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/* Copyright (c) 1991 Regents of the University of California */ |
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/* Copyright (c) 1992 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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* 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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#include "ray.h" |
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#include "otypes.h" |
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|
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#include "random.h" |
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|
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extern double specthresh; /* specular sampling threshold */ |
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extern double specjitter; /* specular sampling jitter */ |
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|
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static gaussamp(); |
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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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|
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#define BSPEC(m) (6.0) /* specularity parameter b */ |
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|
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extern double exp(); |
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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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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 omega; /* light source size */ |
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{ |
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double ldot; |
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double dtmp; |
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double dtmp, d2; |
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FVECT vtmp; |
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COLOR ctmp; |
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setcolor(cval, 0.0, 0.0, 0.0); |
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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/(4.0*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*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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dtmp *= omega; |
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dtmp *= 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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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/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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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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double dtmp; |
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COLOR ctmp; |
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register int i; |
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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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|
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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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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]; |
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nd.alpha2 *= 2.0 * nd.alpha2; |
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> |
if ((nd.alpha2 *= nd.alpha2) <= FTINY) |
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nd.specfl |= SP_PURE; |
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/* reorient if necessary */ |
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if (r->rod < 0.0) |
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flipsurface(r); |
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/* get modifiers */ |
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raytexture(r, m->omod); |
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nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
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if (nd.pdot < .001) |
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nd.pdot = .001; /* non-zero for dirnorm() */ |
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multcolor(nd.mcolor, r->pcol); /* modify material color */ |
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transtest = 0; |
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/* get specular component */ |
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nd.rspec = m->oargs.farg[3]; |
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|
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if (nd.rspec > FTINY) { /* has specular component */ |
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if ((nd.rspec = m->oargs.farg[3]) > 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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copycolor(nd.scolor, nd.mcolor); |
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for (i = 0; i < 3; i++) |
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colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp; |
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nd.rspec += (1.0-nd.rspec)*dtmp; |
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/* check threshold */ |
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if (!(nd.specfl & SP_PURE) && |
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specthresh > FTINY && |
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(specthresh >= 1.-FTINY || |
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specthresh + .05 - .1*frandom() > nd.rspec)) |
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nd.specfl |= SP_RBLT; |
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/* compute reflected ray */ |
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for (i = 0; i < 3; i++) |
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nd.vrefl[i] = r->rdir[i] + 2.0*nd.pdot*nd.pnorm[i]; |
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if (DOT(nd.vrefl, r->ron) <= FTINY) /* penetration? */ |
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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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|
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if (nd.alpha2 <= FTINY && !(r->crtype & SHADOW)) { |
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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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nd.trans = m->oargs.farg[5]*(1.0 - nd.rspec); |
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nd.tspec = nd.trans * m->oargs.farg[6]; |
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nd.tdiff = nd.trans - nd.tspec; |
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if (nd.tspec > FTINY) { |
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nd.specfl |= SP_TRAN; |
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/* check threshold */ |
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if (!(nd.specfl & SP_PURE) && specthresh > FTINY && |
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(specthresh >= 1.-FTINY || |
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specthresh + .05 - .1*frandom() > nd.tspec)) |
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nd.specfl |= SP_TBLT; |
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if (r->crtype & SHADOW || |
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DOT(r->pert,r->pert) <= FTINY*FTINY) { |
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VCOPY(nd.prdir, r->rdir); |
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transtest = 2; |
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} else { |
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for (i = 0; i < 3; i++) /* perturb */ |
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nd.prdir[i] = r->rdir[i] - r->pert[i]; |
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if (DOT(nd.prdir, r->ron) < -FTINY) |
| 246 |
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normalize(nd.prdir); /* OK */ |
| 247 |
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else |
| 248 |
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VCOPY(nd.prdir, r->rdir); |
| 249 |
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} |
| 250 |
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} |
| 251 |
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} else |
| 252 |
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nd.tdiff = nd.tspec = nd.trans = 0.0; |
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/* transmitted ray */ |
| 254 |
< |
if (nd.tspec > FTINY && nd.alpha2 <= FTINY) { |
| 254 |
> |
if ((nd.specfl&(SP_TRAN|SP_PURE)) == (SP_TRAN|SP_PURE)) { |
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RAY lr; |
| 256 |
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if (rayorigin(&lr, r, TRANS, nd.tspec) == 0) { |
| 257 |
< |
if (!(r->crtype & SHADOW) && |
| 200 |
< |
DOT(r->pert,r->pert) > FTINY*FTINY) { |
| 201 |
< |
for (i = 0; i < 3; i++) /* perturb direction */ |
| 202 |
< |
lr.rdir[i] = r->rdir[i] - |
| 203 |
< |
.75*r->pert[i]; |
| 204 |
< |
normalize(lr.rdir); |
| 205 |
< |
} else { |
| 206 |
< |
VCOPY(lr.rdir, r->rdir); |
| 207 |
< |
transtest = 2; |
| 208 |
< |
} |
| 257 |
> |
VCOPY(lr.rdir, nd.prdir); |
| 258 |
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rayvalue(&lr); |
| 259 |
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scalecolor(lr.rcol, nd.tspec); |
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multcolor(lr.rcol, nd.mcolor); /* modified by color */ |
| 262 |
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transtest *= bright(lr.rcol); |
| 263 |
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transdist = r->rot + lr.rt; |
| 264 |
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} |
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< |
} |
| 265 |
> |
} else |
| 266 |
> |
transtest = 0; |
| 267 |
> |
|
| 268 |
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if (r->crtype & SHADOW) /* the rest is shadow */ |
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return; |
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/* diffuse reflection */ |
| 271 |
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nd.rdiff = 1.0 - nd.trans - nd.rspec; |
| 272 |
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|
| 273 |
< |
if (nd.rdiff <= FTINY && nd.tdiff <= FTINY && nd.alpha2 <= FTINY) |
| 274 |
< |
return; /* purely specular */ |
| 273 |
> |
if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) |
| 274 |
> |
return; /* 100% pure specular */ |
| 275 |
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|
| 276 |
+ |
if (r->ro != NULL && (r->ro->otype == OBJ_FACE || |
| 277 |
+ |
r->ro->otype == OBJ_RING)) |
| 278 |
+ |
nd.specfl |= SP_FLAT; |
| 279 |
+ |
|
| 280 |
+ |
if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_PURE)) |
| 281 |
+ |
gaussamp(r, &nd); |
| 282 |
+ |
|
| 283 |
|
if (nd.rdiff > FTINY) { /* ambient from this side */ |
| 284 |
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ambient(ctmp, r); |
| 285 |
< |
if (nd.alpha2 <= FTINY) |
| 228 |
< |
scalecolor(ctmp, nd.rdiff); |
| 229 |
< |
else |
| 285 |
> |
if (nd.specfl & SP_RBLT) |
| 286 |
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scalecolor(ctmp, 1.0-nd.trans); |
| 287 |
+ |
else |
| 288 |
+ |
scalecolor(ctmp, nd.rdiff); |
| 289 |
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multcolor(ctmp, nd.mcolor); /* modified by material color */ |
| 290 |
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addcolor(r->rcol, ctmp); /* add to returned color */ |
| 291 |
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} |
| 292 |
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if (nd.tdiff > FTINY) { /* ambient from other side */ |
| 293 |
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flipsurface(r); |
| 294 |
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ambient(ctmp, r); |
| 295 |
< |
if (nd.alpha2 <= FTINY) |
| 238 |
< |
scalecolor(ctmp, nd.tdiff); |
| 239 |
< |
else |
| 295 |
> |
if (nd.specfl & SP_TBLT) |
| 296 |
|
scalecolor(ctmp, nd.trans); |
| 297 |
< |
multcolor(ctmp, nd.mcolor); |
| 297 |
> |
else |
| 298 |
> |
scalecolor(ctmp, nd.tdiff); |
| 299 |
> |
multcolor(ctmp, nd.mcolor); /* modified by color */ |
| 300 |
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addcolor(r->rcol, ctmp); |
| 301 |
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flipsurface(r); |
| 302 |
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} |
| 305 |
|
/* check distance */ |
| 306 |
|
if (transtest > bright(r->rcol)) |
| 307 |
|
r->rt = transdist; |
| 308 |
+ |
} |
| 309 |
+ |
|
| 310 |
+ |
|
| 311 |
+ |
static |
| 312 |
+ |
gaussamp(r, np) /* sample gaussian specular */ |
| 313 |
+ |
RAY *r; |
| 314 |
+ |
register NORMDAT *np; |
| 315 |
+ |
{ |
| 316 |
+ |
RAY sr; |
| 317 |
+ |
FVECT u, v, h; |
| 318 |
+ |
double rv[2]; |
| 319 |
+ |
double d, sinp, cosp; |
| 320 |
+ |
register int i; |
| 321 |
+ |
/* quick test */ |
| 322 |
+ |
if ((np->specfl & (SP_REFL|SP_RBLT)) != SP_REFL && |
| 323 |
+ |
(np->specfl & (SP_TRAN|SP_TBLT)) != SP_TRAN) |
| 324 |
+ |
return; |
| 325 |
+ |
/* set up sample coordinates */ |
| 326 |
+ |
v[0] = v[1] = v[2] = 0.0; |
| 327 |
+ |
for (i = 0; i < 3; i++) |
| 328 |
+ |
if (np->pnorm[i] < 0.6 && np->pnorm[i] > -0.6) |
| 329 |
+ |
break; |
| 330 |
+ |
v[i] = 1.0; |
| 331 |
+ |
fcross(u, v, np->pnorm); |
| 332 |
+ |
normalize(u); |
| 333 |
+ |
fcross(v, np->pnorm, u); |
| 334 |
+ |
/* compute reflection */ |
| 335 |
+ |
if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
| 336 |
+ |
rayorigin(&sr, r, SPECULAR, np->rspec) == 0) { |
| 337 |
+ |
dimlist[ndims++] = (int)np->mp; |
| 338 |
+ |
d = urand(ilhash(dimlist,ndims)+samplendx); |
| 339 |
+ |
multisamp(rv, 2, d); |
| 340 |
+ |
d = 2.0*PI * rv[0]; |
| 341 |
+ |
cosp = cos(d); |
| 342 |
+ |
sinp = sin(d); |
| 343 |
+ |
rv[1] = 1.0 - specjitter*rv[1]; |
| 344 |
+ |
if (rv[1] <= FTINY) |
| 345 |
+ |
d = 1.0; |
| 346 |
+ |
else |
| 347 |
+ |
d = sqrt( np->alpha2 * -log(rv[1]) ); |
| 348 |
+ |
for (i = 0; i < 3; i++) |
| 349 |
+ |
h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]); |
| 350 |
+ |
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
| 351 |
+ |
for (i = 0; i < 3; i++) |
| 352 |
+ |
sr.rdir[i] = r->rdir[i] + d*h[i]; |
| 353 |
+ |
if (DOT(sr.rdir, r->ron) <= FTINY) |
| 354 |
+ |
VCOPY(sr.rdir, np->vrefl); /* jitter no good */ |
| 355 |
+ |
rayvalue(&sr); |
| 356 |
+ |
multcolor(sr.rcol, np->scolor); |
| 357 |
+ |
addcolor(r->rcol, sr.rcol); |
| 358 |
+ |
ndims--; |
| 359 |
+ |
} |
| 360 |
+ |
/* compute transmission */ |
| 361 |
+ |
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
| 362 |
+ |
rayorigin(&sr, r, SPECULAR, np->tspec) == 0) { |
| 363 |
+ |
dimlist[ndims++] = (int)np->mp; |
| 364 |
+ |
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
| 365 |
+ |
multisamp(rv, 2, d); |
| 366 |
+ |
d = 2.0*PI * rv[0]; |
| 367 |
+ |
cosp = cos(d); |
| 368 |
+ |
sinp = sin(d); |
| 369 |
+ |
rv[1] = 1.0 - specjitter*rv[1]; |
| 370 |
+ |
if (rv[1] <= FTINY) |
| 371 |
+ |
d = 1.0; |
| 372 |
+ |
else |
| 373 |
+ |
d = sqrt( -log(rv[1]) * np->alpha2 ); |
| 374 |
+ |
for (i = 0; i < 3; i++) |
| 375 |
+ |
sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); |
| 376 |
+ |
if (DOT(sr.rdir, r->ron) < -FTINY) |
| 377 |
+ |
normalize(sr.rdir); /* OK, normalize */ |
| 378 |
+ |
else |
| 379 |
+ |
VCOPY(sr.rdir, np->prdir); /* else no jitter */ |
| 380 |
+ |
rayvalue(&sr); |
| 381 |
+ |
scalecolor(sr.rcol, np->tspec); |
| 382 |
+ |
multcolor(sr.rcol, np->mcolor); /* modified by color */ |
| 383 |
+ |
addcolor(r->rcol, sr.rcol); |
| 384 |
+ |
ndims--; |
| 385 |
+ |
} |
| 386 |
|
} |
