Spectrum UniformSampleOneLight(const Scene *scene,
const Renderer *renderer, MemoryArena &arena, const Point &p,
const Normal &n, const Vector &wo, float rayEpsilon, float time,
BSDF *bsdf, const Sample *sample, RNG &rng, int lightNumOffset,
const LightSampleOffsets *lightSampleOffset,
const BSDFSampleOffsets *bsdfSampleOffset) {
// Randomly choose a single light to sample, _light_
int nLights = int(scene->lights.size());
if (nLights == 0) return Spectrum(0.);
int lightNum;
if (lightNumOffset != -1)
lightNum = Floor2Int(sample->oneD[lightNumOffset][0] * nLights);
else
lightNum = Floor2Int(rng.RandomFloat() * nLights);
lightNum = min(lightNum, nLights-1);
Light *light = scene->lights[lightNum];
// Initialize light and bsdf samples for single light sample
LightSample lightSample;
BSDFSample bsdfSample;
if (lightSampleOffset != NULL && bsdfSampleOffset != NULL) {
lightSample = LightSample(sample, *lightSampleOffset, 0);
bsdfSample = BSDFSample(sample, *bsdfSampleOffset, 0);
}
else {
lightSample = LightSample(rng);
bsdfSample = BSDFSample(rng);
}
return (float)nLights *
EstimateDirect(scene, renderer, arena, light, p, n, wo,
rayEpsilon, time, bsdf, rng, lightSample,
bsdfSample, BxDFType(BSDF_ALL & ~BSDF_SPECULAR));
}
// Integrator Utility Functions
Spectrum UniformSampleAllLights(const Scene *scene,
const Renderer *renderer, MemoryArena &arena, const Point &p,
const Normal &n, const Vector &wo, float rayEpsilon,
float time, BSDF *bsdf, const Sample *sample, RNG &rng,
const LightSampleOffsets *lightSampleOffsets,
const BSDFSampleOffsets *bsdfSampleOffsets) {
Spectrum L(0.);
for (uint32_t i = 0; i < scene->lights.size(); ++i) {
Light *light = scene->lights[i];
int nSamples = lightSampleOffsets ?
lightSampleOffsets[i].nSamples : 1;
// Estimate direct lighting from _light_ samples
Spectrum Ld(0.);
for (int j = 0; j < nSamples; ++j) {
// Find light and BSDF sample values for direct lighting estimate
LightSample lightSample;
BSDFSample bsdfSample;
if (lightSampleOffsets != NULL && bsdfSampleOffsets != NULL) {
lightSample = LightSample(sample, lightSampleOffsets[i], j);
bsdfSample = BSDFSample(sample, bsdfSampleOffsets[i], j);
}
else {
lightSample = LightSample(rng);
bsdfSample = BSDFSample(rng);
}
Ld += EstimateDirect(scene, renderer, arena, light, p, n, wo,
rayEpsilon, time, bsdf, rng, lightSample, bsdfSample,
BxDFType(BSDF_ALL & ~BSDF_SPECULAR));
}
L += Ld / nSamples;
}
return L;
}
Spectrum IrradianceCacheIntegrator::pathL(Ray &r, const Scene *scene,
const Renderer *renderer, const Sample *sample, MemoryArena &arena) const {
Spectrum L(0.f);
Spectrum pathThroughput = 1.;
RayDifferential ray(r);
bool specularBounce = false;
for (int pathLength = 0; ; ++pathLength) {
// Find next vertex of path
Intersection isect;
if (!scene->Intersect(ray, &isect))
break;
if (pathLength == 0)
r.maxt = ray.maxt;
else if (pathLength == 1)
pathThroughput *= renderer->Transmittance(scene, ray, sample, arena, NULL);
else
pathThroughput *= renderer->Transmittance(scene, ray, NULL, arena, sample->rng);
// Possibly add emitted light at path vertex
if (specularBounce)
L += pathThroughput * isect.Le(-ray.d);
// Evaluate BSDF at hit point
BSDF *bsdf = isect.GetBSDF(ray, arena);
// Sample illumination from lights to find path contribution
const Point &p = bsdf->dgShading.p;
const Normal &n = bsdf->dgShading.nn;
Vector wo = -ray.d;
L += pathThroughput *
UniformSampleOneLight(scene, renderer, arena, p, n, wo, isect.rayEpsilon,
bsdf, sample);
if (pathLength+1 == maxIndirectDepth) break;
// Sample BSDF to get new path direction
// Get random numbers for sampling new direction, \mono{bs1}, \mono{bs2}, and \mono{bcs}
Vector wi;
float pdf;
BxDFType flags;
Spectrum f = bsdf->Sample_f(wo, &wi, BSDFSample(*sample->rng),
&pdf, BSDF_ALL, &flags);
if (f.IsBlack() || pdf == 0.)
break;
specularBounce = (flags & BSDF_SPECULAR) != 0;
pathThroughput *= f * AbsDot(wi, n) / pdf;
ray = RayDifferential(p, wi, ray, isect.rayEpsilon);
// Possibly terminate the path
if (pathLength > 2) {
float rrProb = min(1.f, pathThroughput.y());
if (sample->rng->RandomFloat() > rrProb)
break;
pathThroughput /= rrProb;
}
}
return L;
}
Spectrum SpecularTransmit(const RayDifferential &ray, BSDF *bsdf,
RNG &rng, const Intersection &isect, const Renderer *renderer,
const Scene *scene, const Sample *sample, MemoryArena &arena) {
Vector wo = -ray.d, wi;
float pdf;
const Point &p = bsdf->dgShading.p;
const Normal &n = bsdf->dgShading.nn;
Spectrum f = bsdf->Sample_f(wo, &wi, BSDFSample(rng), &pdf,
BxDFType(BSDF_TRANSMISSION | BSDF_SPECULAR));
Spectrum L = 0.f;
if (pdf > 0.f && !f.IsBlack() && AbsDot(wi, n) != 0.f) {
// Compute ray differential _rd_ for specular transmission
RayDifferential rd(p, wi, ray, isect.rayEpsilon);
if (ray.hasDifferentials) {
rd.hasDifferentials = true;
rd.rxOrigin = p + isect.dg.dpdx;
rd.ryOrigin = p + isect.dg.dpdy;
float eta = bsdf->eta;
Vector w = -wo;
if (Dot(wo, n) < 0) eta = 1.f / eta;
Normal dndx = bsdf->dgShading.dndu * bsdf->dgShading.dudx + bsdf->dgShading.dndv * bsdf->dgShading.dvdx;
Normal dndy = bsdf->dgShading.dndu * bsdf->dgShading.dudy + bsdf->dgShading.dndv * bsdf->dgShading.dvdy;
Vector dwodx = -ray.rxDirection - wo, dwody = -ray.ryDirection - wo;
float dDNdx = Dot(dwodx, n) + Dot(wo, dndx);
float dDNdy = Dot(dwody, n) + Dot(wo, dndy);
float mu = eta * Dot(w, n) - Dot(wi, n);
float dmudx = (eta - (eta*eta*Dot(w,n))/Dot(wi, n)) * dDNdx;
float dmudy = (eta - (eta*eta*Dot(w,n))/Dot(wi, n)) * dDNdy;
rd.rxDirection = wi + eta * dwodx - Vector(mu * dndx + dmudx * n);
rd.ryDirection = wi + eta * dwody - Vector(mu * dndy + dmudy * n);
}
PBRT_STARTED_SPECULAR_REFRACTION_RAY(const_cast<RayDifferential *>(&rd));
Spectrum Li = renderer->Li(scene, rd, sample, rng, arena);
L = f * Li * AbsDot(wi, n) / pdf;
PBRT_FINISHED_SPECULAR_REFRACTION_RAY(const_cast<RayDifferential *>(&rd));
}
return L;
}
Spectrum IGIIntegrator::Li(const Scene *scene, const Renderer *renderer,
const RayDifferential &ray, const Intersection &isect,
const Sample *sample, RNG &rng, MemoryArena &arena) const {
Spectrum L(0.);
Vector wo = -ray.d;
// Compute emitted light if ray hit an area light source
L += isect.Le(wo);
// Evaluate BSDF at hit point
BSDF *bsdf = isect.GetBSDF(ray, arena);
const Point &p = bsdf->dgShading.p;
const Normal &n = bsdf->dgShading.nn;
L += UniformSampleAllLights(scene, renderer, arena, p, n,
wo, isect.rayEpsilon, ray.time, bsdf, sample, rng,
lightSampleOffsets, bsdfSampleOffsets);
// Compute indirect illumination with virtual lights
uint32_t lSet = min(uint32_t(sample->oneD[vlSetOffset][0] * nLightSets),
nLightSets-1);
for (uint32_t i = 0; i < virtualLights[lSet].size(); ++i) {
const VirtualLight &vl = virtualLights[lSet][i];
// Compute virtual light's tentative contribution _Llight_
float d2 = DistanceSquared(p, vl.p);
Vector wi = Normalize(vl.p - p);
float G = AbsDot(wi, n) * AbsDot(wi, vl.n) / d2;
G = min(G, gLimit);
Spectrum f = bsdf->f(wo, wi);
if (G == 0.f || f.IsBlack()) continue;
Spectrum Llight = f * G * vl.pathContrib / nLightPaths;
RayDifferential connectRay(p, wi, ray, isect.rayEpsilon,
sqrtf(d2) * (1.f - vl.rayEpsilon));
Llight *= renderer->Transmittance(scene, connectRay, NULL, rng, arena);
// Possibly skip virtual light shadow ray with Russian roulette
if (Llight.y() < rrThreshold) {
float continueProbability = .1f;
if (rng.RandomFloat() > continueProbability)
continue;
Llight /= continueProbability;
}
// Add contribution from _VirtualLight_ _vl_
if (!scene->IntersectP(connectRay))
L += Llight;
}
if (ray.depth < maxSpecularDepth) {
// Do bias compensation for bounding geometry term
int nSamples = (ray.depth == 0) ? nGatherSamples : 1;
for (int i = 0; i < nSamples; ++i) {
Vector wi;
float pdf;
BSDFSample bsdfSample = (ray.depth == 0) ?
BSDFSample(sample, gatherSampleOffset, i) : BSDFSample(rng);
Spectrum f = bsdf->Sample_f(wo, &wi, bsdfSample,
&pdf, BxDFType(BSDF_ALL & ~BSDF_SPECULAR));
if (!f.IsBlack() && pdf > 0.f) {
// Trace ray for bias compensation gather sample
float maxDist = sqrtf(AbsDot(wi, n) / gLimit);
RayDifferential gatherRay(p, wi, ray, isect.rayEpsilon, maxDist);
Intersection gatherIsect;
Spectrum Li = renderer->Li(scene, gatherRay, sample, rng, arena,
&gatherIsect);
if (Li.IsBlack()) continue;
// Add bias compensation ray contribution to radiance sum
float Ggather = AbsDot(wi, n) * AbsDot(-wi, gatherIsect.dg.nn) /
DistanceSquared(p, gatherIsect.dg.p);
if (Ggather - gLimit > 0.f && !isinf(Ggather)) {
float gs = (Ggather - gLimit) / Ggather;
L += f * Li * (AbsDot(wi, n) * gs / (nSamples * pdf));
}
}
}
}
if (ray.depth + 1 < maxSpecularDepth) {
Vector wi;
// Trace rays for specular reflection and refraction
L += SpecularReflect(ray, bsdf, rng, isect, renderer, scene, sample,
arena);
L += SpecularTransmit(ray, bsdf, rng, isect, renderer, scene, sample,
arena);
}
return L;
}
void PhotonShootingTask::Run() {
// Declare local variables for _PhotonShootingTask_
MemoryArena arena;
RNG rng(31 * taskNum);
vector<Photon> localDirectPhotons, localIndirectPhotons, localCausticPhotons;
vector<RadiancePhoton> localRadiancePhotons;
uint32_t totalPaths = 0;
bool causticDone = (integrator->nCausticPhotonsWanted == 0);
bool indirectDone = (integrator->nIndirectPhotonsWanted == 0);
PermutedHalton halton(6, rng);
vector<Spectrum> localRpReflectances, localRpTransmittances;
while (true) {
// Follow photon paths for a block of samples
const uint32_t blockSize = 4096;
for (uint32_t i = 0; i < blockSize; ++i) {
float u[6];
halton.Sample(++totalPaths, u);
// Choose light to shoot photon from
float lightPdf;
int lightNum = lightDistribution->SampleDiscrete(u[0], &lightPdf);
const Light *light = scene->lights[lightNum];
// Generate _photonRay_ from light source and initialize _alpha_
RayDifferential photonRay;
float pdf;
LightSample ls(u[1], u[2], u[3]);
Normal Nl;
Spectrum Le = light->Sample_L(scene, ls, u[4], u[5],
time, &photonRay, &Nl, &pdf);
if (pdf == 0.f || Le.IsBlack()) continue;
Spectrum alpha = (AbsDot(Nl, photonRay.d) * Le) / (pdf * lightPdf);
if (!alpha.IsBlack()) {
// Follow photon path through scene and record intersections
PBRT_PHOTON_MAP_STARTED_RAY_PATH(&photonRay, &alpha);
bool specularPath = true;
Intersection photonIsect;
int nIntersections = 0;
while (scene->Intersect(photonRay, &photonIsect)) {
++nIntersections;
// Handle photon/surface intersection
alpha *= renderer->Transmittance(scene, photonRay, NULL, rng, arena);
BSDF *photonBSDF = photonIsect.GetBSDF(photonRay, arena);
BxDFType specularType = BxDFType(BSDF_REFLECTION |
BSDF_TRANSMISSION | BSDF_SPECULAR);
bool hasNonSpecular = (photonBSDF->NumComponents() >
photonBSDF->NumComponents(specularType));
Vector wo = -photonRay.d;
if (hasNonSpecular) {
// Deposit photon at surface
Photon photon(photonIsect.dg.p, alpha, wo);
bool depositedPhoton = false;
if (specularPath && nIntersections > 1) {
if (!causticDone) {
PBRT_PHOTON_MAP_DEPOSITED_CAUSTIC_PHOTON(&photonIsect.dg, &alpha, &wo);
depositedPhoton = true;
localCausticPhotons.push_back(photon);
}
}
else {
// Deposit either direct or indirect photon
// stop depositing direct photons once indirectDone is true; don't
// want to waste memory storing too many if we're going a long time
// trying to get enough caustic photons desposited.
if (nIntersections == 1 && !indirectDone && integrator->finalGather) {
PBRT_PHOTON_MAP_DEPOSITED_DIRECT_PHOTON(&photonIsect.dg, &alpha, &wo);
depositedPhoton = true;
localDirectPhotons.push_back(photon);
}
else if (nIntersections > 1 && !indirectDone) {
PBRT_PHOTON_MAP_DEPOSITED_INDIRECT_PHOTON(&photonIsect.dg, &alpha, &wo);
depositedPhoton = true;
localIndirectPhotons.push_back(photon);
}
}
// Possibly create radiance photon at photon intersection point
if (depositedPhoton && integrator->finalGather &&
rng.RandomFloat() < .125f) {
Normal n = photonIsect.dg.nn;
n = Faceforward(n, -photonRay.d);
localRadiancePhotons.push_back(RadiancePhoton(photonIsect.dg.p, n));
Spectrum rho_r = photonBSDF->rho(rng, BSDF_ALL_REFLECTION);
localRpReflectances.push_back(rho_r);
Spectrum rho_t = photonBSDF->rho(rng, BSDF_ALL_TRANSMISSION);
localRpTransmittances.push_back(rho_t);
}
}
if (nIntersections >= integrator->maxPhotonDepth) break;
// Sample new photon ray direction
Vector wi;
float pdf;
BxDFType flags;
Spectrum fr = photonBSDF->Sample_f(wo, &wi, BSDFSample(rng),
&pdf, BSDF_ALL, &flags);
if (fr.IsBlack() || pdf == 0.f) break;
Spectrum anew = alpha * fr *
AbsDot(wi, photonBSDF->dgShading.nn) / pdf;
// Possibly terminate photon path with Russian roulette
float continueProb = min(1.f, anew.y() / alpha.y());
if (rng.RandomFloat() > continueProb)
break;
alpha = anew / continueProb;
specularPath &= ((flags & BSDF_SPECULAR) != 0);
if (indirectDone && !specularPath) break;
photonRay = RayDifferential(photonIsect.dg.p, wi, photonRay,
photonIsect.rayEpsilon);
}
PBRT_PHOTON_MAP_FINISHED_RAY_PATH(&photonRay, &alpha);
}
arena.FreeAll();
}
// Merge local photon data with data in _PhotonIntegrator_
{ MutexLock lock(mutex);
// Give up if we're not storing enough photons
if (abortTasks)
return;
if (nshot > 500000 &&
(unsuccessful(integrator->nCausticPhotonsWanted,
causticPhotons.size(), blockSize) ||
unsuccessful(integrator->nIndirectPhotonsWanted,
indirectPhotons.size(), blockSize))) {
Error("Unable to store enough photons. Giving up.\n");
causticPhotons.erase(causticPhotons.begin(), causticPhotons.end());
indirectPhotons.erase(indirectPhotons.begin(), indirectPhotons.end());
radiancePhotons.erase(radiancePhotons.begin(), radiancePhotons.end());
abortTasks = true;
return;
}
progress.Update(localIndirectPhotons.size() + localCausticPhotons.size());
nshot += blockSize;
// Merge indirect photons into shared array
if (!indirectDone) {
integrator->nIndirectPaths += blockSize;
for (uint32_t i = 0; i < localIndirectPhotons.size(); ++i)
indirectPhotons.push_back(localIndirectPhotons[i]);
localIndirectPhotons.erase(localIndirectPhotons.begin(),
localIndirectPhotons.end());
if (indirectPhotons.size() >= integrator->nIndirectPhotonsWanted)
indirectDone = true;
nDirectPaths += blockSize;
for (uint32_t i = 0; i < localDirectPhotons.size(); ++i)
directPhotons.push_back(localDirectPhotons[i]);
localDirectPhotons.erase(localDirectPhotons.begin(),
localDirectPhotons.end());
}
// Merge direct, caustic, and radiance photons into shared array
if (!causticDone) {
integrator->nCausticPaths += blockSize;
for (uint32_t i = 0; i < localCausticPhotons.size(); ++i)
causticPhotons.push_back(localCausticPhotons[i]);
localCausticPhotons.erase(localCausticPhotons.begin(), localCausticPhotons.end());
if (causticPhotons.size() >= integrator->nCausticPhotonsWanted)
causticDone = true;
}
for (uint32_t i = 0; i < localRadiancePhotons.size(); ++i)
radiancePhotons.push_back(localRadiancePhotons[i]);
localRadiancePhotons.erase(localRadiancePhotons.begin(), localRadiancePhotons.end());
for (uint32_t i = 0; i < localRpReflectances.size(); ++i)
rpReflectances.push_back(localRpReflectances[i]);
localRpReflectances.erase(localRpReflectances.begin(), localRpReflectances.end());
for (uint32_t i = 0; i < localRpTransmittances.size(); ++i)
rpTransmittances.push_back(localRpTransmittances[i]);
localRpTransmittances.erase(localRpTransmittances.begin(), localRpTransmittances.end());
}
// Exit task if enough photons have been found
if (indirectDone && causticDone)
break;
}
}
Spectrum PathIntegrator::Li(const Scene *scene, const Renderer *renderer,
const RayDifferential &r, const Intersection &isect,
const Sample *sample, MemoryArena &arena) const {
// Declare common path integration variables
Spectrum pathThroughput = 1., L = 0.;
RayDifferential ray(r);
bool specularBounce = false;
Intersection localIsect;
const Intersection *isectp = &isect;
for (int pathLength = 0; ; ++pathLength) {
// Possibly add emitted light at path vertex
if (pathLength == 0 || specularBounce)
L += pathThroughput * isectp->Le(-ray.d);
// Sample illumination from lights to find path contribution
BSDF *bsdf = isectp->GetBSDF(ray, arena);
const Point &p = bsdf->dgShading.p;
const Normal &n = bsdf->dgShading.nn;
Vector wo = -ray.d;
if (pathLength < SAMPLE_DEPTH)
L += pathThroughput *
UniformSampleOneLight(scene, renderer, arena, p, n, wo,
isectp->RayEpsilon, bsdf, sample, lightNumOffset[pathLength],
&lightSampleOffsets[pathLength], &bsdfSampleOffsets[pathLength]);
else
L += pathThroughput *
UniformSampleOneLight(scene, renderer, arena, p, n, wo,
isectp->RayEpsilon, bsdf, sample);
// Sample BSDF to get new path direction
// Get _outgoingBSDFSample_ for sampling new path direction
BSDFSample outgoingBSDFSample;
if (pathLength < SAMPLE_DEPTH)
outgoingBSDFSample = BSDFSample(sample, pathSampleOffsets[pathLength], 0);
else
outgoingBSDFSample = BSDFSample(*sample->rng);
Vector wi;
float pdf;
BxDFType flags;
Spectrum f = bsdf->Sample_f(wo, &wi, outgoingBSDFSample,
&pdf, BSDF_ALL, &flags);
if (f.IsBlack() || pdf == 0.)
break;
specularBounce = (flags & BSDF_SPECULAR) != 0;
pathThroughput *= f * AbsDot(wi, n) / pdf;
ray = RayDifferential(p, wi, ray, isectp->RayEpsilon);
// Possibly terminate the path
if (pathLength > 3) {
float continueProbability = min(.5f, pathThroughput.y());
if (sample->rng->RandomFloat() > continueProbability)
break;
pathThroughput /= continueProbability;
}
if (pathLength == maxDepth)
break;
// Find next vertex of path
if (!scene->Intersect(ray, &localIsect)) {
if (specularBounce) {
for (u_int i = 0; i < scene->lights.size(); ++i)
L += pathThroughput * scene->lights[i]->Le(ray);
}
break;
}
if (pathLength > 1)
pathThroughput *= renderer->Transmittance(scene, ray, NULL, arena, sample->rng);
isectp = &localIsect;
}
return L;
}
void RefractShader::generateDir(const SurfacePoint & sp,
const glm::vec3 & out,
unsigned numSamples,
BSDFSamples & samples) const
{
samples.resize (numSamples);
// assume refraction index 1.0 for outer medium
glm::float_t n1 = 1.0f;
glm::float_t n2 = m_index;
// normal should point to medium n1
glm::vec3 normal = sp.normal;
const glm::vec3 incident = -out;
// Flip normal and count new n if the ray is coming from
// inside the surface (ie. from n2 to n1)
if (sp.cos_theta(out) < 0) {
normal = -normal;
std::swap(n1, n2);
}
// n = n1 / n2 where ray comes from n1 to n2
/*const glm::float_t n = n1 / n2;
const glm::float_t cosI = glm::dot(normal, -incident);*/
for (unsigned i = 0; i < numSamples; ++i)
{
glm::vec3 result, value;
glm::vec3 refracted;
glm::float_t refl;
if(refract(n1, n2, normal, incident, refracted, refl))
{
// always reflect
//refl = 1.0f;
// always transmit
//refl = 0.0f;
assert(0 <= refl && refl <= 1);
// choose between refracted and reflected rays based on fresnel term
const glm::float_t roulette = Sampling::uniform();
if(roulette < refl)
{
// reflect
result = reflect(normal, incident);
value = (1 / refl) * (refl) * m_reflectance / sp.cos_theta(result);
}
else
{
const real cos_theta = glm::dot(normal, result);
// transmit
result = refracted;
value = (1 / (1 - refl)) * (1 - refl) * m_transmittance / sp.cos_theta(result);
}
}
else
{
result = reflect(normal, incident);
value = m_reflectance / sp.cos_theta(result);
}
samples[i] = BSDFSample(result, value, 1);
}
}
Spectrum GlossyPRTIntegrator::Li(const Scene *scene, const Renderer *,
const RayDifferential &ray, const Intersection &isect,
const Sample *sample, RNG &rng, MemoryArena &arena) const {
Spectrum L = 0.f;
Vector wo = -ray.d;
// Compute emitted light if ray hit an area light source
L += isect.Le(wo);
// Evaluate BSDF at hit point
BSDF *bsdf = isect.GetBSDF(ray, arena);
const Point &p = bsdf->dgShading.p;
// Compute reflected radiance with glossy PRT at point
// Compute SH radiance transfer matrix at point and SH coefficients
Spectrum *c_t = arena.Alloc<Spectrum>(SHTerms(lmax));
Spectrum *T = arena.Alloc<Spectrum>(SHTerms(lmax)*SHTerms(lmax));
SHComputeTransferMatrix(p, isect.rayEpsilon, scene, rng, nSamples,
lmax, T);
SHMatrixVectorMultiply(T, c_in, c_t, lmax);
// Rotate incident SH lighting to local coordinate frame
Vector r1 = bsdf->LocalToWorld(Vector(1,0,0));
Vector r2 = bsdf->LocalToWorld(Vector(0,1,0));
Normal nl = Normal(bsdf->LocalToWorld(Vector(0,0,1)));
Matrix4x4 rot(r1.x, r2.x, nl.x, 0,
r1.y, r2.y, nl.y, 0,
r1.z, r2.z, nl.z, 0,
0, 0, 0, 1);
Spectrum *c_l = arena.Alloc<Spectrum>(SHTerms(lmax));
SHRotate(c_t, c_l, rot, lmax, arena);
#if 0
// Sample BSDF and integrate against direct SH coefficients
float *Ylm = ALLOCA(float, SHTerms(lmax));
int ns = 1024;
for (int i = 0; i < ns; ++i) {
Vector wi;
float pdf;
Spectrum f = bsdf->Sample_f(wo, &wi, BSDFSample(rng), &pdf);
if (pdf > 0.f && !f.IsBlack() && !scene->IntersectP(Ray(p, wi))) {
f *= fabsf(Dot(wi, n)) / (pdf * ns);
SHEvaluate(bsdf->WorldToLocal(wi), lmax, Ylm);
Spectrum Li = 0.f;
for (int j = 0; j < SHTerms(lmax); ++j)
Li += Ylm[j] * c_l[j] * f;
L += Li.Clamp();
}
}
#else
// Compute final coefficients _c\_o_ using BSDF matrix
Spectrum *c_o = arena.Alloc<Spectrum>(SHTerms(lmax));
SHMatrixVectorMultiply(B, c_l, c_o, lmax);
// Evaluate outgoing radiance function for $\wo$ and add to _L_
Vector woLocal = bsdf->WorldToLocal(wo);
float *Ylm = ALLOCA(float, SHTerms(lmax));
SHEvaluate(woLocal, lmax, Ylm);
Spectrum Li = 0.f;
for (int i = 0; i < SHTerms(lmax); ++i)
Li += Ylm[i] * c_o[i];
L += Li.Clamp();
#endif
return L;
}
void LightShootingTask::Run() {
// tady by mel byt kod z photon mappingu
MemoryArena arena;
uint32_t totalPaths = 0;
RNG rng(seed);
PermutedHalton halton(6, rng);
while (true) {
// Follow photon paths for a block of samples
const uint32_t blockSize = 4096;
for (uint32_t i = 0; i < blockSize; ++i) {
float u[6];
halton.Sample(++totalPaths, u);
// Choose light to shoot photon from
float lightPdf;
int lightNum = lightDistribution->SampleDiscrete(u[0], &lightPdf);
const Light *light = scene->lights[lightNum];
// Generate _photonRay_ from light source and initialize _alpha_
RayDifferential photonRay;
float pdf;
LightSample ls(u[1], u[2], u[3]);
Normal Nl;
Spectrum Le = light->Sample_L(scene, ls, u[4], u[5],time, &photonRay, &Nl, &pdf);
if (pdf == 0.f || Le.IsBlack()) continue;
Spectrum alpha = (AbsDot(Nl, photonRay.d) * Le) / (pdf * lightPdf);
if (!alpha.IsBlack()) {
// Follow photon path through scene and record intersections
PBRT_PHOTON_MAP_STARTED_RAY_PATH(&photonRay, &alpha);
bool specularPath = true;
Intersection photonIsect;
int nIntersections = 0;
while (scene->Intersect(photonRay, &photonIsect)) {
++nIntersections;
//MC tady by mel byt i kod pro volumetriku
// Handle photon/surface intersection
// alpha *= renderer->Transmittance(scene, photonRay, NULL, rng, arena);
BSDF *photonBSDF = photonIsect.GetBSDF(photonRay, arena);
Vector wo = -photonRay.d;
//MC tady se ukladaly photony takze tady bych mel ukladat samples do filmu kamery
// // Deposit photon at surface
//Photon photon(photonIsect.dg.p, alpha, wo);
//tuhle metodu chci pouzit
//filmAddSample()
if (nIntersections >= maxDepth) break;
// Sample new photon ray direction
Vector wi;
float pdf;
BxDFType flags;
Spectrum fr = photonBSDF->Sample_f(wo, &wi, BSDFSample(rng),
&pdf, BSDF_ALL, &flags);
if (fr.IsBlack() || pdf == 0.f) break;
Spectrum anew = alpha * fr *
AbsDot(wi, photonBSDF->dgShading.nn) / pdf;
// Possibly terminate photon path with Russian roulette
float continueProb = min(1.f, anew.y() / alpha.y());
if (rng.RandomFloat() > continueProb)
break;
alpha = anew / continueProb;
specularPath &= ((flags & BSDF_SPECULAR) != 0);
photonRay = RayDifferential(photonIsect.dg.p, wi, photonRay,
photonIsect.rayEpsilon);
}
PBRT_PHOTON_MAP_FINISHED_RAY_PATH(&photonRay, &alpha);
}
arena.FreeAll();
}
//termination criteria ???
if (totalPaths==maxPathCount) {
break;
}
}
}
