| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: checkBSDF.c,v 2.1 2021/12/14 02:33:18 greg Exp $"; |
| 3 |
#endif |
| 4 |
/* |
| 5 |
* checkBSDF.c |
| 6 |
* |
| 7 |
* Load BSDF XML file and check Helmholtz reciprocity |
| 8 |
*/ |
| 9 |
|
| 10 |
#define _USE_MATH_DEFINES |
| 11 |
#include <math.h> |
| 12 |
#include "rtio.h" |
| 13 |
#include "random.h" |
| 14 |
#include "bsdf.h" |
| 15 |
#include "bsdf_m.h" |
| 16 |
#include "bsdf_t.h" |
| 17 |
|
| 18 |
#define F_IN_COLOR 0x1 |
| 19 |
#define F_ISOTROPIC 0x2 |
| 20 |
#define F_MATRIX 0x4 |
| 21 |
#define F_TTREE 0x8 |
| 22 |
|
| 23 |
typedef struct { |
| 24 |
double vmin, vmax; /* extrema */ |
| 25 |
double vsum; /* straight sum */ |
| 26 |
long nvals; /* number of values */ |
| 27 |
} SimpleStats; |
| 28 |
|
| 29 |
const SimpleStats SSinit = {FHUGE, -FHUGE, .0, 0}; |
| 30 |
|
| 31 |
/* relative difference formula */ |
| 32 |
#define rdiff(a,b) ((a)>(b) ? ((a)-(b))/(a) : ((b)-(a))/(b)) |
| 33 |
|
| 34 |
/* Figure out BSDF type (and optionally determine if in color) */ |
| 35 |
const char * |
| 36 |
getBSDFtype(const SDData *bsdf, int *flags) |
| 37 |
{ |
| 38 |
const SDSpectralDF *df = bsdf->tb; |
| 39 |
|
| 40 |
if (flags) *flags = 0; |
| 41 |
if (!df) df = bsdf->tf; |
| 42 |
if (!df) df = bsdf->rf; |
| 43 |
if (!df) df = bsdf->rb; |
| 44 |
if (!df) return "Pure_Lambertian"; |
| 45 |
if (df->comp[0].func == &SDhandleMtx) { |
| 46 |
const SDMat *m = (const SDMat *)df->comp[0].dist; |
| 47 |
if (flags) { |
| 48 |
*flags |= F_MATRIX; |
| 49 |
*flags |= F_IN_COLOR*(m->chroma != NULL); |
| 50 |
} |
| 51 |
switch (m->ninc) { |
| 52 |
case 145: |
| 53 |
return "Klems_Full"; |
| 54 |
case 73: |
| 55 |
return "Klems_Half"; |
| 56 |
case 41: |
| 57 |
return "Klems_Quarter"; |
| 58 |
} |
| 59 |
return "Unknown_Matrix"; |
| 60 |
} |
| 61 |
if (df->comp[0].func == &SDhandleTre) { |
| 62 |
const SDTre *t = (const SDTre *)df->comp[0].dist; |
| 63 |
if (flags) { |
| 64 |
*flags |= F_TTREE; |
| 65 |
*flags |= F_IN_COLOR*(t->stc[1] != NULL); |
| 66 |
} |
| 67 |
switch (t->stc[0]->ndim) { |
| 68 |
case 4: |
| 69 |
return "Anisotropic_Tensor_Tree"; |
| 70 |
case 3: |
| 71 |
if (flags) *flags |= F_ISOTROPIC; |
| 72 |
return "Isotropic_Tensor_Tree"; |
| 73 |
} |
| 74 |
return "Unknown_Tensor_Tree"; |
| 75 |
} |
| 76 |
return "Unknown"; |
| 77 |
} |
| 78 |
|
| 79 |
/* Report details related to one hemisphere distribution */ |
| 80 |
void |
| 81 |
detailComponent(const char *nm, const SDValue *lamb, const SDSpectralDF *df) |
| 82 |
{ |
| 83 |
printf("%s\t%4.1f %4.1f %4.1f\t\t", nm, |
| 84 |
100.*lamb->cieY*lamb->spec.cx/lamb->spec.cy, |
| 85 |
100.*lamb->cieY, |
| 86 |
100.*lamb->cieY*(1.f - lamb->spec.cx - lamb->spec.cy)/lamb->spec.cy); |
| 87 |
if (df) |
| 88 |
printf("%5.1f%%\t\t%.2f deg\n", 100.*df->maxHemi, |
| 89 |
sqrt(df->minProjSA/M_PI)*(360./M_PI)); |
| 90 |
else |
| 91 |
puts("0%\t\t180"); |
| 92 |
} |
| 93 |
|
| 94 |
/* Add a value to stats */ |
| 95 |
void |
| 96 |
addStat(SimpleStats *ssp, double v) |
| 97 |
{ |
| 98 |
if (v < ssp->vmin) ssp->vmin = v; |
| 99 |
if (v > ssp->vmax) ssp->vmax = v; |
| 100 |
ssp->vsum += v; |
| 101 |
ssp->nvals++; |
| 102 |
} |
| 103 |
|
| 104 |
/* Sample a BSDF hemisphere with callback (quadtree recursion) */ |
| 105 |
int |
| 106 |
qtSampBSDF(double xleft, double ytop, double siz, |
| 107 |
const SDData *bsdf, const int side, const RREAL *v0, |
| 108 |
int (*cf)(const SDData *b, const FVECT v1, const RREAL *v0, void *p), |
| 109 |
void *cdata) |
| 110 |
{ |
| 111 |
if (siz < 0.124) { /* make sure we subdivide, first */ |
| 112 |
FVECT vsmp; |
| 113 |
double sa; |
| 114 |
square2disk(vsmp, xleft + frandom()*siz, ytop + frandom()*siz); |
| 115 |
vsmp[2] = 1. - vsmp[0]*vsmp[0] - vsmp[1]*vsmp[1]; |
| 116 |
if (vsmp[2] <= 0) return 0; |
| 117 |
vsmp[2] = side * sqrt(vsmp[2]); |
| 118 |
if (SDreportError( SDsizeBSDF(&sa, vsmp, v0, SDqueryMin, bsdf), stderr)) |
| 119 |
return 0; |
| 120 |
if (sa >= M_PI*siz*siz - FTINY) /* no further division needed */ |
| 121 |
return (*cf)(bsdf, vsmp, v0, cdata); |
| 122 |
} |
| 123 |
siz *= .5; /* 4-branch recursion */ |
| 124 |
return( qtSampBSDF(xleft, ytop, siz, bsdf, side, v0, cf, cdata) && |
| 125 |
qtSampBSDF(xleft+siz, ytop, siz, bsdf, side, v0, cf, cdata) && |
| 126 |
qtSampBSDF(xleft, ytop+siz, siz, bsdf, side, v0, cf, cdata) && |
| 127 |
qtSampBSDF(xleft+siz, ytop+siz, siz, bsdf, side, v0, cf, cdata) ); |
| 128 |
} |
| 129 |
|
| 130 |
#define sampBSDFhemi(b,s,v0,cf,cd) qtSampBSDF(0,0,1,b,s,v0,cf,cd) |
| 131 |
|
| 132 |
/* Call-back to compute reciprocity difference */ |
| 133 |
int |
| 134 |
diffRecip(const SDData *bsdf, const FVECT v1, const RREAL *v0, void *p) |
| 135 |
{ |
| 136 |
SDValue sdv; |
| 137 |
double otherY; |
| 138 |
|
| 139 |
if (SDreportError( SDevalBSDF(&sdv, v0, v1, bsdf), stderr)) |
| 140 |
return 0; |
| 141 |
otherY = sdv.cieY; |
| 142 |
if (SDreportError( SDevalBSDF(&sdv, v1, v0, bsdf), stderr)) |
| 143 |
return 0; |
| 144 |
|
| 145 |
addStat((SimpleStats *)p, rdiff(sdv.cieY, otherY)); |
| 146 |
return 1; |
| 147 |
} |
| 148 |
|
| 149 |
/* Call-back to compute reciprocity over reflected hemisphere */ |
| 150 |
int |
| 151 |
reflHemi(const SDData *bsdf, const FVECT v1, const RREAL *v0, void *p) |
| 152 |
{ |
| 153 |
return sampBSDFhemi(bsdf, 1 - 2*(v1[2]<0), v1, &diffRecip, p); |
| 154 |
} |
| 155 |
|
| 156 |
/* Call-back to compute reciprocity over transmitted hemisphere */ |
| 157 |
int |
| 158 |
transHemi(const SDData *bsdf, const FVECT v1, const RREAL *v0, void *p) |
| 159 |
{ |
| 160 |
return sampBSDFhemi(bsdf, 1 - 2*(v1[2]>0), v1, &diffRecip, p); |
| 161 |
} |
| 162 |
|
| 163 |
/* Report reciprocity errors for the given directions */ |
| 164 |
void |
| 165 |
checkReciprocity(const char *nm, const int side1, const int side2, |
| 166 |
const SDData *bsdf, const int fl) |
| 167 |
{ |
| 168 |
SimpleStats myStats = SSinit; |
| 169 |
const SDSpectralDF *df = bsdf->tf; |
| 170 |
|
| 171 |
if (side1 == side2) { |
| 172 |
df = (side1 > 0) ? bsdf->rf : bsdf->rb; |
| 173 |
if (!df) goto nothing2do; |
| 174 |
} else if (!bsdf->tf | !bsdf->tb) |
| 175 |
goto nothing2do; |
| 176 |
|
| 177 |
if (fl & F_MATRIX) { /* special case for matrix BSDF */ |
| 178 |
const SDMat *m = (const SDMat *)df->comp[0].dist; |
| 179 |
int i = m->ninc; |
| 180 |
FVECT vin, vout; |
| 181 |
double fwdY; |
| 182 |
SDValue rev; |
| 183 |
while (i--) { |
| 184 |
int o = m->nout; |
| 185 |
if (!mBSDF_incvec(vin, m, i+.5)) |
| 186 |
continue; |
| 187 |
while (o--) { |
| 188 |
if (!mBSDF_outvec(vout, m, o+.5)) |
| 189 |
continue; |
| 190 |
fwdY = mBSDF_value(m, o, i); |
| 191 |
if (fwdY <= 1e-4) |
| 192 |
continue; |
| 193 |
if (SDreportError( SDevalBSDF(&rev, vout, vin, bsdf), stderr)) |
| 194 |
return; |
| 195 |
if (rev.cieY > 1e-4) |
| 196 |
addStat(&myStats, rdiff(fwdY, rev.cieY)); |
| 197 |
} |
| 198 |
} |
| 199 |
} if (fl & F_ISOTROPIC) { /* isotropic case */ |
| 200 |
const double stepSize = sqrt(df->minProjSA/M_PI); |
| 201 |
FVECT vin; |
| 202 |
vin[1] = 0; |
| 203 |
for (vin[0] = 0.5*stepSize; vin[0] < 1; vin[0] += stepSize) { |
| 204 |
vin[2] = side1*sqrt(1. - vin[0]*vin[0]); |
| 205 |
if (!sampBSDFhemi(bsdf, side2, vin, &diffRecip, &myStats)) |
| 206 |
return; |
| 207 |
} |
| 208 |
} else if (!sampBSDFhemi(bsdf, side1, NULL, |
| 209 |
(side1==side2) ? &reflHemi : &transHemi, &myStats)) |
| 210 |
return; |
| 211 |
if (myStats.nvals) { |
| 212 |
printf("%s\t%5.1f\t%5.1f\t%5.1f\n", nm, |
| 213 |
100.*myStats.vmin, |
| 214 |
100.*myStats.vsum/(double)myStats.nvals, |
| 215 |
100.*myStats.vmax); |
| 216 |
return; |
| 217 |
} |
| 218 |
nothing2do: |
| 219 |
printf("%s\t0\t0\t0\n", nm); |
| 220 |
} |
| 221 |
|
| 222 |
/* Report on the given BSDF XML file */ |
| 223 |
int |
| 224 |
checkXML(char *fname) |
| 225 |
{ |
| 226 |
int flags; |
| 227 |
SDData myBSDF; |
| 228 |
char *pth; |
| 229 |
|
| 230 |
puts("====================================================="); |
| 231 |
printf("File: '%s'\n", fname); |
| 232 |
SDclearBSDF(&myBSDF, fname); |
| 233 |
pth = getpath(fname, getrlibpath(), R_OK); |
| 234 |
if (!pth) { |
| 235 |
fprintf(stderr, "Cannot find file '%s'\n", fname); |
| 236 |
return 0; |
| 237 |
} |
| 238 |
if (SDreportError( SDloadFile(&myBSDF, pth), stderr)) |
| 239 |
return 0; |
| 240 |
printf("Manufacturer: '%s'\n", myBSDF.makr); |
| 241 |
printf("BSDF Name: '%s'\n", myBSDF.matn); |
| 242 |
printf("Dimensions (W x H x Thickness): %g x %g x %g cm\n", 100.*myBSDF.dim[0], |
| 243 |
100.*myBSDF.dim[1], 100.*myBSDF.dim[2]); |
| 244 |
printf("Type: %s\n", getBSDFtype(&myBSDF, &flags)); |
| 245 |
printf("Color: %d\n", (flags & F_IN_COLOR) != 0); |
| 246 |
printf("Has Geometry: %d\n", (myBSDF.mgf != NULL)); |
| 247 |
puts("Component\tLambertian XYZ %\tMax. Dir\tMin. Angle"); |
| 248 |
detailComponent("Internal Refl", &myBSDF.rLambFront, myBSDF.rf); |
| 249 |
detailComponent("External Refl", &myBSDF.rLambBack, myBSDF.rb); |
| 250 |
detailComponent("Int->Ext Trans", &myBSDF.tLambFront, myBSDF.tf); |
| 251 |
detailComponent("Ext->Int Trans", &myBSDF.tLambBack, myBSDF.tb); |
| 252 |
puts("Component\tReciprocity Error (min avg max %)"); |
| 253 |
checkReciprocity("Front Refl", 1, 1, &myBSDF, flags); |
| 254 |
checkReciprocity("Back Refl", -1, -1, &myBSDF, flags); |
| 255 |
checkReciprocity("Transmission", -1, 1, &myBSDF, flags); |
| 256 |
SDfreeBSDF(&myBSDF); |
| 257 |
return 1; |
| 258 |
} |
| 259 |
|
| 260 |
int |
| 261 |
main(int argc, char *argv[]) |
| 262 |
{ |
| 263 |
int i; |
| 264 |
|
| 265 |
if (argc < 2) { |
| 266 |
fprintf(stderr, "Usage: %s bsdf.xml ..\n", argv[0]); |
| 267 |
return 1; |
| 268 |
} |
| 269 |
for (i = 1; i < argc; i++) |
| 270 |
if (!checkXML(argv[i])) |
| 271 |
return 1; |
| 272 |
return 0; |
| 273 |
} |
