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#ifndef lint
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static const char RCSid[] = "$Id: srcsupp.c,v 2.24 2022/08/04 22:43:46 greg Exp $";
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#endif
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/*
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* Support routines for source objects and materials
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*
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* External symbols declared in source.h
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*/
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#include "copyright.h"
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#include "ray.h"
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#include "otypes.h"
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#include "source.h"
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#include "cone.h"
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#include "face.h"
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#define SRCINC 32 /* realloc increment for array */
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SRCREC *source = NULL; /* our list of sources */
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int nsources = 0; /* the number of sources */
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SRCFUNC sfun[NUMOTYPE]; /* source dispatch table */
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void
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initstypes(void) /* initialize source dispatch table */
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{
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extern VSMATERIAL mirror_vs, direct1_vs, direct2_vs;
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static SOBJECT fsobj = {fsetsrc, flatpart, fgetplaneq, fgetmaxdisk};
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static SOBJECT ssobj = {ssetsrc, nopart};
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static SOBJECT sphsobj = {sphsetsrc, nopart};
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static SOBJECT cylsobj = {cylsetsrc, cylpart};
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static SOBJECT rsobj = {rsetsrc, flatpart, rgetplaneq, rgetmaxdisk};
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sfun[MAT_MIRROR].mf = &mirror_vs;
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sfun[MAT_DIRECT1].mf = &direct1_vs;
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sfun[MAT_DIRECT2].mf = &direct2_vs;
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sfun[OBJ_FACE].of = &fsobj;
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sfun[OBJ_SOURCE].of = &ssobj;
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sfun[OBJ_SPHERE].of = &sphsobj;
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sfun[OBJ_CYLINDER].of = &cylsobj;
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sfun[OBJ_RING].of = &rsobj;
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}
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int
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newsource(void) /* allocate new source in our array */
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{
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if (nsources == 0)
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source = (SRCREC *)malloc(SRCINC*sizeof(SRCREC));
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else if (nsources%SRCINC == 0)
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source = (SRCREC *)realloc((void *)source,
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(unsigned)(nsources+SRCINC)*sizeof(SRCREC));
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if (source == NULL)
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return(-1);
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source[nsources].sflags = 0;
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source[nsources].nhits = 1;
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source[nsources].ntests = 2; /* initial hit probability = 50% */
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#if SHADCACHE
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source[nsources].obscache = NULL;
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#endif
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return(nsources++);
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}
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void
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setflatss( /* set sampling for a flat source */
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SRCREC *src
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)
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{
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double mult;
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int i;
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getperpendicular(src->ss[SU], src->snorm, rand_samp);
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mult = .5 * sqrt( src->ss2 );
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for (i = 0; i < 3; i++)
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src->ss[SU][i] *= mult;
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fcross(src->ss[SV], src->snorm, src->ss[SU]);
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}
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void
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fsetsrc( /* set a face as a source */
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SRCREC *src,
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OBJREC *so
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)
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{
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FACE *f;
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int i, j;
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double d;
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src->sa.success = 2*AIMREQT-1; /* bitch on second failure */
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src->so = so;
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/* get the face */
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f = getface(so);
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if (f->area == 0.)
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objerror(so, USER, "zero source area");
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/* find the center */
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for (j = 0; j < 3; j++) {
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src->sloc[j] = 0.0;
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for (i = 0; i < f->nv; i++)
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src->sloc[j] += VERTEX(f,i)[j];
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src->sloc[j] /= (double)f->nv;
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}
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if (!inface(src->sloc, f))
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objerror(so, USER, "cannot hit source center");
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src->sflags |= SFLAT;
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VCOPY(src->snorm, f->norm);
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src->ss2 = f->area;
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/* find maximum radius */
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src->srad = 0.;
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for (i = 0; i < f->nv; i++) {
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d = dist2(VERTEX(f,i), src->sloc);
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if (d > src->srad)
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src->srad = d;
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}
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src->srad = sqrt(src->srad);
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/* compute size vectors */
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if (f->nv == 4) { /* parallelogram case */
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for (j = 0; j < 3; j++) {
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src->ss[SU][j] = .5*(VERTEX(f,1)[j]-VERTEX(f,0)[j]);
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src->ss[SV][j] = .5*(VERTEX(f,3)[j]-VERTEX(f,0)[j]);
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}
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} else if (f->nv == 3) { /* triangle case */
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int near0 = 2;
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double dmin = dist2line(src->sloc, VERTEX(f,2), VERTEX(f,0));
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for (i = 0; i < 2; i++) {
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double d2 = dist2line(src->sloc, VERTEX(f,i), VERTEX(f,i+1));
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if (d2 >= dmin)
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continue;
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near0 = i;
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dmin = d2; /* radius = min distance */
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}
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if (dmin < .08*f->area)
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objerror(so, WARNING, "triangular source with poor aspect");
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i = (near0 + 1) % 3;
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for (j = 0; j < 3; j++)
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src->ss[SU][j] = VERTEX(f,i)[j] - VERTEX(f,near0)[j];
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normalize(src->ss[SU]);
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dmin = sqrt(dmin);
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for (j = 0; j < 3; j++)
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src->ss[SU][j] *= dmin;
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fcross(src->ss[SV], f->norm, src->ss[SU]);
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} else
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setflatss(src); /* hope for convex! */
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}
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void
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ssetsrc( /* set a source as a source */
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SRCREC *src,
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OBJREC *so
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)
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{
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double theta;
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src->sa.success = 2*AIMREQT-1; /* bitch on second failure */
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src->so = so;
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if (so->oargs.nfargs != 4)
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objerror(so, USER, "bad arguments");
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src->sflags |= (SDISTANT|SCIR);
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VCOPY(src->sloc, so->oargs.farg);
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if (normalize(src->sloc) == 0.0)
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objerror(so, USER, "zero direction");
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theta = PI/180.0/2.0 * so->oargs.farg[3];
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if (theta <= FTINY)
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objerror(so, USER, "zero size");
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src->ss2 = 2.0*PI * (1.0 - cos(theta));
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/* the following is approximate */
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src->srad = sqrt(src->ss2/PI);
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VCOPY(src->snorm, src->sloc);
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setflatss(src); /* hey, whatever works */
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src->ss[SW][0] = src->ss[SW][1] = src->ss[SW][2] = 0.0;
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}
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void
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sphsetsrc( /* set a sphere as a source */
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SRCREC *src,
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OBJREC *so
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)
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{
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int i;
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src->sa.success = 2*AIMREQT-1; /* bitch on second failure */
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src->so = so;
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if (so->oargs.nfargs != 4)
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objerror(so, USER, "bad # arguments");
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if (so->oargs.farg[3] <= FTINY)
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objerror(so, USER, "illegal source radius");
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src->sflags |= SCIR;
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VCOPY(src->sloc, so->oargs.farg);
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src->srad = so->oargs.farg[3];
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src->ss2 = PI * src->srad * src->srad;
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memset(src->ss, 0, sizeof(src->ss));
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for (i = 0; i < 3; i++)
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src->ss[i][i] = 0.7236 * so->oargs.farg[3];
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}
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void
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rsetsrc( /* set a ring (disk) as a source */
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SRCREC *src,
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OBJREC *so
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)
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{
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CONE *co;
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src->sa.success = 2*AIMREQT-1; /* bitch on second failure */
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src->so = so;
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/* get the ring */
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co = getcone(so, 0);
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if (co == NULL)
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objerror(so, USER, "illegal source");
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if (CO_R1(co) <= FTINY)
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objerror(so, USER, "illegal source radius");
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VCOPY(src->sloc, CO_P0(co));
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if (CO_R0(co) > 0.0)
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objerror(so, USER, "cannot hit source center");
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src->sflags |= (SFLAT|SCIR);
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VCOPY(src->snorm, co->ad);
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src->srad = CO_R1(co);
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src->ss2 = PI * src->srad * src->srad;
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setflatss(src);
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}
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void
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cylsetsrc( /* set a cylinder as a source */
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SRCREC *src,
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OBJREC *so
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)
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{
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CONE *co;
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int i;
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src->sa.success = 4*AIMREQT-1; /* bitch on fourth failure */
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src->so = so;
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/* get the cylinder */
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co = getcone(so, 0);
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if (co == NULL)
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objerror(so, USER, "illegal source");
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if (CO_R0(co) <= FTINY)
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objerror(so, USER, "illegal source radius");
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if (CO_R0(co) > .2*co->al) /* heuristic constraint */
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objerror(so, WARNING, "source aspect too small");
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src->sflags |= SCYL;
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for (i = 0; i < 3; i++)
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src->sloc[i] = .5 * (CO_P1(co)[i] + CO_P0(co)[i]);
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src->srad = .5*co->al;
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src->ss2 = 2.*CO_R0(co)*co->al;
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/* set sampling vectors */
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for (i = 0; i < 3; i++)
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src->ss[SU][i] = .5 * co->al * co->ad[i];
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getperpendicular(src->ss[SW], co->ad, rand_samp);
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for (i = 0; i < 3; i++)
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src->ss[SW][i] *= .8559 * CO_R0(co);
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fcross(src->ss[SV], src->ss[SW], co->ad);
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}
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SPOT *
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makespot( /* make a spotlight */
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OBJREC *m
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)
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{
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SPOT *ns;
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if ((ns = (SPOT *)m->os) != NULL)
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return(ns);
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if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL)
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return(NULL);
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if (m->oargs.farg[3] <= FTINY)
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objerror(m, USER, "zero angle");
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ns->siz = 2.0*PI * (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3]));
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VCOPY(ns->aim, m->oargs.farg+4);
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if ((ns->flen = normalize(ns->aim)) == 0.0)
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objerror(m, USER, "zero focus vector");
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m->os = (char *)ns;
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return(ns);
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}
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int
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spotout( /* check if we're outside spot region */
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RAY *r,
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SPOT *s
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)
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{
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double d;
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FVECT vd;
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if (s == NULL)
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return(0);
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if (s->flen < -FTINY) { /* distant source */
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vd[0] = s->aim[0] - r->rorg[0];
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vd[1] = s->aim[1] - r->rorg[1];
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vd[2] = s->aim[2] - r->rorg[2];
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d = DOT(r->rdir,vd);
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/* wrong side?
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if (d <= FTINY)
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return(1); */
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d = DOT(vd,vd) - d*d;
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if (PI*d > s->siz)
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return(1); /* out */
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return(0); /* OK */
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}
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/* local source */
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if (s->siz < 2.0*PI * (1.0 + DOT(s->aim,r->rdir)))
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return(1); /* out */
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return(0); /* OK */
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}
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double
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fgetmaxdisk( /* get center and squared radius of face */
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FVECT ocent,
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OBJREC *op
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)
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{
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double maxrad2;
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double d;
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int i, j;
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FACE *f;
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f = getface(op);
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if (f->area == 0.)
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return(0.);
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for (i = 0; i < 3; i++) {
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ocent[i] = 0.;
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for (j = 0; j < f->nv; j++)
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ocent[i] += VERTEX(f,j)[i];
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ocent[i] /= (double)f->nv;
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}
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d = DOT(ocent,f->norm);
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for (i = 0; i < 3; i++)
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ocent[i] += (f->offset - d)*f->norm[i];
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maxrad2 = 0.;
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| 344 |
for (j = 0; j < f->nv; j++) {
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| 345 |
d = dist2(VERTEX(f,j), ocent);
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| 346 |
if (d > maxrad2)
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| 347 |
maxrad2 = d;
|
| 348 |
}
|
| 349 |
return(maxrad2);
|
| 350 |
}
|
| 351 |
|
| 352 |
|
| 353 |
double
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rgetmaxdisk( /* get center and squared radius of ring */
|
| 355 |
FVECT ocent,
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| 356 |
OBJREC *op
|
| 357 |
)
|
| 358 |
{
|
| 359 |
CONE *co;
|
| 360 |
|
| 361 |
co = getcone(op, 0);
|
| 362 |
if (co == NULL)
|
| 363 |
return(0.);
|
| 364 |
VCOPY(ocent, CO_P0(co));
|
| 365 |
return(CO_R1(co)*CO_R1(co));
|
| 366 |
}
|
| 367 |
|
| 368 |
|
| 369 |
double
|
| 370 |
fgetplaneq( /* get plane equation for face */
|
| 371 |
FVECT nvec,
|
| 372 |
OBJREC *op
|
| 373 |
)
|
| 374 |
{
|
| 375 |
FACE *fo;
|
| 376 |
|
| 377 |
fo = getface(op);
|
| 378 |
VCOPY(nvec, fo->norm);
|
| 379 |
return(fo->offset);
|
| 380 |
}
|
| 381 |
|
| 382 |
|
| 383 |
double
|
| 384 |
rgetplaneq( /* get plane equation for ring */
|
| 385 |
FVECT nvec,
|
| 386 |
OBJREC *op
|
| 387 |
)
|
| 388 |
{
|
| 389 |
CONE *co;
|
| 390 |
|
| 391 |
co = getcone(op, 0);
|
| 392 |
if (co == NULL) {
|
| 393 |
memset(nvec, 0, sizeof(FVECT));
|
| 394 |
return(0.);
|
| 395 |
}
|
| 396 |
VCOPY(nvec, co->ad);
|
| 397 |
return(DOT(nvec, CO_P0(co)));
|
| 398 |
}
|
| 399 |
|
| 400 |
|
| 401 |
int
|
| 402 |
commonspot( /* set sp1 to intersection of sp1 and sp2 */
|
| 403 |
SPOT *sp1,
|
| 404 |
SPOT *sp2,
|
| 405 |
FVECT org
|
| 406 |
)
|
| 407 |
{
|
| 408 |
FVECT cent;
|
| 409 |
double rad2, cos1, cos2;
|
| 410 |
|
| 411 |
cos1 = 1. - sp1->siz/(2.*PI);
|
| 412 |
cos2 = 1. - sp2->siz/(2.*PI);
|
| 413 |
if (sp2->siz >= 2.*PI-FTINY) /* BIG, just check overlap */
|
| 414 |
return(DOT(sp1->aim,sp2->aim) >= cos1*cos2 -
|
| 415 |
sqrt((1.-cos1*cos1)*(1.-cos2*cos2)));
|
| 416 |
/* compute and check disks */
|
| 417 |
rad2 = intercircle(cent, sp1->aim, sp2->aim,
|
| 418 |
1./(cos1*cos1) - 1., 1./(cos2*cos2) - 1.);
|
| 419 |
if (rad2 <= FTINY || normalize(cent) == 0.)
|
| 420 |
return(0);
|
| 421 |
VCOPY(sp1->aim, cent);
|
| 422 |
sp1->siz = 2.*PI*(1. - 1./sqrt(1.+rad2));
|
| 423 |
return(1);
|
| 424 |
}
|
| 425 |
|
| 426 |
|
| 427 |
int
|
| 428 |
commonbeam( /* set sp1 to intersection of sp1 and sp2 */
|
| 429 |
SPOT *sp1,
|
| 430 |
SPOT *sp2,
|
| 431 |
FVECT dir
|
| 432 |
)
|
| 433 |
{
|
| 434 |
FVECT cent, c1, c2;
|
| 435 |
double rad2, d;
|
| 436 |
/* move centers to common plane */
|
| 437 |
d = DOT(sp1->aim, dir);
|
| 438 |
VSUM(c1, sp1->aim, dir, -d);
|
| 439 |
d = DOT(sp2->aim, dir);
|
| 440 |
VSUM(c2, sp2->aim, dir, -d);
|
| 441 |
/* compute overlap */
|
| 442 |
rad2 = intercircle(cent, c1, c2, sp1->siz/PI, sp2->siz/PI);
|
| 443 |
if (rad2 <= FTINY)
|
| 444 |
return(0);
|
| 445 |
VCOPY(sp1->aim, cent);
|
| 446 |
sp1->siz = PI*rad2;
|
| 447 |
return(1);
|
| 448 |
}
|
| 449 |
|
| 450 |
|
| 451 |
int
|
| 452 |
checkspot( /* check spotlight for behind source */
|
| 453 |
SPOT *sp, /* spotlight */
|
| 454 |
FVECT nrm /* source surface normal */
|
| 455 |
)
|
| 456 |
{
|
| 457 |
double d, d1;
|
| 458 |
|
| 459 |
d = DOT(sp->aim, nrm);
|
| 460 |
if (d > FTINY) /* center in front? */
|
| 461 |
return(1);
|
| 462 |
/* else check horizon */
|
| 463 |
d1 = 1. - sp->siz/(2.*PI);
|
| 464 |
return(1.-FTINY-d*d < d1*d1);
|
| 465 |
}
|
| 466 |
|
| 467 |
|
| 468 |
double
|
| 469 |
spotdisk( /* intersect spot with object op */
|
| 470 |
FVECT oc,
|
| 471 |
OBJREC *op,
|
| 472 |
SPOT *sp,
|
| 473 |
FVECT pos
|
| 474 |
)
|
| 475 |
{
|
| 476 |
FVECT onorm;
|
| 477 |
double offs, d, dist;
|
| 478 |
|
| 479 |
offs = getplaneq(onorm, op);
|
| 480 |
d = -DOT(onorm, sp->aim);
|
| 481 |
if (d >= -FTINY && d <= FTINY)
|
| 482 |
return(0.);
|
| 483 |
dist = (DOT(pos, onorm) - offs)/d;
|
| 484 |
if (dist < 0.)
|
| 485 |
return(0.);
|
| 486 |
VSUM(oc, pos, sp->aim, dist);
|
| 487 |
return(sp->siz*dist*dist/PI/(d*d));
|
| 488 |
}
|
| 489 |
|
| 490 |
|
| 491 |
double
|
| 492 |
beamdisk( /* intersect beam with object op */
|
| 493 |
FVECT oc,
|
| 494 |
OBJREC *op,
|
| 495 |
SPOT *sp,
|
| 496 |
FVECT dir
|
| 497 |
)
|
| 498 |
{
|
| 499 |
FVECT onorm;
|
| 500 |
double offs, d, dist;
|
| 501 |
|
| 502 |
offs = getplaneq(onorm, op);
|
| 503 |
d = -DOT(onorm, dir);
|
| 504 |
if (d >= -FTINY && d <= FTINY)
|
| 505 |
return(0.);
|
| 506 |
dist = (DOT(sp->aim, onorm) - offs)/d;
|
| 507 |
VSUM(oc, sp->aim, dir, dist);
|
| 508 |
return(sp->siz/PI/(d*d));
|
| 509 |
}
|
| 510 |
|
| 511 |
|
| 512 |
double
|
| 513 |
intercircle( /* intersect two circles */
|
| 514 |
FVECT cc, /* midpoint (return value) */
|
| 515 |
FVECT c1, /* circle centers */
|
| 516 |
FVECT c2,
|
| 517 |
double r1s, /* radii squared */
|
| 518 |
double r2s
|
| 519 |
)
|
| 520 |
{
|
| 521 |
double a2, d2, l;
|
| 522 |
FVECT disp;
|
| 523 |
|
| 524 |
VSUB(disp, c2, c1);
|
| 525 |
d2 = DOT(disp,disp);
|
| 526 |
/* circle within overlap? */
|
| 527 |
if (r1s < r2s) {
|
| 528 |
if (r2s >= r1s + d2) {
|
| 529 |
VCOPY(cc, c1);
|
| 530 |
return(r1s);
|
| 531 |
}
|
| 532 |
} else {
|
| 533 |
if (r1s >= r2s + d2) {
|
| 534 |
VCOPY(cc, c2);
|
| 535 |
return(r2s);
|
| 536 |
}
|
| 537 |
}
|
| 538 |
a2 = .25*(2.*(r1s+r2s) - d2 - (r2s-r1s)*(r2s-r1s)/d2);
|
| 539 |
/* no overlap? */
|
| 540 |
if (a2 <= 0.)
|
| 541 |
return(0.);
|
| 542 |
/* overlap, compute center */
|
| 543 |
l = sqrt((r1s - a2)/d2);
|
| 544 |
VSUM(cc, c1, disp, l);
|
| 545 |
return(a2);
|
| 546 |
}
|
