--- ray/src/rt/normal.c 1992/05/15 13:07:55 2.18 +++ ray/src/rt/normal.c 1995/09/15 15:47:30 2.29 @@ -23,11 +23,13 @@ static char SCCSid[] = "$SunId$ LBL"; extern double specthresh; /* specular sampling threshold */ extern double specjitter; /* specular sampling jitter */ +extern int backvis; /* back faces visible? */ + +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. * @@ -38,8 +40,6 @@ 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 */ @@ -104,12 +104,13 @@ double omega; /* light source size */ /* + source if flat */ if (np->specfl & SP_FLAT) dtmp += omega/(4.0*PI); - /* delta */ + /* 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 = 2.0 - 2.0*d2/sqrt(DOT(vtmp,vtmp)); + d2 *= d2; + d2 = (DOT(vtmp,vtmp) - d2) / d2; /* gaussian */ dtmp = exp(-d2/dtmp)/(4.*PI*dtmp); /* worth using? */ @@ -135,9 +136,9 @@ double omega; /* light source size */ * is always modified by material color. */ /* roughness + source */ - dtmp = np->alpha2/4.0 + omega/PI; + dtmp = np->alpha2 + omega/PI; /* gaussian */ - dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(4.*PI*dtmp); + dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(PI*dtmp); /* worth using? */ if (dtmp > FTINY) { copycolor(ctmp, np->mcolor); @@ -155,15 +156,25 @@ register RAY *r; { NORMDAT nd; double transtest, transdist; - double dtmp; + double mirtest, mirdist; + int hastexture; + double d; COLOR ctmp; register 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 && m->otype != MAT_TRANS) { + raytrans(r); + return(1); + } + flipsurface(r); /* reorient if backvis */ + } nd.mp = m; nd.rp = r; /* get material color */ @@ -175,16 +186,21 @@ 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); + if (r->ro != NULL && isflat(r->ro->otype)) + nd.specfl |= SP_FLAT; /* 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 (nd.pdot < .001) nd.pdot = .001; /* non-zero for dirnorm() */ multcolor(nd.mcolor, r->pcol); /* modify material color */ - transtest = 0; + mirtest = transtest = 0; + mirdist = transdist = r->rot; /* get specular component */ if ((nd.rspec = m->oargs.farg[3]) > FTINY) { nd.specfl |= SP_REFL; @@ -194,21 +210,14 @@ register RAY *r; 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 (!(nd.specfl & SP_PURE) && - specthresh > FTINY && - (specthresh >= 1.-FTINY || - specthresh + .05 - .1*frandom() > nd.rspec)) + if (!(nd.specfl & SP_PURE) && specthresh >= nd.rspec-FTINY) 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 (DOT(nd.vrefl, r->ron) <= FTINY) /* penetration? */ + nd.vrefl[i] = r->rdir[i] + 2.*nd.pdot*nd.pnorm[i]; + /* penetration? */ + if (hastexture && DOT(nd.vrefl, r->ron) <= FTINY) for (i = 0; i < 3; i++) /* safety measure */ nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; @@ -219,6 +228,10 @@ register RAY *r; rayvalue(&lr); multcolor(lr.rcol, nd.scolor); addcolor(r->rcol, lr.rcol); + if (!hastexture && nd.specfl & SP_FLAT) { + mirtest = 2.*bright(lr.rcol); + mirdist = r->rot + lr.rt; + } } } } @@ -230,18 +243,15 @@ register RAY *r; if (nd.tspec > FTINY) { nd.specfl |= SP_TRAN; /* check threshold */ - if (!(nd.specfl & SP_PURE) && specthresh > FTINY && - (specthresh >= 1.-FTINY || - specthresh + .05 - .1*frandom() > 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] - - 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 @@ -265,18 +275,16 @@ register RAY *r; } 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); + } /* 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 != 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)) gaussamp(r, &nd); @@ -303,8 +311,13 @@ register RAY *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); } @@ -370,7 +383,7 @@ 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)