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pmcontrib2.c
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Tue, Apr 16, 12:00

pmcontrib2.c
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#ifndef lint
static const char RCSid[] = "$Id: pmcontrib2.c,v 2.5 2018/11/08 00:54:07 greg Exp $";
#endif
/*
======================================================================
Photon map support for using 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: pmcontrib2.c,v 2.5 2018/11/08 00:54:07 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"
static void setPmapContribParams (PhotonMap *pmap, LUTAB *srcContrib)
/* Set parameters for light source contributions */
{
/* Set light source modifier list and appropriate callback to extract
* their contributions from the photon map */
if (pmap) {
pmap -> srcContrib = srcContrib;
pmap -> lookup = photonContrib;
/* Ensure we get all requested photon contribs during lookups */
pmap -> gatherTolerance = 1.0;
}
}
static void checkPmapContribs (const PhotonMap *pmap, LUTAB *srcContrib)
/* Check modifiers for light source contributions */
{
const PhotonPrimary *primary = pmap -> primaries;
PhotonPrimaryIdx i, found = 0;
OBJREC *srcMod;
/* Make sure at least one of the modifiers is actually in the pmap,
* otherwise findPhotons() winds up in an infinite loop! */
for (i = pmap -> numPrimary; i; --i, ++primary) {
if (primary -> srcIdx < 0 || primary -> srcIdx >= nsources)
error(INTERNAL, "invalid light source index in photon map");
srcMod = findmaterial(source [primary -> srcIdx].so);
if ((MODCONT*)lu_find(srcContrib, srcMod -> oname) -> data)
++found;
}
if (!found)
error(USER, "modifiers not in photon map");
}
void initPmapContrib (LUTAB *srcContrib, unsigned numSrcContrib)
{
unsigned t;
for (t = 0; t < NUM_PMAP_TYPES; t++)
if (photonMaps [t] && t != PMAP_TYPE_CONTRIB) {
sprintf(errmsg, "%s photon map does not support contributions",
pmapName [t]);
error(USER, errmsg);
}
/* Get params */
setPmapContribParams(contribPmap, srcContrib);
if (contribPhotonMapping) {
if (contribPmap -> maxGather < numSrcContrib) {
#if 0
/* Adjust density estimate bandwidth if lower than modifier
* count, otherwise contributions are missing */
error(WARNING, "contrib density estimate bandwidth too low, "
"adjusting to modifier count");
contribPmap -> maxGather = numSrcContrib;
#else
/* Warn if density estimate bandwidth is lower than modifier
* count, since some contributions will be missing */
error(WARNING, "photon density estimate bandwidth too low,"
" contributions may be underestimated");
#endif
}
/* Sanity check */
checkPmapContribs(contribPmap, srcContrib);
}
}
void photonContrib (PhotonMap *pmap, RAY *ray, COLOR irrad)
/* Sum up light source contributions from photons in pmap->srcContrib */
{
unsigned i;
PhotonSearchQueueNode *sqn;
float r2, invArea;
RREAL rayCoeff [3];
Photon *photon;
static char warnPos = 1, warnDir = 1;
setcolor(irrad, 0, 0, 0);
if (!pmap -> maxGather)
return;
/* Ignore sources */
if (ray -> ro && islight(objptr(ray -> ro -> omod) -> otype))
return;
/* Get cumulative path coefficient up to photon lookup point */
raycontrib(rayCoeff, ray, PRIMARY);
/* Lookup photons */
pmap -> squeue.tail = 0;
findPhotons(pmap, ray);
/* Need at least 2 photons */
if (pmap -> squeue.tail < 2) {
#ifdef PMAP_NONEFOUND
sprintf(errmsg, "no photons found on %s at (%.3f, %.3f, %.3f)",
ray -> ro ? ray -> ro -> oname : "<null>",
ray -> rop [0], ray -> rop [1], ray -> rop [2]);
error(WARNING, errmsg);
#endif
return;
}
/* Average radius^2 between furthest two photons to improve accuracy and
* get inverse search area 1 / (PI * r^2), with extra normalisation
* factor 1 / PI for ambient calculation */
sqn = pmap -> squeue.node + 1;
r2 = max(sqn -> dist2, (sqn + 1) -> dist2);
r2 = 0.25 * (pmap -> maxDist2 + r2 + 2 * sqrt(pmap -> maxDist2 * r2));
invArea = 1 / (PI * PI * r2);
/* Skip the extra photon */
for (i = 1 ; i < pmap -> squeue.tail; i++, sqn++) {
COLOR flux;
/* Get photon's contribution to density estimate */
photon = getNearestPhoton(&pmap -> squeue, sqn -> idx);
getPhotonFlux(photon, flux);
scalecolor(flux, invArea);
#ifdef PMAP_EPANECHNIKOV
/* Apply Epanechnikov kernel to photon flux based on photon distance */
scalecolor(flux, 2 * (1 - sqn -> dist2 / r2));
#endif
addcolor(irrad, flux);
if (pmap -> srcContrib) {
const PhotonPrimary *primary = pmap -> primaries +
photon -> primary;
const SRCREC *sp = &source [primary -> srcIdx];
OBJREC *srcMod = findmaterial(sp -> so);
MODCONT *srcContrib = (MODCONT*)lu_find(pmap -> srcContrib,
srcMod -> oname) -> data;
double srcBinReal;
int srcBin;
RAY srcRay;
if (!srcContrib)
continue;
/* Photon's emitting light source has modifier whose contributions
* are sought */
if (srcContrib -> binv -> type != NUM) {
/* Use intersection function to set shadow ray parameters if
* it's not simply a constant */
rayorigin(&srcRay, SHADOW, NULL, NULL);
srcRay.rsrc = primary -> srcIdx;
#ifdef PMAP_PRIMARYPOS
VCOPY(srcRay.rorg, primary -> pos);
#else
/* No primary hitpoints; set dummy ray origin and warn once */
srcRay.rorg [0] = srcRay.rorg [1] = srcRay.rorg [2] = 0;
if (warnPos) {
error(WARNING,
"no photon primary hitpoints for bin evaluation; "
"using dummy (0,0,0)! Recompile with -DPMAP_CBDM.");
warnPos = 0;
}
#endif
#ifdef PMAP_PRIMARYDIR
decodedir(srcRay.rdir, primary -> dir);
#else
/* No primary incident direction; set dummy and warn once */
if (warnDir) {
error(WARNING,
"no photon primary directions for bin evaluation; "
"using dummy (0,0,0)! Recompile with -DPMAP_CBDM.");
warnDir = 0;
}
srcRay.rdir [0] = srcRay.rdir [1] = srcRay.rdir [2] = 0;
#endif
if (!(sp->sflags & SDISTANT
? sourcehit(&srcRay)
: (*ofun[sp -> so -> otype].funp)(sp -> so, &srcRay)))
continue; /* XXX shouldn't happen! */
worldfunc(RCCONTEXT, &srcRay);
set_eparams((char *)srcContrib -> params);
}
if ((srcBinReal = evalue(srcContrib -> binv)) < -.5)
continue; /* silently ignore negative bins */
if ((srcBin = srcBinReal + .5) >= srcContrib -> nbins) {
error(WARNING, "bad bin number (ignored)");
continue;
}
if (!contrib) {
/* Ray coefficient mode; normalise by light source radiance
* after applying distrib pattern */
int j;
raytexture(ray, srcMod -> omod);
setcolor(ray -> rcol, srcMod -> oargs.farg [0],
srcMod -> oargs.farg [1], srcMod -> oargs.farg [2]);
multcolor(ray -> rcol, ray -> pcol);
for (j = 0; j < 3; j++)
flux [j] = ray -> rcol [j] ? flux [j] / ray -> rcol [j] : 0;
}
multcolor(flux, rayCoeff);
addcolor(srcContrib -> cbin [srcBin], flux);
}
}
return;
}

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