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#ifndef lint |
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static const char RCSid[] = "$Id: cmbsdf.c,v 2.2 2014/01/20 22:18:29 greg Exp $"; |
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#endif |
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/* |
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* Load and convert BSDF into color coefficient matrix representation. |
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* |
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* G. Ward |
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*/ |
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|
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#include "standard.h" |
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#include "cmatrix.h" |
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#include "paths.h" |
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#include "bsdf.h" |
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#include "bsdf_m.h" |
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|
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/* Convert a BSDF to our matrix representation */ |
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static CMATRIX * |
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cm_bsdf(const COLOR diffBSDF, const SDMat *bsdf) |
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{ |
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CMATRIX *cm = cm_alloc(bsdf->nout, bsdf->ninc); |
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int nbadohm = 0; |
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int nneg = 0; |
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int r, c; |
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/* loop over incident angles */ |
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for (c = 0; c < cm->ncols; c++) { |
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const double dom = mBSDF_incohm(bsdf,c); |
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/* projected solid angle */ |
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nbadohm += (dom <= 0); |
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|
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for (r = 0; r < cm->nrows; r++) { |
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float f = mBSDF_value(bsdf,c,r); |
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COLORV *mp = cm_lval(cm,r,c); |
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/* check BSDF value */ |
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if ((f <= 0) | (dom <= 0)) { |
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nneg += (f < -FTINY); |
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setcolor(mp, .0f, .0f, .0f); |
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} else if (bsdf->chroma != NULL) { |
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C_COLOR cxy; |
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c_decodeChroma(&cxy, |
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bsdf->chroma[r*bsdf->ninc + c]); |
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ccy2rgb(&cxy, f, mp); |
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} else |
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setcolor(mp, f, f, f); |
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addcolor(mp, diffBSDF); |
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scalecolor(mp, dom); |
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} |
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} |
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if (nneg | nbadohm) { |
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sprintf(errmsg, |
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"BTDF has %d negatives and %d bad incoming solid angles", |
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nneg, nbadohm); |
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error(WARNING, errmsg); |
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} |
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return(cm); |
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} |
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|
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/* Convert between input and output indices for reciprocity */ |
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static int |
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recip_out_from_in(const SDMat *bsdf, int in_recip) |
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{ |
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FVECT v; |
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|
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if (!mBSDF_incvec(v, bsdf, in_recip+.5)) |
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return(in_recip); /* XXX should be error! */ |
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v[2] = -v[2]; |
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return(mBSDF_outndx(bsdf, v)); |
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} |
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|
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/* Convert between output and input indices for reciprocity */ |
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static int |
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recip_in_from_out(const SDMat *bsdf, int out_recip) |
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{ |
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FVECT v; |
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|
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if (!mBSDF_outvec(v, bsdf, out_recip+.5)) |
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return(out_recip); /* XXX should be error! */ |
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v[2] = -v[2]; |
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return(mBSDF_incndx(bsdf, v)); |
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} |
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|
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/* Convert a BSDF to our matrix representation, applying reciprocity */ |
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static CMATRIX * |
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cm_bsdf_recip(const COLOR diffBSDF, const SDMat *bsdf) |
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{ |
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CMATRIX *cm = cm_alloc(bsdf->ninc, bsdf->nout); |
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int nbadohm = 0; |
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int nneg = 0; |
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int r, c; |
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/* loop over incident angles */ |
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for (c = 0; c < cm->ncols; c++) { |
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const int ro = recip_out_from_in(bsdf,c); |
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const double dom = mBSDF_outohm(bsdf,ro); |
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/* projected solid angle */ |
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nbadohm += (dom <= 0); |
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|
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for (r = 0; r < cm->nrows; r++) { |
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const int ri = recip_in_from_out(bsdf,r); |
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float f = mBSDF_value(bsdf,ri,ro); |
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COLORV *mp = cm_lval(cm,r,c); |
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/* check BSDF value */ |
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if ((f <= 0) | (dom <= 0)) { |
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nneg += (f < -FTINY); |
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setcolor(mp, .0f, .0f, .0f); |
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} else if (bsdf->chroma != NULL) { |
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C_COLOR cxy; |
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c_decodeChroma(&cxy, |
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bsdf->chroma[ro*bsdf->ninc + ri]); |
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ccy2rgb(&cxy, f, mp); |
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} else |
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setcolor(mp, f, f, f); |
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addcolor(mp, diffBSDF); |
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scalecolor(mp, dom); |
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} |
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} |
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if (nneg | nbadohm) { |
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sprintf(errmsg, |
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"BTDF has %d negatives and %d bad incoming solid angles", |
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nneg, nbadohm); |
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error(WARNING, errmsg); |
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} |
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return(cm); |
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} |
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|
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/* Return a Lambertian (diffuse) matrix */ |
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static CMATRIX * |
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cm_bsdf_Lamb(const COLOR diffBSDF) |
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{ |
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CMATRIX *cm = cm_alloc(145, 145); /* this is a hack */ |
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int r, c; |
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|
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for (c = 0; c < cm->ncols; c++) |
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for (r = 0; r < cm->nrows; r++) { |
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COLORV *mp = cm_lval(cm,r,c); |
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copycolor(mp, diffBSDF); |
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} |
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return(cm); |
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} |
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|
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/* Load and convert a matrix BTDF from the given XML file */ |
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CMATRIX * |
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cm_loadBTDF(char *fname) |
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{ |
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CMATRIX *Tmat; |
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char *fpath; |
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int recip; |
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SDError ec; |
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SDData myBSDF; |
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SDSpectralDF *tdf; |
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COLOR diffBSDF; |
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/* find path to BSDF file */ |
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fpath = getpath(fname, getrlibpath(), R_OK); |
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if (fpath == NULL) { |
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sprintf(errmsg, "cannot find BSDF file '%s'", fname); |
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error(USER, errmsg); |
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} |
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SDclearBSDF(&myBSDF, fname); /* load XML and check type */ |
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ec = SDloadFile(&myBSDF, fpath); |
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if (ec) |
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error(USER, transSDError(ec)); |
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ccy2rgb(&myBSDF.tLamb.spec, myBSDF.tLamb.cieY/PI, diffBSDF); |
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recip = (myBSDF.tb == NULL); |
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tdf = recip ? myBSDF.tf : myBSDF.tb; |
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if (tdf == NULL) { /* no non-Lambertian transmission? */ |
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SDfreeBSDF(&myBSDF); |
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return(cm_bsdf_Lamb(diffBSDF)); |
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} |
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if (tdf->ncomp != 1 || tdf->comp[0].func != &SDhandleMtx) { |
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sprintf(errmsg, "unsupported BSDF '%s'", fpath); |
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error(USER, errmsg); |
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} |
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/* convert BTDF to matrix */ |
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Tmat = recip ? cm_bsdf_recip(diffBSDF, (SDMat *)tdf->comp[0].dist) |
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: cm_bsdf(diffBSDF, (SDMat *)tdf->comp[0].dist); |
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/* free BSDF and return */ |
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SDfreeBSDF(&myBSDF); |
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return(Tmat); |
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} |
