int OOC_FilterPhoton (void *p, void *fd)
/* Filter callback for photon kNN search, used by OOC_FindNearest() */
{
const Photon *photon = p;
const OOC_FilterData *filtData = fd;
const PhotonMap *pmap = filtData -> pmap;
/* Reject photon if normal faces away (ignored for volume photons) with
* tolerance to account for perturbation; note photon normal is coded
* in range [-127,127], hence we factor this in */
if (filtData -> norm &&
DOT(filtData->norm, photon->norm) <= PMAP_NORM_TOL * 127 * frandom())
return 0;
if (isContribPmap(pmap)) {
/* Lookup in contribution photon map; filter according to emitting
* light source if contrib list set, else accept all */
if (pmap -> srcContrib) {
OBJREC *srcMod;
const int srcIdx = photonSrcIdx(pmap, photon);
if (srcIdx < 0 || srcIdx >= nsources)
error(INTERNAL, "invalid light source index in photon map");
srcMod = findmaterial(source [srcIdx].so);
/* Reject photon if contributions from light source which emitted
* it are not sought */
if (!lu_find(pmap -> srcContrib, srcMod -> oname) -> data)
return 0;
}
/* Reject non-caustic photon if lookup for caustic contribs */
if (pmap -> lookupCaustic && !photon -> caustic)
return 0;
}
/* Accept photon */
return 1;
}
void buildPhotonMap (PhotonMap *pmap, double *photonFlux,
PhotonPrimaryIdx *primaryOfs, unsigned nproc)
{
unsigned long n, nCheck = 0;
unsigned i;
Photon *p;
COLOR flux;
char nuHeapFname [sizeof(PMAP_TMPFNAME)];
FILE *nuHeap;
/* Need double here to reduce summation errors */
double avgFlux [3] = {0, 0, 0}, CoG [3] = {0, 0, 0}, CoGdist = 0;
FVECT d;
if (!pmap)
error(INTERNAL, "undefined photon map in buildPhotonMap");
/* Get number of photons from heapfile size */
if (fseek(pmap -> heap, 0, SEEK_END) < 0)
error(SYSTEM, "failed seek to end of photon heap in buildPhotonMap");
pmap -> numPhotons = ftell(pmap -> heap) / sizeof(Photon);
if (!pmap -> numPhotons)
error(INTERNAL, "empty photon map in buildPhotonMap");
if (!pmap -> heap)
error(INTERNAL, "no heap in buildPhotonMap");
#ifdef DEBUG_PMAP
eputs("Checking photon heap consistency...\n");
checkPhotonHeap(pmap -> heap);
sprintf(errmsg, "Heap contains %ld photons\n", pmap -> numPhotons);
eputs(errmsg);
#endif
/* Allocate heap buffa */
if (!pmap -> heapBuf) {
pmap -> heapBufSize = PMAP_HEAPBUFSIZE;
pmap -> heapBuf = calloc(pmap -> heapBufSize, sizeof(Photon));
if (!pmap -> heapBuf)
error(SYSTEM, "failed to allocate postprocessed photon heap in"
"buildPhotonMap");
}
/* We REALLY don't need yet another @%&*! heap just to hold the scaled
* photons, but can't think of a quicker fix... */
mktemp(strcpy(nuHeapFname, PMAP_TMPFNAME));
if (!(nuHeap = fopen(nuHeapFname, "w+b")))
error(SYSTEM, "failed to open postprocessed photon heap in "
"buildPhotonMap");
rewind(pmap -> heap);
#ifdef DEBUG_PMAP
eputs("Postprocessing photons...\n");
#endif
while (!feof(pmap -> heap)) {
#ifdef DEBUG_PMAP
printf("Reading %lu at %lu... ", pmap -> heapBufSize, ftell(pmap->heap));
#endif
pmap -> heapBufLen = fread(pmap -> heapBuf, sizeof(Photon),
pmap -> heapBufSize, pmap -> heap);
#ifdef DEBUG_PMAP
printf("Got %lu\n", pmap -> heapBufLen);
#endif
if (ferror(pmap -> heap))
error(SYSTEM, "failed to read photon heap in buildPhotonMap");
for (n = pmap -> heapBufLen, p = pmap -> heapBuf; n; n--, p++) {
/* Update min and max pos and set photon flux */
for (i = 0; i <= 2; i++) {
if (p -> pos [i] < pmap -> minPos [i])
pmap -> minPos [i] = p -> pos [i];
else if (p -> pos [i] > pmap -> maxPos [i])
pmap -> maxPos [i] = p -> pos [i];
/* Update centre of gravity with photon position */
CoG [i] += p -> pos [i];
}
if (primaryOfs)
/* Linearise photon primary index from subprocess index using the
* per-subprocess offsets in primaryOfs */
p -> primary += primaryOfs [p -> proc];
/* Scale photon's flux (hitherto normalised to 1 over RGB); in
* case of a contrib photon map, this is done per light source,
* and photonFlux is assumed to be an array */
getPhotonFlux(p, flux);
if (photonFlux) {
scalecolor(flux, photonFlux [isContribPmap(pmap) ?
photonSrcIdx(pmap, p) : 0]);
setPhotonFlux(p, flux);
}
/* Update average photon flux; need a double here */
addcolor(avgFlux, flux);
}
/* Write modified photons to new heap */
fwrite(pmap -> heapBuf, sizeof(Photon), pmap -> heapBufLen, nuHeap);
if (ferror(nuHeap))
error(SYSTEM, "failed postprocessing photon flux in "
"buildPhotonMap");
nCheck += pmap -> heapBufLen;
}
#ifdef DEBUG_PMAP
if (nCheck < pmap -> numPhotons)
error(INTERNAL, "truncated photon heap in buildPhotonMap");
#endif
/* Finalise average photon flux */
scalecolor(avgFlux, 1.0 / pmap -> numPhotons);
copycolor(pmap -> photonFlux, avgFlux);
/* Average photon positions to get centre of gravity */
for (i = 0; i < 3; i++)
pmap -> CoG [i] = CoG [i] /= pmap -> numPhotons;
rewind(pmap -> heap);
/* Compute average photon distance to centre of gravity */
while (!feof(pmap -> heap)) {
pmap -> heapBufLen = fread(pmap -> heapBuf, sizeof(Photon),
pmap -> heapBufSize, pmap -> heap);
for (n = pmap -> heapBufLen, p = pmap -> heapBuf; n; n--, p++) {
VSUB(d, p -> pos, CoG);
CoGdist += DOT(d, d);
}
}
pmap -> CoGdist = CoGdist /= pmap -> numPhotons;
/* Swap heaps, discarding unscaled photons */
fclose(pmap -> heap);
unlink(pmap -> heapFname);
pmap -> heap = nuHeap;
strcpy(pmap -> heapFname, nuHeapFname);
#ifdef PMAP_OOC
OOC_BuildPhotonMap(pmap, nproc);
#else
kdT_BuildPhotonMap(pmap);
#endif
/* Trash heap and its buffa */
free(pmap -> heapBuf);
fclose(pmap -> heap);
unlink(pmap -> heapFname);
pmap -> heap = NULL;
pmap -> heapBuf = NULL;
}
