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/* Copyright (c) 1986 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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/* |
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* normal.c - shading function for normal materials. |
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* |
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* 12/19/85 - added stuff for metals. |
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* 6/26/87 - improved specular model. |
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* 9/28/87 - added model for translucent materials. |
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* Later changes described in delta comments. |
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*/ |
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|
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#include "ray.h" |
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#include "copyright.h" |
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|
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#include "ray.h" |
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#include "ambient.h" |
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#include "source.h" |
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#include "otypes.h" |
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#include "rtotypes.h" |
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#include "random.h" |
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|
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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(-5.85*(ci)) - 0.00287989916) |
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#define FRESTHRESH 0.017999 /* minimum specularity for approx. */ |
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|
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|
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/* |
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* This routine uses portions of the reflection |
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* model described by Cook and Torrance. |
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* The computation of specular components has been simplified by |
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* numerous approximations and ommisions to improve speed. |
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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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* We orient the surface towards the incoming ray, so a single |
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* surface can be used to represent an infinitely thin object. |
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* |
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* red grn blu rspec rough trans tspec |
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*/ |
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|
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#define BSPEC(m) (6.0) /* specularity parameter b */ |
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/* specularity flags */ |
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#define SP_REFL 01 /* has reflected specular component */ |
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#define SP_TRAN 02 /* has transmitted specular */ |
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#define SP_PURE 04 /* purely specular (zero roughness) */ |
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#define SP_FLAT 010 /* flat reflecting surface */ |
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#define SP_RBLT 020 /* reflection below sample threshold */ |
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#define SP_TBLT 040 /* transmission below threshold */ |
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|
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extern double exp(); |
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|
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typedef struct { |
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OBJREC *mp; /* material pointer */ |
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RAY *pr; /* intersected ray */ |
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RAY *rp; /* ray pointer */ |
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short specfl; /* specularity flags, defined above */ |
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COLOR mcolor; /* color of this material */ |
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COLOR scolor; /* color of specular component */ |
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FVECT vrefl; /* vector in direction of reflected ray */ |
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double alpha2; /* roughness squared times 2 */ |
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FVECT prdir; /* vector in transmitted direction */ |
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double alpha2; /* roughness squared */ |
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double rdiff, rspec; /* reflected specular, diffuse */ |
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double trans; /* transmissivity */ |
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double tdiff, tspec; /* transmitted specular, diffuse */ |
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double pdot; /* perturbed dot product */ |
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} NORMDAT; /* normal material data */ |
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|
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static srcdirf_t dirnorm; |
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static void gaussamp(RAY *r, NORMDAT *np); |
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|
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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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FVECT ldir; /* light source direction */ |
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double omega; /* light source size */ |
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|
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static void |
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dirnorm( /* compute source contribution */ |
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COLOR cval, /* returned coefficient */ |
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void *nnp, /* material data */ |
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FVECT ldir, /* light source direction */ |
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double omega /* light source size */ |
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) |
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{ |
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register NORMDAT *np = nnp; |
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double ldot; |
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double dtmp; |
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double lrdiff, ltdiff; |
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double dtmp, d2; |
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FVECT vtmp; |
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COLOR ctmp; |
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|
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setcolor(cval, 0.0, 0.0, 0.0); |
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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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|
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if (ldot > FTINY && np->rdiff > FTINY) { |
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/* Fresnel estimate */ |
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lrdiff = np->rdiff; |
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ltdiff = np->tdiff; |
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if (np->specfl & SP_PURE && np->rspec >= FRESTHRESH && |
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(lrdiff > FTINY) | (ltdiff > FTINY)) { |
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dtmp = 1. - FRESNE(fabs(ldot)); |
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lrdiff *= dtmp; |
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ltdiff *= dtmp; |
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} |
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|
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if (ldot > FTINY && lrdiff > 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 * lrdiff * (1.0/PI); |
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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
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if (ldot > FTINY && np->rspec > FTINY && np->alpha2 > FTINY) { |
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if (ldot > FTINY && (np->specfl&(SP_REFL|SP_PURE)) == SP_REFL) { |
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/* |
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* Compute specular reflection coefficient using |
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* gaussian distribution model. |
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*/ |
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/* roughness + source */ |
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dtmp = np->alpha2 + omega/(2.0*PI); |
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/* roughness */ |
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dtmp = np->alpha2; |
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/* + source if flat */ |
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if (np->specfl & SP_FLAT) |
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dtmp += omega * (0.25/PI); |
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/* half vector */ |
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vtmp[0] = ldir[0] - np->rp->rdir[0]; |
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vtmp[1] = ldir[1] - np->rp->rdir[1]; |
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vtmp[2] = ldir[2] - np->rp->rdir[2]; |
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d2 = DOT(vtmp, np->pnorm); |
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d2 *= d2; |
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d2 = (DOT(vtmp,vtmp) - d2) / d2; |
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/* gaussian */ |
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< |
dtmp = exp((DOT(np->vrefl,ldir)-1.)/dtmp)/(2.*PI)/dtmp; |
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> |
dtmp = exp(-d2/dtmp)/(4.*PI * np->pdot * dtmp); |
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/* worth using? */ |
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if (dtmp > FTINY) { |
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copycolor(ctmp, np->scolor); |
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addcolor(cval, ctmp); |
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} |
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} |
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< |
if (ldot < -FTINY && np->tdiff > FTINY) { |
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> |
if (ldot < -FTINY && ltdiff > FTINY) { |
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/* |
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* Compute diffuse transmission. |
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*/ |
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copycolor(ctmp, np->mcolor); |
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dtmp = -ldot * omega * np->tdiff / PI; |
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> |
dtmp = -ldot * omega * ltdiff * (1.0/PI); |
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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
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if (ldot < -FTINY && np->tspec > FTINY && np->alpha2 > FTINY) { |
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> |
if (ldot < -FTINY && (np->specfl&(SP_TRAN|SP_PURE)) == SP_TRAN) { |
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/* |
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* Compute specular transmission. Specular transmission |
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* is unaffected by material color. |
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* is always modified by material color. |
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*/ |
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/* roughness + source */ |
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dtmp = np->alpha2 + omega/(2.0*PI); |
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dtmp = np->alpha2 + omega*(1.0/PI); |
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/* gaussian */ |
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dtmp = exp((DOT(np->pr->rdir,ldir)-1.)/dtmp)/(2.*PI)/dtmp; |
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dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(PI*dtmp); |
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/* worth using? */ |
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if (dtmp > FTINY) { |
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dtmp *= np->tspec * omega; |
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setcolor(ctmp, dtmp, dtmp, dtmp); |
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copycolor(ctmp, np->mcolor); |
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dtmp *= np->tspec * omega * sqrt(-ldot/np->pdot); |
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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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} |
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|
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|
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m_normal(m, r) /* color a ray which hit something normal */ |
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register OBJREC *m; |
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register RAY *r; |
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> |
extern int |
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m_normal( /* 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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{ |
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NORMDAT nd; |
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< |
double ldot; |
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double omega; |
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double dtmp; |
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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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> |
double d; |
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COLOR ctmp; |
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register int i; |
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|
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if (m->oargs.nfargs != (m->otype == MAT_TRANS ? 7 : 5)) |
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objerror(m, USER, "bad # arguments"); |
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/* easy shadow test */ |
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if (r->crtype & SHADOW && m->otype != MAT_TRANS) |
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< |
return; |
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> |
return(1); |
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> |
|
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> |
if (m->oargs.nfargs != (m->otype == MAT_TRANS ? 7 : 5)) |
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> |
objerror(m, USER, "bad number of arguments"); |
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> |
/* check for back side */ |
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> |
if (r->rod < 0.0) { |
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> |
if (!backvis && m->otype != MAT_TRANS) { |
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> |
raytrans(r); |
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> |
return(1); |
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> |
} |
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> |
raytexture(r, m->omod); |
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> |
flipsurface(r); /* reorient if backvis */ |
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> |
} else |
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> |
raytexture(r, m->omod); |
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nd.mp = m; |
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< |
nd.pr = r; |
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> |
nd.rp = r; |
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/* get material color */ |
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setcolor(nd.mcolor, m->oargs.farg[0], |
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m->oargs.farg[1], |
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m->oargs.farg[2]); |
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/* get roughness */ |
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+ |
nd.specfl = 0; |
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nd.alpha2 = m->oargs.farg[4]; |
| 210 |
< |
nd.alpha2 *= 2.0 * nd.alpha2; |
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< |
/* reorient if necessary */ |
| 153 |
< |
if (r->rod < 0.0) |
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< |
flipsurface(r); |
| 155 |
< |
/* get modifiers */ |
| 156 |
< |
raytexture(r, m->omod); |
| 157 |
< |
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
| 158 |
< |
multcolor(nd.mcolor, r->pcol); /* modify material color */ |
| 159 |
< |
/* get specular component */ |
| 160 |
< |
nd.rspec = m->oargs.farg[3]; |
| 210 |
> |
if ((nd.alpha2 *= nd.alpha2) <= FTINY) |
| 211 |
> |
nd.specfl |= SP_PURE; |
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|
| 213 |
< |
if (nd.rspec > FTINY) { /* has specular component */ |
| 214 |
< |
/* compute specular color */ |
| 215 |
< |
if (m->otype == MAT_METAL) |
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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); |
| 168 |
< |
scalecolor(nd.scolor, nd.rspec); |
| 169 |
< |
/* improved model */ |
| 170 |
< |
dtmp = exp(-BSPEC(m)*nd.pdot); |
| 171 |
< |
for (i = 0; i < 3; i++) |
| 172 |
< |
colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp; |
| 173 |
< |
nd.rspec += (1.0-nd.rspec)*dtmp; |
| 174 |
< |
/* compute reflected ray */ |
| 175 |
< |
for (i = 0; i < 3; i++) |
| 176 |
< |
nd.vrefl[i] = r->rdir[i] + 2.0*nd.pdot*nd.pnorm[i]; |
| 177 |
< |
|
| 178 |
< |
if (nd.alpha2 <= FTINY && !(r->crtype & SHADOW)) { |
| 179 |
< |
RAY lr; |
| 180 |
< |
if (rayorigin(&lr, r, REFLECTED, nd.rspec) == 0) { |
| 181 |
< |
VCOPY(lr.rdir, nd.vrefl); |
| 182 |
< |
rayvalue(&lr); |
| 183 |
< |
multcolor(lr.rcol, nd.scolor); |
| 184 |
< |
addcolor(r->rcol, lr.rcol); |
| 185 |
< |
} |
| 186 |
< |
} |
| 213 |
> |
if ( (hastexture = (DOT(r->pert,r->pert) > FTINY*FTINY)) ) { |
| 214 |
> |
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
| 215 |
> |
} else { |
| 216 |
> |
VCOPY(nd.pnorm, r->ron); |
| 217 |
> |
nd.pdot = r->rod; |
| 218 |
|
} |
| 219 |
+ |
if (r->ro != NULL && isflat(r->ro->otype)) |
| 220 |
+ |
nd.specfl |= SP_FLAT; |
| 221 |
+ |
if (nd.pdot < .001) |
| 222 |
+ |
nd.pdot = .001; /* non-zero for dirnorm() */ |
| 223 |
+ |
multcolor(nd.mcolor, r->pcol); /* modify material color */ |
| 224 |
+ |
mirtest = transtest = 0; |
| 225 |
+ |
mirdist = transdist = r->rot; |
| 226 |
+ |
nd.rspec = m->oargs.farg[3]; |
| 227 |
+ |
/* compute Fresnel approx. */ |
| 228 |
+ |
if (nd.specfl & SP_PURE && nd.rspec >= FRESTHRESH) { |
| 229 |
+ |
fest = FRESNE(r->rod); |
| 230 |
+ |
nd.rspec += fest*(1. - nd.rspec); |
| 231 |
+ |
} else |
| 232 |
+ |
fest = 0.; |
| 233 |
|
/* compute transmission */ |
| 234 |
|
if (m->otype == MAT_TRANS) { |
| 235 |
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nd.trans = m->oargs.farg[5]*(1.0 - nd.rspec); |
| 236 |
|
nd.tspec = nd.trans * m->oargs.farg[6]; |
| 237 |
|
nd.tdiff = nd.trans - nd.tspec; |
| 238 |
+ |
if (nd.tspec > FTINY) { |
| 239 |
+ |
nd.specfl |= SP_TRAN; |
| 240 |
+ |
/* check threshold */ |
| 241 |
+ |
if (!(nd.specfl & SP_PURE) && |
| 242 |
+ |
specthresh >= nd.tspec-FTINY) |
| 243 |
+ |
nd.specfl |= SP_TBLT; |
| 244 |
+ |
if (!hastexture || r->crtype & SHADOW) { |
| 245 |
+ |
VCOPY(nd.prdir, r->rdir); |
| 246 |
+ |
transtest = 2; |
| 247 |
+ |
} else { |
| 248 |
+ |
for (i = 0; i < 3; i++) /* perturb */ |
| 249 |
+ |
nd.prdir[i] = r->rdir[i] - r->pert[i]; |
| 250 |
+ |
if (DOT(nd.prdir, r->ron) < -FTINY) |
| 251 |
+ |
normalize(nd.prdir); /* OK */ |
| 252 |
+ |
else |
| 253 |
+ |
VCOPY(nd.prdir, r->rdir); |
| 254 |
+ |
} |
| 255 |
+ |
} |
| 256 |
|
} else |
| 257 |
|
nd.tdiff = nd.tspec = nd.trans = 0.0; |
| 258 |
|
/* transmitted ray */ |
| 259 |
< |
if (nd.tspec > FTINY && nd.alpha2 <= FTINY) { |
| 259 |
> |
if ((nd.specfl&(SP_TRAN|SP_PURE|SP_TBLT)) == (SP_TRAN|SP_PURE)) { |
| 260 |
|
RAY lr; |
| 261 |
< |
if (rayorigin(&lr, r, TRANS, nd.tspec) == 0) { |
| 262 |
< |
VCOPY(lr.rdir, r->rdir); |
| 261 |
> |
copycolor(lr.rcoef, nd.mcolor); /* modified by color */ |
| 262 |
> |
scalecolor(lr.rcoef, nd.tspec); |
| 263 |
> |
if (rayorigin(&lr, TRANS, r, lr.rcoef) == 0) { |
| 264 |
> |
VCOPY(lr.rdir, nd.prdir); |
| 265 |
|
rayvalue(&lr); |
| 266 |
< |
scalecolor(lr.rcol, nd.tspec); |
| 266 |
> |
multcolor(lr.rcol, lr.rcoef); |
| 267 |
|
addcolor(r->rcol, lr.rcol); |
| 268 |
+ |
transtest *= bright(lr.rcol); |
| 269 |
+ |
transdist = r->rot + lr.rt; |
| 270 |
|
} |
| 271 |
+ |
} else |
| 272 |
+ |
transtest = 0; |
| 273 |
+ |
|
| 274 |
+ |
if (r->crtype & SHADOW) { /* the rest is shadow */ |
| 275 |
+ |
r->rt = transdist; |
| 276 |
+ |
return(1); |
| 277 |
|
} |
| 278 |
< |
if (r->crtype & SHADOW) /* the rest is shadow */ |
| 279 |
< |
return; |
| 278 |
> |
/* get specular reflection */ |
| 279 |
> |
if (nd.rspec > FTINY) { |
| 280 |
> |
nd.specfl |= SP_REFL; |
| 281 |
> |
/* compute specular color */ |
| 282 |
> |
if (m->otype != MAT_METAL) { |
| 283 |
> |
setcolor(nd.scolor, nd.rspec, nd.rspec, nd.rspec); |
| 284 |
> |
} else if (fest > FTINY) { |
| 285 |
> |
d = nd.rspec*(1. - fest); |
| 286 |
> |
for (i = 0; i < 3; i++) |
| 287 |
> |
nd.scolor[i] = fest + nd.mcolor[i]*d; |
| 288 |
> |
} else { |
| 289 |
> |
copycolor(nd.scolor, nd.mcolor); |
| 290 |
> |
scalecolor(nd.scolor, nd.rspec); |
| 291 |
> |
} |
| 292 |
> |
/* check threshold */ |
| 293 |
> |
if (!(nd.specfl & SP_PURE) && specthresh >= nd.rspec-FTINY) |
| 294 |
> |
nd.specfl |= SP_RBLT; |
| 295 |
> |
/* compute reflected ray */ |
| 296 |
> |
for (i = 0; i < 3; i++) |
| 297 |
> |
nd.vrefl[i] = r->rdir[i] + 2.*nd.pdot*nd.pnorm[i]; |
| 298 |
> |
/* penetration? */ |
| 299 |
> |
if (hastexture && DOT(nd.vrefl, r->ron) <= FTINY) |
| 300 |
> |
for (i = 0; i < 3; i++) /* safety measure */ |
| 301 |
> |
nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; |
| 302 |
> |
checknorm(nd.vrefl); |
| 303 |
> |
} |
| 304 |
> |
/* reflected ray */ |
| 305 |
> |
if ((nd.specfl&(SP_REFL|SP_PURE|SP_RBLT)) == (SP_REFL|SP_PURE)) { |
| 306 |
> |
RAY lr; |
| 307 |
> |
if (rayorigin(&lr, REFLECTED, r, nd.scolor) == 0) { |
| 308 |
> |
VCOPY(lr.rdir, nd.vrefl); |
| 309 |
> |
rayvalue(&lr); |
| 310 |
> |
multcolor(lr.rcol, lr.rcoef); |
| 311 |
> |
addcolor(r->rcol, lr.rcol); |
| 312 |
> |
if (!hastexture && nd.specfl & SP_FLAT) { |
| 313 |
> |
mirtest = 2.*bright(lr.rcol); |
| 314 |
> |
mirdist = r->rot + lr.rt; |
| 315 |
> |
} |
| 316 |
> |
} |
| 317 |
> |
} |
| 318 |
|
/* diffuse reflection */ |
| 319 |
|
nd.rdiff = 1.0 - nd.trans - nd.rspec; |
| 320 |
|
|
| 321 |
< |
if (nd.rdiff <= FTINY && nd.tdiff <= FTINY && nd.alpha2 <= FTINY) |
| 322 |
< |
return; /* purely specular */ |
| 321 |
> |
if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) |
| 322 |
> |
return(1); /* 100% pure specular */ |
| 323 |
|
|
| 324 |
+ |
if (!(nd.specfl & SP_PURE)) |
| 325 |
+ |
gaussamp(r, &nd); /* checks *BLT flags */ |
| 326 |
+ |
|
| 327 |
|
if (nd.rdiff > FTINY) { /* ambient from this side */ |
| 328 |
< |
ambient(ctmp, r); |
| 329 |
< |
if (nd.alpha2 <= FTINY) |
| 216 |
< |
scalecolor(ctmp, nd.rdiff); |
| 217 |
< |
else |
| 328 |
> |
copycolor(ctmp, nd.mcolor); /* modified by material color */ |
| 329 |
> |
if (nd.specfl & SP_RBLT) |
| 330 |
|
scalecolor(ctmp, 1.0-nd.trans); |
| 331 |
< |
multcolor(ctmp, nd.mcolor); /* modified by material color */ |
| 331 |
> |
else |
| 332 |
> |
scalecolor(ctmp, nd.rdiff); |
| 333 |
> |
multambient(ctmp, r, hastexture ? nd.pnorm : r->ron); |
| 334 |
|
addcolor(r->rcol, ctmp); /* add to returned color */ |
| 335 |
|
} |
| 336 |
|
if (nd.tdiff > FTINY) { /* ambient from other side */ |
| 337 |
< |
flipsurface(r); |
| 338 |
< |
ambient(ctmp, r); |
| 225 |
< |
if (nd.alpha2 <= FTINY) |
| 226 |
< |
scalecolor(ctmp, nd.tdiff); |
| 227 |
< |
else |
| 337 |
> |
copycolor(ctmp, nd.mcolor); /* modified by color */ |
| 338 |
> |
if (nd.specfl & SP_TBLT) |
| 339 |
|
scalecolor(ctmp, nd.trans); |
| 340 |
< |
multcolor(ctmp, nd.mcolor); |
| 340 |
> |
else |
| 341 |
> |
scalecolor(ctmp, nd.tdiff); |
| 342 |
> |
flipsurface(r); |
| 343 |
> |
if (hastexture) { |
| 344 |
> |
FVECT bnorm; |
| 345 |
> |
bnorm[0] = -nd.pnorm[0]; |
| 346 |
> |
bnorm[1] = -nd.pnorm[1]; |
| 347 |
> |
bnorm[2] = -nd.pnorm[2]; |
| 348 |
> |
multambient(ctmp, r, bnorm); |
| 349 |
> |
} else |
| 350 |
> |
multambient(ctmp, r, r->ron); |
| 351 |
|
addcolor(r->rcol, ctmp); |
| 352 |
|
flipsurface(r); |
| 353 |
|
} |
| 354 |
|
/* add direct component */ |
| 355 |
|
direct(r, dirnorm, &nd); |
| 356 |
+ |
/* check distance */ |
| 357 |
+ |
d = bright(r->rcol); |
| 358 |
+ |
if (transtest > d) |
| 359 |
+ |
r->rt = transdist; |
| 360 |
+ |
else if (mirtest > d) |
| 361 |
+ |
r->rt = mirdist; |
| 362 |
+ |
|
| 363 |
+ |
return(1); |
| 364 |
+ |
} |
| 365 |
+ |
|
| 366 |
+ |
|
| 367 |
+ |
static void |
| 368 |
+ |
gaussamp( /* sample gaussian specular */ |
| 369 |
+ |
RAY *r, |
| 370 |
+ |
register NORMDAT *np |
| 371 |
+ |
) |
| 372 |
+ |
{ |
| 373 |
+ |
RAY sr; |
| 374 |
+ |
FVECT u, v, h; |
| 375 |
+ |
double rv[2]; |
| 376 |
+ |
double d, sinp, cosp; |
| 377 |
+ |
int niter; |
| 378 |
+ |
register int i; |
| 379 |
+ |
/* quick test */ |
| 380 |
+ |
if ((np->specfl & (SP_REFL|SP_RBLT)) != SP_REFL && |
| 381 |
+ |
(np->specfl & (SP_TRAN|SP_TBLT)) != SP_TRAN) |
| 382 |
+ |
return; |
| 383 |
+ |
/* set up sample coordinates */ |
| 384 |
+ |
v[0] = v[1] = v[2] = 0.0; |
| 385 |
+ |
for (i = 0; i < 3; i++) |
| 386 |
+ |
if (np->pnorm[i] < 0.6 && np->pnorm[i] > -0.6) |
| 387 |
+ |
break; |
| 388 |
+ |
v[i] = 1.0; |
| 389 |
+ |
fcross(u, v, np->pnorm); |
| 390 |
+ |
normalize(u); |
| 391 |
+ |
fcross(v, np->pnorm, u); |
| 392 |
+ |
/* compute reflection */ |
| 393 |
+ |
if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
| 394 |
+ |
rayorigin(&sr, SPECULAR, r, np->scolor) == 0) { |
| 395 |
+ |
dimlist[ndims++] = (int)np->mp; |
| 396 |
+ |
for (niter = 0; niter < MAXITER; niter++) { |
| 397 |
+ |
if (niter) |
| 398 |
+ |
d = frandom(); |
| 399 |
+ |
else |
| 400 |
+ |
d = urand(ilhash(dimlist,ndims)+samplendx); |
| 401 |
+ |
multisamp(rv, 2, d); |
| 402 |
+ |
d = 2.0*PI * rv[0]; |
| 403 |
+ |
cosp = tcos(d); |
| 404 |
+ |
sinp = tsin(d); |
| 405 |
+ |
rv[1] = 1.0 - specjitter*rv[1]; |
| 406 |
+ |
if (rv[1] <= FTINY) |
| 407 |
+ |
d = 1.0; |
| 408 |
+ |
else |
| 409 |
+ |
d = sqrt( np->alpha2 * -log(rv[1]) ); |
| 410 |
+ |
for (i = 0; i < 3; i++) |
| 411 |
+ |
h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]); |
| 412 |
+ |
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
| 413 |
+ |
for (i = 0; i < 3; i++) |
| 414 |
+ |
sr.rdir[i] = r->rdir[i] + d*h[i]; |
| 415 |
+ |
if (DOT(sr.rdir, r->ron) > FTINY) { |
| 416 |
+ |
rayvalue(&sr); |
| 417 |
+ |
multcolor(sr.rcol, sr.rcoef); |
| 418 |
+ |
addcolor(r->rcol, sr.rcol); |
| 419 |
+ |
break; |
| 420 |
+ |
} |
| 421 |
+ |
} |
| 422 |
+ |
ndims--; |
| 423 |
+ |
} |
| 424 |
+ |
/* compute transmission */ |
| 425 |
+ |
copycolor(sr.rcoef, np->mcolor); /* modified by color */ |
| 426 |
+ |
scalecolor(sr.rcoef, np->tspec); |
| 427 |
+ |
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
| 428 |
+ |
rayorigin(&sr, SPECULAR, r, sr.rcoef) == 0) { |
| 429 |
+ |
dimlist[ndims++] = (int)np->mp; |
| 430 |
+ |
for (niter = 0; niter < MAXITER; niter++) { |
| 431 |
+ |
if (niter) |
| 432 |
+ |
d = frandom(); |
| 433 |
+ |
else |
| 434 |
+ |
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
| 435 |
+ |
multisamp(rv, 2, d); |
| 436 |
+ |
d = 2.0*PI * rv[0]; |
| 437 |
+ |
cosp = tcos(d); |
| 438 |
+ |
sinp = tsin(d); |
| 439 |
+ |
rv[1] = 1.0 - specjitter*rv[1]; |
| 440 |
+ |
if (rv[1] <= FTINY) |
| 441 |
+ |
d = 1.0; |
| 442 |
+ |
else |
| 443 |
+ |
d = sqrt( np->alpha2 * -log(rv[1]) ); |
| 444 |
+ |
for (i = 0; i < 3; i++) |
| 445 |
+ |
sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); |
| 446 |
+ |
if (DOT(sr.rdir, r->ron) < -FTINY) { |
| 447 |
+ |
normalize(sr.rdir); /* OK, normalize */ |
| 448 |
+ |
rayvalue(&sr); |
| 449 |
+ |
multcolor(sr.rcol, sr.rcoef); |
| 450 |
+ |
addcolor(r->rcol, sr.rcol); |
| 451 |
+ |
break; |
| 452 |
+ |
} |
| 453 |
+ |
} |
| 454 |
+ |
ndims--; |
| 455 |
+ |
} |
| 456 |
|
} |
