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/* Copyright (c) 1986 Regents of the University of California */ |
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/* Copyright (c) 1991 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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typedef struct { |
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OBJREC *mp; /* material pointer */ |
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RAY *pr; /* intersected ray */ |
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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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FVECT prdir; /* vector in transmitted direction */ |
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double alpha2; /* roughness squared times 2 */ |
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double rdiff, rspec; /* reflected specular, diffuse */ |
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double trans; /* transmissivity */ |
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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 / np->pdot; |
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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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/* |
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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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/* gaussian */ |
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dtmp = exp((DOT(np->pr->rdir,ldir)-1.)/dtmp)/(2.*PI)/dtmp; |
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dtmp = exp((DOT(np->prdir,ldir)-1.)/dtmp)/(2.*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 / 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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register RAY *r; |
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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 transtest, transdist; |
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double dtmp; |
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COLOR ctmp; |
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register int i; |
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if (r->crtype & SHADOW && m->otype != MAT_TRANS) |
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return; |
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nd.mp = m; |
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nd.pr = 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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/* 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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r->rt = r->rot; /* default ray length */ |
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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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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 (nd.rspec > 0.5 && m->omod == OVOID) |
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r->rt = r->rot + lr.rt; |
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} |
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} |
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} |
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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 (r->crtype & SHADOW || 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 direction */ |
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nd.prdir[i] = r->rdir[i] - .75*r->pert[i]; |
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normalize(nd.prdir); |
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} |
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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.tspec > FTINY && nd.alpha2 <= FTINY) { |
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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, r->rdir); |
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VCOPY(lr.rdir, nd.prdir); |
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rayvalue(&lr); |
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scalecolor(lr.rcol, nd.tspec); |
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multcolor(lr.rcol, nd.mcolor); /* modified by color */ |
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addcolor(r->rcol, lr.rcol); |
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if (nd.tspec > .5) |
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r->rt = r->rot + lr.rt; |
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transtest *= bright(lr.rcol); |
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transdist = r->rot + lr.rt; |
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} |
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} |
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if (r->crtype & SHADOW) /* the rest is shadow */ |
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scalecolor(ctmp, nd.tdiff); |
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else |
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scalecolor(ctmp, nd.trans); |
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multcolor(ctmp, nd.mcolor); |
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multcolor(ctmp, nd.mcolor); /* modified by color */ |
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addcolor(r->rcol, ctmp); |
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flipsurface(r); |
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} |
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/* add direct component */ |
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direct(r, dirnorm, &nd); |
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/* check distance */ |
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if (transtest > bright(r->rcol)) |
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r->rt = transdist; |
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} |
