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/* Copyright (c) 1995 Regents of the University of California */ |
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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static const char RCSid[] = "$Id$"; |
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#endif |
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/* |
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* normal.c - shading function for normal materials. |
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* |
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* Later changes described in delta comments. |
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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 "random.h" |
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extern double specthresh; /* specular sampling threshold */ |
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extern double specjitter; /* specular sampling jitter */ |
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#ifndef MAXITER |
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#define MAXITER 10 /* maximum # specular ray attempts */ |
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#endif |
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/* estimate of Fresnel function */ |
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#define FRESNE(ci) (exp(-6.0*(ci)) - 0.00247875217) |
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extern int backvis; /* back faces visible? */ |
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static void gaussamp(); |
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static gaussamp(); |
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/* |
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* This routine implements the isotropic Gaussian |
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* model described by Ward in Siggraph `92 article. |
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} NORMDAT; /* normal material data */ |
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static void |
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dirnorm(cval, np, ldir, omega) /* compute source contribution */ |
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COLOR cval; /* returned coefficient */ |
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register NORMDAT *np; /* material data */ |
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double omega; /* light source size */ |
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{ |
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double ldot; |
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double ldiff; |
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double dtmp, d2; |
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FVECT vtmp; |
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COLOR ctmp; |
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if (ldot < 0.0 ? np->trans <= FTINY : np->trans >= 1.0-FTINY) |
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return; /* wrong side */ |
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if (ldot > FTINY && np->rdiff > FTINY) { |
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/* Fresnel estimate */ |
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ldiff = np->rdiff; |
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if (np->specfl & SP_PURE && (np->rspec > FTINY & ldiff > FTINY)) |
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ldiff *= 1. - FRESNE(fabs(ldot)); |
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|
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if (ldot > FTINY && ldiff > FTINY) { |
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/* |
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* Compute and add diffuse reflected component to returned |
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* color. The diffuse reflected component will always be |
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* modified by the color of the material. |
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*/ |
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copycolor(ctmp, np->mcolor); |
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dtmp = ldot * omega * np->rdiff / PI; |
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dtmp = ldot * omega * ldiff / PI; |
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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
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} |
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int |
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m_normal(m, r) /* color a ray that hit something normal */ |
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register OBJREC *m; |
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register RAY *r; |
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{ |
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NORMDAT nd; |
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double fest; |
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double transtest, transdist; |
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double mirtest, mirdist; |
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int hastexture; |
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mirtest = transtest = 0; |
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mirdist = transdist = r->rot; |
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nd.rspec = m->oargs.farg[3]; |
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/* compute Fresnel approx. */ |
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if (nd.specfl & SP_PURE && nd.rspec > FTINY) { |
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fest = FRESNE(r->rod); |
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nd.rspec += fest*(1. - nd.rspec); |
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} else |
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fest = 0.; |
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/* compute transmission */ |
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if (m->otype == MAT_TRANS) { |
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nd.trans = m->oargs.farg[5]*(1.0 - nd.rspec); |
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} else |
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nd.tdiff = nd.tspec = nd.trans = 0.0; |
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/* transmitted ray */ |
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if ((nd.specfl&(SP_TRAN|SP_PURE)) == (SP_TRAN|SP_PURE)) { |
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if ((nd.specfl&(SP_TRAN|SP_PURE|SP_TBLT)) == (SP_TRAN|SP_PURE)) { |
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RAY lr; |
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if (rayorigin(&lr, r, TRANS, nd.tspec) == 0) { |
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VCOPY(lr.rdir, nd.prdir); |
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if (nd.rspec > FTINY) { |
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nd.specfl |= SP_REFL; |
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/* compute specular color */ |
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if (m->otype == MAT_METAL) |
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if (m->otype != MAT_METAL) { |
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setcolor(nd.scolor, nd.rspec, nd.rspec, nd.rspec); |
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} else if (fest > FTINY) { |
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d = nd.rspec*(1. - fest); |
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for (i = 0; i < 3; i++) |
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nd.scolor[i] = fest + nd.mcolor[i]*d; |
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} else { |
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copycolor(nd.scolor, nd.mcolor); |
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else |
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setcolor(nd.scolor, 1.0, 1.0, 1.0); |
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scalecolor(nd.scolor, nd.rspec); |
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scalecolor(nd.scolor, nd.rspec); |
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} |
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/* check threshold */ |
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if (!(nd.specfl & SP_PURE) && specthresh >= nd.rspec-FTINY) |
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nd.specfl |= SP_RBLT; |
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if (hastexture && DOT(nd.vrefl, r->ron) <= FTINY) |
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for (i = 0; i < 3; i++) /* safety measure */ |
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nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; |
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if (!(r->crtype & SHADOW) && nd.specfl & SP_PURE) { |
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RAY lr; |
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if (rayorigin(&lr, r, REFLECTED, nd.rspec) == 0) { |
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VCOPY(lr.rdir, nd.vrefl); |
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rayvalue(&lr); |
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multcolor(lr.rcol, nd.scolor); |
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addcolor(r->rcol, lr.rcol); |
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if (!hastexture && nd.specfl & SP_FLAT) { |
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mirtest = 2.*bright(lr.rcol); |
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mirdist = r->rot + lr.rt; |
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} |
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} |
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/* reflected ray */ |
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if ((nd.specfl&(SP_REFL|SP_PURE|SP_RBLT)) == (SP_REFL|SP_PURE)) { |
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RAY lr; |
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if (rayorigin(&lr, r, REFLECTED, nd.rspec) == 0) { |
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VCOPY(lr.rdir, nd.vrefl); |
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rayvalue(&lr); |
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multcolor(lr.rcol, nd.scolor); |
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addcolor(r->rcol, lr.rcol); |
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if (!hastexture && nd.specfl & SP_FLAT) { |
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mirtest = 2.*bright(lr.rcol); |
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mirdist = r->rot + lr.rt; |
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} |
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} |
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} |
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if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) |
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return(1); /* 100% pure specular */ |
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if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_PURE)) |
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gaussamp(r, &nd); |
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if (!(nd.specfl & SP_PURE)) |
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gaussamp(r, &nd); /* checks *BLT flags */ |
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if (nd.rdiff > FTINY) { /* ambient from this side */ |
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ambient(ctmp, r, hastexture?nd.pnorm:r->ron); |
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} |
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if (nd.tdiff > FTINY) { /* ambient from other side */ |
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flipsurface(r); |
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ambient(ctmp, r, hastexture?nd.pnorm:r->ron); |
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if (hastexture) { |
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FVECT bnorm; |
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bnorm[0] = -nd.pnorm[0]; |
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bnorm[1] = -nd.pnorm[1]; |
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bnorm[2] = -nd.pnorm[2]; |
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ambient(ctmp, r, bnorm); |
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} else |
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ambient(ctmp, r, r->ron); |
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if (nd.specfl & SP_TBLT) |
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scalecolor(ctmp, nd.trans); |
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else |
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} |
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static |
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static void |
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gaussamp(r, np) /* sample gaussian specular */ |
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RAY *r; |
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register NORMDAT *np; |
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FVECT u, v, h; |
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double rv[2]; |
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double d, sinp, cosp; |
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int niter; |
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register int i; |
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/* quick test */ |
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if ((np->specfl & (SP_REFL|SP_RBLT)) != SP_REFL && |
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if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
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rayorigin(&sr, r, SPECULAR, np->rspec) == 0) { |
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dimlist[ndims++] = (int)np->mp; |
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d = urand(ilhash(dimlist,ndims)+samplendx); |
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multisamp(rv, 2, d); |
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d = 2.0*PI * rv[0]; |
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cosp = cos(d); |
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sinp = sin(d); |
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rv[1] = 1.0 - specjitter*rv[1]; |
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if (rv[1] <= FTINY) |
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d = 1.0; |
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else |
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d = sqrt( np->alpha2 * -log(rv[1]) ); |
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for (i = 0; i < 3; i++) |
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h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]); |
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d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
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for (i = 0; i < 3; i++) |
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sr.rdir[i] = r->rdir[i] + d*h[i]; |
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if (DOT(sr.rdir, r->ron) <= FTINY) |
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VCOPY(sr.rdir, np->vrefl); /* jitter no good */ |
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rayvalue(&sr); |
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multcolor(sr.rcol, np->scolor); |
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addcolor(r->rcol, sr.rcol); |
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for (niter = 0; niter < MAXITER; niter++) { |
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if (niter) |
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d = frandom(); |
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else |
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d = urand(ilhash(dimlist,ndims)+samplendx); |
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multisamp(rv, 2, d); |
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d = 2.0*PI * rv[0]; |
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cosp = tcos(d); |
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sinp = tsin(d); |
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rv[1] = 1.0 - specjitter*rv[1]; |
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if (rv[1] <= FTINY) |
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d = 1.0; |
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else |
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d = sqrt( np->alpha2 * -log(rv[1]) ); |
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for (i = 0; i < 3; i++) |
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h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]); |
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d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
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for (i = 0; i < 3; i++) |
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sr.rdir[i] = r->rdir[i] + d*h[i]; |
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if (DOT(sr.rdir, r->ron) > FTINY) { |
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rayvalue(&sr); |
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multcolor(sr.rcol, np->scolor); |
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addcolor(r->rcol, sr.rcol); |
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break; |
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} |
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} |
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ndims--; |
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} |
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/* compute transmission */ |
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if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
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rayorigin(&sr, r, SPECULAR, np->tspec) == 0) { |
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dimlist[ndims++] = (int)np->mp; |
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d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
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multisamp(rv, 2, d); |
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d = 2.0*PI * rv[0]; |
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cosp = cos(d); |
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sinp = sin(d); |
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rv[1] = 1.0 - specjitter*rv[1]; |
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if (rv[1] <= FTINY) |
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d = 1.0; |
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else |
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d = sqrt( -log(rv[1]) * np->alpha2 ); |
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for (i = 0; i < 3; i++) |
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sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); |
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if (DOT(sr.rdir, r->ron) < -FTINY) |
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normalize(sr.rdir); /* OK, normalize */ |
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else |
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VCOPY(sr.rdir, np->prdir); /* else no jitter */ |
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rayvalue(&sr); |
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scalecolor(sr.rcol, np->tspec); |
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multcolor(sr.rcol, np->mcolor); /* modified by color */ |
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addcolor(r->rcol, sr.rcol); |
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for (niter = 0; niter < MAXITER; niter++) { |
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if (niter) |
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d = frandom(); |
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else |
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d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
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multisamp(rv, 2, d); |
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d = 2.0*PI * rv[0]; |
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cosp = tcos(d); |
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sinp = tsin(d); |
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rv[1] = 1.0 - specjitter*rv[1]; |
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if (rv[1] <= FTINY) |
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d = 1.0; |
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else |
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d = sqrt( np->alpha2 * -log(rv[1]) ); |
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for (i = 0; i < 3; i++) |
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sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); |
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if (DOT(sr.rdir, r->ron) < -FTINY) { |
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normalize(sr.rdir); /* OK, normalize */ |
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rayvalue(&sr); |
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scalecolor(sr.rcol, np->tspec); |
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multcolor(sr.rcol, np->mcolor); /* modified */ |
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addcolor(r->rcol, sr.rcol); |
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break; |
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} |
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} |
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ndims--; |
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} |
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} |