1 |
#ifndef lint |
2 |
static const char RCSid[] = "$Id: pabopto2xml.c,v 2.5 2012/08/25 22:39:03 greg Exp $"; |
3 |
#endif |
4 |
/* |
5 |
* Convert PAB-Opto measurements to XML format using tensor tree representation |
6 |
* Employs Bonneel et al. Earth Mover's Distance interpolant. |
7 |
* |
8 |
* G.Ward |
9 |
*/ |
10 |
|
11 |
#define _USE_MATH_DEFINES |
12 |
#include <stdio.h> |
13 |
#include <stdlib.h> |
14 |
#include <string.h> |
15 |
#include <ctype.h> |
16 |
#include <math.h> |
17 |
#include "bsdf.h" |
18 |
|
19 |
#ifndef GRIDRES |
20 |
#define GRIDRES 200 /* max. grid resolution per side */ |
21 |
#endif |
22 |
|
23 |
#define RSCA 2.7 /* radius scaling factor (empirical) */ |
24 |
|
25 |
/* convert to/from coded radians */ |
26 |
#define ANG2R(r) (int)((r)*((1<<16)/M_PI)) |
27 |
#define R2ANG(c) (((c)+.5)*(M_PI/(1<<16))) |
28 |
|
29 |
typedef struct { |
30 |
float vsum; /* DSF sum */ |
31 |
unsigned short nval; /* number of values in sum */ |
32 |
unsigned short crad; /* radius (coded angle) */ |
33 |
} GRIDVAL; /* grid value */ |
34 |
|
35 |
typedef struct { |
36 |
float peak; /* lobe value at peak */ |
37 |
unsigned short crad; /* radius (coded angle) */ |
38 |
unsigned char gx, gy; /* grid position */ |
39 |
} RBFVAL; /* radial basis function value */ |
40 |
|
41 |
typedef struct s_rbflist { |
42 |
struct s_rbflist *next; /* next in our RBF list */ |
43 |
FVECT invec; /* incident vector direction */ |
44 |
int nrbf; /* number of RBFs */ |
45 |
RBFVAL rbfa[1]; /* RBF array (extends struct) */ |
46 |
} RBFLIST; /* RBF representation of DSF @ 1 incidence */ |
47 |
|
48 |
/* our loaded grid for this incident angle */ |
49 |
static double theta_in_deg, phi_in_deg; |
50 |
static GRIDVAL dsf_grid[GRIDRES][GRIDRES]; |
51 |
|
52 |
/* processed incident DSF measurements */ |
53 |
static RBFLIST *dsf_list = NULL; |
54 |
|
55 |
/* Compute outgoing vector from grid position */ |
56 |
static void |
57 |
vec_from_pos(FVECT vec, int xpos, int ypos) |
58 |
{ |
59 |
double uv[2]; |
60 |
double r2; |
61 |
|
62 |
SDsquare2disk(uv, (1./GRIDRES)*(xpos+.5), (1./GRIDRES)*(ypos+.5)); |
63 |
/* uniform hemispherical projection */ |
64 |
r2 = uv[0]*uv[0] + uv[1]*uv[1]; |
65 |
vec[0] = vec[1] = sqrt(2. - r2); |
66 |
vec[0] *= uv[0]; |
67 |
vec[1] *= uv[1]; |
68 |
vec[2] = 1. - r2; |
69 |
} |
70 |
|
71 |
/* Compute grid position from normalized outgoing vector */ |
72 |
static void |
73 |
pos_from_vec(int pos[2], const FVECT vec) |
74 |
{ |
75 |
double sq[2]; /* uniform hemispherical projection */ |
76 |
double norm = 1./sqrt(1. + vec[2]); |
77 |
|
78 |
SDdisk2square(sq, vec[0]*norm, vec[1]*norm); |
79 |
|
80 |
pos[0] = (int)(sq[0]*GRIDRES); |
81 |
pos[1] = (int)(sq[1]*GRIDRES); |
82 |
} |
83 |
|
84 |
/* Evaluate RBF for DSF at the given normalized outgoing direction */ |
85 |
static double |
86 |
eval_rbfrep(const RBFLIST *rp, const FVECT outvec) |
87 |
{ |
88 |
double res = .0; |
89 |
const RBFVAL *rbfp; |
90 |
FVECT odir; |
91 |
double sig2; |
92 |
int n; |
93 |
|
94 |
rbfp = rp->rbfa; |
95 |
for (n = rp->nrbf; n--; rbfp++) { |
96 |
vec_from_pos(odir, rbfp->gx, rbfp->gy); |
97 |
sig2 = R2ANG(rbfp->crad); |
98 |
sig2 = (DOT(odir,outvec) - 1.) / (sig2*sig2); |
99 |
if (sig2 > -19.) |
100 |
res += rbfp->peak * exp(sig2); |
101 |
} |
102 |
return(res); |
103 |
} |
104 |
|
105 |
/* Count up filled nodes and build RBF representation from current grid */ |
106 |
static RBFLIST * |
107 |
make_rbfrep(void) |
108 |
{ |
109 |
int niter = 16; |
110 |
double lastVar, thisVar = 100.; |
111 |
int nn; |
112 |
RBFLIST *newnode; |
113 |
int i, j; |
114 |
|
115 |
nn = 0; /* count selected bins */ |
116 |
for (i = 0; i < GRIDRES; i++) |
117 |
for (j = 0; j < GRIDRES; j++) |
118 |
nn += dsf_grid[i][j].nval; |
119 |
/* allocate RBF array */ |
120 |
newnode = (RBFLIST *)malloc(sizeof(RBFLIST) + sizeof(RBFVAL)*(nn-1)); |
121 |
if (newnode == NULL) { |
122 |
fputs("Out of memory in make_rbfrep\n", stderr); |
123 |
exit(1); |
124 |
} |
125 |
newnode->next = NULL; |
126 |
newnode->invec[2] = sin(M_PI/180.*theta_in_deg); |
127 |
newnode->invec[0] = cos(M_PI/180.*phi_in_deg)*newnode->invec[2]; |
128 |
newnode->invec[1] = sin(M_PI/180.*phi_in_deg)*newnode->invec[2]; |
129 |
newnode->invec[2] = sqrt(1. - newnode->invec[2]*newnode->invec[2]); |
130 |
newnode->nrbf = nn; |
131 |
nn = 0; /* fill RBF array */ |
132 |
for (i = 0; i < GRIDRES; i++) |
133 |
for (j = 0; j < GRIDRES; j++) |
134 |
if (dsf_grid[i][j].nval) { |
135 |
newnode->rbfa[nn].peak = dsf_grid[i][j].vsum; |
136 |
newnode->rbfa[nn].crad = RSCA*dsf_grid[i][j].crad + .5; |
137 |
newnode->rbfa[nn].gx = i; |
138 |
newnode->rbfa[nn].gy = j; |
139 |
++nn; |
140 |
} |
141 |
/* iterate to improve interpolation accuracy */ |
142 |
do { |
143 |
double dsum = .0, dsum2 = .0; |
144 |
nn = 0; |
145 |
for (i = 0; i < GRIDRES; i++) |
146 |
for (j = 0; j < GRIDRES; j++) |
147 |
if (dsf_grid[i][j].nval) { |
148 |
FVECT odir; |
149 |
double corr; |
150 |
vec_from_pos(odir, i, j); |
151 |
newnode->rbfa[nn++].peak *= corr = |
152 |
dsf_grid[i][j].vsum / |
153 |
eval_rbfrep(newnode, odir); |
154 |
dsum += corr - 1.; |
155 |
dsum2 += (corr-1.)*(corr-1.); |
156 |
} |
157 |
lastVar = thisVar; |
158 |
thisVar = dsum2/(double)nn; |
159 |
/* |
160 |
fprintf(stderr, "Avg., RMS error: %.1f%% %.1f%%\n", |
161 |
100.*dsum/(double)nn, |
162 |
100.*sqrt(thisVar)); |
163 |
*/ |
164 |
} while (--niter > 0 && lastVar-thisVar > 0.02*lastVar); |
165 |
|
166 |
newnode->next = dsf_list; |
167 |
return(dsf_list = newnode); |
168 |
} |
169 |
|
170 |
/* Load a set of measurements corresponding to a particular incident angle */ |
171 |
static int |
172 |
load_bsdf_meas(const char *fname) |
173 |
{ |
174 |
FILE *fp = fopen(fname, "r"); |
175 |
int inp_is_DSF = -1; |
176 |
double theta_out, phi_out, val; |
177 |
char buf[2048]; |
178 |
int n, c; |
179 |
|
180 |
if (fp == NULL) { |
181 |
fputs(fname, stderr); |
182 |
fputs(": cannot open\n", stderr); |
183 |
return(0); |
184 |
} |
185 |
memset(dsf_grid, 0, sizeof(dsf_grid)); |
186 |
/* read header information */ |
187 |
while ((c = getc(fp)) == '#' || c == EOF) { |
188 |
if (fgets(buf, sizeof(buf), fp) == NULL) { |
189 |
fputs(fname, stderr); |
190 |
fputs(": unexpected EOF\n", stderr); |
191 |
fclose(fp); |
192 |
return(0); |
193 |
} |
194 |
if (!strcmp(buf, "format: theta phi DSF\n")) { |
195 |
inp_is_DSF = 1; |
196 |
continue; |
197 |
} |
198 |
if (!strcmp(buf, "format: theta phi BSDF\n")) { |
199 |
inp_is_DSF = 0; |
200 |
continue; |
201 |
} |
202 |
if (sscanf(buf, "intheta %lf", &theta_in_deg) == 1) |
203 |
continue; |
204 |
if (sscanf(buf, "inphi %lf", &phi_in_deg) == 1) |
205 |
continue; |
206 |
if (sscanf(buf, "incident_angle %lf %lf", |
207 |
&theta_in_deg, &phi_in_deg) == 2) |
208 |
continue; |
209 |
} |
210 |
if (inp_is_DSF < 0) { |
211 |
fputs(fname, stderr); |
212 |
fputs(": unknown format\n", stderr); |
213 |
fclose(fp); |
214 |
return(0); |
215 |
} |
216 |
ungetc(c, fp); /* read actual data */ |
217 |
while (fscanf(fp, "%lf %lf %lf\n", &theta_out, &phi_out, &val) == 3) { |
218 |
FVECT ovec; |
219 |
int pos[2]; |
220 |
|
221 |
ovec[2] = sin(M_PI/180.*theta_out); |
222 |
ovec[0] = cos(M_PI/180.*phi_out) * ovec[2]; |
223 |
ovec[1] = sin(M_PI/180.*phi_out) * ovec[2]; |
224 |
ovec[2] = sqrt(1. - ovec[2]*ovec[2]); |
225 |
|
226 |
if (!inp_is_DSF) |
227 |
val *= ovec[2]; /* convert from BSDF to DSF */ |
228 |
|
229 |
pos_from_vec(pos, ovec); |
230 |
|
231 |
dsf_grid[pos[0]][pos[1]].vsum += val; |
232 |
dsf_grid[pos[0]][pos[1]].nval++; |
233 |
} |
234 |
n = 0; |
235 |
while ((c = getc(fp)) != EOF) |
236 |
n += !isspace(c); |
237 |
if (n) |
238 |
fprintf(stderr, |
239 |
"%s: warning: %d unexpected characters past EOD\n", |
240 |
fname, n); |
241 |
fclose(fp); |
242 |
return(1); |
243 |
} |
244 |
|
245 |
/* Compute radii for non-empty bins */ |
246 |
/* (distance to furthest empty bin for which non-empty bin is the closest) */ |
247 |
static void |
248 |
compute_radii(void) |
249 |
{ |
250 |
unsigned int fill_grid[GRIDRES][GRIDRES]; |
251 |
unsigned short fill_cnt[GRIDRES][GRIDRES]; |
252 |
FVECT ovec0, ovec1; |
253 |
double ang2, lastang2; |
254 |
int r, i, j, jn, ii, jj, inear, jnear; |
255 |
|
256 |
r = GRIDRES/2; /* proceed in zig-zag */ |
257 |
for (i = 0; i < GRIDRES; i++) |
258 |
for (jn = 0; jn < GRIDRES; jn++) { |
259 |
j = (i&1) ? jn : GRIDRES-1-jn; |
260 |
if (dsf_grid[i][j].nval) /* find empty grid pos. */ |
261 |
continue; |
262 |
vec_from_pos(ovec0, i, j); |
263 |
inear = jnear = -1; /* find nearest non-empty */ |
264 |
lastang2 = M_PI*M_PI; |
265 |
for (ii = i-r; ii <= i+r; ii++) { |
266 |
if (ii < 0) continue; |
267 |
if (ii >= GRIDRES) break; |
268 |
for (jj = j-r; jj <= j+r; jj++) { |
269 |
if (jj < 0) continue; |
270 |
if (jj >= GRIDRES) break; |
271 |
if (!dsf_grid[ii][jj].nval) |
272 |
continue; |
273 |
vec_from_pos(ovec1, ii, jj); |
274 |
ang2 = 2. - 2.*DOT(ovec0,ovec1); |
275 |
if (ang2 >= lastang2) |
276 |
continue; |
277 |
lastang2 = ang2; |
278 |
inear = ii; jnear = jj; |
279 |
} |
280 |
} |
281 |
if (inear < 0) { |
282 |
fputs("Could not find non-empty neighbor!\n", stderr); |
283 |
exit(1); |
284 |
} |
285 |
ang2 = sqrt(lastang2); |
286 |
r = ANG2R(ang2); /* record if > previous */ |
287 |
if (r > dsf_grid[inear][jnear].crad) |
288 |
dsf_grid[inear][jnear].crad = r; |
289 |
/* next search radius */ |
290 |
r = ang2*(2.*GRIDRES/M_PI) + 1; |
291 |
} |
292 |
/* blur radii over hemisphere */ |
293 |
memset(fill_grid, 0, sizeof(fill_grid)); |
294 |
memset(fill_cnt, 0, sizeof(fill_cnt)); |
295 |
for (i = 0; i < GRIDRES; i++) |
296 |
for (j = 0; j < GRIDRES; j++) { |
297 |
if (!dsf_grid[i][j].crad) |
298 |
continue; /* missing distance */ |
299 |
r = R2ANG(dsf_grid[i][j].crad)*(2.*RSCA*GRIDRES/M_PI); |
300 |
for (ii = i-r; ii <= i+r; ii++) { |
301 |
if (ii < 0) continue; |
302 |
if (ii >= GRIDRES) break; |
303 |
for (jj = j-r; jj <= j+r; jj++) { |
304 |
if (jj < 0) continue; |
305 |
if (jj >= GRIDRES) break; |
306 |
if ((ii-i)*(ii-i) + (jj-j)*(jj-j) > r*r) |
307 |
continue; |
308 |
fill_grid[ii][jj] += dsf_grid[i][j].crad; |
309 |
fill_cnt[ii][jj]++; |
310 |
} |
311 |
} |
312 |
} |
313 |
/* copy back blurred radii */ |
314 |
for (i = 0; i < GRIDRES; i++) |
315 |
for (j = 0; j < GRIDRES; j++) |
316 |
if (fill_cnt[i][j]) |
317 |
dsf_grid[i][j].crad = fill_grid[i][j]/fill_cnt[i][j]; |
318 |
} |
319 |
|
320 |
/* Cull points for more uniform distribution, leave all nval 0 or 1 */ |
321 |
static void |
322 |
cull_values(void) |
323 |
{ |
324 |
FVECT ovec0, ovec1; |
325 |
double maxang, maxang2; |
326 |
int i, j, ii, jj, r; |
327 |
/* simple greedy algorithm */ |
328 |
for (i = 0; i < GRIDRES; i++) |
329 |
for (j = 0; j < GRIDRES; j++) { |
330 |
if (!dsf_grid[i][j].nval) |
331 |
continue; |
332 |
if (!dsf_grid[i][j].crad) |
333 |
continue; /* shouldn't happen */ |
334 |
vec_from_pos(ovec0, i, j); |
335 |
maxang = 2.*R2ANG(dsf_grid[i][j].crad); |
336 |
if (maxang > ovec0[2]) /* clamp near horizon */ |
337 |
maxang = ovec0[2]; |
338 |
r = maxang*(2.*GRIDRES/M_PI) + 1; |
339 |
maxang2 = maxang*maxang; |
340 |
for (ii = i-r; ii <= i+r; ii++) { |
341 |
if (ii < 0) continue; |
342 |
if (ii >= GRIDRES) break; |
343 |
for (jj = j-r; jj <= j+r; jj++) { |
344 |
if (jj < 0) continue; |
345 |
if (jj >= GRIDRES) break; |
346 |
if (!dsf_grid[ii][jj].nval) |
347 |
continue; |
348 |
if ((ii == i) & (jj == j)) |
349 |
continue; /* don't get self-absorbed */ |
350 |
vec_from_pos(ovec1, ii, jj); |
351 |
if (2. - 2.*DOT(ovec0,ovec1) >= maxang2) |
352 |
continue; |
353 |
/* absorb sum */ |
354 |
dsf_grid[i][j].vsum += dsf_grid[ii][jj].vsum; |
355 |
dsf_grid[i][j].nval += dsf_grid[ii][jj].nval; |
356 |
/* keep value, though */ |
357 |
dsf_grid[ii][jj].vsum /= (float)dsf_grid[ii][jj].nval; |
358 |
dsf_grid[ii][jj].nval = 0; |
359 |
} |
360 |
} |
361 |
} |
362 |
/* final averaging pass */ |
363 |
for (i = 0; i < GRIDRES; i++) |
364 |
for (j = 0; j < GRIDRES; j++) |
365 |
if (dsf_grid[i][j].nval > 1) { |
366 |
dsf_grid[i][j].vsum /= (float)dsf_grid[i][j].nval; |
367 |
dsf_grid[i][j].nval = 1; |
368 |
} |
369 |
} |
370 |
|
371 |
|
372 |
#if 1 |
373 |
/* Test main produces a Radiance model from the given input file */ |
374 |
int |
375 |
main(int argc, char *argv[]) |
376 |
{ |
377 |
char buf[128]; |
378 |
FILE *pfp; |
379 |
double bsdf; |
380 |
FVECT dir; |
381 |
int i, j, n; |
382 |
|
383 |
if (argc != 2) { |
384 |
fprintf(stderr, "Usage: %s input.dat > output.rad\n", argv[0]); |
385 |
return(1); |
386 |
} |
387 |
if (!load_bsdf_meas(argv[1])) |
388 |
return(1); |
389 |
|
390 |
compute_radii(); |
391 |
cull_values(); |
392 |
make_rbfrep(); |
393 |
/* produce spheres at meas. */ |
394 |
puts("void plastic yellow\n0\n0\n5 .6 .4 .01 .04 .08\n"); |
395 |
puts("void plastic pink\n0\n0\n5 .5 .05 .9 .04 .08\n"); |
396 |
n = 0; |
397 |
for (i = 0; i < GRIDRES; i++) |
398 |
for (j = 0; j < GRIDRES; j++) |
399 |
if (dsf_grid[i][j].vsum > .0f) { |
400 |
vec_from_pos(dir, i, j); |
401 |
bsdf = dsf_grid[i][j].vsum / dir[2]; |
402 |
if (dsf_grid[i][j].nval) { |
403 |
printf("pink cone c%04d\n0\n0\n8\n", ++n); |
404 |
printf("\t%.6g %.6g %.6g\n", |
405 |
dir[0]*bsdf, dir[1]*bsdf, dir[2]*bsdf); |
406 |
printf("\t%.6g %.6g %.6g\n", |
407 |
dir[0]*(bsdf+.005), dir[1]*(bsdf+.005), |
408 |
dir[2]*(bsdf+.005)); |
409 |
puts("\t.003\t0\n"); |
410 |
} else { |
411 |
vec_from_pos(dir, i, j); |
412 |
printf("yellow sphere s%04d\n0\n0\n", ++n); |
413 |
printf("4 %.6g %.6g %.6g .0015\n\n", |
414 |
dir[0]*bsdf, dir[1]*bsdf, dir[2]*bsdf); |
415 |
} |
416 |
} |
417 |
/* output continuous surface */ |
418 |
puts("void trans tgreen\n0\n0\n7 .7 1 .7 .04 .04 .9 .9\n"); |
419 |
fflush(stdout); |
420 |
sprintf(buf, "gensurf tgreen bsdf - - - %d %d", GRIDRES-1, GRIDRES-1); |
421 |
pfp = popen(buf, "w"); |
422 |
if (pfp == NULL) { |
423 |
fputs(buf, stderr); |
424 |
fputs(": cannot start command\n", stderr); |
425 |
return(1); |
426 |
} |
427 |
for (i = 0; i < GRIDRES; i++) |
428 |
for (j = 0; j < GRIDRES; j++) { |
429 |
vec_from_pos(dir, i, j); |
430 |
bsdf = eval_rbfrep(dsf_list, dir) / dir[2]; |
431 |
fprintf(pfp, "%.8e %.8e %.8e\n", |
432 |
dir[0]*bsdf, dir[1]*bsdf, dir[2]*bsdf); |
433 |
} |
434 |
return(pclose(pfp)==0 ? 0 : 1); |
435 |
} |
436 |
#endif |