Spectrum BidirIntegrator::Li(const Scene *scene,
const RayDifferential &ray,
const Sample *sample, float *alpha) const {
Spectrum L(0.);
// Generate eye and light sub-paths
BidirVertex eyePath[MAX_VERTS], lightPath[MAX_VERTS];
int nEye = generatePath(scene, ray, sample, eyeBSDFOffset,
eyeBSDFCompOffset, eyePath, MAX_VERTS);
if (nEye == 0) {
*alpha = 0.;
return L;
}
*alpha = 1;
// Choose light for bidirectional path
int lightNum = Floor2Int(sample->oneD[lightNumOffset][0] *
scene->lights.size());
lightNum = min(lightNum, (int)scene->lights.size() - 1);
Light *light = scene->lights[lightNum];
float lightWeight = float(scene->lights.size());
// Sample ray from light source to start light path
Ray lightRay;
float lightPdf;
float u[4];
u[0] = sample->twoD[lightPosOffset][0];
u[1] = sample->twoD[lightPosOffset][1];
u[2] = sample->twoD[lightDirOffset][0];
u[3] = sample->twoD[lightDirOffset][1];
Spectrum Le = light->Sample_L(scene, u[0], u[1], u[2], u[3],
&lightRay, &lightPdf);
if (lightPdf == 0.) return 0.f;
Le = lightWeight / lightPdf;
int nLight = generatePath(scene, lightRay, sample, lightBSDFOffset,
lightBSDFCompOffset, lightPath, MAX_VERTS);
// Connect bidirectional path prefixes and evaluate throughput
Spectrum directWt(1.0);
for (int i = 1; i <= nEye; ++i) {
// Handle direct lighting for bidirectional integrator
directWt /= eyePath[i-1].rrWeight;
L += directWt *
UniformSampleOneLight(scene, eyePath[i-1].p, eyePath[i-1].ng, eyePath[i-1].wi,
eyePath[i-1].bsdf, sample, directLightOffset[i-1], directLightNumOffset[i-1],
directBSDFOffset[i-1], directBSDFCompOffset[i-1]) /
weightPath(eyePath, i, lightPath, 0);
directWt *= eyePath[i-1].bsdf->f(eyePath[i-1].wi, eyePath[i-1].wo) *
AbsDot(eyePath[i-1].wo, eyePath[i-1].ng) /
eyePath[i-1].bsdfWeight;
for (int j = 1; j <= nLight; ++j)
L += Le * evalPath(scene, eyePath, i, lightPath, j) /
weightPath(eyePath, i, lightPath, j);
}
return L;
}
Spectrum SingleScatteringFluorescenceRWLIntegrator::Li(const Scene *scene,
const Renderer *renderer, const RayDifferential &ray,
const Sample *sample, RNG &rng, Spectrum *T, MemoryArena &arena) const {
VolumeRegion *vr = scene->volumeRegion;
float t0, t1;
if (!vr || !vr->IntersectP(ray, &t0, &t1) || (t1-t0) == 0.f) {
*T = 1.f;
return 0.f;
}
// Do single scattering volume integration in _vr_
Spectrum Lv(0.);
// Prepare for volume integration stepping
int nSamples = Ceil2Int((t1-t0) / stepSize);
float step = (t1 - t0) / nSamples;
Spectrum Tr(1.f);
Point p = ray(t0), pPrev;
Vector w = -ray.d;
t0 += sample->oneD[scatterSampleOffset][0] * step;
// Compute sample patterns for single scattering samples
float *lightNum = arena.Alloc<float>(nSamples);
LDShuffleScrambled1D(1, nSamples, lightNum, rng);
float *lightComp = arena.Alloc<float>(nSamples);
LDShuffleScrambled1D(1, nSamples, lightComp, rng);
float *lightPos = arena.Alloc<float>(2*nSamples);
LDShuffleScrambled2D(1, nSamples, lightPos, rng);
uint32_t sampOffset = 0;
for (int i = 0; i < nSamples; ++i, t0 += step) {
// Advance to sample at _t0_ and update _T_
pPrev = p;
p = ray(t0);
Ray tauRay(pPrev, p - pPrev, 0.f, 1.f, ray.time, ray.depth);
Spectrum stepTau = vr->tau(tauRay, 0.5f * stepSize, rng.RandomFloat());
Tr *= Exp(-stepTau);
// Possibly terminate ray marching if transmittance is small
if (Tr.y() < 1e-3) {
const float continueProb = .5f;
if (rng.RandomFloat() > continueProb) {
Tr = 0.f;
break;
}
Tr /= continueProb;
}
// Compute fluorescence emission
Spectrum sigma = vr->Mu(p, w, ray.time);
if (!sigma.IsBlack() && scene->lights.size() > 0) {
int nLights = scene->lights.size();
int ln = min(Floor2Int(lightNum[sampOffset] * nLights),
nLights-1);
Light *light = scene->lights[ln];
// Add contribution of _light_ due to the in-scattering at _p_
float pdf;
VisibilityTester vis;
Vector wo;
LightSample ls(lightComp[sampOffset], lightPos[2*sampOffset],
lightPos[2*sampOffset+1]);
Spectrum L = light->Sample_L(p, 0.f, ls, ray.time, &wo, &pdf, &vis);
if (!L.IsBlack() && pdf > 0.f && vis.Unoccluded(scene)) {
Spectrum Ld = L * vis.Transmittance(scene, renderer, NULL, rng,
arena);
int lambdaExcIndex = light->GetLaserWavelengthIndex();
float Lpower = Ld.GetLaserEmissionPower(lambdaExcIndex);
float yield = vr->Yeild(Point());
Spectrum fEx = vr->fEx(Point());
Spectrum fEm = vr->fEm(Point());
float scale = fEx.GetSampleValueAtWavelengthIndex(lambdaExcIndex);
Lv += Lpower * Tr * sigma * vr->p(p, w, -wo, ray.time) *
scale * fEm * yield * float(nLights) / pdf;
}
}
++sampOffset;
}
*T = Tr;
return Lv * step;
}
void IGIIntegrator::Preprocess(const Scene *scene, const Camera *camera,
const Renderer *renderer) {
if (scene->lights.size() == 0) return;
MemoryArena arena;
RNG rng;
// Compute samples for emitted rays from lights
vector<float> lightNum(nLightPaths * nLightSets);
vector<float> lightSampPos(2 * nLightPaths * nLightSets, 0.f);
vector<float> lightSampComp(nLightPaths * nLightSets, 0.f);
vector<float> lightSampDir(2 * nLightPaths * nLightSets, 0.f);
LDShuffleScrambled1D(nLightPaths, nLightSets, &lightNum[0], rng);
LDShuffleScrambled2D(nLightPaths, nLightSets, &lightSampPos[0], rng);
LDShuffleScrambled1D(nLightPaths, nLightSets, &lightSampComp[0], rng);
LDShuffleScrambled2D(nLightPaths, nLightSets, &lightSampDir[0], rng);
// Precompute information for light sampling densities
Distribution1D *lightDistribution = ComputeLightSamplingCDF(scene);
for (uint32_t s = 0; s < nLightSets; ++s) {
for (uint32_t i = 0; i < nLightPaths; ++i) {
// Follow path _i_ from light to create virtual lights
int sampOffset = s*nLightPaths + i;
// Choose light source to trace virtual light path from
float lightPdf;
int ln = lightDistribution->SampleDiscrete(lightNum[sampOffset],
&lightPdf);
Light *light = scene->lights[ln];
// Sample ray leaving light source for virtual light path
RayDifferential ray;
float pdf;
LightSample ls(lightSampPos[2*sampOffset], lightSampPos[2*sampOffset+1],
lightSampComp[sampOffset]);
Normal Nl;
Spectrum alpha = light->Sample_L(scene, ls, lightSampDir[2*sampOffset],
lightSampDir[2*sampOffset+1],
camera->shutterOpen, &ray, &Nl, &pdf);
if (pdf == 0.f || alpha.IsBlack()) continue;
alpha /= pdf * lightPdf;
Intersection isect;
while (scene->Intersect(ray, &isect) && !alpha.IsBlack()) {
// Create virtual light and sample new ray for path
alpha *= renderer->Transmittance(scene, RayDifferential(ray), NULL,
rng, arena);
Vector wo = -ray.d;
BSDF *bsdf = isect.GetBSDF(ray, arena);
// Create virtual light at ray intersection point
Spectrum contrib = alpha * bsdf->rho(wo, rng) / M_PI;
virtualLights[s].push_back(VirtualLight(isect.dg.p, isect.dg.nn, contrib,
isect.rayEpsilon));
// Sample new ray direction and update weight for virtual light path
Vector wi;
float pdf;
BSDFSample bsdfSample(rng);
Spectrum fr = bsdf->Sample_f(wo, &wi, bsdfSample, &pdf);
if (fr.IsBlack() || pdf == 0.f)
break;
Spectrum contribScale = fr * AbsDot(wi, bsdf->dgShading.nn) / pdf;
// Possibly terminate virtual light path with Russian roulette
float rrProb = min(1.f, contribScale.y());
if (rng.RandomFloat() > rrProb)
break;
alpha *= contribScale / rrProb;
ray = RayDifferential(isect.dg.p, wi, ray, isect.rayEpsilon);
}
arena.FreeAll();
}
}
delete lightDistribution;
}
Spectrum SingleScatteringIntegrator::Li(const Scene *scene, const Renderer *renderer,
const RayDifferential &ray, const Sample *sample,
Spectrum *T, MemoryArena &arena) const {
VolumeRegion *vr = scene->volumeRegion;
float t0, t1;
if (!vr || !vr->IntersectP(ray, &t0, &t1)) {
*T = 1.f;
return 0.f;
}
// Do single scattering volume integration in _vr_
Spectrum Lv(0.);
// Prepare for volume integration stepping
int nSamples = Ceil2Int((t1-t0) / stepSize);
float step = (t1 - t0) / nSamples;
Spectrum Tr(1.f);
Point p = ray(t0), pPrev;
Vector w = -ray.d;
t0 += sample->oneD[scatterSampleOffset][0] * step;
// Compute sample patterns for single scattering samples
float *lightNum = arena.Alloc<float>(nSamples);
LDShuffleScrambled1D(1, nSamples, lightNum, *sample->rng);
float *lightComp = arena.Alloc<float>(nSamples);
LDShuffleScrambled1D(1, nSamples, lightComp, *sample->rng);
float *lightPos = arena.Alloc<float>(2*nSamples);
LDShuffleScrambled2D(1, nSamples, lightPos, *sample->rng);
u_int sampOffset = 0;
for (int i = 0; i < nSamples; ++i, t0 += step) {
// Advance to sample at _t0_ and update _T_
pPrev = p;
p = ray(t0);
Ray tauRay(pPrev, p - pPrev, 0.f, 1.f, ray.time, ray.depth);
Spectrum stepTau = vr->tau(tauRay,
.5f * stepSize, sample->rng->RandomFloat());
Tr *= Exp(-stepTau);
// Possibly terminate ray marching if transmittance is small
if (Tr.y() < 1e-3) {
const float continueProb = .5f;
if (sample->rng->RandomFloat() > continueProb) break;
Tr /= continueProb;
}
// Compute single-scattering source term at _p_
Lv += Tr * vr->Lve(p, w, ray.time);
Spectrum ss = vr->sigma_s(p, w, ray.time);
if (!ss.IsBlack() && scene->lights.size() > 0) {
int nLights = scene->lights.size();
int ln = min(Floor2Int(lightNum[sampOffset] * nLights),
nLights-1);
Light *light = scene->lights[ln];
// Add contribution of _light_ due to scattering at _p_
float pdf;
VisibilityTester vis;
Vector wo;
LightSample ls(lightComp[sampOffset], lightPos[2*sampOffset],
lightPos[2*sampOffset+1]);
Spectrum L = light->Sample_L(p, 0.f, ls, ray.time, &wo, &pdf, &vis);
if (!L.IsBlack() && pdf > 0.f && vis.Unoccluded(scene)) {
Spectrum Ld = L * vis.Transmittance(scene, renderer, NULL, sample->rng, arena);
Lv += Tr * ss * vr->p(p, w, -wo, ray.time) * Ld * float(nLights) / pdf;
}
}
++sampOffset;
}
*T = Tr;
return Lv * step;
}
Spectrum PhotonVolumeIntegrator::Li(const Scene *scene, const Renderer *renderer,
const RayDifferential &ray, const Sample *sample, RNG &rng,
Spectrum *T, MemoryArena &arena) const {
VolumeRegion *vr = scene->volumeRegion;
RainbowVolume* rv = dynamic_cast<RainbowVolume*>(vr);
KdTree<Photon>* volumeMap = photonShooter->volumeMap;
float t0, t1;
if (!vr || !vr->IntersectP(ray, &t0, &t1) || (t1-t0) == 0.f){
*T = 1.f;
return 0.f;
}
// Do single scattering & photon multiple scattering volume integration in _vr_
Spectrum Lv(0.);
// Prepare for volume integration stepping
int nSamples = Ceil2Int((t1-t0) / stepSize);
float step = (t1 - t0) / nSamples;
Spectrum Tr(1.f);
Point p = ray(t0), pPrev;
Vector w = -ray.d;
t0 += sample->oneD[scatterSampleOffset][0] * step;
float *lightNum = arena.Alloc<float>(nSamples);
LDShuffleScrambled1D(1, nSamples, lightNum, rng);
float *lightComp = arena.Alloc<float>(nSamples);
LDShuffleScrambled1D(1, nSamples, lightComp, rng);
float *lightPos = arena.Alloc<float>(2*nSamples);
LDShuffleScrambled2D(1, nSamples, lightPos, rng);
int sampOffset = 0;
ClosePhoton *lookupBuf = new ClosePhoton[nSamples];
for (int i = 0; i < nSamples; ++i, t0 += step) {
// Advance to sample at _t0_ and update _T_
pPrev = p;
p = ray(t0);
Ray tauRay(pPrev, p - pPrev, 0.f, 1.f, ray.time, ray.depth);
Spectrum stepTau = vr->tau(tauRay,.5f * stepSize, rng.RandomFloat());
Tr = Exp(-stepTau);
// Possibly terminate raymarching if transmittance is small.
if (Tr.y() < 1e-3) {
const float continueProb = .5f;
if (rng.RandomFloat() > continueProb){
Tr = 0.f;
break;
}
Tr /= continueProb;
}
// Compute single-scattering source term at _p_ & photon mapped MS
Spectrum L_i(0.);
Spectrum L_d(0.);
Spectrum L_ii(0.);
// Lv += Tr*vr->Lve(p, w, ray.time);
Spectrum ss = vr->sigma_s(p, w, ray.time);
Spectrum sa = vr->sigma_a(p, w, ray.time);
if (!ss.IsBlack() && scene->lights.size() > 0) {
int nLights = scene->lights.size();
int ln =
min(Floor2Int(lightNum[sampOffset] * nLights),
nLights-1);
Light *light = scene->lights[ln];
// Add contribution of _light_ due to scattering at _p_
float pdf;
VisibilityTester vis;
Vector wo;
LightSample ls(lightComp[sampOffset], lightPos[2*sampOffset],
lightPos[2*sampOffset+1]);
Spectrum L = light->Sample_L(p, 0.f, ls, ray.time, &wo, &pdf, &vis);
if (!L.IsBlack() && pdf > 0.f && vis.Unoccluded(scene)) {
Spectrum Ld = L * vis.Transmittance(scene,renderer, NULL, rng, arena);
if(rv){
L_d = rv->rainbowReflection(Ld, ray.d, wo);
}
else {
L_d = vr->p(p, w, -wo, ray.time) * Ld * float(nLights)/pdf;
}
}
}
// Compute 'indirect' in-scattered radiance from photon map
if(!rv){
L_ii += LPhoton(volumeMap, nUsed, lookupBuf, w, p, vr, maxDistSquared, ray.time);
}
// Compute total in-scattered radiance
if (sa.y()!=0.0 || ss.y()!=0.0)
L_i = L_d + (ss/(sa+ss))*L_ii;
else
L_i = L_d;
Spectrum nLv = (sa*vr->Lve(p,w,ray.time)*step) + (ss*L_i*step) + (Tr * Lv) ;
Lv = nLv;
sampOffset++;
}
*T = Tr;
return Lv;
}
void IGIIntegrator::Preprocess(const Scene *scene) {
if (scene->lights.size() == 0) return;
// Compute samples for emitted rays from lights
float *lightNum = new float[nLightPaths * nLightSets];
float *lightSamp0 = new float[2 * nLightPaths * nLightSets];
float *lightSamp1 = new float[2 * nLightPaths * nLightSets];
LDShuffleScrambled1D(nLightPaths, nLightSets, lightNum);
LDShuffleScrambled2D(nLightPaths, nLightSets, lightSamp0);
LDShuffleScrambled2D(nLightPaths, nLightSets, lightSamp1);
// Precompute information for light sampling densities
int nLights = int(scene->lights.size());
float *lightPower = (float *)alloca(nLights * sizeof(float));
float *lightCDF = (float *)alloca((nLights+1) * sizeof(float));
for (int i = 0; i < nLights; ++i)
lightPower[i] = scene->lights[i]->Power(scene).y();
float totalPower;
ComputeStep1dCDF(lightPower, nLights, &totalPower, lightCDF);
for (u_int s = 0; s < nLightSets; ++s) {
for (u_int i = 0; i < nLightPaths; ++i) {
// Follow path _i_ from light to create virtual lights
int sampOffset = s*nLightPaths + i;
// Choose light source to trace path from
float lightPdf;
int lNum = Floor2Int(SampleStep1d(lightPower, lightCDF,
totalPower, nLights, lightNum[sampOffset], &lightPdf) * nLights);
// fprintf(stderr, "samp %f -> num %d\n", lightNum[sampOffset], lNum);
Light *light = scene->lights[lNum];
// Sample ray leaving light source
RayDifferential ray;
float pdf;
Spectrum alpha =
light->Sample_L(scene, lightSamp0[2*sampOffset],
lightSamp0[2*sampOffset+1],
lightSamp1[2*sampOffset],
lightSamp1[2*sampOffset+1],
&ray, &pdf);
if (pdf == 0.f || alpha.Black()) continue;
alpha /= pdf * lightPdf;
// fprintf(stderr, "initial alpha %f, light # %d\n", alpha.y(), lNum);
Intersection isect;
int nIntersections = 0;
while (scene->Intersect(ray, &isect) && !alpha.Black()) {
++nIntersections;
alpha *= scene->Transmittance(ray);
Vector wo = -ray.d;
BSDF *bsdf = isect.GetBSDF(ray);
// Create virtual light at ray intersection point
static StatsCounter vls("IGI Integrator", "Virtual Lights Created"); //NOBOOK
++vls; //NOBOOK
Spectrum Le = alpha * bsdf->rho(wo) / M_PI;
// fprintf(stderr, "\tmade light with le y %f\n", Le.y());
virtualLights[s].push_back(VirtualLight(isect.dg.p, isect.dg.nn, Le));
// Sample new ray direction and update weight
Vector wi;
float pdf;
BxDFType flags;
Spectrum fr = bsdf->Sample_f(wo, &wi, RandomFloat(),
RandomFloat(), RandomFloat(),
&pdf, BSDF_ALL, &flags);
if (fr.Black() || pdf == 0.f)
break;
Spectrum anew = alpha * fr * AbsDot(wi, bsdf->dgShading.nn) / pdf;
float r = anew.y() / alpha.y();
// fprintf(stderr, "\tr = %f\n", r);
if (RandomFloat() > r)
break;
alpha = anew / r;
// fprintf(stderr, "\tnew alpha %f\n", alpha.y());
ray = RayDifferential(isect.dg.p, wi);
}
BSDF::FreeAll();
}
}
delete[] lightNum; // NOBOOK
delete[] lightSamp0; // NOBOOK
delete[] lightSamp1; // NOBOOK
}
void PhotonIntegrator::Preprocess(const Scene *scene) {
if (scene->lights.size() == 0) return;
ProgressReporter progress(nCausticPhotons+nDirectPhotons+ // NOBOOK
nIndirectPhotons, "Shooting photons"); // NOBOOK
vector<Photon> causticPhotons;
vector<Photon> directPhotons;
vector<Photon> indirectPhotons;
causticPhotons.reserve(nCausticPhotons); // NOBOOK
directPhotons.reserve(nDirectPhotons); // NOBOOK
indirectPhotons.reserve(nIndirectPhotons); // NOBOOK
// Initialize photon shooting statistics
static StatsCounter nshot("Photon Map",
"Number of photons shot from lights");
bool causticDone = (nCausticPhotons == 0);
bool directDone = (nDirectPhotons == 0);
bool indirectDone = (nIndirectPhotons == 0);
while (!causticDone || !directDone || !indirectDone) {
++nshot;
// Give up if we're not storing enough photons
if (nshot > 500000 &&
(unsuccessful(nCausticPhotons,
causticPhotons.size(),
nshot) ||
unsuccessful(nDirectPhotons,
directPhotons.size(),
nshot) ||
unsuccessful(nIndirectPhotons,
indirectPhotons.size(),
nshot))) {
Error("Unable to store enough photons. Giving up.\n");
return;
}
// Trace a photon path and store contribution
// Choose 4D sample values for photon
float u[4];
u[0] = (float)RadicalInverse((int)nshot+1, 2);
u[1] = (float)RadicalInverse((int)nshot+1, 3);
u[2] = (float)RadicalInverse((int)nshot+1, 5);
u[3] = (float)RadicalInverse((int)nshot+1, 7);
// Choose light to shoot photon from
int nLights = int(scene->lights.size());
int lightNum =
min(Floor2Int(nLights * (float)RadicalInverse((int)nshot+1, 11)),
nLights-1);
Light *light = scene->lights[lightNum];
float lightPdf = 1.f / nLights;
// Generate _photonRay_ from light source and initialize _alpha_
RayDifferential photonRay;
float pdf;
Spectrum alpha =
light->Sample_L(scene, u[0], u[1], u[2], u[3],
&photonRay, &pdf);
if (pdf == 0.f || alpha.Black()) continue;
alpha /= pdf * lightPdf;
if (!alpha.Black()) {
// Follow photon path through scene and record intersections
bool specularPath = false;
Intersection photonIsect;
int nIntersections = 0;
while (scene->Intersect(photonRay, &photonIsect)) {
++nIntersections;
// Handle photon/surface intersection
alpha *= scene->Transmittance(photonRay);
Vector wo = -photonRay.d;
BSDF *photonBSDF = photonIsect.GetBSDF(photonRay);
BxDFType specularType = BxDFType(BSDF_REFLECTION |
BSDF_TRANSMISSION | BSDF_SPECULAR);
bool hasNonSpecular = (photonBSDF->NumComponents() >
photonBSDF->NumComponents(specularType));
if (hasNonSpecular) {
// Deposit photon at surface
Photon photon(photonIsect.dg.p, alpha, wo);
if (nIntersections == 1) {
// Process direct lighting photon intersection
if (!directDone) {
directPhotons.push_back(photon);
if (directPhotons.size() == nDirectPhotons) {
directDone = true;
nDirectPaths = (int)nshot;
directMap =
new KdTree<Photon,
PhotonProcess>(directPhotons);
}
progress.Update(); // NOBOOK
}
}
else if (specularPath) {
// Process caustic photon intersection
if (!causticDone) {
causticPhotons.push_back(photon);
if (causticPhotons.size() == nCausticPhotons) {
causticDone = true;
nCausticPaths = (int)nshot;
causticMap =
new KdTree<Photon,
PhotonProcess>(causticPhotons);
}
progress.Update();
}
}
else {
// Process indirect lighting photon intersection
if (!indirectDone) {
indirectPhotons.push_back(photon);
if (indirectPhotons.size() == nIndirectPhotons) {
indirectDone = true;
nIndirectPaths = (int)nshot;
indirectMap =
new KdTree<Photon,
PhotonProcess>(indirectPhotons);
}
progress.Update();
}
}
}
// Sample new photon ray direction
Vector wi;
float pdf;
BxDFType flags;
// Get random numbers for sampling outgoing photon direction
float u1, u2, u3;
if (nIntersections == 1) {
u1 = (float)RadicalInverse((int)nshot+1, 13);
u2 = (float)RadicalInverse((int)nshot+1, 17);
u3 = (float)RadicalInverse((int)nshot+1, 19);
}
else {
u1 = RandomFloat();
u2 = RandomFloat();
u3 = RandomFloat();
}
Spectrum fr = photonBSDF->Sample_f(wo, &wi, u1, u2, u3,
&pdf, BSDF_ALL, &flags);
if (fr.Black() || pdf == 0.f)
break;
specularPath = (nIntersections == 1 || specularPath) &&
((flags & BSDF_SPECULAR) != 0);
alpha *= fr * AbsDot(wi, photonBSDF->dgShading.nn) / pdf;
photonRay = RayDifferential(photonIsect.dg.p, wi);
// Possibly terminate photon path
if (nIntersections > 3) {
float continueProbability = .5f;
if (RandomFloat() > continueProbability)
break;
alpha /= continueProbability;
}
}
}
BSDF::FreeAll();
}
progress.Done(); // NOBOOK
}