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#include "random.h" |
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extern double specthresh; /* specular sampling threshold */ |
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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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#define SP_TRAN 02 /* has transmitted specular */ |
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#define SP_PURE 010 /* purely specular (zero roughness) */ |
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#define SP_FLAT 020 /* flat reflecting surface */ |
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#define SP_RBLT 040 /* reflection below sample threshold */ |
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#define SP_TBLT 0100 /* transmission below threshold */ |
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typedef struct { |
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OBJREC *mp; /* material pointer */ |
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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.rspec <= specthresh+FTINY) |
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nd.specfl |= SP_RBLT; |
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/* compute reflected ray */ |
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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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nd.tdiff = nd.trans - nd.tspec; |
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if (nd.tspec > FTINY) { |
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nd.specfl |= SP_TRAN; |
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/* check threshold */ |
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if (nd.tspec <= specthresh+FTINY) |
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nd.specfl |= SP_TBLT; |
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if (r->crtype & SHADOW || |
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DOT(r->pert,r->pert) <= FTINY*FTINY) { |
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VCOPY(nd.prdir, r->rdir); |
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if (nd.rdiff > FTINY) { /* ambient from this side */ |
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ambient(ctmp, r); |
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scalecolor(ctmp, nd.rdiff); |
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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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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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flipsurface(r); |
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ambient(ctmp, r); |
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scalecolor(ctmp, nd.tdiff); |
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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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addcolor(r->rcol, ctmp); |
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flipsurface(r); |
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FVECT u, v, h; |
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double rv[2]; |
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double d, sinp, cosp; |
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int confuse; |
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int ntries; |
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register int i; |
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/* set up sample coordinates */ |
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v[0] = v[1] = v[2] = 0.0; |
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normalize(u); |
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fcross(v, np->pnorm, u); |
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/* compute reflection */ |
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if (np->specfl & SP_REFL && |
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if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
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rayorigin(&sr, r, SPECULAR, np->rspec) == 0) { |
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confuse = 0; |
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dimlist[ndims++] = (int)np->mp; |
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refagain: |
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dimlist[ndims] = confuse += 3601; |
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d = urand(ilhash(dimlist,ndims+1)+samplendx); |
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multisamp(rv, 2, d); |
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d = 2.0*PI * rv[0]; |
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cosp = cos(d); |
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sinp = sin(d); |
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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 * -log(rv[1]) ); |
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for (i = 0; i < 3; i++) |
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h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]); |
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d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
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for (i = 0; i < 3; i++) |
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sr.rdir[i] = r->rdir[i] + d*h[i]; |
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if (DOT(sr.rdir, r->ron) <= FTINY) /* oops! */ |
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goto refagain; |
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rayvalue(&sr); |
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multcolor(sr.rcol, np->scolor); |
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addcolor(r->rcol, sr.rcol); |
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for (ntries = 0; ntries < 10; ntries++) { |
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dimlist[ndims] = ntries * 8912; |
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d = urand(ilhash(dimlist,ndims+1)+samplendx); |
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multisamp(rv, 2, d); |
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d = 2.0*PI * rv[0]; |
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cosp = cos(d); |
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sinp = sin(d); |
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rv[1] = 1.0 - specjitter*rv[1]; |
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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 * -log(rv[1]) ); |
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for (i = 0; i < 3; i++) |
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h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]); |
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d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
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for (i = 0; i < 3; i++) |
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sr.rdir[i] = r->rdir[i] + d*h[i]; |
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if (DOT(sr.rdir, r->ron) > FTINY) { |
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rayvalue(&sr); |
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multcolor(sr.rcol, np->scolor); |
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addcolor(r->rcol, sr.rcol); |
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break; |
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} |
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} |
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ndims--; |
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} |
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/* compute transmission */ |
