--- ray/src/rt/normal.c 1992/01/15 11:02:40 2.6 +++ ray/src/rt/normal.c 2014/01/25 18:27:39 2.66 @@ -1,9 +1,6 @@ -/* Copyright (c) 1992 Regents of the University of California */ - #ifndef lint -static char SCCSid[] = "$SunId$ LBL"; +static const char RCSid[] = "$Id: normal.c,v 2.66 2014/01/25 18:27:39 greg Exp $"; #endif - /* * normal.c - shading function for normal materials. * @@ -14,20 +11,26 @@ static char SCCSid[] = "$SunId$ LBL"; * Later changes described in delta comments. */ -#include "ray.h" +#include "copyright.h" +#include "ray.h" +#include "ambient.h" +#include "source.h" #include "otypes.h" - +#include "rtotypes.h" #include "random.h" -extern double specthresh; /* specular sampling threshold */ -extern double specjitter; /* specular sampling jitter */ +#ifndef MAXITER +#define MAXITER 10 /* maximum # specular ray attempts */ +#endif + /* estimate of Fresnel function */ +#define FRESNE(ci) (exp(-5.85*(ci)) - 0.00287989916) +#define FRESTHRESH 0.017999 /* minimum specularity for approx. */ + /* - * This routine uses portions of the reflection - * model described by Cook and Torrance. - * The computation of specular components has been simplified by - * numerous approximations and ommisions to improve speed. + * This routine implements the isotropic Gaussian + * model described by Ward in Siggraph `92 article. * We orient the surface towards the incoming ray, so a single * surface can be used to represent an infinitely thin object. * @@ -38,18 +41,17 @@ extern double specjitter; /* specular sampling jitte * red grn blu rspec rough trans tspec */ -#define BSPEC(m) (6.0) /* specularity parameter b */ - /* specularity flags */ #define SP_REFL 01 /* has reflected specular component */ #define SP_TRAN 02 /* has transmitted specular */ -#define SP_PURE 010 /* purely specular (zero roughness) */ -#define SP_FLAT 020 /* flat reflecting surface */ -#define SP_RBLT 040 /* reflection below sample threshold */ -#define SP_TBLT 0100 /* transmission below threshold */ +#define SP_PURE 04 /* purely specular (zero roughness) */ +#define SP_FLAT 010 /* flat reflecting surface */ +#define SP_RBLT 020 /* reflection below sample threshold */ +#define SP_TBLT 040 /* transmission below threshold */ typedef struct { OBJREC *mp; /* material pointer */ + RAY *rp; /* ray pointer */ short specfl; /* specularity flags, defined above */ COLOR mcolor; /* color of this material */ COLOR scolor; /* color of specular component */ @@ -63,16 +65,22 @@ typedef struct { double pdot; /* perturbed dot product */ } NORMDAT; /* normal material data */ +static void gaussamp(NORMDAT *np); -dirnorm(cval, np, ldir, omega) /* compute source contribution */ -COLOR cval; /* returned coefficient */ -register NORMDAT *np; /* material data */ -FVECT ldir; /* light source direction */ -double omega; /* light source size */ + +static void +dirnorm( /* compute source contribution */ + COLOR cval, /* returned coefficient */ + void *nnp, /* material data */ + FVECT ldir, /* light source direction */ + double omega /* light source size */ +) { + NORMDAT *np = nnp; double ldot; - double dtmp; - int i; + double lrdiff, ltdiff; + double dtmp, d2, d3, d4; + FVECT vtmp; COLOR ctmp; setcolor(cval, 0.0, 0.0, 0.0); @@ -82,43 +90,59 @@ double omega; /* light source size */ if (ldot < 0.0 ? np->trans <= FTINY : np->trans >= 1.0-FTINY) return; /* wrong side */ - if (ldot > FTINY && np->rdiff > FTINY) { + /* Fresnel estimate */ + lrdiff = np->rdiff; + ltdiff = np->tdiff; + if (np->specfl & SP_PURE && np->rspec >= FRESTHRESH && + (lrdiff > FTINY) | (ltdiff > FTINY)) { + dtmp = 1. - FRESNE(fabs(ldot)); + lrdiff *= dtmp; + ltdiff *= dtmp; + } + + if (ldot > FTINY && lrdiff > FTINY) { /* * Compute and add diffuse reflected component to returned * color. The diffuse reflected component will always be * modified by the color of the material. */ copycolor(ctmp, np->mcolor); - dtmp = ldot * omega * np->rdiff / PI; + dtmp = ldot * omega * lrdiff * (1.0/PI); scalecolor(ctmp, dtmp); addcolor(cval, ctmp); } if (ldot > FTINY && (np->specfl&(SP_REFL|SP_PURE)) == SP_REFL) { /* * Compute specular reflection coefficient using - * gaussian distribution model. + * Gaussian distribution model. */ /* roughness */ - dtmp = 2.0*np->alpha2; + dtmp = np->alpha2; /* + source if flat */ if (np->specfl & SP_FLAT) - dtmp += omega/(2.0*PI); - /* gaussian */ - dtmp = exp((DOT(np->vrefl,ldir)-1.)/dtmp)/(2.*PI)/dtmp; + dtmp += omega * (0.25/PI); + /* half vector */ + VSUB(vtmp, ldir, np->rp->rdir); + d2 = DOT(vtmp, np->pnorm); + d2 *= d2; + d3 = DOT(vtmp,vtmp); + d4 = (d3 - d2) / d2; + /* new W-G-M-D model */ + dtmp = exp(-d4/dtmp) * d3 / (PI * d2*d2 * dtmp); /* worth using? */ if (dtmp > FTINY) { copycolor(ctmp, np->scolor); - dtmp *= omega / np->pdot; + dtmp *= ldot * omega; scalecolor(ctmp, dtmp); addcolor(cval, ctmp); } } - if (ldot < -FTINY && np->tdiff > FTINY) { + if (ldot < -FTINY && ltdiff > FTINY) { /* * Compute diffuse transmission. */ copycolor(ctmp, np->mcolor); - dtmp = -ldot * omega * np->tdiff / PI; + dtmp = -ldot * omega * ltdiff * (1.0/PI); scalecolor(ctmp, dtmp); addcolor(cval, ctmp); } @@ -128,13 +152,13 @@ double omega; /* light source size */ * is always modified by material color. */ /* roughness + source */ - dtmp = np->alpha2 + omega/(2.0*PI); - /* gaussian */ - dtmp = exp((DOT(np->prdir,ldir)-1.)/dtmp)/(2.*PI)/dtmp; + dtmp = np->alpha2 + omega*(1.0/PI); + /* Gaussian */ + dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(PI*dtmp); /* worth using? */ if (dtmp > FTINY) { copycolor(ctmp, np->mcolor); - dtmp *= np->tspec * omega / np->pdot; + dtmp *= np->tspec * omega * sqrt(-ldot/np->pdot); scalecolor(ctmp, dtmp); addcolor(cval, ctmp); } @@ -142,22 +166,38 @@ double omega; /* light source size */ } -m_normal(m, r) /* color a ray that hit something normal */ -register OBJREC *m; -register RAY *r; +int +m_normal( /* color a ray that hit something normal */ + OBJREC *m, + RAY *r +) { NORMDAT nd; + double fest; double transtest, transdist; - double dtmp; + double mirtest, mirdist; + int hastexture; + double d; COLOR ctmp; - register int i; + int i; /* easy shadow test */ if (r->crtype & SHADOW && m->otype != MAT_TRANS) - return; + return(1); if (m->oargs.nfargs != (m->otype == MAT_TRANS ? 7 : 5)) objerror(m, USER, "bad number of arguments"); + /* check for back side */ + if (r->rod < 0.0) { + if (!backvis) { + raytrans(r); + return(1); + } + raytexture(r, m->omod); + flipsurface(r); /* reorient if backvis */ + } else + raytexture(r, m->omod); nd.mp = m; + nd.rp = r; /* get material color */ setcolor(nd.mcolor, m->oargs.farg[0], m->oargs.farg[1], @@ -167,50 +207,27 @@ register RAY *r; nd.alpha2 = m->oargs.farg[4]; if ((nd.alpha2 *= nd.alpha2) <= FTINY) nd.specfl |= SP_PURE; - /* reorient if necessary */ - if (r->rod < 0.0) - flipsurface(r); - /* get modifiers */ - raytexture(r, m->omod); - nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ + + if ( (hastexture = (DOT(r->pert,r->pert) > FTINY*FTINY)) ) { + nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ + } else { + VCOPY(nd.pnorm, r->ron); + nd.pdot = r->rod; + } + if (r->ro != NULL && isflat(r->ro->otype)) + nd.specfl |= SP_FLAT; if (nd.pdot < .001) nd.pdot = .001; /* non-zero for dirnorm() */ multcolor(nd.mcolor, r->pcol); /* modify material color */ - transtest = 0; - /* get specular component */ - if ((nd.rspec = m->oargs.farg[3]) > FTINY) { - nd.specfl |= SP_REFL; - /* compute specular color */ - if (m->otype == MAT_METAL) - copycolor(nd.scolor, nd.mcolor); - else - setcolor(nd.scolor, 1.0, 1.0, 1.0); - scalecolor(nd.scolor, nd.rspec); - /* improved model */ - dtmp = exp(-BSPEC(m)*nd.pdot); - for (i = 0; i < 3; i++) - colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp; - nd.rspec += (1.0-nd.rspec)*dtmp; - /* check threshold */ - if (specthresh > FTINY && - ((specthresh >= 1.-FTINY || - specthresh + (.1 - .2*urand(8199+samplendx)) - > nd.rspec))) - nd.specfl |= SP_RBLT; - /* compute reflected ray */ - for (i = 0; i < 3; i++) - nd.vrefl[i] = r->rdir[i] + 2.0*nd.pdot*nd.pnorm[i]; - - if (!(r->crtype & SHADOW) && nd.specfl & SP_PURE) { - RAY lr; - if (rayorigin(&lr, r, REFLECTED, nd.rspec) == 0) { - VCOPY(lr.rdir, nd.vrefl); - rayvalue(&lr); - multcolor(lr.rcol, nd.scolor); - addcolor(r->rcol, lr.rcol); - } - } - } + mirtest = transtest = 0; + mirdist = transdist = r->rot; + nd.rspec = m->oargs.farg[3]; + /* compute Fresnel approx. */ + if (nd.specfl & SP_PURE && nd.rspec >= FRESTHRESH) { + fest = FRESNE(nd.pdot); + nd.rspec += fest*(1. - nd.rspec); + } else + fest = 0.; /* compute transmission */ if (m->otype == MAT_TRANS) { nd.trans = m->oargs.farg[5]*(1.0 - nd.rspec); @@ -219,92 +236,146 @@ register RAY *r; if (nd.tspec > FTINY) { nd.specfl |= SP_TRAN; /* check threshold */ - if (specthresh > FTINY && - ((specthresh >= 1.-FTINY || - specthresh + - (.1 - .2*urand(7241+samplendx)) - > nd.tspec))) + if (!(nd.specfl & SP_PURE) && + specthresh >= nd.tspec-FTINY) nd.specfl |= SP_TBLT; - if (r->crtype & SHADOW || - DOT(r->pert,r->pert) <= FTINY*FTINY) { + if (!hastexture || r->crtype & SHADOW) { VCOPY(nd.prdir, r->rdir); transtest = 2; } else { for (i = 0; i < 3; i++) /* perturb */ - nd.prdir[i] = r->rdir[i] - - .75*r->pert[i]; - normalize(nd.prdir); + nd.prdir[i] = r->rdir[i] - r->pert[i]; + if (DOT(nd.prdir, r->ron) < -FTINY) + normalize(nd.prdir); /* OK */ + else + VCOPY(nd.prdir, r->rdir); } } } else nd.tdiff = nd.tspec = nd.trans = 0.0; /* transmitted ray */ - if ((nd.specfl&(SP_TRAN|SP_PURE)) == (SP_TRAN|SP_PURE)) { + if ((nd.specfl&(SP_TRAN|SP_PURE|SP_TBLT)) == (SP_TRAN|SP_PURE)) { RAY lr; - if (rayorigin(&lr, r, TRANS, nd.tspec) == 0) { + copycolor(lr.rcoef, nd.mcolor); /* modified by color */ + scalecolor(lr.rcoef, nd.tspec); + if (rayorigin(&lr, TRANS, r, lr.rcoef) == 0) { VCOPY(lr.rdir, nd.prdir); rayvalue(&lr); - scalecolor(lr.rcol, nd.tspec); - multcolor(lr.rcol, nd.mcolor); /* modified by color */ + multcolor(lr.rcol, lr.rcoef); addcolor(r->rcol, lr.rcol); transtest *= bright(lr.rcol); transdist = r->rot + lr.rt; } - } + } else + transtest = 0; - if (r->crtype & SHADOW) /* the rest is shadow */ - return; + if (r->crtype & SHADOW) { /* the rest is shadow */ + r->rt = transdist; + return(1); + } + /* get specular reflection */ + if (nd.rspec > FTINY) { + nd.specfl |= SP_REFL; + /* compute specular color */ + if (m->otype != MAT_METAL) { + setcolor(nd.scolor, nd.rspec, nd.rspec, nd.rspec); + } else if (fest > FTINY) { + d = m->oargs.farg[3]*(1. - fest); + for (i = 0; i < 3; i++) + colval(nd.scolor,i) = fest + + colval(nd.mcolor,i)*d; + } else { + copycolor(nd.scolor, nd.mcolor); + scalecolor(nd.scolor, nd.rspec); + } + /* check threshold */ + if (!(nd.specfl & SP_PURE) && specthresh >= nd.rspec-FTINY) + nd.specfl |= SP_RBLT; + /* compute reflected ray */ + VSUM(nd.vrefl, r->rdir, nd.pnorm, 2.*nd.pdot); + /* penetration? */ + if (hastexture && DOT(nd.vrefl, r->ron) <= FTINY) + VSUM(nd.vrefl, r->rdir, r->ron, 2.*r->rod); + checknorm(nd.vrefl); + } + /* reflected ray */ + if ((nd.specfl&(SP_REFL|SP_PURE|SP_RBLT)) == (SP_REFL|SP_PURE)) { + RAY lr; + if (rayorigin(&lr, REFLECTED, r, nd.scolor) == 0) { + VCOPY(lr.rdir, nd.vrefl); + rayvalue(&lr); + multcolor(lr.rcol, lr.rcoef); + addcolor(r->rcol, lr.rcol); + if (!hastexture && nd.specfl & SP_FLAT) { + mirtest = 2.*bright(lr.rcol); + mirdist = r->rot + lr.rt; + } + } + } /* diffuse reflection */ nd.rdiff = 1.0 - nd.trans - nd.rspec; if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) - return; /* 100% pure specular */ + return(1); /* 100% pure specular */ - if (r->ro->otype == OBJ_FACE || r->ro->otype == OBJ_RING) - nd.specfl |= SP_FLAT; + if (!(nd.specfl & SP_PURE)) + gaussamp(&nd); /* checks *BLT flags */ - if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_PURE)) - gaussamp(r, &nd); - if (nd.rdiff > FTINY) { /* ambient from this side */ - ambient(ctmp, r); - if (nd.specfl & SP_RBLT) - scalecolor(ctmp, 1.0-nd.trans); - else - scalecolor(ctmp, nd.rdiff); - multcolor(ctmp, nd.mcolor); /* modified by material color */ + copycolor(ctmp, nd.mcolor); /* modified by material color */ + scalecolor(ctmp, nd.rdiff); + if (nd.specfl & SP_RBLT) /* add in specular as well? */ + addcolor(ctmp, nd.scolor); + multambient(ctmp, r, hastexture ? nd.pnorm : r->ron); addcolor(r->rcol, ctmp); /* add to returned color */ } if (nd.tdiff > FTINY) { /* ambient from other side */ - flipsurface(r); - ambient(ctmp, r); + copycolor(ctmp, nd.mcolor); /* modified by color */ if (nd.specfl & SP_TBLT) scalecolor(ctmp, nd.trans); else scalecolor(ctmp, nd.tdiff); - multcolor(ctmp, nd.mcolor); /* modified by color */ + flipsurface(r); + if (hastexture) { + FVECT bnorm; + bnorm[0] = -nd.pnorm[0]; + bnorm[1] = -nd.pnorm[1]; + bnorm[2] = -nd.pnorm[2]; + multambient(ctmp, r, bnorm); + } else + multambient(ctmp, r, r->ron); addcolor(r->rcol, ctmp); flipsurface(r); } /* add direct component */ direct(r, dirnorm, &nd); /* check distance */ - if (transtest > bright(r->rcol)) + d = bright(r->rcol); + if (transtest > d) r->rt = transdist; + else if (mirtest > d) + r->rt = mirdist; + + return(1); } -static -gaussamp(r, np) /* sample gaussian specular */ -RAY *r; -register NORMDAT *np; +static void +gaussamp( /* sample Gaussian specular */ + NORMDAT *np +) { RAY sr; FVECT u, v, h; double rv[2]; double d, sinp, cosp; - int ntries; - register int i; + COLOR scol; + int maxiter, ntrials, nstarget, nstaken; + int i; + /* quick test */ + if ((np->specfl & (SP_REFL|SP_RBLT)) != SP_REFL && + (np->specfl & (SP_TRAN|SP_TBLT)) != SP_TRAN) + return; /* set up sample coordinates */ v[0] = v[1] = v[2] = 0.0; for (i = 0; i < 3; i++) @@ -316,33 +387,115 @@ register NORMDAT *np; fcross(v, np->pnorm, u); /* compute reflection */ if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && - rayorigin(&sr, r, SPECULAR, np->rspec) == 0) { - dimlist[ndims++] = (int)np->mp; - for (ntries = 0; ntries < 10; ntries++) { - dimlist[ndims] = ntries * 8912; - d = urand(ilhash(dimlist,ndims+1)+samplendx); + rayorigin(&sr, SPECULAR, np->rp, np->scolor) == 0) { + nstarget = 1; + if (specjitter > 1.5) { /* multiple samples? */ + nstarget = specjitter*np->rp->rweight + .5; + if (sr.rweight <= minweight*nstarget) + nstarget = sr.rweight/minweight; + if (nstarget > 1) { + d = 1./nstarget; + scalecolor(sr.rcoef, d); + sr.rweight *= d; + } else + nstarget = 1; + } + setcolor(scol, 0., 0., 0.); + dimlist[ndims++] = (int)(size_t)np->mp; + maxiter = MAXITER*nstarget; + for (nstaken = ntrials = 0; nstaken < nstarget && + ntrials < maxiter; ntrials++) { + if (ntrials) + d = frandom(); + else + d = urand(ilhash(dimlist,ndims)+samplendx); multisamp(rv, 2, d); d = 2.0*PI * rv[0]; - cosp = cos(d); - sinp = sin(d); - rv[1] = 1.0 - specjitter*rv[1]; + cosp = tcos(d); + sinp = tsin(d); + if ((0. <= specjitter) & (specjitter < 1.)) + rv[1] = 1.0 - specjitter*rv[1]; if (rv[1] <= FTINY) d = 1.0; else d = sqrt( np->alpha2 * -log(rv[1]) ); for (i = 0; i < 3; i++) h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]); - d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); - for (i = 0; i < 3; i++) - sr.rdir[i] = r->rdir[i] + d*h[i]; - if (DOT(sr.rdir, r->ron) > FTINY) { + d = -2.0 * DOT(h, np->rp->rdir) / (1.0 + d*d); + VSUM(sr.rdir, np->rp->rdir, h, d); + /* sample rejection test */ + if ((d = DOT(sr.rdir, np->rp->ron)) <= FTINY) + continue; + checknorm(sr.rdir); + if (nstarget > 1) { /* W-G-M-D adjustment */ + if (nstaken) rayclear(&sr); rayvalue(&sr); - multcolor(sr.rcol, np->scolor); - addcolor(r->rcol, sr.rcol); - break; + d = 2./(1. + np->rp->rod/d); + scalecolor(sr.rcol, d); + addcolor(scol, sr.rcol); + } else { + rayvalue(&sr); + multcolor(sr.rcol, sr.rcoef); + addcolor(np->rp->rcol, sr.rcol); } + ++nstaken; } + if (nstarget > 1) { /* final W-G-M-D weighting */ + multcolor(scol, sr.rcoef); + d = (double)nstarget/ntrials; + scalecolor(scol, d); + addcolor(np->rp->rcol, scol); + } ndims--; } /* compute transmission */ + copycolor(sr.rcoef, np->mcolor); /* modified by color */ + scalecolor(sr.rcoef, np->tspec); + if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && + rayorigin(&sr, SPECULAR, np->rp, sr.rcoef) == 0) { + nstarget = 1; + if (specjitter > 1.5) { /* multiple samples? */ + nstarget = specjitter*np->rp->rweight + .5; + if (sr.rweight <= minweight*nstarget) + nstarget = sr.rweight/minweight; + if (nstarget > 1) { + d = 1./nstarget; + scalecolor(sr.rcoef, d); + sr.rweight *= d; + } else + nstarget = 1; + } + dimlist[ndims++] = (int)(size_t)np->mp; + maxiter = MAXITER*nstarget; + for (nstaken = ntrials = 0; nstaken < nstarget && + ntrials < maxiter; ntrials++) { + if (ntrials) + d = frandom(); + else + d = urand(ilhash(dimlist,ndims)+samplendx); + multisamp(rv, 2, d); + d = 2.0*PI * rv[0]; + cosp = tcos(d); + sinp = tsin(d); + if ((0. <= specjitter) & (specjitter < 1.)) + rv[1] = 1.0 - specjitter*rv[1]; + if (rv[1] <= FTINY) + d = 1.0; + else + d = sqrt( np->alpha2 * -log(rv[1]) ); + for (i = 0; i < 3; i++) + sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); + /* sample rejection test */ + if (DOT(sr.rdir, np->rp->ron) >= -FTINY) + continue; + normalize(sr.rdir); /* OK, normalize */ + if (nstaken) /* multi-sampling */ + rayclear(&sr); + rayvalue(&sr); + multcolor(sr.rcol, sr.rcoef); + addcolor(np->rp->rcol, sr.rcol); + ++nstaken; + } + ndims--; + } }