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#ifndef lint |
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static const char RCSid[] = "$Id: checkBSDF.c,v 2.2 2021/12/15 02:13:27 greg Exp $"; |
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#endif |
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/* |
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* checkBSDF.c |
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* |
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* Load BSDF XML file and check Helmholtz reciprocity |
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*/ |
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|
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#define _USE_MATH_DEFINES |
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#include <math.h> |
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#include "rtio.h" |
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#include "random.h" |
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#include "bsdf.h" |
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#include "bsdf_m.h" |
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#include "bsdf_t.h" |
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|
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#define F_IN_COLOR 0x1 |
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#define F_ISOTROPIC 0x2 |
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#define F_MATRIX 0x4 |
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#define F_TTREE 0x8 |
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|
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typedef struct { |
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double vmin, vmax; /* extrema */ |
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double vsum; /* straight sum */ |
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long nvals; /* number of values */ |
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} SimpleStats; |
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|
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const SimpleStats SSinit = {FHUGE, -FHUGE, .0, 0}; |
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|
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/* relative difference formula */ |
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#define rdiff(a,b) ((a)>(b) ? ((a)-(b))/(a) : ((b)-(a))/(b)) |
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|
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/* Figure out BSDF type (and optionally determine if in color) */ |
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const char * |
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getBSDFtype(const SDData *bsdf, int *flags) |
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{ |
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const SDSpectralDF *df = bsdf->tb; |
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|
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if (flags) *flags = 0; |
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if (!df) df = bsdf->tf; |
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if (!df) df = bsdf->rf; |
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if (!df) df = bsdf->rb; |
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if (!df) return "Pure_Lambertian"; |
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if (df->comp[0].func == &SDhandleMtx) { |
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const SDMat *m = (const SDMat *)df->comp[0].dist; |
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if (flags) { |
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*flags |= F_MATRIX; |
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*flags |= F_IN_COLOR*(m->chroma != NULL); |
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} |
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switch (m->ninc) { |
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case 145: |
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return "Klems_Full"; |
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case 73: |
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return "Klems_Half"; |
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case 41: |
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return "Klems_Quarter"; |
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} |
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return "Unknown_Matrix"; |
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} |
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if (df->comp[0].func == &SDhandleTre) { |
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const SDTre *t = (const SDTre *)df->comp[0].dist; |
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if (flags) { |
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*flags |= F_TTREE; |
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*flags |= F_IN_COLOR*(t->stc[1] != NULL); |
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} |
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switch (t->stc[0]->ndim) { |
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case 4: |
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return "Anisotropic_Tensor_Tree"; |
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case 3: |
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if (flags) *flags |= F_ISOTROPIC; |
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return "Isotropic_Tensor_Tree"; |
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} |
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return "Unknown_Tensor_Tree"; |
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} |
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return "Unknown"; |
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} |
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|
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/* Report details related to one hemisphere distribution */ |
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void |
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detailComponent(const char *nm, const SDValue *lamb, const SDSpectralDF *df) |
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{ |
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printf("%s\t%4.1f %4.1f %4.1f\t\t", nm, |
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100.*lamb->cieY*lamb->spec.cx/lamb->spec.cy, |
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100.*lamb->cieY, |
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100.*lamb->cieY*(1.f - lamb->spec.cx - lamb->spec.cy)/lamb->spec.cy); |
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if (df) |
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printf("%5.1f%%\t\t%.2f deg\n", 100.*df->maxHemi, |
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sqrt(df->minProjSA/M_PI)*(360./M_PI)); |
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else |
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puts("0%\t\t180"); |
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} |
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|
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/* Add a value to stats */ |
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void |
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addStat(SimpleStats *ssp, double v) |
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{ |
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if (v < ssp->vmin) ssp->vmin = v; |
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if (v > ssp->vmax) ssp->vmax = v; |
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ssp->vsum += v; |
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ssp->nvals++; |
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} |
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|
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/* Sample a BSDF hemisphere with callback (quadtree recursion) */ |
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int |
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qtSampBSDF(double xleft, double ytop, double siz, |
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const SDData *bsdf, const int side, const RREAL *v0, |
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int (*cf)(const SDData *b, const FVECT v1, const RREAL *v0, void *p), |
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void *cdata) |
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{ |
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if (siz < 0.124) { /* make sure we subdivide, first */ |
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FVECT vsmp; |
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double sa; |
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square2disk(vsmp, xleft + frandom()*siz, ytop + frandom()*siz); |
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vsmp[2] = 1. - vsmp[0]*vsmp[0] - vsmp[1]*vsmp[1]; |
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if (vsmp[2] <= 0) return 0; |
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vsmp[2] = side * sqrt(vsmp[2]); |
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if (SDreportError( SDsizeBSDF(&sa, vsmp, v0, SDqueryMin, bsdf), stderr)) |
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return 0; |
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if (sa >= M_PI*siz*siz - FTINY) /* no further division needed */ |
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return (*cf)(bsdf, vsmp, v0, cdata); |
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} |
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siz *= .5; /* 4-branch recursion */ |
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return( qtSampBSDF(xleft, ytop, siz, bsdf, side, v0, cf, cdata) && |
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qtSampBSDF(xleft+siz, ytop, siz, bsdf, side, v0, cf, cdata) && |
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qtSampBSDF(xleft, ytop+siz, siz, bsdf, side, v0, cf, cdata) && |
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qtSampBSDF(xleft+siz, ytop+siz, siz, bsdf, side, v0, cf, cdata) ); |
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} |
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|
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#define sampBSDFhemi(b,s,v0,cf,cd) qtSampBSDF(0,0,1,b,s,v0,cf,cd) |
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|
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/* Call-back to compute reciprocity difference */ |
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int |
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diffRecip(const SDData *bsdf, const FVECT v1, const RREAL *v0, void *p) |
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{ |
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SDValue sdv; |
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double otherY; |
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|
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if (SDreportError( SDevalBSDF(&sdv, v0, v1, bsdf), stderr)) |
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return 0; |
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otherY = sdv.cieY; |
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if (SDreportError( SDevalBSDF(&sdv, v1, v0, bsdf), stderr)) |
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return 0; |
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|
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addStat((SimpleStats *)p, rdiff(sdv.cieY, otherY)); |
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return 1; |
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} |
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|
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/* Call-back to compute reciprocity over reflected hemisphere */ |
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int |
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reflHemi(const SDData *bsdf, const FVECT v1, const RREAL *v0, void *p) |
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{ |
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return sampBSDFhemi(bsdf, 1 - 2*(v1[2]<0), v1, &diffRecip, p); |
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} |
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|
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/* Call-back to compute reciprocity over transmitted hemisphere */ |
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int |
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transHemi(const SDData *bsdf, const FVECT v1, const RREAL *v0, void *p) |
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{ |
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return sampBSDFhemi(bsdf, 1 - 2*(v1[2]>0), v1, &diffRecip, p); |
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} |
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|
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/* Report reciprocity errors for the given directions */ |
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void |
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checkReciprocity(const char *nm, const int side1, const int side2, |
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const SDData *bsdf, const int fl) |
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{ |
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SimpleStats myStats = SSinit; |
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const SDSpectralDF *df = bsdf->tf; |
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|
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if (side1 == side2) { |
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df = (side1 > 0) ? bsdf->rf : bsdf->rb; |
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if (!df) goto nothing2do; |
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} else if (!bsdf->tf | !bsdf->tb) |
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goto nothing2do; |
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|
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if (fl & F_MATRIX) { /* special case for matrix BSDF */ |
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const SDMat *m = (const SDMat *)df->comp[0].dist; |
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int i = m->ninc; |
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double diffuseY; |
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FVECT vin, vout; |
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double fwdY; |
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SDValue rev; |
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if (side1 == side2) |
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diffuseY = (side1 > 0) ? bsdf->rLambFront.cieY : bsdf->rLambBack.cieY; |
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else |
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diffuseY = (side1 > 0) ? bsdf->tLambFront.cieY : bsdf->tLambBack.cieY; |
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diffuseY /= M_PI; |
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while (i--) { |
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int o = m->nout; |
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if (!mBSDF_incvec(vin, m, i+.5)) |
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continue; |
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while (o--) { |
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if (!mBSDF_outvec(vout, m, o+.5)) |
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continue; |
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fwdY = mBSDF_value(m, o, i) + diffuseY; |
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if (fwdY <= 1e-4) |
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continue; |
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if (SDreportError( SDevalBSDF(&rev, vout, vin, bsdf), stderr)) |
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return; |
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if (rev.cieY > 1e-4) |
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addStat(&myStats, rdiff(fwdY, rev.cieY)); |
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} |
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} |
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} else if (fl & F_ISOTROPIC) { /* isotropic case */ |
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const double stepSize = sqrt(df->minProjSA/M_PI); |
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FVECT vin; |
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vin[1] = 0; |
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for (vin[0] = 0.5*stepSize; vin[0] < 1; vin[0] += stepSize) { |
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vin[2] = side1*sqrt(1. - vin[0]*vin[0]); |
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if (!sampBSDFhemi(bsdf, side2, vin, &diffRecip, &myStats)) |
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return; |
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} |
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} else if (!sampBSDFhemi(bsdf, side1, NULL, |
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(side1==side2) ? &reflHemi : &transHemi, &myStats)) |
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return; |
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if (myStats.nvals) { |
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printf("%s\t%5.1f\t%5.1f\t%5.1f\n", nm, |
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100.*myStats.vmin, |
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100.*myStats.vsum/(double)myStats.nvals, |
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100.*myStats.vmax); |
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return; |
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} |
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nothing2do: |
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printf("%s\t0\t0\t0\n", nm); |
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} |
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|
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/* Report on the given BSDF XML file */ |
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int |
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checkXML(char *fname) |
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{ |
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int flags; |
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SDData myBSDF; |
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char *pth; |
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|
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puts("====================================================="); |
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printf("File: '%s'\n", fname); |
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SDclearBSDF(&myBSDF, fname); |
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pth = getpath(fname, getrlibpath(), R_OK); |
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if (!pth) { |
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fprintf(stderr, "Cannot find file '%s'\n", fname); |
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return 0; |
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} |
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if (SDreportError( SDloadFile(&myBSDF, pth), stderr)) |
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return 0; |
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printf("Manufacturer: '%s'\n", myBSDF.makr); |
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printf("BSDF Name: '%s'\n", myBSDF.matn); |
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printf("Dimensions (W x H x Thickness): %g x %g x %g cm\n", 100.*myBSDF.dim[0], |
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100.*myBSDF.dim[1], 100.*myBSDF.dim[2]); |
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printf("Type: %s\n", getBSDFtype(&myBSDF, &flags)); |
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printf("Color: %d\n", (flags & F_IN_COLOR) != 0); |
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printf("Has Geometry: %d\n", (myBSDF.mgf != NULL)); |
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puts("Component\tLambertian XYZ %\tMax. Dir\tMin. Angle"); |
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detailComponent("Internal Refl", &myBSDF.rLambFront, myBSDF.rf); |
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detailComponent("External Refl", &myBSDF.rLambBack, myBSDF.rb); |
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detailComponent("Int->Ext Trans", &myBSDF.tLambFront, myBSDF.tf); |
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detailComponent("Ext->Int Trans", &myBSDF.tLambBack, myBSDF.tb); |
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puts("Component\tReciprocity Error (min avg max %)"); |
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checkReciprocity("Front Refl", 1, 1, &myBSDF, flags); |
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checkReciprocity("Back Refl", -1, -1, &myBSDF, flags); |
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checkReciprocity("Transmission", -1, 1, &myBSDF, flags); |
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SDfreeBSDF(&myBSDF); |
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return 1; |
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} |
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|
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int |
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main(int argc, char *argv[]) |
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{ |
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int i; |
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|
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if (argc < 2) { |
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fprintf(stderr, "Usage: %s bsdf.xml ..\n", argv[0]); |
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return 1; |
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} |
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for (i = 1; i < argc; i++) |
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if (!checkXML(argv[i])) |
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return 1; |
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return 0; |
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} |
