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pmapcontrib.c
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#ifndef lint
static const char RCSid[] = "$Id: pmapcontrib.c,v 2.20 2021/02/16 20:06:06 greg Exp $";
#endif
/*
======================================================================
Photon map for light source contributions
Roland Schregle (roland.schregle@{hslu.ch, gmail.com})
(c) Lucerne University of Applied Sciences and Arts,
supported by the Swiss National Science Foundation (SNSF, #147053)
======================================================================
$Id: pmapcontrib.c,v 2.20 2021/02/16 20:06:06 greg Exp $
*/
#include "pmapcontrib.h"
#include "pmapmat.h"
#include "pmapsrc.h"
#include "pmaprand.h"
#include "pmapio.h"
#include "pmapdiag.h"
#include "rcontrib.h"
#include "otypes.h"
#include "otspecial.h"
#if NIX
#include <sys/mman.h>
#include <sys/wait.h>
#endif
static PhotonPrimaryIdx newPhotonPrimary (PhotonMap *pmap,
const RAY *primRay,
FILE *primHeap)
/* Add primary ray for emitted photon and save light source index, origin on
* source, and emitted direction; used by contrib photons. The current
* primary is stored in pmap -> lastPrimary. If the previous primary
* contributed photons (has srcIdx >= 0), it's appended to primHeap. If
* primRay == NULL, the current primary is still flushed, but no new primary
* is set. Returns updated primary counter pmap -> numPrimary. */
{
if (!pmap || !primHeap)
return 0;
/* Check if last primary ray has spawned photons (srcIdx >= 0, see
* newPhoton()), in which case we save it to the primary heap file
* before clobbering it */
if (pmap -> lastPrimary.srcIdx >= 0) {
if (!fwrite(&pmap -> lastPrimary, sizeof(PhotonPrimary), 1, primHeap))
error(SYSTEM, "failed writing photon primary in newPhotonPrimary");
pmap -> numPrimary++;
if (pmap -> numPrimary > PMAP_MAXPRIMARY)
error(INTERNAL, "photon primary overflow in newPhotonPrimary");
}
/* Mark unused with negative source index until path spawns a photon (see
* newPhoton()) */
pmap -> lastPrimary.srcIdx = -1;
if (primRay) {
FVECT dvec;
#ifdef PMAP_PRIMARYDIR
/* Reverse incident direction to point to light source */
dvec [0] = -primRay -> rdir [0];
dvec [1] = -primRay -> rdir [1];
dvec [2] = -primRay -> rdir [2];
pmap -> lastPrimary.dir = encodedir(dvec);
#endif
#ifdef PMAP_PRIMARYPOS
VCOPY(pmap -> lastPrimary.pos, primRay -> rop);
#endif
}
return pmap -> numPrimary;
}
#ifdef DEBUG_PMAP
static int checkPrimaryHeap (FILE *file)
/* Check heap for ordered primaries */
{
Photon p, lastp;
int i, dup;
rewind(file);
memset(&lastp, 0, sizeof(lastp));
while (fread(&p, sizeof(p), 1, file)) {
dup = 1;
for (i = 0; i <= 2; i++) {
if (p.pos [i] < thescene.cuorg [i] ||
p.pos [i] > thescene.cuorg [i] + thescene.cusize) {
sprintf(errmsg, "corrupt photon in heap at [%f, %f, %f]\n",
p.pos [0], p.pos [1], p.pos [2]);
error(WARNING, errmsg);
}
dup &= p.pos [i] == lastp.pos [i];
}
if (dup) {
sprintf(errmsg,
"consecutive duplicate photon in heap at [%f, %f, %f]\n",
p.pos [0], p.pos [1], p.pos [2]);
error(WARNING, errmsg);
}
}
return 0;
}
#endif
static PhotonPrimaryIdx buildPrimaries (PhotonMap *pmap, FILE **primaryHeap,
char **primaryHeapFname,
PhotonPrimaryIdx *primaryOfs,
unsigned numHeaps)
/* Consolidate per-subprocess photon primary heaps into the primary array
* pmap -> primaries. Returns offset for primary index linearisation in
* numPrimary. The heap files in primaryHeap are closed on return. */
{
PhotonPrimaryIdx heapLen;
unsigned heap;
if (!pmap || !primaryHeap || !primaryOfs || !numHeaps)
return 0;
pmap -> numPrimary = 0;
for (heap = 0; heap < numHeaps; heap++) {
primaryOfs [heap] = pmap -> numPrimary;
if (fseek(primaryHeap [heap], 0, SEEK_END) < 0)
error(SYSTEM, "failed photon primary seek in buildPrimaries");
pmap -> numPrimary += heapLen = ftell(primaryHeap [heap]) /
sizeof(PhotonPrimary);
pmap -> primaries = realloc(pmap -> primaries,
pmap -> numPrimary *
sizeof(PhotonPrimary));
if (!pmap -> primaries)
error(SYSTEM, "failed photon primary alloc in buildPrimaries");
rewind(primaryHeap [heap]);
if (fread(pmap -> primaries + primaryOfs [heap], sizeof(PhotonPrimary),
heapLen, primaryHeap [heap]) != heapLen)
error(SYSTEM, "failed reading photon primaries in buildPrimaries");
fclose(primaryHeap [heap]);
unlink(primaryHeapFname [heap]);
}
return pmap -> numPrimary;
}
/* Defs for photon emission counter array passed by sub-processes to parent
* via shared memory */
typedef unsigned long PhotonContribCnt;
/* Indices for photon emission counter array: num photons stored and num
* emitted per source */
#define PHOTONCNT_NUMPHOT 0
#define PHOTONCNT_NUMEMIT(n) (1 + n)
void distribPhotonContrib (PhotonMap* pm, unsigned numProc)
{
EmissionMap emap;
char errmsg2 [128], shmFname [PMAP_TMPFNLEN];
unsigned srcIdx, proc;
int shmFile, stat, pid;
double *srcFlux, /* Emitted flux per light source */
srcDistribTarget; /* Target photon count per source */
PhotonContribCnt *photonCnt; /* Photon emission counter array */
unsigned photonCntSize = sizeof(PhotonContribCnt) *
PHOTONCNT_NUMEMIT(nsources);
FILE **primaryHeap = NULL;
char **primaryHeapFname = NULL;
PhotonPrimaryIdx *primaryOfs = NULL;
if (!pm)
error(USER, "no photon map defined in distribPhotonContrib");
if (!nsources)
error(USER, "no light sources in distribPhotonContrib");
/* Allocate photon flux per light source; this differs for every
* source as all sources contribute the same number of distributed
* photons (srcDistribTarget), hence the number of photons emitted per
* source does not correlate with its emitted flux. The resulting flux
* per photon is therefore adjusted individually for each source. */
if (!(srcFlux = calloc(nsources, sizeof(double))))
error(SYSTEM, "can't allocate source flux in distribPhotonContrib");
/* ===================================================================
* INITIALISATION - Set up emission and scattering funcs
* =================================================================== */
emap.samples = NULL;
emap.src = NULL;
emap.maxPartitions = MAXSPART;
emap.partitions = (unsigned char*)malloc(emap.maxPartitions >> 1);
if (!emap.partitions)
error(USER, "can't allocate source partitions in distribPhotonContrib");
/* Initialise contrib photon map */
initPhotonMap(pm, PMAP_TYPE_CONTRIB);
initPhotonHeap(pm);
initPhotonEmissionFuncs();
initPhotonScatterFuncs();
/* Per-subprocess / per-source target counts */
pm -> distribTarget /= numProc;
srcDistribTarget = nsources ? (double)pm -> distribTarget / nsources : 0;
if (!pm -> distribTarget)
error(INTERNAL, "no photons to distribute in distribPhotonContrib");
/* Get photon ports from modifier list */
getPhotonPorts(photonPortList);
/* Get photon sensor modifiers */
getPhotonSensors(photonSensorList);
#if NIX
/* Set up shared mem for photon counters (zeroed by ftruncate) */
strcpy(shmFname, PMAP_TMPFNAME);
shmFile = mkstemp(shmFname);
if (shmFile < 0 || ftruncate(shmFile, photonCntSize) < 0)
error(SYSTEM, "failed shared mem init in distribPhotonContrib");
photonCnt = mmap(NULL, photonCntSize, PROT_READ | PROT_WRITE,
MAP_SHARED, shmFile, 0);
if (photonCnt == MAP_FAILED)
error(SYSTEM, "failed shared mem mapping in distribPhotonContrib");
#else
/* Allocate photon counters statically on Windoze */
if (!(photonCnt = malloc(photonCntSize)))
error(SYSTEM, "failed trivial malloc in distribPhotonContrib");
for (srcIdx = 0; srcIdx < PHOTONCNT_NUMEMIT(nsources); srcIdx++)
photonCnt [srcIdx] = 0;
#endif /* NIX */
if (verbose) {
sprintf(errmsg, "\nIntegrating flux from %d sources", nsources);
if (photonPorts) {
sprintf(errmsg2, " via %d ports", numPhotonPorts);
strcat(errmsg, errmsg2);
}
strcat(errmsg, "\n");
eputs(errmsg);
}
/* =============================================================
* FLUX INTEGRATION - Get total flux emitted from sources/ports
* ============================================================= */
for (srcIdx = 0; srcIdx < nsources; srcIdx++) {
unsigned portCnt = 0;
srcFlux [srcIdx] = 0;
emap.src = source + srcIdx;
do { /* Need at least one iteration if no ports! */
emap.port = emap.src -> sflags & SDISTANT ? photonPorts + portCnt
: NULL;
photonPartition [emap.src -> so -> otype] (&emap);
if (verbose) {
sprintf(errmsg, "\tIntegrating flux from source %s ",
source [srcIdx].so -> oname);
if (emap.port) {
sprintf(errmsg2, "via port %s ",
photonPorts [portCnt].so -> oname);
strcat(errmsg, errmsg2);
}
sprintf(errmsg2, "(%lu partitions)\n", emap.numPartitions);
strcat(errmsg, errmsg2);
eputs(errmsg);
#if NIX
fflush(stderr);
#endif
}
for (emap.partitionCnt = 0; emap.partitionCnt < emap.numPartitions;
emap.partitionCnt++) {
initPhotonEmission(&emap, pdfSamples);
srcFlux [srcIdx] += colorAvg(emap.partFlux);
}
portCnt++;
} while (portCnt < numPhotonPorts);
if (srcFlux [srcIdx] < FTINY) {
sprintf(errmsg, "source %s has zero emission",
source [srcIdx].so -> oname);
error(WARNING, errmsg);
}
}
/* Allocate & init per-subprocess primary heap files */
primaryHeap = calloc(numProc, sizeof(FILE*));
primaryHeapFname = calloc(numProc, sizeof(char*));
primaryOfs = calloc(numProc, sizeof(PhotonPrimaryIdx));
if (!primaryHeap || !primaryHeapFname || !primaryOfs)
error(SYSTEM, "failed primary heap allocation in "
"distribPhotonContrib");
for (proc = 0; proc < numProc; proc++) {
primaryHeapFname [proc] = malloc(PMAP_TMPFNLEN);
if (!primaryHeapFname [proc])
error(SYSTEM, "failed primary heap file allocation in "
"distribPhotonContrib");
mktemp(strcpy(primaryHeapFname [proc], PMAP_TMPFNAME));
if (!(primaryHeap [proc] = fopen(primaryHeapFname [proc], "w+b")))
error(SYSTEM, "failed opening primary heap file in "
"distribPhotonContrib");
}
/* Record start time for progress reports */
repStartTime = time(NULL);
if (verbose) {
sprintf(errmsg, "\nPhoton distribution @ %d procs\n", numProc);
eputs(errmsg);
}
/* MAIN LOOP */
for (proc = 0; proc < numProc; proc++) {
#if NIX
if (!(pid = fork())) {
/* SUBPROCESS ENTERS HERE; opened and mmapped files inherited */
#else
if (1) {
/* No subprocess under Windoze */
#endif
/* Local photon counters for this subprocess */
unsigned long lastNumPhotons = 0, localNumEmitted = 0;
double photonFluxSum = 0; /* Accum. photon flux */
/* Seed RNGs from PID for decorellated photon distribution */
pmapSeed(randSeed + proc, partState);
pmapSeed(randSeed + (proc + 1) % numProc, emitState);
pmapSeed(randSeed + (proc + 2) % numProc, cntState);
pmapSeed(randSeed + (proc + 3) % numProc, mediumState);
pmapSeed(randSeed + (proc + 4) % numProc, scatterState);
pmapSeed(randSeed + (proc + 5) % numProc, rouletteState);
#ifdef PMAP_SIGUSR
double partNumEmit;
unsigned long partEmitCnt;
double srcPhotonFlux, avgPhotonFlux;
unsigned portCnt, passCnt, prePassCnt;
float srcPreDistrib;
double srcNumEmit; /* # to emit from source */
unsigned long srcNumDistrib; /* # stored */
void sigUsrDiags()
/* Loop diags via SIGUSR1 */
{
sprintf(errmsg,
"********************* Proc %d Diags *********************\n"
"srcIdx = %d (%s)\nportCnt = %d (%s)\npassCnt = %d\n"
"srcFlux = %f\nsrcPhotonFlux = %f\navgPhotonFlux = %f\n"
"partNumEmit = %f\npartEmitCnt = %lu\n\n",
proc, srcIdx, findmaterial(source [srcIdx].so) -> oname,
portCnt, photonPorts [portCnt].so -> oname,
passCnt, srcFlux [srcIdx], srcPhotonFlux, avgPhotonFlux,
partNumEmit, partEmitCnt);
eputs(errmsg);
fflush(stderr);
}
#endif
#ifdef PMAP_SIGUSR
signal(SIGUSR1, sigUsrDiags);
#endif
#ifdef DEBUG_PMAP
/* Output child process PID after random delay to prevent corrupted
* console output due to race condition */
usleep(1e6 * pmapRandom(rouletteState));
fprintf(stderr, "Proc %d: PID = %d "
"(waiting 10 sec to attach debugger...)\n",
proc, getpid());
/* Allow time for debugger to attach to child process */
sleep(10);
#endif
/* =============================================================
* 2-PASS PHOTON DISTRIBUTION
* Pass 1 (pre): emit fraction of target photon count
* Pass 2 (main): based on outcome of pass 1, estimate remaining
* number of photons to emit to approximate target
* count
* ============================================================= */
for (srcIdx = 0; srcIdx < nsources; srcIdx++) {
#ifndef PMAP_SIGUSR
unsigned portCnt, passCnt = 0, prePassCnt = 0;
float srcPreDistrib = preDistrib;
double srcNumEmit = 0; /* # to emit from source */
unsigned long srcNumDistrib = pm -> numPhotons; /* # stored */
#else
passCnt = prePassCnt = 0;
srcPreDistrib = preDistrib;
srcNumEmit = 0; /* # to emit from source */
srcNumDistrib = pm -> numPhotons; /* # stored */
#endif
if (srcFlux [srcIdx] < FTINY)
continue;
while (passCnt < 2) {
if (!passCnt) {
/* INIT PASS 1 */
if (++prePassCnt > maxPreDistrib) {
/* Warn if no photons contributed after sufficient
* iterations; only output from subprocess 0 to reduce
* console clutter */
if (!proc) {
sprintf(errmsg,
"source %s: too many prepasses, skipped",
source [srcIdx].so -> oname);
error(WARNING, errmsg);
}
break;
}
/* Num to emit is fraction of target count */
srcNumEmit = srcPreDistrib * srcDistribTarget;
}
else {
/* INIT PASS 2 */
#ifndef PMAP_SIGUSR
double srcPhotonFlux, avgPhotonFlux;
#endif
/* Based on the outcome of the predistribution we can now
* figure out how many more photons we have to emit from
* the current source to meet the target count,
* srcDistribTarget. This value is clamped to 0 in case
* the target has already been exceeded in pass 1.
* srcNumEmit and srcNumDistrib is the number of photons
* emitted and distributed (stored) from the current
* source in pass 1, respectively. */
srcNumDistrib = pm -> numPhotons - srcNumDistrib;
srcNumEmit *= srcNumDistrib
? max(srcDistribTarget/srcNumDistrib, 1) - 1
: 0;
if (!srcNumEmit)
/* No photons left to distribute in main pass */
break;
srcPhotonFlux = srcFlux [srcIdx] / srcNumEmit;
avgPhotonFlux = photonFluxSum / (srcIdx + 1);
if (avgPhotonFlux > FTINY &&
srcPhotonFlux / avgPhotonFlux < FTINY) {
/* Skip source if its photon flux is grossly below the
* running average, indicating negligible contributions
* at the expense of excessive distribution time; only
* output from subproc 0 to reduce console clutter */
if (!proc) {
sprintf(errmsg,
"source %s: itsy bitsy photon flux, skipped",
source [srcIdx].so -> oname);
error(WARNING, errmsg);
}
srcNumEmit = 0; /* Or just break??? */
}
/* Update sum of photon flux per light source */
photonFluxSum += srcPhotonFlux;
}
portCnt = 0;
do { /* Need at least one iteration if no ports! */
emap.src = source + srcIdx;
emap.port = emap.src -> sflags & SDISTANT
? photonPorts + portCnt : NULL;
photonPartition [emap.src -> so -> otype] (&emap);
if (verbose && !proc) {
/* Output from subproc 0 only to avoid race condition
* on console I/O */
if (!passCnt)
sprintf(errmsg, "\tPREPASS %d on source %s ",
prePassCnt, source [srcIdx].so -> oname);
else
sprintf(errmsg, "\tMAIN PASS on source %s ",
source [srcIdx].so -> oname);
if (emap.port) {
sprintf(errmsg2, "via port %s ",
photonPorts [portCnt].so -> oname);
strcat(errmsg, errmsg2);
}
sprintf(errmsg2, "(%lu partitions)\n",
emap.numPartitions);
strcat(errmsg, errmsg2);
eputs(errmsg);
#if NIX
fflush(stderr);
#endif
}
for (emap.partitionCnt = 0; emap.partitionCnt < emap.numPartitions;
emap.partitionCnt++) {
#ifndef PMAP_SIGUSR
double partNumEmit;
unsigned long partEmitCnt;
#endif
/* Get photon origin within current source partishunn
* and build emission map */
photonOrigin [emap.src -> so -> otype] (&emap);
initPhotonEmission(&emap, pdfSamples);
/* Number of photons to emit from ziss partishunn;
* scale according to its normalised contribushunn to
* the emitted source flux */
partNumEmit = srcNumEmit * colorAvg(emap.partFlux) /
srcFlux [srcIdx];
partEmitCnt = (unsigned long)partNumEmit;
/* Probabilistically account for fractional photons */
if (pmapRandom(cntState) < partNumEmit - partEmitCnt)
partEmitCnt++;
/* Update local and shared global emission counter */
photonCnt [PHOTONCNT_NUMEMIT(srcIdx)] += partEmitCnt;
localNumEmitted += partEmitCnt;
/* Integer counter avoids FP rounding errors during
* iteration */
while (partEmitCnt--) {
RAY photonRay;
/* Emit photon according to PDF (if any), allocate
* associated primary ray, and trace through scene
* until absorbed/leaked; emitPhoton() sets the
* emitting light source index in photonRay */
emitPhoton(&emap, &photonRay);
#if 1
if (emap.port)
/* !!! PHOTON PORT REJECTION SAMPLING HACK: set
* !!! photon port as fake hit object for
* !!! primary ray to check for intersection in
* !!! tracePhoton() */
photonRay.ro = emap.port -> so;
#endif
newPhotonPrimary(pm, &photonRay, primaryHeap[proc]);
/* Set subprocess index in photonRay for post-
* distrib primary index linearisation; this is
* propagated with the primary index in photonRay
* and set for photon hits by newPhoton() */
PMAP_SETRAYPROC(&photonRay, proc);
tracePhoton(&photonRay);
}
/* Update shared global photon count */
photonCnt [PHOTONCNT_NUMPHOT] += pm -> numPhotons -
lastNumPhotons;
lastNumPhotons = pm -> numPhotons;
#if !NIX
/* Synchronous progress report on Windoze */
if (!proc && photonRepTime > 0 &&
time(NULL) >= repLastTime + photonRepTime) {
unsigned s;
repComplete = pm -> distribTarget * numProc;
repProgress = photonCnt [PHOTONCNT_NUMPHOT];
for (repEmitted = 0, s = 0; s < nsources; s++)
repEmitted += photonCnt [PHOTONCNT_NUMEMIT(s)];
pmapDistribReport();
}
#endif
}
portCnt++;
} while (portCnt < numPhotonPorts);
if (pm -> numPhotons == srcNumDistrib) {
/* Double predistrib factor in case no photons were stored
* for this source and redo pass 1 */
srcPreDistrib *= 2;
}
else {
/* Now do pass 2 */
passCnt++;
}
}
}
/* Flush heap buffa one final time to prevent data corruption */
flushPhotonHeap(pm);
/* Flush final photon primary to primary heap file */
newPhotonPrimary(pm, NULL, primaryHeap [proc]);
/* Heap files closed automatically on exit
fclose(pm -> heap);
fclose(primaryHeap [proc]); */
#ifdef DEBUG_PMAP
sprintf(errmsg, "Proc %d total %ld photons\n", proc,
pm -> numPhotons);
eputs(errmsg);
fflush(stderr);
#endif
#ifdef PMAP_SIGUSR
signal(SIGUSR1, SIG_DFL);
#endif
#if NIX
/* Terminate subprocess */
exit(0);
#endif
}
else if (pid < 0)
error(SYSTEM, "failed to fork subprocess in distribPhotonContrib");
}
#if NIX
/* PARENT PROCESS CONTINUES HERE */
#ifdef SIGCONT
/* Enable progress report signal handler */
signal(SIGCONT, pmapDistribReport);
#endif
/* Wait for subprocesses to complete while reporting progress */
proc = numProc;
while (proc) {
while (waitpid(-1, &stat, WNOHANG) > 0) {
/* Subprocess exited; check status */
if (!WIFEXITED(stat) || WEXITSTATUS(stat))
error(USER, "failed photon distribution");
--proc;
}
/* Nod off for a bit and update progress */
sleep(1);
/* Asynchronous progress report from shared subprocess counters */
repComplete = pm -> distribTarget * numProc;
repProgress = photonCnt [PHOTONCNT_NUMPHOT];
for (repEmitted = 0, srcIdx = 0; srcIdx < nsources; srcIdx++)
repEmitted += photonCnt [PHOTONCNT_NUMEMIT(srcIdx)];
/* Get global photon count from shmem updated by subprocs */
pm -> numPhotons = photonCnt [PHOTONCNT_NUMPHOT];
if (photonRepTime > 0 && time(NULL) >= repLastTime + photonRepTime)
pmapDistribReport();
#ifdef SIGCONT
else signal(SIGCONT, pmapDistribReport);
#endif
}
#endif /* NIX */
/* ================================================================
* POST-DISTRIBUTION - Set photon flux and build kd-tree, etc.
* ================================================================ */
#ifdef SIGCONT
/* Reset signal handler */
signal(SIGCONT, SIG_DFL);
#endif
free(emap.samples);
if (!pm -> numPhotons)
error(USER, "empty contribution photon map");
/* Load per-subprocess primary rays into pm -> primary array */
/* Dumb compilers apparently need the char** cast */
pm -> numPrimary = buildPrimaries(pm, primaryHeap,
(char**)primaryHeapFname,
primaryOfs, numProc);
if (!pm -> numPrimary)
error(INTERNAL, "no primary rays in contribution photon map");
/* Set photon flux per source */
for (srcIdx = 0; srcIdx < nsources; srcIdx++)
srcFlux [srcIdx] /= photonCnt [PHOTONCNT_NUMEMIT(srcIdx)];
#if NIX
/* Photon counters no longer needed, unmap shared memory */
munmap(photonCnt, sizeof(*photonCnt));
close(shmFile);
unlink(shmFname);
#else
free(photonCnt);
#endif
if (verbose) {
eputs("\nBuilding contribution photon map...\n");
#if NIX
fflush(stderr);
#endif
}
/* Build underlying data structure; heap is destroyed */
buildPhotonMap(pm, srcFlux, primaryOfs, numProc);
/* Free per-subprocess primary heap files */
for (proc = 0; proc < numProc; proc++)
free(primaryHeapFname [proc]);
free(primaryHeapFname);
free(primaryHeap);
free(primaryOfs);
if (verbose)
eputs("\n");
}
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