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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 anisotropic reflection model uses a variant on the |
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* exponential Gaussian used in normal.c. |
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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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#define SP_PURE 010 /* purely specular (zero roughness) */ |
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#define SP_BADU 020 /* bad u direction calculation */ |
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#define SP_FLAT 040 /* reflecting surface is flat */ |
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#define SP_FLAT 020 /* reflecting surface is flat */ |
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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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#define SP_BADU 0200 /* bad u direction calculation */ |
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typedef struct { |
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OBJREC *mp; /* material pointer */ |
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short specfl; /* specularity flags, defined above */ |
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COLOR mcolor; /* color of this material */ |
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COLOR scolor; /* color of specular component */ |
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FVECT vrefl; /* vector in reflected direction */ |
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FVECT prdir; /* vector in transmitted direction */ |
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FVECT u, v; /* u and v vectors orienting anisotropy */ |
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double u_alpha; /* u roughness */ |
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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 (specthresh > FTINY && |
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((specthresh >= 1.-FTINY || |
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specthresh + (.05 - .1*frandom()) > nd.rspec))) |
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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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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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if (!(r->crtype & SHADOW) && nd.specfl & SP_PURE) { |
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RAY lr; |
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if (rayorigin(&lr, r, REFLECTED, nd.rspec) == 0) { |
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for (i = 0; i < 3; i++) |
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lr.rdir[i] = r->rdir[i] + |
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2.0*nd.pdot*nd.pnorm[i]; |
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VCOPY(lr.rdir, nd.vrefl); |
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rayvalue(&lr); |
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multcolor(lr.rcol, nd.scolor); |
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addcolor(r->rcol, lr.rcol); |
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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 (specthresh > FTINY && |
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((specthresh >= 1.-FTINY || |
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specthresh + |
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(.05 - .1*frandom()) > nd.tspec))) |
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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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} else { |
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for (i = 0; i < 3; i++) /* perturb */ |
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nd.prdir[i] = r->rdir[i] - |
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.75*r->pert[i]; |
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normalize(nd.prdir); |
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0.5*r->pert[i]; |
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if (DOT(nd.prdir, r->ron) < -FTINY) |
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normalize(nd.prdir); /* OK */ |
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else |
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VCOPY(nd.prdir, r->rdir); |
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} |
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} |
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} else |
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if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) |
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return; /* 100% pure specular */ |
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if (r->ro->otype == OBJ_FACE || r->ro->otype == OBJ_RING) |
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nd.specfl |= SP_FLAT; |
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getacoords(r, &nd); /* set up coordinates */ |
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if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & (SP_PURE|SP_BADU))) |
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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 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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register int i; |
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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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d = urand(ilhash(dimlist,ndims)+samplendx); |
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multisamp(rv, 2, d); |
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d = 2.0*PI * rv[0]; |
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cosp = np->u_alpha * cos(d); |
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d = sqrt(cosp*cosp + sinp*sinp); |
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cosp /= d; |
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sinp /= 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( -log(rv[1]) / |
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d = sqrt(-log(rv[1]) / |
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(cosp*cosp/(np->u_alpha*np->u_alpha) + |
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sinp*sinp/(np->v_alpha*np->v_alpha)) ); |
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sinp*sinp/(np->v_alpha*np->v_alpha))); |
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for (i = 0; i < 3; i++) |
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h[i] = np->pnorm[i] + |
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d*(cosp*np->u[i] + sinp*np->v[i]); |
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d*(cosp*np->u[i] + sinp*np->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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if (DOT(sr.rdir, r->ron) <= FTINY) /* penetration? */ |
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VCOPY(sr.rdir, np->vrefl); /* jitter no good */ |
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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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ndims--; |
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} |
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/* compute transmission */ |
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if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
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rayorigin(&sr, r, SPECULAR, np->tspec) == 0) { |
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dimlist[ndims++] = (int)np->mp; |
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d = urand(ilhash(dimlist,ndims)+1823+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(-log(rv[1]) / |
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(cosp*cosp*4./(np->u_alpha*np->u_alpha) + |
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sinp*sinp*4./(np->v_alpha*np->v_alpha))); |
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for (i = 0; i < 3; i++) |
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sr.rdir[i] = np->prdir[i] + |
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d*(cosp*np->u[i] + sinp*np->v[i]); |
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if (DOT(sr.rdir, r->ron) < -FTINY) |
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normalize(sr.rdir); /* OK, normalize */ |
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else |
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VCOPY(sr.rdir, np->prdir); /* else no jitter */ |
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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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ndims--; |
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} |
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} |
