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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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static const char RCSid[] = "$Id$"; |
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#endif |
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/* |
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* Shading for materials with arbitrary BRDF's |
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*/ |
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#include "copyright.h" |
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#include "ray.h" |
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#include "data.h" |
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#include "func.h" |
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extern int backvis; /* back faces visible? */ |
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/* |
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* Arguments to this material include the color and specularity. |
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* String arguments include the reflection function and files. |
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} BRDFDAT; /* BRDF material data */ |
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static void |
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dirbrdf(cval, np, ldir, omega) /* compute source contribution */ |
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COLOR cval; /* returned coefficient */ |
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register BRDFDAT *np; /* material data */ |
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} |
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m_brdf(m, r) /* color a ray which hit a BRDTF material */ |
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int |
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m_brdf(m, r) /* color a ray that hit a BRDTfunc material */ |
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register OBJREC *m; |
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register RAY *r; |
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{ |
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int hitfront = 1; |
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BRDFDAT nd; |
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RAY sr; |
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double transtest, transdist; |
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int hasrefl, hastrans; |
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COLOR ctmp; |
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FVECT vtmp; |
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register MFUNC *mf; |
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register int i; |
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/* check arguments */ |
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setcolor(nd.tdiff, m->oargs.farg[6], |
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m->oargs.farg[7], |
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m->oargs.farg[8]); |
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/* get modifiers */ |
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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 (r->rod < 0.0) { /* orient perturbed values */ |
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nd.pnorm[i] = -nd.pnorm[i]; |
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r->pert[i] = -r->pert[i]; |
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} |
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hitfront = 0; |
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} |
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copycolor(nd.mcolor, r->pcol); /* get pattern color */ |
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multcolor(nd.rdiff, nd.mcolor); /* modify diffuse values */ |
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} |
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/* compute ambient */ |
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if (hasrefl) { |
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if (nd.pdot < 0.0) |
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if (!hitfront) |
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flipsurface(r); |
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ambient(ctmp, r); |
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ambient(ctmp, r, nd.pnorm); |
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multcolor(ctmp, nd.rdiff); |
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addcolor(r->rcol, ctmp); /* add to returned color */ |
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if (nd.pdot < 0.0) |
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if (!hitfront) |
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flipsurface(r); |
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} |
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if (hastrans) { /* from other side */ |
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if (nd.pdot > 0.0) |
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if (hitfront) |
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flipsurface(r); |
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ambient(ctmp, r); |
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vtmp[0] = -nd.pnorm[0]; |
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vtmp[1] = -nd.pnorm[1]; |
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vtmp[2] = -nd.pnorm[2]; |
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ambient(ctmp, r, vtmp); |
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multcolor(ctmp, nd.tdiff); |
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addcolor(r->rcol, ctmp); |
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if (nd.pdot > 0.0) |
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if (hitfront) |
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flipsurface(r); |
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} |
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if (hasrefl | hastrans || m->oargs.sarg[6][0] != '0') |
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m_brdf2(m, r) /* color a ray which hit a BRDF material */ |
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int |
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m_brdf2(m, r) /* color a ray that hit a BRDF material */ |
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register OBJREC *m; |
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register RAY *r; |
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{ |
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BRDFDAT nd; |
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COLOR ctmp; |
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FVECT vtmp; |
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double dtmp; |
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/* always a shadow */ |
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if (r->crtype & SHADOW) |
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if (m->oargs.nsargs < (hasdata(m->otype)?4:2) | m->oargs.nfargs < |
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(m->otype==MAT_TFUNC|m->otype==MAT_TDATA?6:4)) |
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objerror(m, USER, "bad # 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_TFUNC |
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&& m->otype != MAT_TDATA) { |
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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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/* get material color */ |
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/* compute reflectance */ |
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dtmp = 1.0 - nd.trans - nd.rspec; |
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setcolor(nd.rdiff, dtmp, dtmp, dtmp); |
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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_TFUNC |
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&& m->otype != MAT_TDATA) { |
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raytrans(r); |
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return(1); |
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} |
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flipsurface(r); /* reorient if backvis */ |
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} |
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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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multcolor(nd.mcolor, r->pcol); /* modify material color */ |
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multcolor(nd.rdiff, nd.mcolor); |
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} |
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/* compute ambient */ |
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if (nd.trans < 1.0-FTINY) { |
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ambient(ctmp, r); |
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ambient(ctmp, r, nd.pnorm); |
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scalecolor(ctmp, 1.0-nd.trans); |
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multcolor(ctmp, nd.mcolor); /* modified by material color */ |
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addcolor(r->rcol, ctmp); /* add to returned color */ |
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} |
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if (nd.trans > FTINY) { /* from other side */ |
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flipsurface(r); |
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ambient(ctmp, r); |
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vtmp[0] = -nd.pnorm[0]; |
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vtmp[1] = -nd.pnorm[1]; |
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vtmp[2] = -nd.pnorm[2]; |
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ambient(ctmp, r, vtmp); |
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scalecolor(ctmp, nd.trans); |
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multcolor(ctmp, nd.mcolor); |
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addcolor(r->rcol, ctmp); |
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} |
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int |
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setbrdfunc(np) /* set up brdf function and variables */ |
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register BRDFDAT *np; |
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{ |