--- ray/src/rt/normal.c 1992/01/16 12:05:29 2.9 +++ ray/src/rt/normal.c 1993/03/08 12:37:27 2.24 @@ -23,11 +23,11 @@ static char SCCSid[] = "$SunId$ LBL"; extern double specthresh; /* specular sampling threshold */ extern double specjitter; /* specular sampling jitter */ +static gaussamp(); + /* - * 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. * @@ -43,13 +43,14 @@ extern double specjitter; /* specular sampling jitte /* 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 */ @@ -71,8 +72,8 @@ FVECT ldir; /* light source direction */ double omega; /* light source size */ { double ldot; - double dtmp; - int i; + double dtmp, d2; + FVECT vtmp; COLOR ctmp; setcolor(cval, 0.0, 0.0, 0.0); @@ -99,16 +100,23 @@ double omega; /* light source size */ * 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); + dtmp += omega/(4.0*PI); + /* half vector */ + vtmp[0] = ldir[0] - np->rp->rdir[0]; + vtmp[1] = ldir[1] - np->rp->rdir[1]; + vtmp[2] = ldir[2] - np->rp->rdir[2]; + d2 = DOT(vtmp, np->pnorm); + d2 *= d2; + d2 = (DOT(vtmp,vtmp) - d2) / d2; /* gaussian */ - dtmp = exp((DOT(np->vrefl,ldir)-1.)/dtmp)/(2.*PI)/dtmp; + dtmp = exp(-d2/dtmp)/(4.*PI*dtmp); /* worth using? */ if (dtmp > FTINY) { copycolor(ctmp, np->scolor); - dtmp *= omega / np->pdot; + dtmp *= omega * sqrt(ldot/np->pdot); scalecolor(ctmp, dtmp); addcolor(cval, ctmp); } @@ -128,13 +136,13 @@ double omega; /* light source size */ * is always modified by material color. */ /* roughness + source */ - dtmp = np->alpha2/2.0 + omega/(2.0*PI); + dtmp = np->alpha2 + omega/PI; /* gaussian */ - dtmp = exp((DOT(np->prdir,ldir)-1.)/dtmp)/(2.*PI)/dtmp; + 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); } @@ -158,6 +166,7 @@ register RAY *r; if (m->oargs.nfargs != (m->otype == MAT_TRANS ? 7 : 5)) objerror(m, USER, "bad number of arguments"); nd.mp = m; + nd.rp = r; /* get material color */ setcolor(nd.mcolor, m->oargs.farg[0], m->oargs.farg[1], @@ -192,10 +201,10 @@ register RAY *r; 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 + (.05 - .1*urand(8199+samplendx)) - > nd.rspec))) + if (!(nd.specfl & SP_PURE) && + specthresh > FTINY && + (specthresh >= 1.-FTINY || + specthresh + .05 - .1*frandom() > nd.rspec)) nd.specfl |= SP_RBLT; /* compute reflected ray */ for (i = 0; i < 3; i++) @@ -222,11 +231,9 @@ register RAY *r; if (nd.tspec > FTINY) { nd.specfl |= SP_TRAN; /* check threshold */ - if (specthresh > FTINY && - ((specthresh >= 1.-FTINY || - specthresh + - (.05 - .1*urand(7241+samplendx)) - > nd.tspec))) + if (!(nd.specfl & SP_PURE) && specthresh > FTINY && + (specthresh >= 1.-FTINY || + specthresh + .05 - .1*frandom() > nd.tspec)) nd.specfl |= SP_TBLT; if (r->crtype & SHADOW || DOT(r->pert,r->pert) <= FTINY*FTINY) { @@ -234,8 +241,7 @@ register RAY *r; transtest = 2; } else { for (i = 0; i < 3; i++) /* perturb */ - nd.prdir[i] = r->rdir[i] - - 0.5*r->pert[i]; + nd.prdir[i] = r->rdir[i] - r->pert[i]; if (DOT(nd.prdir, r->ron) < -FTINY) normalize(nd.prdir); /* OK */ else @@ -256,7 +262,8 @@ register RAY *r; transtest *= bright(lr.rcol); transdist = r->rot + lr.rt; } - } + } else + transtest = 0; if (r->crtype & SHADOW) /* the rest is shadow */ return; @@ -266,7 +273,8 @@ register RAY *r; if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) return; /* 100% pure specular */ - if (r->ro->otype == OBJ_FACE || r->ro->otype == OBJ_RING) + if (r->ro != NULL && (r->ro->otype == OBJ_FACE || + r->ro->otype == OBJ_RING)) nd.specfl |= SP_FLAT; if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_PURE)) @@ -310,6 +318,10 @@ register NORMDAT *np; double rv[2]; double d, sinp, cosp; register 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++) @@ -358,7 +370,7 @@ register NORMDAT *np; if (rv[1] <= FTINY) d = 1.0; else - d = sqrt( np->alpha2/4.0 * -log(rv[1]) ); + d = sqrt( -log(rv[1]) * np->alpha2 ); for (i = 0; i < 3; i++) sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); if (DOT(sr.rdir, r->ron) < -FTINY) @@ -366,7 +378,8 @@ register NORMDAT *np; else VCOPY(sr.rdir, np->prdir); /* else no jitter */ rayvalue(&sr); - multcolor(sr.rcol, np->scolor); + scalecolor(sr.rcol, np->tspec); + multcolor(sr.rcol, np->mcolor); /* modified by color */ addcolor(r->rcol, sr.rcol); ndims--; }