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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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static const char RCSid[] = "$Id$"; |
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#endif |
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|
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/* |
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* Shading functions for anisotropic materials. |
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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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#include "ray.h" |
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#include "ambient.h" |
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#include "otypes.h" |
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#include "rtotypes.h" |
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#include "source.h" |
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#include "func.h" |
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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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#ifndef MAXITER |
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#define MAXITER 10 /* maximum # specular ray attempts */ |
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#endif |
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|
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static agaussamp(), getacoords(); |
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|
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/* |
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* This routine implements the anisotropic Gaussian |
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* model described by Ward in Siggraph `92 article. |
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double pdot; /* perturbed dot product */ |
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} ANISODAT; /* anisotropic material data */ |
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|
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static srcdirf_t diraniso; |
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static void getacoords(RAY *r, ANISODAT *np); |
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static void agaussamp(RAY *r, ANISODAT *np); |
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|
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diraniso(cval, np, ldir, omega) /* compute source contribution */ |
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COLOR cval; /* returned coefficient */ |
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register ANISODAT *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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diraniso( /* 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 ANISODAT *np = nnp; |
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double ldot; |
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double dtmp, dtmp1, dtmp2; |
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FVECT h; |
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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 * np->rdiff * (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->specfl&(SP_REFL|SP_BADU)) == SP_REFL) { |
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/* |
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* Compute specular reflection coefficient using |
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* anisotropic gaussian distribution model. |
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* anisotropic Gaussian distribution model. |
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*/ |
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/* add source width if flat */ |
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if (np->specfl & SP_FLAT) |
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au2 = av2 = omega/(4.0*PI); |
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au2 = av2 = omega * (0.25/PI); |
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else |
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au2 = av2 = 0.0; |
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au2 += np->u_alpha*np->u_alpha; |
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dtmp1 *= dtmp1 / au2; |
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dtmp2 = DOT(np->v, h); |
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dtmp2 *= dtmp2 / av2; |
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/* gaussian */ |
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/* new W-G-M-D model */ |
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dtmp = DOT(np->pnorm, h); |
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dtmp = (dtmp1 + dtmp2) / (dtmp*dtmp); |
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dtmp = exp(-dtmp) * (0.25/PI) |
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* sqrt(ldot/(np->pdot*au2*av2)); |
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dtmp *= dtmp; |
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dtmp1 = (dtmp1 + dtmp2) / dtmp; |
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dtmp = exp(-dtmp1) * DOT(h,h) / |
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(PI * dtmp*dtmp * sqrt(au2*av2)); |
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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 *= ldot * omega; |
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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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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 * np->tdiff * (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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* is always modified by material color. |
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*/ |
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/* roughness + source */ |
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au2 = av2 = omega / PI; |
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au2 = av2 = omega * (1.0/PI); |
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au2 += np->u_alpha*np->u_alpha; |
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av2 += np->v_alpha*np->v_alpha; |
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/* "half vector" */ |
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} |
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} else |
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dtmp = 0.0; |
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/* gaussian */ |
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dtmp = exp(-dtmp) * (1.0/PI) |
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* sqrt(-ldot/(np->pdot*au2*av2)); |
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/* Gaussian */ |
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dtmp = exp(-dtmp) * (1.0/PI) * sqrt(-ldot/(np->pdot*au2*av2)); |
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/* worth using? */ |
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if (dtmp > FTINY) { |
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copycolor(ctmp, np->mcolor); |
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} |
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m_aniso(m, r) /* shade ray that hit something anisotropic */ |
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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_aniso( /* shade ray that hit something anisotropic */ |
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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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ANISODAT nd; |
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COLOR ctmp; |
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|
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if (m->oargs.nfargs != (m->otype == MAT_TRANS2 ? 8 : 6)) |
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objerror(m, USER, "bad number of real 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_TRANS2) { |
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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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/* get material color */ |
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nd.mp = m; |
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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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nd.specfl = 0; |
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nd.u_alpha = m->oargs.farg[4]; |
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nd.v_alpha = m->oargs.farg[5]; |
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if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY) |
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> |
if (nd.u_alpha <= FTINY || nd.v_alpha <= FTINY) |
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objerror(m, USER, "roughness too small"); |
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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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> |
|
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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 diraniso() */ |
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if (specthresh >= nd.rspec-FTINY) |
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nd.specfl |= SP_RBLT; |
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/* compute refl. direction */ |
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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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> |
VSUM(nd.vrefl, r->rdir, nd.pnorm, 2.0*nd.pdot); |
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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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> |
VSUM(nd.vrefl, r->rdir, r->ron, 2.0*r->rod); |
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} |
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/* compute transmission */ |
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if (m->otype == MAT_TRANS2) { |
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/* diffuse reflection */ |
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nd.rdiff = 1.0 - nd.trans - nd.rspec; |
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|
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if (r->ro != NULL && (r->ro->otype == OBJ_FACE || |
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r->ro->otype == OBJ_RING)) |
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> |
if (r->ro != NULL && isflat(r->ro->otype)) |
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nd.specfl |= SP_FLAT; |
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getacoords(r, &nd); /* set up coordinates */ |
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agaussamp(r, &nd); |
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if (nd.rdiff > FTINY) { /* ambient from this side */ |
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< |
ambient(ctmp, r); |
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> |
copycolor(ctmp, nd.mcolor); /* modified by material color */ |
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if (nd.specfl & SP_RBLT) |
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scalecolor(ctmp, 1.0-nd.trans); |
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else |
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scalecolor(ctmp, nd.rdiff); |
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< |
multcolor(ctmp, nd.mcolor); /* modified by material color */ |
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> |
multambient(ctmp, r, nd.pnorm); |
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addcolor(r->rcol, ctmp); /* add to returned color */ |
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} |
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if (nd.tdiff > FTINY) { /* ambient from other side */ |
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+ |
FVECT bnorm; |
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+ |
|
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flipsurface(r); |
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< |
ambient(ctmp, r); |
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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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> |
copycolor(ctmp, nd.mcolor); /* modified by color */ |
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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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scalecolor(ctmp, nd.tdiff); |
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< |
multcolor(ctmp, nd.mcolor); /* modified by color */ |
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> |
multambient(ctmp, r, bnorm); |
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addcolor(r->rcol, ctmp); |
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flipsurface(r); |
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} |
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} |
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|
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|
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< |
static |
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< |
getacoords(r, np) /* set up coordinate system */ |
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< |
RAY *r; |
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< |
register ANISODAT *np; |
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> |
static void |
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> |
getacoords( /* set up coordinate system */ |
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> |
RAY *r, |
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> |
register ANISODAT *np |
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> |
) |
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{ |
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register MFUNC *mf; |
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register int i; |
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errno = 0; |
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for (i = 0; i < 3; i++) |
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np->u[i] = evalue(mf->ep[i]); |
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< |
if (errno) { |
| 324 |
> |
if (errno == EDOM || errno == ERANGE) { |
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objerror(np->mp, WARNING, "compute error"); |
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np->specfl |= SP_BADU; |
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return; |
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} |
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|
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|
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< |
static |
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< |
agaussamp(r, np) /* sample anisotropic gaussian specular */ |
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< |
RAY *r; |
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< |
register ANISODAT *np; |
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> |
static void |
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> |
agaussamp( /* sample anisotropic Gaussian specular */ |
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> |
RAY *r, |
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> |
register ANISODAT *np |
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> |
) |
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{ |
| 347 |
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RAY sr; |
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FVECT h; |
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double rv[2]; |
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double d, sinp, cosp; |
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+ |
COLOR scol; |
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+ |
int maxiter, ntrials, nstarget, nstaken; |
| 353 |
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register int i; |
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/* compute reflection */ |
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if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
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< |
rayorigin(&sr, r, SPECULAR, np->rspec) == 0) { |
| 356 |
> |
rayorigin(&sr, SPECULAR, r, np->scolor) == 0) { |
| 357 |
> |
nstarget = 1; |
| 358 |
> |
if (specjitter > 1.5) { /* multiple samples? */ |
| 359 |
> |
nstarget = specjitter*r->rweight + .5; |
| 360 |
> |
if (sr.rweight <= minweight*nstarget) |
| 361 |
> |
nstarget = sr.rweight/minweight; |
| 362 |
> |
if (nstarget > 1) { |
| 363 |
> |
d = 1./nstarget; |
| 364 |
> |
scalecolor(sr.rcoef, d); |
| 365 |
> |
sr.rweight *= d; |
| 366 |
> |
} else |
| 367 |
> |
nstarget = 1; |
| 368 |
> |
} |
| 369 |
> |
setcolor(scol, 0., 0., 0.); |
| 370 |
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dimlist[ndims++] = (int)np->mp; |
| 371 |
< |
d = urand(ilhash(dimlist,ndims)+samplendx); |
| 372 |
< |
multisamp(rv, 2, d); |
| 373 |
< |
d = 2.0*PI * rv[0]; |
| 374 |
< |
cosp = cos(d) * np->u_alpha; |
| 375 |
< |
sinp = sin(d) * np->v_alpha; |
| 376 |
< |
d = sqrt(cosp*cosp + sinp*sinp); |
| 377 |
< |
cosp /= d; |
| 378 |
< |
sinp /= d; |
| 379 |
< |
rv[1] = 1.0 - specjitter*rv[1]; |
| 380 |
< |
if (rv[1] <= FTINY) |
| 381 |
< |
d = 1.0; |
| 382 |
< |
else |
| 383 |
< |
d = sqrt(-log(rv[1]) / |
| 384 |
< |
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
| 385 |
< |
sinp*sinp/(np->v_alpha*np->v_alpha))); |
| 386 |
< |
for (i = 0; i < 3; i++) |
| 387 |
< |
h[i] = np->pnorm[i] + |
| 388 |
< |
d*(cosp*np->u[i] + sinp*np->v[i]); |
| 389 |
< |
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
| 390 |
< |
for (i = 0; i < 3; i++) |
| 391 |
< |
sr.rdir[i] = r->rdir[i] + d*h[i]; |
| 392 |
< |
if (DOT(sr.rdir, r->ron) <= FTINY) /* penetration? */ |
| 393 |
< |
VCOPY(sr.rdir, np->vrefl); /* jitter no good */ |
| 394 |
< |
rayvalue(&sr); |
| 395 |
< |
multcolor(sr.rcol, np->scolor); |
| 396 |
< |
addcolor(r->rcol, sr.rcol); |
| 371 |
> |
maxiter = MAXITER*nstarget; |
| 372 |
> |
for (nstaken = ntrials = 0; nstaken < nstarget && |
| 373 |
> |
ntrials < maxiter; ntrials++) { |
| 374 |
> |
if (ntrials) |
| 375 |
> |
d = frandom(); |
| 376 |
> |
else |
| 377 |
> |
d = urand(ilhash(dimlist,ndims)+samplendx); |
| 378 |
> |
multisamp(rv, 2, d); |
| 379 |
> |
d = 2.0*PI * rv[0]; |
| 380 |
> |
cosp = tcos(d) * np->u_alpha; |
| 381 |
> |
sinp = tsin(d) * np->v_alpha; |
| 382 |
> |
d = 1./sqrt(cosp*cosp + sinp*sinp); |
| 383 |
> |
cosp *= d; |
| 384 |
> |
sinp *= d; |
| 385 |
> |
if ((0. <= specjitter) & (specjitter < 1.)) |
| 386 |
> |
rv[1] = 1.0 - specjitter*rv[1]; |
| 387 |
> |
if (rv[1] <= FTINY) |
| 388 |
> |
d = 1.0; |
| 389 |
> |
else |
| 390 |
> |
d = sqrt(-log(rv[1]) / |
| 391 |
> |
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
| 392 |
> |
sinp*sinp/(np->v_alpha*np->v_alpha))); |
| 393 |
> |
for (i = 0; i < 3; i++) |
| 394 |
> |
h[i] = np->pnorm[i] + |
| 395 |
> |
d*(cosp*np->u[i] + sinp*np->v[i]); |
| 396 |
> |
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
| 397 |
> |
VSUM(sr.rdir, r->rdir, h, d); |
| 398 |
> |
/* sample rejection test */ |
| 399 |
> |
if ((d = DOT(sr.rdir, r->ron)) <= FTINY) |
| 400 |
> |
continue; |
| 401 |
> |
checknorm(sr.rdir); |
| 402 |
> |
if (nstarget > 1) { /* W-G-M-D adjustment */ |
| 403 |
> |
if (nstaken) rayclear(&sr); |
| 404 |
> |
rayvalue(&sr); |
| 405 |
> |
d = 2./(1. + r->rod/d); |
| 406 |
> |
scalecolor(sr.rcol, d); |
| 407 |
> |
addcolor(scol, sr.rcol); |
| 408 |
> |
} else { |
| 409 |
> |
rayvalue(&sr); |
| 410 |
> |
multcolor(sr.rcol, sr.rcoef); |
| 411 |
> |
addcolor(r->rcol, sr.rcol); |
| 412 |
> |
} |
| 413 |
> |
++nstaken; |
| 414 |
> |
} |
| 415 |
> |
if (nstarget > 1) { /* final W-G-M-D weighting */ |
| 416 |
> |
multcolor(scol, sr.rcoef); |
| 417 |
> |
d = (double)nstarget/ntrials; |
| 418 |
> |
scalecolor(scol, d); |
| 419 |
> |
addcolor(r->rcol, scol); |
| 420 |
> |
} |
| 421 |
|
ndims--; |
| 422 |
|
} |
| 423 |
|
/* compute transmission */ |
| 424 |
+ |
copycolor(sr.rcoef, np->mcolor); /* modify by material color */ |
| 425 |
+ |
scalecolor(sr.rcoef, np->tspec); |
| 426 |
|
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
| 427 |
< |
rayorigin(&sr, r, SPECULAR, np->tspec) == 0) { |
| 427 |
> |
rayorigin(&sr, SPECULAR, r, sr.rcoef) == 0) { |
| 428 |
> |
nstarget = 1; |
| 429 |
> |
if (specjitter > 1.5) { /* multiple samples? */ |
| 430 |
> |
nstarget = specjitter*r->rweight + .5; |
| 431 |
> |
if (sr.rweight <= minweight*nstarget) |
| 432 |
> |
nstarget = sr.rweight/minweight; |
| 433 |
> |
if (nstarget > 1) { |
| 434 |
> |
d = 1./nstarget; |
| 435 |
> |
scalecolor(sr.rcoef, d); |
| 436 |
> |
sr.rweight *= d; |
| 437 |
> |
} else |
| 438 |
> |
nstarget = 1; |
| 439 |
> |
} |
| 440 |
|
dimlist[ndims++] = (int)np->mp; |
| 441 |
< |
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
| 442 |
< |
multisamp(rv, 2, d); |
| 443 |
< |
d = 2.0*PI * rv[0]; |
| 444 |
< |
cosp = cos(d) * np->u_alpha; |
| 445 |
< |
sinp = sin(d) * np->v_alpha; |
| 446 |
< |
d = sqrt(cosp*cosp + sinp*sinp); |
| 447 |
< |
cosp /= d; |
| 448 |
< |
sinp /= d; |
| 449 |
< |
rv[1] = 1.0 - specjitter*rv[1]; |
| 450 |
< |
if (rv[1] <= FTINY) |
| 451 |
< |
d = 1.0; |
| 452 |
< |
else |
| 453 |
< |
d = sqrt(-log(rv[1]) / |
| 454 |
< |
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
| 455 |
< |
sinp*sinp/(np->v_alpha*np->u_alpha))); |
| 456 |
< |
for (i = 0; i < 3; i++) |
| 457 |
< |
sr.rdir[i] = np->prdir[i] + |
| 458 |
< |
d*(cosp*np->u[i] + sinp*np->v[i]); |
| 459 |
< |
if (DOT(sr.rdir, r->ron) < -FTINY) |
| 460 |
< |
normalize(sr.rdir); /* OK, normalize */ |
| 461 |
< |
else |
| 462 |
< |
VCOPY(sr.rdir, np->prdir); /* else no jitter */ |
| 463 |
< |
rayvalue(&sr); |
| 464 |
< |
scalecolor(sr.rcol, np->tspec); |
| 465 |
< |
multcolor(sr.rcol, np->mcolor); /* modify by color */ |
| 466 |
< |
addcolor(r->rcol, sr.rcol); |
| 441 |
> |
maxiter = MAXITER*nstarget; |
| 442 |
> |
for (nstaken = ntrials = 0; nstaken < nstarget && |
| 443 |
> |
ntrials < maxiter; ntrials++) { |
| 444 |
> |
if (ntrials) |
| 445 |
> |
d = frandom(); |
| 446 |
> |
else |
| 447 |
> |
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
| 448 |
> |
multisamp(rv, 2, d); |
| 449 |
> |
d = 2.0*PI * rv[0]; |
| 450 |
> |
cosp = tcos(d) * np->u_alpha; |
| 451 |
> |
sinp = tsin(d) * np->v_alpha; |
| 452 |
> |
d = 1./sqrt(cosp*cosp + sinp*sinp); |
| 453 |
> |
cosp *= d; |
| 454 |
> |
sinp *= d; |
| 455 |
> |
if ((0. <= specjitter) & (specjitter < 1.)) |
| 456 |
> |
rv[1] = 1.0 - specjitter*rv[1]; |
| 457 |
> |
if (rv[1] <= FTINY) |
| 458 |
> |
d = 1.0; |
| 459 |
> |
else |
| 460 |
> |
d = sqrt(-log(rv[1]) / |
| 461 |
> |
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
| 462 |
> |
sinp*sinp/(np->v_alpha*np->v_alpha))); |
| 463 |
> |
for (i = 0; i < 3; i++) |
| 464 |
> |
sr.rdir[i] = np->prdir[i] + |
| 465 |
> |
d*(cosp*np->u[i] + sinp*np->v[i]); |
| 466 |
> |
if (DOT(sr.rdir, r->ron) >= -FTINY) |
| 467 |
> |
continue; |
| 468 |
> |
normalize(sr.rdir); /* OK, normalize */ |
| 469 |
> |
if (nstaken) /* multi-sampling */ |
| 470 |
> |
rayclear(&sr); |
| 471 |
> |
rayvalue(&sr); |
| 472 |
> |
multcolor(sr.rcol, sr.rcoef); |
| 473 |
> |
addcolor(r->rcol, sr.rcol); |
| 474 |
> |
++nstaken; |
| 475 |
> |
} |
| 476 |
|
ndims--; |
| 477 |
|
} |
| 478 |
|
} |
