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greg |
2.2 |
/* Copyright (c) 1992 Regents of the University of California */ |
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greg |
1.1 |
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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/* |
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* normal.c - shading function for normal materials. |
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* |
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* 8/19/85 |
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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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greg |
2.2 |
* Later changes described in delta comments. |
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greg |
1.1 |
*/ |
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#include "ray.h" |
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#include "otypes.h" |
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greg |
2.2 |
#include "random.h" |
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greg |
2.5 |
extern double specthresh; /* specular sampling threshold */ |
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extern double specjitter; /* specular sampling jitter */ |
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greg |
1.1 |
/* |
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greg |
2.22 |
* This routine implements the isotropic Gaussian |
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* model described by Ward in Siggraph `92 article. |
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greg |
1.1 |
* 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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* Arguments for MAT_PLASTIC and MAT_METAL are: |
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* red grn blu specular-frac. facet-slope |
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* |
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* Arguments for MAT_TRANS are: |
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* red grn blu rspec rough trans tspec |
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*/ |
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#define BSPEC(m) (6.0) /* specularity parameter b */ |
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greg |
2.2 |
/* 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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greg |
2.11 |
#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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greg |
1.1 |
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greg |
1.3 |
typedef struct { |
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OBJREC *mp; /* material pointer */ |
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greg |
2.16 |
RAY *rp; /* ray pointer */ |
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greg |
2.2 |
short specfl; /* specularity flags, defined above */ |
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greg |
1.1 |
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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greg |
1.14 |
FVECT prdir; /* vector in transmitted direction */ |
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greg |
2.2 |
double alpha2; /* roughness squared */ |
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greg |
1.1 |
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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FVECT pnorm; /* perturbed surface normal */ |
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double pdot; /* perturbed dot product */ |
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greg |
1.3 |
} NORMDAT; /* normal material data */ |
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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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greg |
1.1 |
double ldot; |
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greg |
2.16 |
double dtmp, d2; |
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FVECT vtmp; |
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greg |
1.3 |
COLOR ctmp; |
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setcolor(cval, 0.0, 0.0, 0.0); |
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ldot = DOT(np->pnorm, ldir); |
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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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if (ldot > FTINY && np->rdiff > FTINY) { |
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/* |
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greg |
1.4 |
* 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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greg |
1.3 |
*/ |
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copycolor(ctmp, np->mcolor); |
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dtmp = ldot * omega * np->rdiff / PI; |
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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
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greg |
2.2 |
if (ldot > FTINY && (np->specfl&(SP_REFL|SP_PURE)) == SP_REFL) { |
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greg |
1.3 |
/* |
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* Compute specular reflection coefficient using |
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* gaussian distribution model. |
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*/ |
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greg |
2.3 |
/* roughness */ |
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greg |
2.16 |
dtmp = np->alpha2; |
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greg |
2.3 |
/* + source if flat */ |
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if (np->specfl & SP_FLAT) |
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greg |
2.16 |
dtmp += omega/(4.0*PI); |
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/* delta */ |
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greg |
2.18 |
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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greg |
2.16 |
d2 = DOT(vtmp, np->pnorm); |
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d2 = 2.0 - 2.0*d2/sqrt(DOT(vtmp,vtmp)); |
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greg |
1.3 |
/* gaussian */ |
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greg |
2.16 |
dtmp = exp(-d2/dtmp)/(4.*PI*dtmp); |
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greg |
1.3 |
/* worth using? */ |
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if (dtmp > FTINY) { |
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copycolor(ctmp, np->scolor); |
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greg |
2.14 |
dtmp *= omega * sqrt(ldot/np->pdot); |
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greg |
1.3 |
scalecolor(ctmp, dtmp); |
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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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/* |
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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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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
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greg |
2.2 |
if (ldot < -FTINY && (np->specfl&(SP_TRAN|SP_PURE)) == SP_TRAN) { |
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greg |
1.3 |
/* |
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greg |
1.4 |
* Compute specular transmission. Specular transmission |
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greg |
1.13 |
* is always modified by material color. |
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greg |
1.3 |
*/ |
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/* roughness + source */ |
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greg |
2.19 |
dtmp = np->alpha2 + omega/PI; |
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greg |
1.3 |
/* gaussian */ |
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greg |
2.21 |
dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(PI*dtmp); |
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greg |
1.3 |
/* worth using? */ |
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if (dtmp > FTINY) { |
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greg |
1.13 |
copycolor(ctmp, np->mcolor); |
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greg |
2.18 |
dtmp *= np->tspec * omega * sqrt(-ldot/np->pdot); |
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greg |
1.13 |
scalecolor(ctmp, dtmp); |
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greg |
1.3 |
addcolor(cval, ctmp); |
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} |
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} |
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} |
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greg |
2.2 |
m_normal(m, r) /* color a ray that hit something normal */ |
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greg |
1.3 |
register OBJREC *m; |
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register RAY *r; |
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{ |
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NORMDAT nd; |
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greg |
1.9 |
double transtest, transdist; |
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greg |
1.1 |
double dtmp; |
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COLOR ctmp; |
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register int i; |
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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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greg |
2.2 |
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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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greg |
1.3 |
nd.mp = m; |
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greg |
2.16 |
nd.rp = r; |
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greg |
1.1 |
/* get material color */ |
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greg |
1.3 |
setcolor(nd.mcolor, m->oargs.farg[0], |
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greg |
1.1 |
m->oargs.farg[1], |
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m->oargs.farg[2]); |
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/* get roughness */ |
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greg |
2.2 |
nd.specfl = 0; |
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greg |
1.3 |
nd.alpha2 = m->oargs.farg[4]; |
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greg |
2.2 |
if ((nd.alpha2 *= nd.alpha2) <= FTINY) |
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nd.specfl |= SP_PURE; |
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greg |
1.1 |
/* 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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greg |
1.3 |
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
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greg |
1.13 |
if (nd.pdot < .001) |
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nd.pdot = .001; /* non-zero for dirnorm() */ |
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greg |
1.3 |
multcolor(nd.mcolor, r->pcol); /* modify material color */ |
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greg |
1.9 |
transtest = 0; |
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greg |
1.1 |
/* get specular component */ |
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greg |
2.2 |
if ((nd.rspec = m->oargs.farg[3]) > FTINY) { |
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nd.specfl |= SP_REFL; |
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greg |
1.1 |
/* compute specular color */ |
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if (m->otype == MAT_METAL) |
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greg |
1.3 |
copycolor(nd.scolor, nd.mcolor); |
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greg |
1.1 |
else |
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greg |
1.3 |
setcolor(nd.scolor, 1.0, 1.0, 1.0); |
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scalecolor(nd.scolor, nd.rspec); |
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greg |
2.15 |
/* improved model */ |
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dtmp = exp(-BSPEC(m)*nd.pdot); |
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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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greg |
2.13 |
(specthresh >= 1.-FTINY || |
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greg |
2.17 |
specthresh + .05 - .1*frandom() > nd.rspec)) |
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greg |
2.5 |
nd.specfl |= SP_RBLT; |
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greg |
1.1 |
/* compute reflected ray */ |
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for (i = 0; i < 3; i++) |
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greg |
1.3 |
nd.vrefl[i] = r->rdir[i] + 2.0*nd.pdot*nd.pnorm[i]; |
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greg |
2.7 |
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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greg |
1.1 |
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greg |
2.2 |
if (!(r->crtype & SHADOW) && nd.specfl & SP_PURE) { |
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greg |
1.3 |
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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greg |
1.1 |
rayvalue(&lr); |
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greg |
1.3 |
multcolor(lr.rcol, nd.scolor); |
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greg |
1.1 |
addcolor(r->rcol, lr.rcol); |
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} |
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greg |
1.3 |
} |
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greg |
1.1 |
} |
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greg |
1.3 |
/* compute transmission */ |
| 224 |
greg |
1.1 |
if (m->otype == MAT_TRANS) { |
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greg |
1.3 |
nd.trans = m->oargs.farg[5]*(1.0 - nd.rspec); |
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nd.tspec = nd.trans * m->oargs.farg[6]; |
| 227 |
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nd.tdiff = nd.trans - nd.tspec; |
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greg |
2.2 |
if (nd.tspec > FTINY) { |
| 229 |
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nd.specfl |= SP_TRAN; |
| 230 |
greg |
2.5 |
/* check threshold */ |
| 231 |
greg |
2.13 |
if (!(nd.specfl & SP_PURE) && specthresh > FTINY && |
| 232 |
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(specthresh >= 1.-FTINY || |
| 233 |
greg |
2.17 |
specthresh + .05 - .1*frandom() > nd.tspec)) |
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greg |
2.5 |
nd.specfl |= SP_TBLT; |
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greg |
2.2 |
if (r->crtype & SHADOW || |
| 236 |
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DOT(r->pert,r->pert) <= FTINY*FTINY) { |
| 237 |
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VCOPY(nd.prdir, r->rdir); |
| 238 |
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transtest = 2; |
| 239 |
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} else { |
| 240 |
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for (i = 0; i < 3; i++) /* perturb */ |
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greg |
2.19 |
nd.prdir[i] = r->rdir[i] - r->pert[i]; |
| 242 |
greg |
2.7 |
if (DOT(nd.prdir, r->ron) < -FTINY) |
| 243 |
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normalize(nd.prdir); /* OK */ |
| 244 |
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else |
| 245 |
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VCOPY(nd.prdir, r->rdir); |
| 246 |
greg |
2.2 |
} |
| 247 |
greg |
1.14 |
} |
| 248 |
greg |
1.1 |
} else |
| 249 |
greg |
1.3 |
nd.tdiff = nd.tspec = nd.trans = 0.0; |
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greg |
1.1 |
/* transmitted ray */ |
| 251 |
greg |
2.2 |
if ((nd.specfl&(SP_TRAN|SP_PURE)) == (SP_TRAN|SP_PURE)) { |
| 252 |
greg |
1.3 |
RAY lr; |
| 253 |
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if (rayorigin(&lr, r, TRANS, nd.tspec) == 0) { |
| 254 |
greg |
1.14 |
VCOPY(lr.rdir, nd.prdir); |
| 255 |
greg |
1.1 |
rayvalue(&lr); |
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greg |
1.3 |
scalecolor(lr.rcol, nd.tspec); |
| 257 |
greg |
1.8 |
multcolor(lr.rcol, nd.mcolor); /* modified by color */ |
| 258 |
greg |
1.1 |
addcolor(r->rcol, lr.rcol); |
| 259 |
greg |
1.9 |
transtest *= bright(lr.rcol); |
| 260 |
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transdist = r->rot + lr.rt; |
| 261 |
greg |
1.1 |
} |
| 262 |
greg |
2.11 |
} else |
| 263 |
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transtest = 0; |
| 264 |
greg |
2.2 |
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| 265 |
greg |
1.1 |
if (r->crtype & SHADOW) /* the rest is shadow */ |
| 266 |
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return; |
| 267 |
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/* diffuse reflection */ |
| 268 |
greg |
1.3 |
nd.rdiff = 1.0 - nd.trans - nd.rspec; |
| 269 |
greg |
1.1 |
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| 270 |
greg |
2.2 |
if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) |
| 271 |
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return; /* 100% pure specular */ |
| 272 |
greg |
2.3 |
|
| 273 |
greg |
2.12 |
if (r->ro != NULL && (r->ro->otype == OBJ_FACE || |
| 274 |
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r->ro->otype == OBJ_RING)) |
| 275 |
greg |
2.3 |
nd.specfl |= SP_FLAT; |
| 276 |
greg |
1.1 |
|
| 277 |
greg |
2.2 |
if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_PURE)) |
| 278 |
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gaussamp(r, &nd); |
| 279 |
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| 280 |
greg |
1.3 |
if (nd.rdiff > FTINY) { /* ambient from this side */ |
| 281 |
greg |
1.2 |
ambient(ctmp, r); |
| 282 |
greg |
2.5 |
if (nd.specfl & SP_RBLT) |
| 283 |
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scalecolor(ctmp, 1.0-nd.trans); |
| 284 |
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else |
| 285 |
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scalecolor(ctmp, nd.rdiff); |
| 286 |
greg |
1.3 |
multcolor(ctmp, nd.mcolor); /* modified by material color */ |
| 287 |
greg |
1.2 |
addcolor(r->rcol, ctmp); /* add to returned color */ |
| 288 |
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} |
| 289 |
greg |
1.3 |
if (nd.tdiff > FTINY) { /* ambient from other side */ |
| 290 |
greg |
1.1 |
flipsurface(r); |
| 291 |
greg |
1.2 |
ambient(ctmp, r); |
| 292 |
greg |
2.5 |
if (nd.specfl & SP_TBLT) |
| 293 |
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scalecolor(ctmp, nd.trans); |
| 294 |
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else |
| 295 |
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scalecolor(ctmp, nd.tdiff); |
| 296 |
greg |
1.13 |
multcolor(ctmp, nd.mcolor); /* modified by color */ |
| 297 |
greg |
1.1 |
addcolor(r->rcol, ctmp); |
| 298 |
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flipsurface(r); |
| 299 |
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} |
| 300 |
greg |
1.3 |
/* add direct component */ |
| 301 |
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direct(r, dirnorm, &nd); |
| 302 |
greg |
1.9 |
/* check distance */ |
| 303 |
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if (transtest > bright(r->rcol)) |
| 304 |
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r->rt = transdist; |
| 305 |
greg |
2.2 |
} |
| 306 |
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| 307 |
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| 308 |
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static |
| 309 |
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gaussamp(r, np) /* sample gaussian specular */ |
| 310 |
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RAY *r; |
| 311 |
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register NORMDAT *np; |
| 312 |
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{ |
| 313 |
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RAY sr; |
| 314 |
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FVECT u, v, h; |
| 315 |
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double rv[2]; |
| 316 |
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double d, sinp, cosp; |
| 317 |
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register int i; |
| 318 |
greg |
2.13 |
/* quick test */ |
| 319 |
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if ((np->specfl & (SP_REFL|SP_RBLT)) != SP_REFL && |
| 320 |
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(np->specfl & (SP_TRAN|SP_TBLT)) != SP_TRAN) |
| 321 |
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return; |
| 322 |
greg |
2.2 |
/* set up sample coordinates */ |
| 323 |
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v[0] = v[1] = v[2] = 0.0; |
| 324 |
|
|
for (i = 0; i < 3; i++) |
| 325 |
|
|
if (np->pnorm[i] < 0.6 && np->pnorm[i] > -0.6) |
| 326 |
|
|
break; |
| 327 |
|
|
v[i] = 1.0; |
| 328 |
|
|
fcross(u, v, np->pnorm); |
| 329 |
|
|
normalize(u); |
| 330 |
|
|
fcross(v, np->pnorm, u); |
| 331 |
|
|
/* compute reflection */ |
| 332 |
greg |
2.5 |
if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
| 333 |
greg |
2.2 |
rayorigin(&sr, r, SPECULAR, np->rspec) == 0) { |
| 334 |
|
|
dimlist[ndims++] = (int)np->mp; |
| 335 |
greg |
2.7 |
d = urand(ilhash(dimlist,ndims)+samplendx); |
| 336 |
|
|
multisamp(rv, 2, d); |
| 337 |
|
|
d = 2.0*PI * rv[0]; |
| 338 |
|
|
cosp = cos(d); |
| 339 |
|
|
sinp = sin(d); |
| 340 |
|
|
rv[1] = 1.0 - specjitter*rv[1]; |
| 341 |
|
|
if (rv[1] <= FTINY) |
| 342 |
|
|
d = 1.0; |
| 343 |
|
|
else |
| 344 |
|
|
d = sqrt( np->alpha2 * -log(rv[1]) ); |
| 345 |
|
|
for (i = 0; i < 3; i++) |
| 346 |
|
|
h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]); |
| 347 |
|
|
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
| 348 |
|
|
for (i = 0; i < 3; i++) |
| 349 |
|
|
sr.rdir[i] = r->rdir[i] + d*h[i]; |
| 350 |
|
|
if (DOT(sr.rdir, r->ron) <= FTINY) |
| 351 |
|
|
VCOPY(sr.rdir, np->vrefl); /* jitter no good */ |
| 352 |
|
|
rayvalue(&sr); |
| 353 |
|
|
multcolor(sr.rcol, np->scolor); |
| 354 |
|
|
addcolor(r->rcol, sr.rcol); |
| 355 |
greg |
2.2 |
ndims--; |
| 356 |
|
|
} |
| 357 |
|
|
/* compute transmission */ |
| 358 |
greg |
2.8 |
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
| 359 |
|
|
rayorigin(&sr, r, SPECULAR, np->tspec) == 0) { |
| 360 |
|
|
dimlist[ndims++] = (int)np->mp; |
| 361 |
|
|
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
| 362 |
|
|
multisamp(rv, 2, d); |
| 363 |
|
|
d = 2.0*PI * rv[0]; |
| 364 |
|
|
cosp = cos(d); |
| 365 |
|
|
sinp = sin(d); |
| 366 |
|
|
rv[1] = 1.0 - specjitter*rv[1]; |
| 367 |
|
|
if (rv[1] <= FTINY) |
| 368 |
|
|
d = 1.0; |
| 369 |
|
|
else |
| 370 |
greg |
2.20 |
d = sqrt( -log(rv[1]) * np->alpha2 ); |
| 371 |
greg |
2.8 |
for (i = 0; i < 3; i++) |
| 372 |
|
|
sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); |
| 373 |
|
|
if (DOT(sr.rdir, r->ron) < -FTINY) |
| 374 |
|
|
normalize(sr.rdir); /* OK, normalize */ |
| 375 |
|
|
else |
| 376 |
|
|
VCOPY(sr.rdir, np->prdir); /* else no jitter */ |
| 377 |
|
|
rayvalue(&sr); |
| 378 |
greg |
2.11 |
scalecolor(sr.rcol, np->tspec); |
| 379 |
|
|
multcolor(sr.rcol, np->mcolor); /* modified by color */ |
| 380 |
greg |
2.8 |
addcolor(r->rcol, sr.rcol); |
| 381 |
|
|
ndims--; |
| 382 |
|
|
} |
| 383 |
greg |
1.1 |
} |
