{
148			register FACE *f;
149			register int i, j;
150	greg	1.14	double d;
151	greg	1.1
152			src->sa.success = 2AIMREQT-1; / bitch on second failure */
153			src->so = so;
154			/* get the face */
155			f = getface(so);
156			/* find the center */
157			for (j = 0; j < 3; j++) {
158			src->sloc[j] = 0.0;
159			for (i = 0; i < f->nv; i++)
160			src->sloc[j] += VERTEX(f,i)[j];
161			src->sloc[j] /= (double)f->nv;
162			}
163			if (!inface(src->sloc, f))
164			objerror(so, USER, "cannot hit center");
165			src->sflags \|= SFLAT;
166			VCOPY(src->snorm, f->norm);
167			src->ss2 = f->area;
168	greg	1.14	/* find maximum radius */
169			src->srad = 0.;
170			for (i = 0; i < f->nv; i++) {
171			d = dist2(VERTEX(f,i), src->sloc);
172			if (d > src->srad)
173			src->srad = d;
174			}
175			src->srad = sqrt(src->srad);
176			/* compute size vectors */
177	greg	2.7	if (f->nv == 4) /* parallelogram case */
178	greg	1.14	for (j = 0; j < 3; j++) {
179			src->ss[SU][j] = .5*(VERTEX(f,1)[j]-VERTEX(f,0)[j]);
180			src->ss[SV][j] = .5*(VERTEX(f,3)[j]-VERTEX(f,0)[j]);
181			}
182			else
183			setflatss(src);
184	greg	1.1	}
185
186
187	greg	2.9	void
188	greg	1.1	ssetsrc(src, so) /* set a source as a source */
189			register SRCREC *src;
190			register OBJREC *so;
191			{
192			double theta;
193
194			src->sa.success = 2AIMREQT-1; / bitch on second failure */
195			src->so = so;
196			if (so->oargs.nfargs != 4)
197			objerror(so, USER, "bad arguments");
198			src->sflags \|= SDISTANT;
199			VCOPY(src->sloc, so->oargs.farg);
200			if (normalize(src->sloc) == 0.0)
201			objerror(so, USER, "zero direction");
202			theta = PI/180.0/2.0 * so->oargs.farg[3];
203			if (theta <= FTINY)
204			objerror(so, USER, "zero size");
205			src->ss2 = 2.0PI (1.0 - cos(theta));
206	greg	1.14	/* the following is approximate */
207			src->srad = sqrt(src->ss2/PI);
208			VCOPY(src->snorm, src->sloc);
209			setflatss(src); /* hey, whatever works */
210			src->ss[SW][0] = src->ss[SW][1] = src->ss[SW][2] = 0.0;
211	greg	1.1	}
212
213
214	greg	2.9	void
215	greg	1.1	sphsetsrc(src, so) /* set a sphere as a source */
216			register SRCREC *src;
217			register OBJREC *so;
218			{
219	greg	1.14	register int i;
220
221	greg	1.1	src->sa.success = 2AIMREQT-1; / bitch on second failure */
222			src->so = so;
223			if (so->oargs.nfargs != 4)
224			objerror(so, USER, "bad # arguments");
225			if (so->oargs.farg[3] <= FTINY)
226			objerror(so, USER, "illegal radius");
227			VCOPY(src->sloc, so->oargs.farg);
228	greg	1.14	src->srad = so->oargs.farg[3];
229			src->ss2 = PI * src->srad * src->srad;
230			for (i = 0; i < 3; i++)
231			src->ss[SU][i] = src->ss[SV][i] = src->ss[SW][i] = 0.0;
232			for (i = 0; i < 3; i++)
233	greg	1.15	src->ss[i][i] = .7236 * so->oargs.farg[3];
234	greg	1.1	}
235
236
237	greg	2.9	void
238	greg	1.1	rsetsrc(src, so) /* set a ring (disk) as a source */
239			register SRCREC *src;
240			OBJREC *so;
241			{
242			register CONE *co;
243
244			src->sa.success = 2AIMREQT-1; / bitch on second failure */
245			src->so = so;
246			/* get the ring */
247			co = getcone(so, 0);
248			VCOPY(src->sloc, CO_P0(co));
249			if (CO_R0(co) > 0.0)
250			objerror(so, USER, "cannot hit center");
251			src->sflags \|= SFLAT;
252			VCOPY(src->snorm, co->ad);
253	greg	1.14	src->srad = CO_R1(co);
254			src->ss2 = PI * src->srad * src->srad;
255			setflatss(src);
256			}
257
258
259	greg	2.9	void
260	greg	1.14	cylsetsrc(src, so) /* set a cylinder as a source */
261			register SRCREC *src;
262			OBJREC *so;
263			{
264			register CONE *co;
265			register int i;
266
267			src->sa.success = 4AIMREQT-1; / bitch on fourth failure */
268			src->so = so;
269			/* get the cylinder */
270			co = getcone(so, 0);
271			if (CO_R0(co) > .2co->al) / heuristic constraint */
272			objerror(so, WARNING, "source aspect too small");
273	greg	1.15	src->sflags \|= SCYL;
274	greg	1.14	for (i = 0; i < 3; i++)
275			src->sloc[i] = .5 * (CO_P1(co)[i] + CO_P0(co)[i]);
276	greg	1.15	src->srad = .5*co->al;
277	greg	1.14	src->ss2 = 2.CO_R0(co)co->al;
278			/* set sampling vectors */
279			for (i = 0; i < 3; i++)
280			src->ss[SU][i] = .5 * co->al * co->ad[i];
281			src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0;
282			for (i = 0; i < 3; i++)
283			if (co->ad[i] < 0.6 && co->ad[i] > -0.6)
284			break;
285			src->ss[SV][i] = 1.0;
286			fcross(src->ss[SW], src->ss[SV], co->ad);
287			normalize(src->ss[SW]);
288			for (i = 0; i < 3; i++)
289	greg	1.15	src->ss[SW][i] = .8559 CO_R0(co);
290	greg	1.14	fcross(src->ss[SV], src->ss[SW], co->ad);
291	greg	1.1	}
292
293
294			SPOT *
295			makespot(m) /* make a spotlight */
296			register OBJREC *m;
297			{
298			register SPOT *ns;
299
300	greg	2.5	if ((ns = (SPOT *)m->os) != NULL)
301			return(ns);
302	greg	1.1	if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL)
303			return(NULL);
304			ns->siz = 2.0PI (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3]));
305			VCOPY(ns->aim, m->oargs.farg+4);
306			if ((ns->flen = normalize(ns->aim)) == 0.0)
307			objerror(m, USER, "zero focus vector");
308	greg	2.5	m->os = (char *)ns;
309	greg	1.1	return(ns);
310			}
311
312
313	greg	2.9	int
314	greg	2.8	spotout(r, s) /* check if we're outside spot region */
315	greg	2.5	register RAY *r;
316			register SPOT *s;
317			{
318			double d;
319			FVECT vd;
320
321			if (s == NULL)
322			return(0);
323	greg	2.8	if (s->flen < -FTINY) { /* distant source */
324	greg	2.5	vd[0] = s->aim[0] - r->rorg[0];
325			vd[1] = s->aim[1] - r->rorg[1];
326			vd[2] = s->aim[2] - r->rorg[2];
327			d = DOT(r->rdir,vd);
328			/* wrong side?
329			if (d <= FTINY)
330			return(1); */
331			d = DOT(vd,vd) - d*d;
332			if (PI*d > s->siz)
333			return(1); /* out */
334			return(0); /* OK */
335			}
336			/* local source */
337			if (s->siz < 2.0PI (1.0 + DOT(s->aim,r->rdir)))
338			return(1); /* out */
339			return(0); /* OK */
340			}
341
342
343	greg	1.1	double
344			fgetmaxdisk(ocent, op) /* get center and squared radius of face */
345			FVECT ocent;
346			OBJREC *op;
347			{
348			double maxrad2;
349	greg	1.5	double d;
350	greg	1.1	register int i, j;
351			register FACE *f;
352
353			f = getface(op);
354	greg	1.5	if (f->area == 0.)
355			return(0.);
356	greg	1.1	for (i = 0; i < 3; i++) {
357			ocent[i] = 0.;
358			for (j = 0; j < f->nv; j++)
359			ocent[i] += VERTEX(f,j)[i];
360			ocent[i] /= (double)f->nv;
361			}
362	greg	1.5	d = DOT(ocent,f->norm);
363			for (i = 0; i < 3; i++)
364			ocent[i] += (f->offset - d)*f->norm[i];
365	greg	1.1	maxrad2 = 0.;
366			for (j = 0; j < f->nv; j++) {
367	greg	1.5	d = dist2(VERTEX(f,j), ocent);
368			if (d > maxrad2)
369			maxrad2 = d;
370	greg	1.1	}
371			return(maxrad2);
372			}
373
374
375			double
376			rgetmaxdisk(ocent, op) /* get center and squared radius of ring */
377			FVECT ocent;
378			OBJREC *op;
379			{
380			register CONE *co;
381
382			co = getcone(op, 0);
383			VCOPY(ocent, CO_P0(co));
384			return(CO_R1(co)*CO_R1(co));
385			}
386
387
388			double
389			fgetplaneq(nvec, op) /* get plane equation for face */
390			FVECT nvec;
391			OBJREC *op;
392			{
393			register FACE *fo;
394
395			fo = getface(op);
396			VCOPY(nvec, fo->norm);
397			return(fo->offset);
398			}
399
400
401			double
402			rgetplaneq(nvec, op) /* get plane equation for ring */
403			FVECT nvec;
404			OBJREC *op;
405			{
406			register CONE *co;
407
408			co = getcone(op, 0);
409			VCOPY(nvec, co->ad);
410			return(DOT(nvec, CO_P0(co)));
411	greg	1.4	}
412
413
414	greg	2.9	int
415	greg	1.4	commonspot(sp1, sp2, org) /* set sp1 to intersection of sp1 and sp2 */
416			register SPOT sp1, sp2;
417			FVECT org;
418			{
419			FVECT cent;
420			double rad2, cos1, cos2;
421
422			cos1 = 1. - sp1->siz/(2.*PI);
423			cos2 = 1. - sp2->siz/(2.*PI);
424			if (sp2->siz >= 2.PI-FTINY) / BIG, just check overlap */
425			return(DOT(sp1->aim,sp2->aim) >= cos1*cos2 -
426			sqrt((1.-cos1cos1)(1.-cos2*cos2)));
427			/* compute and check disks */
428			rad2 = intercircle(cent, sp1->aim, sp2->aim,
429			1./(cos1cos1) - 1., 1./(cos2cos2) - 1.);
430			if (rad2 <= FTINY \|\| normalize(cent) == 0.)
431			return(0);
432			VCOPY(sp1->aim, cent);
433			sp1->siz = 2.PI(1. - 1./sqrt(1.+rad2));
434			return(1);
435			}
436
437
438	greg	2.9	int
439	greg	1.4	commonbeam(sp1, sp2, dir) /* set sp1 to intersection of sp1 and sp2 */
440			register SPOT sp1, sp2;
441			FVECT dir;
442			{
443			FVECT cent, c1, c2;
444			double rad2, d;
445			register int i;
446			/* move centers to common plane */
447			d = DOT(sp1->aim, dir);
448			for (i = 0; i < 3; i++)
449			c1[i] = sp1->aim[i] - d*dir[i];
450			d = DOT(sp2->aim, dir);
451			for (i = 0; i < 3; i++)
452			c2[i] = sp2->aim[i] - d*dir[i];
453			/* compute overlap */
454			rad2 = intercircle(cent, c1, c2, sp1->siz/PI, sp2->siz/PI);
455			if (rad2 <= FTINY)
456			return(0);
457			VCOPY(sp1->aim, cent);
458			sp1->siz = PI*rad2;
459			return(1);
460			}
461
462
463	greg	2.9	int
464	greg	1.4	checkspot(sp, nrm) /* check spotlight for behind source */
465			register SPOT sp; / spotlight */
466			FVECT nrm; /* source surface normal */
467			{
468			double d, d1;
469
470			d = DOT(sp->aim, nrm);
471			if (d > FTINY) /* center in front? */
472	greg	1.8	return(1);
473	greg	1.4	/* else check horizon */
474			d1 = 1. - sp->siz/(2.*PI);
475	greg	1.8	return(1.-FTINY-dd < d1d1);
476	greg	1.4	}
477
478
479			double
480	greg	1.6	spotdisk(oc, op, sp, pos) /* intersect spot with object op */
481			FVECT oc;
482			OBJREC *op;
483			register SPOT *sp;
484			FVECT pos;
485			{
486			FVECT onorm;
487			double offs, d, dist;
488			register int i;
489
490			offs = getplaneq(onorm, op);
491			d = -DOT(onorm, sp->aim);
492			if (d >= -FTINY && d <= FTINY)
493			return(0.);
494			dist = (DOT(pos, onorm) - offs)/d;
495			if (dist < 0.)
496			return(0.);
497			for (i = 0; i < 3; i++)
498			oc[i] = pos[i] + dist*sp->aim[i];
499			return(sp->sizdistdist/PI/(d*d));
500			}
501
502
503			double
504			beamdisk(oc, op, sp, dir) /* intersect beam with object op */
505			FVECT oc;
506			OBJREC *op;
507			register SPOT *sp;
508			FVECT dir;
509			{
510			FVECT onorm;
511			double offs, d, dist;
512			register int i;
513
514			offs = getplaneq(onorm, op);
515			d = -DOT(onorm, dir);
516			if (d >= -FTINY && d <= FTINY)
517			return(0.);
518			dist = (DOT(sp->aim, onorm) - offs)/d;
519			for (i = 0; i < 3; i++)
520			oc[i] = sp->aim[i] + dist*dir[i];
521			return(sp->siz/PI/(d*d));
522			}
523
524
525			double
526	greg	1.4	intercircle(cc, c1, c2, r1s, r2s) /* intersect two circles */
527			FVECT cc; /* midpoint (return value) */
528			FVECT c1, c2; /* circle centers */
529			double r1s, r2s; /* radii squared */
530			{
531			double a2, d2, l;
532			FVECT disp;
533			register int i;
534
535			for (i = 0; i < 3; i++)
536			disp[i] = c2[i] - c1[i];
537			d2 = DOT(disp,disp);
538			/* circle within overlap? */
539			if (r1s < r2s) {
540			if (r2s >= r1s + d2) {
541			VCOPY(cc, c1);
542			return(r1s);
543			}
544			} else {
545			if (r1s >= r2s + d2) {
546			VCOPY(cc, c2);
547			return(r2s);
548			}
549			}
550			a2 = .25(2.(r1s+r2s) - d2 - (r2s-r1s)*(r2s-r1s)/d2);
551			/* no overlap? */
552			if (a2 <= 0.)
553			return(0.);
554			/* overlap, compute center */
555			l = sqrt((r1s - a2)/d2);
556			for (i = 0; i < 3; i++)
557			cc[i] = c1[i] + l*disp[i];
558			return(a2);
559	greg	1.1	}