| 1 |
/* |
| 2 |
================================================================== |
| 3 |
Photon map support routines for emission from light sources |
| 4 |
|
| 5 |
Roland Schregle (roland.schregle@{hslu.ch, gmail.com}) |
| 6 |
(c) Fraunhofer Institute for Solar Energy Systems, |
| 7 |
(c) Lucerne University of Applied Sciences and Arts, |
| 8 |
supported by the Swiss National Science Foundation (SNSF, #147053) |
| 9 |
================================================================== |
| 10 |
|
| 11 |
$Id: pmapsrc.c,v 2.2 2015/04/21 19:16:51 greg Exp $ |
| 12 |
*/ |
| 13 |
|
| 14 |
|
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|
| 16 |
#include "pmapsrc.h" |
| 17 |
#include "pmap.h" |
| 18 |
#include "pmaprand.h" |
| 19 |
#include "otypes.h" |
| 20 |
|
| 21 |
|
| 22 |
|
| 23 |
SRCREC *photonPorts = NULL; /* Photon port list */ |
| 24 |
unsigned numPhotonPorts = 0; |
| 25 |
|
| 26 |
void (*photonPartition [NUMOTYPE]) (EmissionMap*); |
| 27 |
void (*photonOrigin [NUMOTYPE]) (EmissionMap*); |
| 28 |
|
| 29 |
extern OBJECT ambset []; |
| 30 |
|
| 31 |
|
| 32 |
|
| 33 |
static int flatPhotonPartition2 (EmissionMap* emap, unsigned long mp, |
| 34 |
FVECT cent, FVECT u, FVECT v, |
| 35 |
double du2, double dv2) |
| 36 |
/* Recursive part of flatPhotonPartition(..) */ |
| 37 |
{ |
| 38 |
FVECT newct, newax; |
| 39 |
unsigned long npl, npu; |
| 40 |
|
| 41 |
if (mp > emap -> maxPartitions) { |
| 42 |
/* Enlarge partition array */ |
| 43 |
emap -> maxPartitions <<= 1; |
| 44 |
emap -> partitions = (unsigned char*)realloc(emap -> partitions, |
| 45 |
emap -> maxPartitions >> 1); |
| 46 |
|
| 47 |
if (!emap -> partitions) |
| 48 |
error(USER, "can't allocate source partitions"); |
| 49 |
|
| 50 |
memset(emap -> partitions + (emap -> maxPartitions >> 2), 0, |
| 51 |
emap -> maxPartitions >> 2); |
| 52 |
} |
| 53 |
|
| 54 |
if (du2 * dv2 <= 1) { /* hit limit? */ |
| 55 |
setpart(emap -> partitions, emap -> partitionCnt, S0); |
| 56 |
emap -> partitionCnt++; |
| 57 |
return 1; |
| 58 |
} |
| 59 |
|
| 60 |
if (du2 > dv2) { /* subdivide in U */ |
| 61 |
setpart(emap -> partitions, emap -> partitionCnt, SU); |
| 62 |
emap -> partitionCnt++; |
| 63 |
newax [0] = 0.5 * u [0]; |
| 64 |
newax [1] = 0.5 * u [1]; |
| 65 |
newax [2] = 0.5 * u [2]; |
| 66 |
u = newax; |
| 67 |
du2 *= 0.25; |
| 68 |
} |
| 69 |
|
| 70 |
else { /* subdivide in V */ |
| 71 |
setpart(emap -> partitions, emap -> partitionCnt, SV); |
| 72 |
emap -> partitionCnt++; |
| 73 |
newax [0] = 0.5 * v [0]; |
| 74 |
newax [1] = 0.5 * v [1]; |
| 75 |
newax [2] = 0.5 * v [2]; |
| 76 |
v = newax; |
| 77 |
dv2 *= 0.25; |
| 78 |
} |
| 79 |
|
| 80 |
/* lower half */ |
| 81 |
newct [0] = cent [0] - newax [0]; |
| 82 |
newct [1] = cent [1] - newax [1]; |
| 83 |
newct [2] = cent [2] - newax [2]; |
| 84 |
npl = flatPhotonPartition2(emap, mp << 1, newct, u, v, du2, dv2); |
| 85 |
|
| 86 |
/* upper half */ |
| 87 |
newct [0] = cent [0] + newax [0]; |
| 88 |
newct [1] = cent [1] + newax [1]; |
| 89 |
newct [2] = cent [2] + newax [2]; |
| 90 |
npu = flatPhotonPartition2(emap, mp << 1, newct, u, v, du2, dv2); |
| 91 |
|
| 92 |
/* return total */ |
| 93 |
return npl + npu; |
| 94 |
} |
| 95 |
|
| 96 |
|
| 97 |
|
| 98 |
static void flatPhotonPartition (EmissionMap* emap) |
| 99 |
/* Partition flat source for photon emission */ |
| 100 |
{ |
| 101 |
RREAL *vp; |
| 102 |
double du2, dv2; |
| 103 |
|
| 104 |
memset(emap -> partitions, 0, emap -> maxPartitions >> 1); |
| 105 |
emap -> partArea = srcsizerat * thescene.cusize; |
| 106 |
emap -> partArea *= emap -> partArea; |
| 107 |
vp = emap -> src -> ss [SU]; |
| 108 |
du2 = DOT(vp, vp) / emap -> partArea; |
| 109 |
vp = emap -> src -> ss [SV]; |
| 110 |
dv2 = DOT(vp, vp) / emap -> partArea; |
| 111 |
emap -> partitionCnt = 0; |
| 112 |
emap -> numPartitions = flatPhotonPartition2(emap, 1, emap -> src -> sloc, |
| 113 |
emap -> src -> ss [SU], |
| 114 |
emap -> src -> ss [SV], |
| 115 |
du2, dv2); |
| 116 |
emap -> partitionCnt = 0; |
| 117 |
emap -> partArea = emap -> src -> ss2 / emap -> numPartitions; |
| 118 |
} |
| 119 |
|
| 120 |
|
| 121 |
|
| 122 |
static void sourcePhotonPartition (EmissionMap* emap) |
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/* Partition scene cube faces or photon port for photon emission from |
| 124 |
distant source */ |
| 125 |
{ |
| 126 |
if (emap -> port) { |
| 127 |
/* Partition photon port */ |
| 128 |
SRCREC *src = emap -> src; |
| 129 |
emap -> src = emap -> port; |
| 130 |
photonPartition [emap -> src -> so -> otype] (emap); |
| 131 |
emap -> src = src; |
| 132 |
} |
| 133 |
|
| 134 |
else { |
| 135 |
/* No photon ports defined, so partition scene cube faces */ |
| 136 |
memset(emap -> partitions, 0, emap -> maxPartitions >> 1); |
| 137 |
setpart(emap -> partitions, 0, S0); |
| 138 |
emap -> partitionCnt = 0; |
| 139 |
emap -> numPartitions = 1 / srcsizerat; |
| 140 |
emap -> numPartitions *= emap -> numPartitions; |
| 141 |
emap -> partArea = sqr(thescene.cusize) / emap -> numPartitions; |
| 142 |
emap -> numPartitions *= 6; |
| 143 |
} |
| 144 |
} |
| 145 |
|
| 146 |
|
| 147 |
|
| 148 |
static void spherePhotonPartition (EmissionMap* emap) |
| 149 |
/* Partition spherical source into equal solid angles using uniform |
| 150 |
mapping for photon emission */ |
| 151 |
{ |
| 152 |
unsigned numTheta, numPhi; |
| 153 |
|
| 154 |
memset(emap -> partitions, 0, emap -> maxPartitions >> 1); |
| 155 |
setpart(emap -> partitions, 0, S0); |
| 156 |
emap -> partArea = 4 * PI * sqr(emap -> src -> srad); |
| 157 |
emap -> numPartitions = emap -> partArea / |
| 158 |
sqr(srcsizerat * thescene.cusize); |
| 159 |
|
| 160 |
numTheta = max(sqrt(2 * emap -> numPartitions / PI) + 0.5, 1); |
| 161 |
numPhi = 0.5 * PI * numTheta + 0.5; |
| 162 |
|
| 163 |
emap -> numPartitions = (unsigned long)numTheta * numPhi; |
| 164 |
emap -> partitionCnt = 0; |
| 165 |
emap -> partArea /= emap -> numPartitions; |
| 166 |
} |
| 167 |
|
| 168 |
|
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|
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static int cylPhotonPartition2 (EmissionMap* emap, unsigned long mp, |
| 171 |
FVECT cent, FVECT axis, double d2) |
| 172 |
/* Recursive part of cyPhotonPartition(..) */ |
| 173 |
{ |
| 174 |
FVECT newct, newax; |
| 175 |
unsigned long npl, npu; |
| 176 |
|
| 177 |
if (mp > emap -> maxPartitions) { |
| 178 |
/* Enlarge partition array */ |
| 179 |
emap -> maxPartitions <<= 1; |
| 180 |
emap -> partitions = (unsigned char*)realloc(emap -> partitions, |
| 181 |
emap -> maxPartitions >> 1); |
| 182 |
if (!emap -> partitions) |
| 183 |
error(USER, "can't allocate source partitions"); |
| 184 |
|
| 185 |
memset(emap -> partitions + (emap -> maxPartitions >> 2), 0, |
| 186 |
emap -> maxPartitions >> 2); |
| 187 |
} |
| 188 |
|
| 189 |
if (d2 <= 1) { |
| 190 |
/* hit limit? */ |
| 191 |
setpart(emap -> partitions, emap -> partitionCnt, S0); |
| 192 |
emap -> partitionCnt++; |
| 193 |
return 1; |
| 194 |
} |
| 195 |
|
| 196 |
/* subdivide */ |
| 197 |
setpart(emap -> partitions, emap -> partitionCnt, SU); |
| 198 |
emap -> partitionCnt++; |
| 199 |
newax [0] = 0.5 * axis [0]; |
| 200 |
newax [1] = 0.5 * axis [1]; |
| 201 |
newax [2] = 0.5 * axis [2]; |
| 202 |
d2 *= 0.25; |
| 203 |
|
| 204 |
/* lower half */ |
| 205 |
newct [0] = cent [0] - newax [0]; |
| 206 |
newct [1] = cent [1] - newax [1]; |
| 207 |
newct [2] = cent [2] - newax [2]; |
| 208 |
npl = cylPhotonPartition2(emap, mp << 1, newct, newax, d2); |
| 209 |
|
| 210 |
/* upper half */ |
| 211 |
newct [0] = cent [0] + newax [0]; |
| 212 |
newct [1] = cent [1] + newax [1]; |
| 213 |
newct [2] = cent [2] + newax [2]; |
| 214 |
npu = cylPhotonPartition2(emap, mp << 1, newct, newax, d2); |
| 215 |
|
| 216 |
/* return total */ |
| 217 |
return npl + npu; |
| 218 |
} |
| 219 |
|
| 220 |
|
| 221 |
|
| 222 |
static void cylPhotonPartition (EmissionMap* emap) |
| 223 |
/* Partition cylindrical source for photon emission */ |
| 224 |
{ |
| 225 |
double d2; |
| 226 |
|
| 227 |
memset(emap -> partitions, 0, emap -> maxPartitions >> 1); |
| 228 |
d2 = srcsizerat * thescene.cusize; |
| 229 |
d2 = PI * emap -> src -> ss2 / (2 * emap -> src -> srad * sqr(d2)); |
| 230 |
d2 *= d2 * DOT(emap -> src -> ss [SU], emap -> src -> ss [SU]); |
| 231 |
|
| 232 |
emap -> partitionCnt = 0; |
| 233 |
emap -> numPartitions = cylPhotonPartition2(emap, 1, emap -> src -> sloc, |
| 234 |
emap -> src -> ss [SU], d2); |
| 235 |
emap -> partitionCnt = 0; |
| 236 |
emap -> partArea = PI * emap -> src -> ss2 / emap -> numPartitions; |
| 237 |
} |
| 238 |
|
| 239 |
|
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|
| 241 |
static void flatPhotonOrigin (EmissionMap* emap) |
| 242 |
/* Init emission map with photon origin and associated surface axes on |
| 243 |
flat light source surface. Also sets source aperture and sampling |
| 244 |
hemisphere axes at origin */ |
| 245 |
{ |
| 246 |
int i, cent[3], size[3], parr[2]; |
| 247 |
FVECT vpos; |
| 248 |
|
| 249 |
cent [0] = cent [1] = cent [2] = 0; |
| 250 |
size [0] = size [1] = size [2] = emap -> maxPartitions; |
| 251 |
parr [0] = 0; |
| 252 |
parr [1] = emap -> partitionCnt; |
| 253 |
|
| 254 |
if (!skipparts(cent, size, parr, emap -> partitions)) |
| 255 |
error(CONSISTENCY, "bad source partition in flatPhotonOrigin"); |
| 256 |
|
| 257 |
vpos [0] = (1 - 2 * pmapRandom(partState)) * size [0] / |
| 258 |
emap -> maxPartitions; |
| 259 |
vpos [1] = (1 - 2 * pmapRandom(partState)) * size [1] / |
| 260 |
emap -> maxPartitions; |
| 261 |
vpos [2] = 0; |
| 262 |
|
| 263 |
for (i = 0; i < 3; i++) |
| 264 |
vpos [i] += (double)cent [i] / emap -> maxPartitions; |
| 265 |
|
| 266 |
/* Get origin */ |
| 267 |
for (i = 0; i < 3; i++) |
| 268 |
emap -> photonOrg [i] = emap -> src -> sloc [i] + |
| 269 |
vpos [SU] * emap -> src -> ss [SU][i] + |
| 270 |
vpos [SV] * emap -> src -> ss [SV][i] + |
| 271 |
vpos [SW] * emap -> src -> ss [SW][i]; |
| 272 |
|
| 273 |
/* Get surface axes */ |
| 274 |
VCOPY(emap -> us, emap -> src -> ss [SU]); |
| 275 |
normalize(emap -> us); |
| 276 |
VCOPY(emap -> ws, emap -> src -> ss [SW]); |
| 277 |
|
| 278 |
if (emap -> port) |
| 279 |
/* Acts as a photon port; reverse normal as it points INSIDE per |
| 280 |
* mkillum convention */ |
| 281 |
for (i = 0; i < 3; i++) |
| 282 |
emap -> ws [i] = -emap -> ws [i]; |
| 283 |
|
| 284 |
fcross(emap -> vs, emap -> ws, emap -> us); |
| 285 |
|
| 286 |
/* Get hemisphere axes & aperture */ |
| 287 |
if (emap -> src -> sflags & SSPOT) { |
| 288 |
VCOPY(emap -> wh, emap -> src -> sl.s -> aim); |
| 289 |
i = 0; |
| 290 |
|
| 291 |
do { |
| 292 |
emap -> vh [0] = emap -> vh [1] = emap -> vh [2] = 0; |
| 293 |
emap -> vh [i++] = 1; |
| 294 |
fcross(emap -> uh, emap -> vh, emap -> wh); |
| 295 |
} while (normalize(emap -> uh) < FTINY); |
| 296 |
|
| 297 |
fcross(emap -> vh, emap -> wh, emap -> uh); |
| 298 |
emap -> cosThetaMax = 1 - emap -> src -> sl.s -> siz / (2 * PI); |
| 299 |
} |
| 300 |
|
| 301 |
else { |
| 302 |
VCOPY(emap -> uh, emap -> us); |
| 303 |
VCOPY(emap -> vh, emap -> vs); |
| 304 |
VCOPY(emap -> wh, emap -> ws); |
| 305 |
emap -> cosThetaMax = 0; |
| 306 |
} |
| 307 |
} |
| 308 |
|
| 309 |
|
| 310 |
|
| 311 |
static void spherePhotonOrigin (EmissionMap* emap) |
| 312 |
/* Init emission map with photon origin and associated surface axes on |
| 313 |
spherical light source. Also sets source aperture and sampling |
| 314 |
hemisphere axes at origin */ |
| 315 |
{ |
| 316 |
int i = 0; |
| 317 |
unsigned numTheta, numPhi, t, p; |
| 318 |
RREAL cosTheta, sinTheta, phi; |
| 319 |
|
| 320 |
/* Get current partition */ |
| 321 |
numTheta = max(sqrt(2 * emap -> numPartitions / PI) + 0.5, 1); |
| 322 |
numPhi = 0.5 * PI * numTheta + 0.5; |
| 323 |
|
| 324 |
t = emap -> partitionCnt / numPhi; |
| 325 |
p = emap -> partitionCnt - t * numPhi; |
| 326 |
|
| 327 |
emap -> ws [2] = cosTheta = 1 - 2 * (t + pmapRandom(partState)) / numTheta; |
| 328 |
sinTheta = sqrt(1 - sqr(cosTheta)); |
| 329 |
phi = 2 * PI * (p + pmapRandom(partState)) / numPhi; |
| 330 |
emap -> ws [0] = cos(phi) * sinTheta; |
| 331 |
emap -> ws [1] = sin(phi) * sinTheta; |
| 332 |
|
| 333 |
if (emap -> port) |
| 334 |
/* Acts as a photon port; reverse normal as it points INSIDE per |
| 335 |
* mkillum convention */ |
| 336 |
for (i = 0; i < 3; i++) |
| 337 |
emap -> ws [i] = -emap -> ws [i]; |
| 338 |
|
| 339 |
/* Get surface axes us & vs perpendicular to ws */ |
| 340 |
do { |
| 341 |
emap -> vs [0] = emap -> vs [1] = emap -> vs [2] = 0; |
| 342 |
emap -> vs [i++] = 1; |
| 343 |
fcross(emap -> us, emap -> vs, emap -> ws); |
| 344 |
} while (normalize(emap -> us) < FTINY); |
| 345 |
|
| 346 |
fcross(emap -> vs, emap -> ws, emap -> us); |
| 347 |
|
| 348 |
/* Get origin */ |
| 349 |
for (i = 0; i < 3; i++) |
| 350 |
emap -> photonOrg [i] = emap -> src -> sloc [i] + |
| 351 |
emap -> src -> srad * emap -> ws [i]; |
| 352 |
|
| 353 |
/* Get hemisphere axes & aperture */ |
| 354 |
if (emap -> src -> sflags & SSPOT) { |
| 355 |
VCOPY(emap -> wh, emap -> src -> sl.s -> aim); |
| 356 |
i = 0; |
| 357 |
|
| 358 |
do { |
| 359 |
emap -> vh [0] = emap -> vh [1] = emap -> vh [2] = 0; |
| 360 |
emap -> vh [i++] = 1; |
| 361 |
fcross(emap -> uh, emap -> vh, emap -> wh); |
| 362 |
} while (normalize(emap -> uh) < FTINY); |
| 363 |
|
| 364 |
fcross(emap -> vh, emap -> wh, emap -> uh); |
| 365 |
emap -> cosThetaMax = 1 - emap -> src -> sl.s -> siz / (2 * PI); |
| 366 |
} |
| 367 |
|
| 368 |
else { |
| 369 |
VCOPY(emap -> uh, emap -> us); |
| 370 |
VCOPY(emap -> vh, emap -> vs); |
| 371 |
VCOPY(emap -> wh, emap -> ws); |
| 372 |
emap -> cosThetaMax = 0; |
| 373 |
} |
| 374 |
} |
| 375 |
|
| 376 |
|
| 377 |
|
| 378 |
static void sourcePhotonOrigin (EmissionMap* emap) |
| 379 |
/* Init emission map with photon origin and associated surface axes |
| 380 |
on scene cube face for distant light source. Also sets source |
| 381 |
aperture (solid angle) and sampling hemisphere axes at origin */ |
| 382 |
{ |
| 383 |
unsigned long i, partsPerDim, partsPerFace; |
| 384 |
unsigned face; |
| 385 |
RREAL du, dv; |
| 386 |
|
| 387 |
if (emap -> port) { |
| 388 |
/* Get origin on photon port */ |
| 389 |
SRCREC *src = emap -> src; |
| 390 |
emap -> src = emap -> port; |
| 391 |
photonOrigin [emap -> src -> so -> otype] (emap); |
| 392 |
emap -> src = src; |
| 393 |
} |
| 394 |
|
| 395 |
else { |
| 396 |
/* No ports defined, so get origin on scene cube face and SUFFA! */ |
| 397 |
/* Get current face from partition number */ |
| 398 |
partsPerDim = 1 / srcsizerat; |
| 399 |
partsPerFace = sqr(partsPerDim); |
| 400 |
face = emap -> partitionCnt / partsPerFace; |
| 401 |
|
| 402 |
if (!(emap -> partitionCnt % partsPerFace)) { |
| 403 |
/* Skipped to a new face; get its normal */ |
| 404 |
emap -> ws [0] = emap -> ws [1] = emap -> ws [2] = 0; |
| 405 |
emap -> ws [face >> 1] = face & 1 ? 1 : -1; |
| 406 |
|
| 407 |
/* Get surface axes us & vs perpendicular to ws */ |
| 408 |
face >>= 1; |
| 409 |
emap -> vs [0] = emap -> vs [1] = emap -> vs [2] = 0; |
| 410 |
emap -> vs [(face + (emap -> ws [face] > 0 ? 2 : 1)) % 3] = 1; |
| 411 |
fcross(emap -> us, emap -> vs, emap -> ws); |
| 412 |
} |
| 413 |
|
| 414 |
/* Get jittered offsets within face from partition number |
| 415 |
(in range [-0.5, 0.5]) */ |
| 416 |
i = emap -> partitionCnt % partsPerFace; |
| 417 |
du = (i / partsPerDim + pmapRandom(partState)) / partsPerDim - 0.5; |
| 418 |
dv = (i % partsPerDim + pmapRandom(partState)) / partsPerDim - 0.5; |
| 419 |
|
| 420 |
/* Jittered destination point within partition */ |
| 421 |
for (i = 0; i < 3; i++) |
| 422 |
emap -> photonOrg [i] = thescene.cuorg [i] + |
| 423 |
thescene.cusize * (0.5 + du * emap -> us [i] + |
| 424 |
dv * emap -> vs [i] + |
| 425 |
0.5 * emap -> ws [i]); |
| 426 |
} |
| 427 |
|
| 428 |
/* Get hemisphere axes & aperture */ |
| 429 |
VCOPY(emap -> wh, emap -> src -> sloc); |
| 430 |
i = 0; |
| 431 |
|
| 432 |
do { |
| 433 |
emap -> vh [0] = emap -> vh [1] = emap -> vh [2] = 0; |
| 434 |
emap -> vh [i++] = 1; |
| 435 |
fcross(emap -> uh, emap -> vh, emap -> wh); |
| 436 |
} while (normalize(emap -> uh) < FTINY); |
| 437 |
|
| 438 |
fcross(emap -> vh, emap -> wh, emap -> uh); |
| 439 |
|
| 440 |
/* Get aperture */ |
| 441 |
emap -> cosThetaMax = 1 - emap -> src -> ss2 / (2 * PI); |
| 442 |
emap -> cosThetaMax = min(1, max(-1, emap -> cosThetaMax)); |
| 443 |
} |
| 444 |
|
| 445 |
|
| 446 |
|
| 447 |
static void cylPhotonOrigin (EmissionMap* emap) |
| 448 |
/* Init emission map with photon origin and associated surface axes |
| 449 |
on cylindrical light source surface. Also sets source aperture |
| 450 |
and sampling hemisphere axes at origin */ |
| 451 |
{ |
| 452 |
int i, cent[3], size[3], parr[2]; |
| 453 |
FVECT v; |
| 454 |
|
| 455 |
cent [0] = cent [1] = cent [2] = 0; |
| 456 |
size [0] = size [1] = size [2] = emap -> maxPartitions; |
| 457 |
parr [0] = 0; |
| 458 |
parr [1] = emap -> partitionCnt; |
| 459 |
|
| 460 |
if (!skipparts(cent, size, parr, emap -> partitions)) |
| 461 |
error(CONSISTENCY, "bad source partition in cylPhotonOrigin"); |
| 462 |
|
| 463 |
v [SU] = 0; |
| 464 |
v [SV] = (1 - 2 * pmapRandom(partState)) * (double)size [1] / |
| 465 |
emap -> maxPartitions; |
| 466 |
v [SW] = (1 - 2 * pmapRandom(partState)) * (double)size [2] / |
| 467 |
emap -> maxPartitions; |
| 468 |
normalize(v); |
| 469 |
v [SU] = (1 - 2 * pmapRandom(partState)) * (double)size [1] / |
| 470 |
emap -> maxPartitions; |
| 471 |
|
| 472 |
for (i = 0; i < 3; i++) |
| 473 |
v [i] += (double)cent [i] / emap -> maxPartitions; |
| 474 |
|
| 475 |
/* Get surface axes */ |
| 476 |
for (i = 0; i < 3; i++) |
| 477 |
emap -> photonOrg [i] = emap -> ws [i] = |
| 478 |
(v [SV] * emap -> src -> ss [SV][i] + |
| 479 |
v [SW] * emap -> src -> ss [SW][i]) / 0.8559; |
| 480 |
|
| 481 |
if (emap -> port) |
| 482 |
/* Acts as a photon port; reverse normal as it points INSIDE per |
| 483 |
* mkillum convention */ |
| 484 |
for (i = 0; i < 3; i++) |
| 485 |
emap -> ws [i] = -emap -> ws [i]; |
| 486 |
|
| 487 |
normalize(emap -> ws); |
| 488 |
VCOPY(emap -> us, emap -> src -> ss [SU]); |
| 489 |
normalize(emap -> us); |
| 490 |
fcross(emap -> vs, emap -> ws, emap -> us); |
| 491 |
|
| 492 |
/* Get origin */ |
| 493 |
for (i = 0; i < 3; i++) |
| 494 |
emap -> photonOrg [i] += v [SU] * emap -> src -> ss [SU][i] + |
| 495 |
emap -> src -> sloc [i]; |
| 496 |
|
| 497 |
/* Get hemisphere axes & aperture */ |
| 498 |
if (emap -> src -> sflags & SSPOT) { |
| 499 |
VCOPY(emap -> wh, emap -> src -> sl.s -> aim); |
| 500 |
i = 0; |
| 501 |
|
| 502 |
do { |
| 503 |
emap -> vh [0] = emap -> vh [1] = emap -> vh [2] = 0; |
| 504 |
emap -> vh [i++] = 1; |
| 505 |
fcross(emap -> uh, emap -> vh, emap -> wh); |
| 506 |
} while (normalize(emap -> uh) < FTINY); |
| 507 |
|
| 508 |
fcross(emap -> vh, emap -> wh, emap -> uh); |
| 509 |
emap -> cosThetaMax = 1 - emap -> src -> sl.s -> siz / (2 * PI); |
| 510 |
} |
| 511 |
|
| 512 |
else { |
| 513 |
VCOPY(emap -> uh, emap -> us); |
| 514 |
VCOPY(emap -> vh, emap -> vs); |
| 515 |
VCOPY(emap -> wh, emap -> ws); |
| 516 |
emap -> cosThetaMax = 0; |
| 517 |
} |
| 518 |
} |
| 519 |
|
| 520 |
|
| 521 |
|
| 522 |
void getPhotonPorts () |
| 523 |
/* Find geometry declared as photon ports */ |
| 524 |
{ |
| 525 |
OBJECT i; |
| 526 |
OBJREC* obj; |
| 527 |
|
| 528 |
/* Check for missing port modifiers */ |
| 529 |
if (!ambset [0]) |
| 530 |
error(USER, "no photon ports found"); |
| 531 |
|
| 532 |
for (i = 0; i < nobjects; i++) { |
| 533 |
obj = objptr(i); |
| 534 |
|
| 535 |
if (inset(ambset, obj -> omod)) { |
| 536 |
/* Add photon port */ |
| 537 |
photonPorts = (SRCREC*)realloc(photonPorts, |
| 538 |
(numPhotonPorts + 1) * |
| 539 |
sizeof(SRCREC)); |
| 540 |
if (!photonPorts) |
| 541 |
error(USER, "can't allocate photon ports"); |
| 542 |
|
| 543 |
photonPorts [numPhotonPorts].so = obj; |
| 544 |
photonPorts [numPhotonPorts].sflags = 0; |
| 545 |
|
| 546 |
if (!sfun [obj -> otype].of || !sfun[obj -> otype].of -> setsrc) |
| 547 |
objerror(obj, USER, "illegal photon port"); |
| 548 |
|
| 549 |
setsource(photonPorts + numPhotonPorts, obj); |
| 550 |
numPhotonPorts++; |
| 551 |
} |
| 552 |
} |
| 553 |
} |
| 554 |
|
| 555 |
|
| 556 |
|
| 557 |
static void defaultEmissionFunc (EmissionMap* emap) |
| 558 |
/* Default behaviour when no emission funcs defined for this source type */ |
| 559 |
{ |
| 560 |
objerror(emap -> src -> so, INTERNAL, |
| 561 |
"undefined photon emission function"); |
| 562 |
} |
| 563 |
|
| 564 |
|
| 565 |
|
| 566 |
void initPhotonEmissionFuncs () |
| 567 |
/* Init photonPartition[] and photonOrigin[] dispatch tables */ |
| 568 |
{ |
| 569 |
int i; |
| 570 |
|
| 571 |
for (i = 0; i < NUMOTYPE; i++) |
| 572 |
photonPartition [i] = photonOrigin [i] = defaultEmissionFunc; |
| 573 |
|
| 574 |
photonPartition [OBJ_FACE] = photonPartition [OBJ_RING] = flatPhotonPartition; |
| 575 |
photonPartition [OBJ_SOURCE] = sourcePhotonPartition; |
| 576 |
photonPartition [OBJ_SPHERE] = spherePhotonPartition; |
| 577 |
photonPartition [OBJ_CYLINDER] = cylPhotonPartition; |
| 578 |
photonOrigin [OBJ_FACE] = photonOrigin [OBJ_RING] = flatPhotonOrigin; |
| 579 |
photonOrigin [OBJ_SOURCE] = sourcePhotonOrigin; |
| 580 |
photonOrigin [OBJ_SPHERE] = spherePhotonOrigin; |
| 581 |
photonOrigin [OBJ_CYLINDER] = cylPhotonOrigin; |
| 582 |
} |
| 583 |
|
| 584 |
|
| 585 |
|
| 586 |
void initPhotonEmission (EmissionMap *emap, float numPdfSamples) |
| 587 |
/* Initialize photon emission from partitioned light source emap -> src; |
| 588 |
* this involves integrating the flux emitted from the current photon |
| 589 |
* origin emap -> photonOrg and setting up a PDF to sample the emission |
| 590 |
* distribution with numPdfSamples samples */ |
| 591 |
{ |
| 592 |
unsigned i, t, p; |
| 593 |
double phi, cosTheta, sinTheta, du, dv, dOmega, thetaScale; |
| 594 |
EmissionSample* sample; |
| 595 |
const OBJREC* mod = objptr(emap -> src -> so -> omod); |
| 596 |
static RAY r; |
| 597 |
#if 0 |
| 598 |
static double lastCosNorm = FHUGE; |
| 599 |
static SRCREC *lastSrc = NULL, *lastPort = NULL; |
| 600 |
#endif |
| 601 |
|
| 602 |
photonOrigin [emap -> src -> so -> otype] (emap); |
| 603 |
cosTheta = DOT(emap -> ws, emap -> wh); |
| 604 |
|
| 605 |
#if 0 |
| 606 |
if (emap -> src == lastSrc && emap -> port == lastPort && |
| 607 |
(emap -> src -> sflags & SDISTANT || mod -> omod == OVOID) && |
| 608 |
cosTheta == lastCosNorm) |
| 609 |
/* Same source, port, and aperture-normal angle, and source is |
| 610 |
either distant (and thus translationally invariant) or has |
| 611 |
no modifier --> flux unchanged */ |
| 612 |
/* BUG: this optimisation ignores partial occlusion of ports and |
| 613 |
can lead to erroneous "zero emission" bailouts. |
| 614 |
It can also lead to bias with modifiers exhibiting high variance! |
| 615 |
Disabled for now -- RS 12/13 */ |
| 616 |
return; |
| 617 |
|
| 618 |
lastSrc = emap -> src; |
| 619 |
lastPort = emap -> port; |
| 620 |
lastCosNorm = cosTheta; |
| 621 |
#endif |
| 622 |
|
| 623 |
/* Need to recompute flux & PDF */ |
| 624 |
setcolor(emap -> partFlux, 0, 0, 0); |
| 625 |
emap -> cdf = 0; |
| 626 |
emap -> numSamples = 0; |
| 627 |
|
| 628 |
if (cosTheta <= 0 && |
| 629 |
sqrt(1 - sqr(cosTheta)) <= emap -> cosThetaMax + FTINY) |
| 630 |
/* Aperture below surface; no emission from current origin */ |
| 631 |
return; |
| 632 |
|
| 633 |
if (mod -> omod == OVOID && !emap -> port && |
| 634 |
(cosTheta >= 1 - FTINY || (emap -> src -> sflags & SDISTANT && |
| 635 |
acos(cosTheta) + acos(emap -> cosThetaMax) <= 0.5 * PI))) { |
| 636 |
/* Source is unmodified and has no port (which requires testing for |
| 637 |
occlusion), and is either local with normal aligned aperture or |
| 638 |
distant with aperture above surface; analytical flux & PDF */ |
| 639 |
setcolor(emap -> partFlux, mod -> oargs.farg [0], |
| 640 |
mod -> oargs.farg [1], mod -> oargs.farg [2]); |
| 641 |
|
| 642 |
/* Multiply radiance by Omega * dA to get flux */ |
| 643 |
scalecolor(emap -> partFlux, |
| 644 |
PI * cosTheta * (1 - sqr(max(emap -> cosThetaMax, 0))) * |
| 645 |
emap -> partArea); |
| 646 |
} |
| 647 |
|
| 648 |
else { |
| 649 |
/* Source is either modified, has a port, is local with off-normal |
| 650 |
aperture, or distant with aperture partly below surface; get flux |
| 651 |
via numerical integration */ |
| 652 |
thetaScale = (1 - emap -> cosThetaMax); |
| 653 |
|
| 654 |
/* Figga out numba of aperture samples for integration; |
| 655 |
numTheta / numPhi ratio is 1 / PI */ |
| 656 |
du = sqrt(pdfSamples * 2 * thetaScale); |
| 657 |
emap -> numTheta = max(du + 0.5, 1); |
| 658 |
emap -> numPhi = max(PI * du + 0.5, 1); |
| 659 |
|
| 660 |
dOmega = 2 * PI * thetaScale / (emap -> numTheta * emap -> numPhi); |
| 661 |
thetaScale /= emap -> numTheta; |
| 662 |
|
| 663 |
/* Allocate PDF, baby */ |
| 664 |
sample = emap -> samples = (EmissionSample*) |
| 665 |
realloc(emap -> samples, |
| 666 |
sizeof(EmissionSample) * |
| 667 |
emap -> numTheta * emap -> numPhi); |
| 668 |
if (!emap -> samples) |
| 669 |
error(USER, "can't allocate emission PDF"); |
| 670 |
|
| 671 |
VCOPY(r.rorg, emap -> photonOrg); |
| 672 |
VCOPY(r.rop, emap -> photonOrg); |
| 673 |
r.rmax = FHUGE; |
| 674 |
|
| 675 |
for (t = 0; t < emap -> numTheta; t++) { |
| 676 |
for (p = 0; p < emap -> numPhi; p++) { |
| 677 |
/* This uniform mapping handles 0 <= thetaMax <= PI */ |
| 678 |
cosTheta = 1 - (t + pmapRandom(emitState)) * thetaScale; |
| 679 |
sinTheta = sqrt(1 - sqr(cosTheta)); |
| 680 |
phi = 2 * PI * (p + pmapRandom(emitState)) / emap -> numPhi; |
| 681 |
du = cos(phi) * sinTheta; |
| 682 |
dv = sin(phi) * sinTheta; |
| 683 |
rayorigin(&r, PRIMARY, NULL, NULL); |
| 684 |
|
| 685 |
for (i = 0; i < 3; i++) |
| 686 |
r.rdir [i] = du * emap -> uh [i] + dv * emap -> vh [i] + |
| 687 |
cosTheta * emap -> wh [i]; |
| 688 |
|
| 689 |
/* Sample behind surface? */ |
| 690 |
VCOPY(r.ron, emap -> ws); |
| 691 |
if ((r.rod = DOT(r.rdir, r.ron)) <= 0) |
| 692 |
continue; |
| 693 |
|
| 694 |
/* Get radiance emitted in this direction; to get flux we |
| 695 |
multiply by cos(theta_surface), dOmega, and dA. Ray |
| 696 |
is directed towards light source for raytexture(). */ |
| 697 |
if (!(emap -> src -> sflags & SDISTANT)) |
| 698 |
for (i = 0; i < 3; i++) |
| 699 |
r.rdir [i] = -r.rdir [i]; |
| 700 |
|
| 701 |
/* Port occluded in this direction? */ |
| 702 |
if (emap -> port && localhit(&r, &thescene)) |
| 703 |
continue; |
| 704 |
|
| 705 |
raytexture(&r, mod -> omod); |
| 706 |
setcolor(r.rcol, mod -> oargs.farg [0], mod -> oargs.farg [1], |
| 707 |
mod -> oargs.farg [2]); |
| 708 |
multcolor(r.rcol, r.pcol); |
| 709 |
|
| 710 |
/* Multiply by cos(theta_surface) */ |
| 711 |
scalecolor(r.rcol, r.rod); |
| 712 |
|
| 713 |
/* Add PDF sample if nonzero; importance info for photon emission |
| 714 |
* could go here... */ |
| 715 |
if (colorAvg(r.rcol)) { |
| 716 |
copycolor(sample -> pdf, r.rcol); |
| 717 |
sample -> cdf = emap -> cdf += colorAvg(sample -> pdf); |
| 718 |
sample -> theta = t; |
| 719 |
sample++ -> phi = p; |
| 720 |
emap -> numSamples++; |
| 721 |
addcolor(emap -> partFlux, r.rcol); |
| 722 |
} |
| 723 |
} |
| 724 |
} |
| 725 |
|
| 726 |
/* Multiply by dOmega * dA */ |
| 727 |
scalecolor(emap -> partFlux, dOmega * emap -> partArea); |
| 728 |
} |
| 729 |
} |
| 730 |
|
| 731 |
|
| 732 |
|
| 733 |
#define vomitPhoton emitPhoton |
| 734 |
#define bluarrrghPhoton vomitPhoton |
| 735 |
|
| 736 |
void emitPhoton (const EmissionMap* emap, RAY* ray) |
| 737 |
/* Emit photon from current partition emap -> partitionCnt based on |
| 738 |
emission distribution. Returns new photon ray. */ |
| 739 |
{ |
| 740 |
unsigned long i, lo, hi; |
| 741 |
const EmissionSample* sample = emap -> samples; |
| 742 |
RREAL du, dv, cosTheta, cosThetaSqr, sinTheta, phi; |
| 743 |
const OBJREC* mod = objptr(emap -> src -> so -> omod); |
| 744 |
|
| 745 |
/* Choose a new origin within current partition for every |
| 746 |
emitted photon to break up clustering artifacts */ |
| 747 |
photonOrigin [emap -> src -> so -> otype] ((EmissionMap*)emap); |
| 748 |
rayorigin(ray, PRIMARY, NULL, NULL); |
| 749 |
ray -> rmax = FHUGE; |
| 750 |
|
| 751 |
if (!emap -> numSamples) { |
| 752 |
/* Source is unmodified and has no port, and either local with |
| 753 |
normal aligned aperture, or distant with aperture above surface; |
| 754 |
use cosine weighted distribution */ |
| 755 |
cosThetaSqr = 1 - pmapRandom(emitState) * |
| 756 |
(1 - sqr(max(emap -> cosThetaMax, 0))); |
| 757 |
cosTheta = sqrt(cosThetaSqr); |
| 758 |
sinTheta = sqrt(1 - cosThetaSqr); |
| 759 |
phi = 2 * PI * pmapRandom(emitState); |
| 760 |
setcolor(ray -> rcol, mod -> oargs.farg [0], mod -> oargs.farg [1], |
| 761 |
mod -> oargs.farg [2]); |
| 762 |
} |
| 763 |
|
| 764 |
else { |
| 765 |
/* Source is either modified, has a port, is local with off-normal |
| 766 |
aperture, or distant with aperture partly below surface; choose |
| 767 |
direction from constructed cumulative distribution function with |
| 768 |
Monte Carlo inversion using binary search. */ |
| 769 |
du = pmapRandom(emitState) * emap -> cdf; |
| 770 |
lo = 1; |
| 771 |
hi = emap -> numSamples; |
| 772 |
|
| 773 |
while (hi > lo) { |
| 774 |
i = (lo + hi) >> 1; |
| 775 |
sample = emap -> samples + i - 1; |
| 776 |
|
| 777 |
if (sample -> cdf >= du) |
| 778 |
hi = i; |
| 779 |
if (sample -> cdf < du) |
| 780 |
lo = i + 1; |
| 781 |
} |
| 782 |
|
| 783 |
/* This is a uniform mapping, mon */ |
| 784 |
cosTheta = 1 - (sample -> theta + pmapRandom(emitState)) * |
| 785 |
(1 - emap -> cosThetaMax) / emap -> numTheta; |
| 786 |
sinTheta = sqrt(1 - sqr(cosTheta)); |
| 787 |
phi = 2 * PI * (sample -> phi + pmapRandom(emitState)) / emap -> numPhi; |
| 788 |
copycolor(ray -> rcol, sample -> pdf); |
| 789 |
} |
| 790 |
|
| 791 |
/* Normalize photon flux so that average over RGB is 1 */ |
| 792 |
colorNorm(ray -> rcol); |
| 793 |
|
| 794 |
VCOPY(ray -> rorg, emap -> photonOrg); |
| 795 |
du = cos(phi) * sinTheta; |
| 796 |
dv = sin(phi) * sinTheta; |
| 797 |
|
| 798 |
for (i = 0; i < 3; i++) |
| 799 |
ray -> rdir [i] = du * emap -> uh [i] + dv * emap -> vh [i] + |
| 800 |
cosTheta * emap -> wh [i]; |
| 801 |
|
| 802 |
if (emap -> src -> sflags & SDISTANT) |
| 803 |
/* Distant source; reverse ray direction to point into the scene. */ |
| 804 |
for (i = 0; i < 3; i++) |
| 805 |
ray -> rdir [i] = -ray -> rdir [i]; |
| 806 |
|
| 807 |
if (emap -> port) |
| 808 |
/* Photon emitted from port; move origin just behind port so it |
| 809 |
will be scattered */ |
| 810 |
for (i = 0; i < 3; i++) |
| 811 |
ray -> rorg [i] -= 2 * FTINY * ray -> rdir [i]; |
| 812 |
|
| 813 |
/* Assign emitting light source index */ |
| 814 |
ray -> rsrc = emap -> src - source; |
| 815 |
} |
| 816 |
|
| 817 |
|
| 818 |
|
| 819 |
void multDirectPmap (RAY *r) |
| 820 |
/* Factor irradiance from direct photons into r -> rcol; interface to |
| 821 |
* direct() */ |
| 822 |
{ |
| 823 |
COLOR photonIrrad; |
| 824 |
|
| 825 |
/* Lookup direct photon irradiance */ |
| 826 |
(directPmap -> lookup)(directPmap, r, photonIrrad); |
| 827 |
|
| 828 |
/* Multiply with coefficient in ray */ |
| 829 |
multcolor(r -> rcol, photonIrrad); |
| 830 |
|
| 831 |
return; |
| 832 |
} |
| 833 |
|
| 834 |
|
| 835 |
|
| 836 |
void inscatterVolumePmap (RAY *r, COLOR inscatter) |
| 837 |
/* Add inscattering from volume photon map; interface to srcscatter() */ |
| 838 |
{ |
| 839 |
/* Add ambient in-scattering via lookup callback */ |
| 840 |
(volumePmap -> lookup)(volumePmap, r, inscatter); |
| 841 |
} |
