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extern double specjitter; /* specular sampling jitter */ |
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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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/* + 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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/* delta */ |
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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 = 2.0 - 2.0*d2/sqrt(DOT(vtmp,vtmp)); |
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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(-d2/dtmp)/(4.*PI*dtmp); |
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/* worth using? */ |
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/* roughness + source */ |
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dtmp = np->alpha2 + omega/PI; |
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/* gaussian */ |
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< |
dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(4.*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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copycolor(ctmp, np->mcolor); |
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if (rv[1] <= FTINY) |
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d = 1.0; |
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else |
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< |
d = sqrt( np->alpha2/4.0 * -log(rv[1]) ); |
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d = sqrt( -log(rv[1]) * np->alpha2 ); |
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for (i = 0; i < 3; i++) |
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sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); |
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if (DOT(sr.rdir, r->ron) < -FTINY) |
