--- ray/src/rt/glass.c 1991/10/29 16:30:46 1.11 +++ ray/src/rt/glass.c 2003/02/22 02:07:28 2.10 @@ -1,17 +1,71 @@ -/* Copyright (c) 1991 Regents of the University of California */ - #ifndef lint -static char SCCSid[] = "$SunId$ LBL"; +static const char RCSid[] = "$Id: glass.c,v 2.10 2003/02/22 02:07:28 greg Exp $"; #endif - /* * glass.c - simpler shading function for thin glass surfaces. + */ + +/* ==================================================================== + * The Radiance Software License, Version 1.0 * - * 11/14/86 + * Copyright (c) 1990 - 2002 The Regents of the University of California, + * through Lawrence Berkeley National Laboratory. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * 3. The end-user documentation included with the redistribution, + * if any, must include the following acknowledgment: + * "This product includes Radiance software + * (http://radsite.lbl.gov/) + * developed by the Lawrence Berkeley National Laboratory + * (http://www.lbl.gov/)." + * Alternately, this acknowledgment may appear in the software itself, + * if and wherever such third-party acknowledgments normally appear. + * + * 4. The names "Radiance," "Lawrence Berkeley National Laboratory" + * and "The Regents of the University of California" must + * not be used to endorse or promote products derived from this + * software without prior written permission. For written + * permission, please contact radiance@radsite.lbl.gov. + * + * 5. Products derived from this software may not be called "Radiance", + * nor may "Radiance" appear in their name, without prior written + * permission of Lawrence Berkeley National Laboratory. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR + * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * ==================================================================== + * + * This software consists of voluntary contributions made by many + * individuals on behalf of Lawrence Berkeley National Laboratory. For more + * information on Lawrence Berkeley National Laboratory, please see + * . */ #include "ray.h" +#include "otypes.h" + /* * This definition of glass provides for a quick calculation * using a single surface where two closely spaced parallel @@ -24,14 +78,17 @@ static char SCCSid[] = "$SunId$ LBL"; * modifier glass id * 0 * 0 - * 3 red grn blu + * 3+ red grn blu [refractive_index] * * The color is used for the transmission at normal incidence. - * To compute transmission (tn) from transmissivity (Tn) use: + * To compute transmissivity (tn) from transmittance (Tn) use: * * tn = (sqrt(.8402528435+.0072522239*Tn*Tn)-.9166530661)/.0036261119/Tn * - * The transmission of standard 88% transmissivity glass is 0.96. + * The transmissivity of standard 88% transmittance glass is 0.96. + * A refractive index other than the default can be used by giving + * it as the fourth real argument. The above formula no longer applies. + * * If we appear to hit the back side of the surface, then we * turn the normal around. */ @@ -43,39 +100,50 @@ m_glass(m, r) /* color a ray which hit a thin glass s OBJREC *m; register RAY *r; { - double sqrt(), pow(); COLOR mcolor; double pdot; FVECT pnorm; - double cos2; + double rindex, cos2; COLOR trans, refl; + int hastexture; double d, r1e, r1m; double transtest, transdist; + double mirtest, mirdist; RAY p; register int i; - - if (m->oargs.nfargs != 3) + /* check arguments */ + if (m->oargs.nfargs == 3) + rindex = RINDEX; /* default value of n */ + else if (m->oargs.nfargs == 4) + rindex = m->oargs.farg[3]; /* use their value */ + else objerror(m, USER, "bad arguments"); setcolor(mcolor, m->oargs.farg[0], m->oargs.farg[1], m->oargs.farg[2]); if (r->rod < 0.0) /* reorient if necessary */ flipsurface(r); - transtest = 0; + mirtest = transtest = 0; + mirdist = transdist = r->rot; /* get modifiers */ raytexture(r, m->omod); - pdot = raynormal(pnorm, r); + if (hastexture = DOT(r->pert,r->pert) > FTINY*FTINY) + pdot = raynormal(pnorm, r); + else { + VCOPY(pnorm, r->ron); + pdot = r->rod; + } /* angular transmission */ - cos2 = sqrt( (1.0-1.0/RINDEX/RINDEX) + - pdot*pdot/(RINDEX*RINDEX) ); + cos2 = sqrt( (1.0-1.0/(rindex*rindex)) + + pdot*pdot/(rindex*rindex) ); setcolor(mcolor, pow(colval(mcolor,RED), 1.0/cos2), pow(colval(mcolor,GRN), 1.0/cos2), pow(colval(mcolor,BLU), 1.0/cos2)); /* compute reflection */ - r1e = (pdot - RINDEX*cos2) / (pdot + RINDEX*cos2); + r1e = (pdot - rindex*cos2) / (pdot + rindex*cos2); r1e *= r1e; - r1m = (1.0/pdot - RINDEX/cos2) / (1.0/pdot + RINDEX/cos2); + r1m = (1.0/pdot - rindex/cos2) / (1.0/pdot + rindex/cos2); r1m *= r1m; /* compute transmittance */ for (i = 0; i < 3; i++) { @@ -85,11 +153,14 @@ register RAY *r; } /* transmitted ray */ if (rayorigin(&p, r, TRANS, bright(trans)) == 0) { - if (!(r->crtype & SHADOW) && - DOT(r->pert,r->pert) > FTINY*FTINY) { + if (!(r->crtype & SHADOW) && hastexture) { for (i = 0; i < 3; i++) /* perturb direction */ - p.rdir[i] = r->rdir[i] - r->pert[i]/RINDEX; - normalize(p.rdir); + p.rdir[i] = r->rdir[i] + + 2.*(1.-rindex)*r->pert[i]; + if (normalize(p.rdir) == 0.0) { + objerror(m, WARNING, "bad perturbation"); + VCOPY(p.rdir, r->rdir); + } } else { VCOPY(p.rdir, r->rdir); transtest = 2; @@ -102,8 +173,10 @@ register RAY *r; transdist = r->rot + p.rt; } - if (r->crtype & SHADOW) /* skip reflected ray */ - return; + if (r->crtype & SHADOW) { /* skip reflected ray */ + r->rt = transdist; + return(1); + } /* compute reflectance */ for (i = 0; i < 3; i++) { d = colval(mcolor, i); @@ -118,7 +191,16 @@ register RAY *r; rayvalue(&p); multcolor(p.rcol, refl); addcolor(r->rcol, p.rcol); + if (!hastexture && r->ro != NULL && isflat(r->ro->otype)) { + mirtest = 2.0*bright(p.rcol); + mirdist = r->rot + p.rt; + } } - if (transtest > bright(r->rcol)) + /* check distance */ + d = bright(r->rcol); + if (transtest > d) r->rt = transdist; + else if (mirtest > d) + r->rt = mirdist; + return(1); }