Spectrum EstimateIrradianceDirect(const Scene* scene,
const Light* light, const Point& p,
const Normal& n,
int lightSamp,
u_int sampleNum)
{
Spectrum Ed(0.); // direct irradiance
// Find light and BSDF sample values for direct lighting estimate
float ls1, ls2;
ls1 = RandomFloat();
ls2 = RandomFloat();
// Sample light source with multiple importance sampling
Vector wi;
float lightPdf;
VisibilityTester visibility;
Spectrum Li = light->Sample_L(p, n, ls1, ls2, &wi, &lightPdf, &visibility);
//printf("got light sample ");
//Li.printSelf();
if (lightPdf > 0. && !Li.Black()) {
if (visibility.Unoccluded(scene)) {
// Add light's contribution to reflected radiance
Li *= visibility.Transmittance(scene);
Ed += Li * AbsDot(wi, n) / lightPdf;
}
}
return Ed;
}
Spectrum EstimateDirect(const Scene *scene, const Renderer *renderer,
MemoryArena &arena, const Light *light, const Point &p,
const Normal &n, const Vector &wo, float rayEpsilon, float time,
const BSDF *bsdf, RNG &rng, const LightSample &lightSample,
const BSDFSample &bsdfSample, BxDFType flags) {
Spectrum Ld(0.);
// Sample light source with multiple importance sampling
Vector wi;
float lightPdf, bsdfPdf;
VisibilityTester visibility;
light->Sample_L(p, rayEpsilon, lightSample, time,
&wi, &lightPdf, &visibility);
Spectrum Li(1.);
if (lightPdf > 0. && !Li.IsBlack()) {
Spectrum f = bsdf->f(wo, wi, flags);
if (!f.IsBlack() && visibility.Unoccluded(scene)) {
// Add light's contribution to reflected radiance
Li *= visibility.Transmittance(scene, renderer, NULL, rng, arena);
if (light->IsDeltaLight())
Ld += f * (AbsDot(wi, n) / lightPdf);
else {
bsdfPdf = bsdf->Pdf(wo, wi, flags);
float weight = PowerHeuristic(1, lightPdf, 1, bsdfPdf);
Ld += f * (AbsDot(wi, n) * weight / lightPdf);
}
}
}
return Ld;
}
void Light::SHProject(const PbrtPoint &p, float pEpsilon, int lmax,
const Scene *scene, bool computeLightVisibility, float time,
RNG &rng, Spectrum *coeffs) const {
for (int i = 0; i < SHTerms(lmax); ++i)
coeffs[i] = 0.f;
uint32_t ns = RoundUpPow2(nSamples);
uint32_t scramble1D = rng.RandomUInt();
uint32_t scramble2D[2] = { rng.RandomUInt(), rng.RandomUInt() };
float *Ylm = ALLOCA(float, SHTerms(lmax));
for (uint32_t i = 0; i < ns; ++i) {
// Compute incident radiance sample from _light_, update SH _coeffs_
float u[2], pdf;
Sample02(i, scramble2D, u);
LightSample lightSample(u[0], u[1], VanDerCorput(i, scramble1D));
Vector wi;
VisibilityTester vis;
Spectrum Li = Sample_L(p, pEpsilon, lightSample, time, &wi, &pdf, &vis);
if (!Li.IsBlack() && pdf > 0.f &&
(!computeLightVisibility || vis.Unoccluded(scene))) {
// Add light sample contribution to MC estimate of SH coefficients
SHEvaluate(wi, lmax, Ylm);
for (int j = 0; j < SHTerms(lmax); ++j)
coeffs[j] += Li * Ylm[j] / (pdf * ns);
}
}
}
Spectrum EstimateDirect(const Scene *scene, const Renderer *renderer,
MemoryArena &arena, const Light *light, const Point &p,
const Normal &n, const Vector &wo, float rayEpsilon, float time,
const BSDF *bsdf, RNG &rng, const LightSample &lightSample,
const BSDFSample &bsdfSample, BxDFType flags) {
Spectrum Ld(0.);
// Sample light source with multiple importance sampling
Vector wi;
float lightPdf, bsdfPdf;
VisibilityTester visibility;
Spectrum Li = light->Sample_L(p, rayEpsilon, lightSample, time,
&wi, &lightPdf, &visibility);
if (lightPdf > 0. && !Li.IsBlack()) {
Spectrum f = bsdf->f(wo, wi, flags);
if (!f.IsBlack() && visibility.Unoccluded(scene)) {
// Add light's contribution to reflected radiance
Li *= visibility.Transmittance(scene, renderer, NULL, rng, arena);
if (light->IsDeltaLight())
Ld += f * Li * (AbsDot(wi, n) / lightPdf);
else {
bsdfPdf = bsdf->Pdf(wo, wi, flags);
float weight = PowerHeuristic(1, lightPdf, 1, bsdfPdf);
Ld += f * Li * (AbsDot(wi, n) * weight / lightPdf);
}
}
}
// Sample BSDF with multiple importance sampling
if (!light->IsDeltaLight()) {
BxDFType sampledType;
Spectrum f = bsdf->Sample_f(wo, &wi, bsdfSample, &bsdfPdf, flags,
&sampledType);
if (!f.IsBlack() && bsdfPdf > 0.) {
float weight = 1.f;
if (!(sampledType & BSDF_SPECULAR)) {
lightPdf = light->Pdf(p, wi);
if (lightPdf == 0.)
return Ld;
weight = PowerHeuristic(1, bsdfPdf, 1, lightPdf);
}
// Add light contribution from BSDF sampling
Intersection lightIsect;
Spectrum Li(0.f);
RayDifferential ray(p, wi, rayEpsilon, INFINITY, time);
if (scene->Intersect(ray, &lightIsect)) {
if (lightIsect.primitive->GetAreaLight() == light)
Li = lightIsect.Le(-wi);
}
else
//Li = light->Le(ray,);
Li = Spectrum(0.);
if (!Li.IsBlack()) {
Li *= renderer->Transmittance(scene, ray, NULL, rng, arena);
Ld += f * Li * AbsDot(wi, n) * weight / bsdfPdf;
}
}
}
return Ld;
}
LightInfo ProjectionLight::Sample_L(const Point &p, float pEpsilon,
const LightSample &ls, float time) const {
auto wi = Normalize(lightPos - p);
VisibilityTester visibility;
visibility.SetSegment(p, pEpsilon, lightPos, 0., time);
auto L = Intensity * Projection(-wi) / DistanceSquared(lightPos, p);
return LightInfo{L,wi,1.f,visibility};
}
csColor ProxyLight::SampleLight (const csVector3& point, const csVector3& n,
float u1, float u2, csVector3& lightVec, float& pdf, VisibilityTester& vistest,
const csPlane3* visLimitPlane)
{
// Setup clipped visibility ray
const csVector3 lightPos = GetLightSamplePosition (u1, u2);
csSegment3 visSegment (lightPos, point);
if (!lightFrustum.Contains (point-lightFrustum.GetOrigin ()) ||
!lightFrustum.Intersect (visSegment))
{
pdf = 0.0f;
return csColor (0,0,0);
}
if (visLimitPlane)
csIntersect3::SegmentPlane (*visLimitPlane, visSegment);
vistest.AddSegment (ownerSector->kdTree, visSegment.Start (), visSegment.End ());
csVector3 parentLightVec;
csPlane3 transformedPlane;
transformedPlane = proxyTransform.Other2This (portalPlane);
const csColor parentLight = parent->SampleLight (point, n, u1, u2,
parentLightVec, pdf, vistest, &transformedPlane);
lightVec = proxyTransform.Other2ThisRelative (parentLightVec);
return parentLight;
}
csColor SpotLight::SampleLight (const csVector3& point, const csVector3& n,
float u1, float u2, csVector3& lightVec, float& pdf, VisibilityTester& vistest,
const csPlane3* visLimitPlane)
{
lightVec = position - point;
float sqD = lightVec.SquaredNorm ();
float d = sqrtf (sqD);
lightVec /= d;
float dot = -dir * lightVec; // negate because dir points away from the light
// early out if we're out of the light cone
if (dot < outer)
return csColor (0.f);
csSegment3 visSegment (position, point);
pdf = 1;
if (visLimitPlane)
csIntersect3::SegmentPlane (*visLimitPlane, visSegment);
vistest.AddSegment (ownerSector->kdTree, visSegment.Start (), visSegment.End ());
float falloff;
// early out if no edge softening
if (fabs (outer - inner) < 0.0001)
falloff = 1.f;
else
falloff = csSmoothStep(dot, inner, outer);
csColor res = color * ComputeAttenuation (sqD) * falloff;
return res;
}
csColor DirectionalLightAttenuationPoint::SampleLight (const csVector3& point, const csVector3& n,
float u1, float u2, csVector3& lightVec, float& pdf, VisibilityTester& vistest,
const csPlane3* visLimitPlane)
{
lightVec = position - point;
float dot = -dir * lightVec;
// project the point onto the light plane
csVector3 P = point - dir * dot;
// have attenuation calculated based on the distance from point
// to light centre
float sqD = lightVec.SquaredNorm ();
lightVec = -dir;
pdf = 1;
csSegment3 visSegment (P, point);
if (visLimitPlane)
csIntersect3::SegmentPlane (*visLimitPlane, visSegment);
vistest.AddSegment (ownerSector->kdTree, visSegment.Start (), visSegment.End ());
csColor res = color * ComputeAttenuation (sqD);
return res;
}
// WhittedIntegrator Method Definitions
Spectrum WhittedIntegrator::Li(const RayDifferential &ray, const Scene &scene,
Sampler &sampler, MemoryArena &arena,
int depth) const {
Spectrum L(0.);
// Find closest ray intersection or return background radiance
SurfaceInteraction isect;
if (!scene.Intersect(ray, &isect)) {
for (const auto &light : scene.lights) L += light->Le(ray);
return L;
}
// Compute emitted and reflected light at ray intersection point
// Initialize common variables for Whitted integrator
const Normal3f &n = isect.shading.n;
Vector3f wo = isect.wo;
// Compute scattering functions for surface interaction
isect.ComputeScatteringFunctions(ray, arena);
if (!isect.bsdf)
return Li(isect.SpawnRay(ray.d), scene, sampler, arena, depth);
// Compute emitted light if ray hit an area light source
L += isect.Le(wo);
// Add contribution of each light source
for (const auto &light : scene.lights) {
Vector3f wi;
Float pdf;
VisibilityTester visibility;
Spectrum Li =
light->Sample_Li(isect, sampler.Get2D(), &wi, &pdf, &visibility);
if (Li.IsBlack() || pdf == 0) continue;
Spectrum f = isect.bsdf->f(wo, wi);
if (!f.IsBlack() && visibility.Unoccluded(scene))
L += f * Li * AbsDot(wi, n) / pdf;
}
if (depth + 1 < maxDepth) {
// Trace rays for specular reflection and refraction
L += SpecularReflect(ray, isect, scene, sampler, arena, depth);
L += SpecularTransmit(ray, isect, scene, sampler, arena, depth);
}
return L;
}
// WhittedIntegrator Method Definitions
Spectrum WhittedIntegrator::Li(const Scene *scene,
const Renderer *renderer, const RayDifferential &ray,
const Intersection &isect, const Sample *sample,
MemoryArena &arena) const {
Spectrum L(0.);
// Compute emitted and reflected light at ray intersection point
// Evaluate BSDF at hit point
BSDF *bsdf = isect.GetBSDF(ray, arena);
// Initialize common variables for Whitted integrator
const Point &p = bsdf->dgShading.p;
const Normal &n = bsdf->dgShading.nn;
Vector wo = -ray.d;
// Compute emitted light if ray hit an area light source
L += isect.Le(wo);
// Add contribution of each light source
Vector wi;
for (u_int i = 0; i < scene->lights.size(); ++i) {
VisibilityTester visibility;
float pdf;
Spectrum Li = scene->lights[i]->Sample_L(p, isect.rayEpsilon,
LightSample(*sample->rng), sample->time, &wi, &pdf, &visibility);
if (Li.IsBlack() || pdf == 0.f) continue;
Li /= pdf;
Spectrum f = bsdf->f(wo, wi);
if (!f.IsBlack() && visibility.Unoccluded(scene))
L += f * Li * AbsDot(wi, n) *
visibility.Transmittance(scene, renderer,
sample, NULL, arena);
}
if (ray.depth + 1 < maxDepth) {
// Trace rays for specular reflection and refraction
L += SpecularReflect(ray, bsdf, *sample->rng, isect, renderer,
scene, sample, arena);
L += SpecularTransmit(ray, bsdf, *sample->rng, isect, renderer,
scene, sample, arena);
}
return L;
}
Spectrum VolumePatIntegrator::EstimateDirectLight(const Scene *scene,
const Renderer *renderer, MemoryArena &arena, const Light *light,
const Point &p, const Normal &n, const Vector &wo, float rayEpsilon,
float time, RNG &rng, const LightSample &lightSample) const {
VolumeRegion *vr = scene->volumeRegion;
if (!vr) Spectrum(0.);
Spectrum Ld(0.);
// Sample light source.
Vector wi;
float lightPdf;
VisibilityTester visibility;
Spectrum Li = light->Sample_L(p, rayEpsilon, lightSample, time,
&wi, &lightPdf, &visibility);
if (lightPdf > 0. && !Li.IsBlack() && visibility.Unoccluded(scene)) {
// Add light's contribution to reflected radiance
Li *= visibility.Transmittance(scene, renderer, NULL, rng, arena);
// Li *= PowerHeuristic(1, lightPdf, 1, (1/M_PI_4));
Ld += vr->p(p, -wi, wo, time) * vr->Sigma_s(p, wo, time) * Li / lightPdf;
}
return Ld;
}
csColor PointLight::SampleLight (const csVector3& point, const csVector3& n,
float u1, float u2, csVector3& lightVec, float& pdf, VisibilityTester& vistest,
const csPlane3* visLimitPlane)
{
csSegment3 visSegment (position, point);
lightVec = position - point;
float sqD = lightVec.SquaredNorm ();
float d = sqrtf (sqD);
lightVec /= d;
pdf = 1;
if (visLimitPlane)
csIntersect3::SegmentPlane (*visLimitPlane, visSegment);
vistest.AddSegment (ownerSector->kdTree, visSegment.Start (), visSegment.End ());
csColor res = color * ComputeAttenuation (sqD);
return res;
}
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;
}
Spectrum EstimateDirect(const Scene *scene,
const Light *light, const Point &p,
const Normal &n, const Vector &wo,
BSDF *bsdf, const Sample *sample, int lightSamp,
int bsdfSamp, int bsdfComponent, u_int sampleNum) {
Spectrum Ld = Spectrum(0.f);
// Find light and BSDF sample values for direct lighting estimate
float ls1, ls2, bs1, bs2, bcs;
if (lightSamp != -1 && bsdfSamp != -1 &&
sampleNum < sample->n2D[lightSamp] &&
sampleNum < sample->n2D[bsdfSamp]) {
ls1 = sample->twoD[lightSamp][2*sampleNum];
ls2 = sample->twoD[lightSamp][2*sampleNum+1];
bs1 = sample->twoD[bsdfSamp][2*sampleNum];
bs2 = sample->twoD[bsdfSamp][2*sampleNum+1];
bcs = sample->oneD[bsdfComponent][sampleNum];
}
else {
ls1 = RandomFloat();
ls2 = RandomFloat();
bs1 = RandomFloat();
bs2 = RandomFloat();
bcs = RandomFloat();
}
// Sample light source with multiple importance sampling
Vector wi;
float lightPdf, bsdfPdf;
VisibilityTester visibility;
Spectrum Li = light->Sample_L(p, n, ls1, ls2, &wi, &lightPdf, &visibility);
if (lightPdf > 0. && !Li.Black()) {
if(bsdf->NumComponents(BSDF_FLUORESCENT) > 0)
{
Bispectrum * fluoro = (Bispectrum*)bsdf->f_ptr(wo, wi, BxDFType(BSDF_FLUORESCENT));
if (visibility.Unoccluded(scene)) {
// Add light's contribution to reflected radiance
Li *= visibility.Transmittance(scene);
if (light->IsDeltaLight())
Ld += fluoro->output(Li, true, false) * AbsDot(wi, n);
else {
bsdfPdf = bsdf->Pdf(wo, wi);
//float weight = PowerHeuristic(1, lightPdf, 1, bsdfPdf);
Ld += fluoro->output(Li, true, false) * AbsDot(wi, n)*bsdfPdf;
}
}
}else{
Spectrum f = bsdf->f(wo, wi, BxDFType(BSDF_ALL & ~BSDF_FLUORESCENT));
if (!f.Black() && visibility.Unoccluded(scene)) {
// Add light's contribution to reflected radiance
Li *= visibility.Transmittance(scene);
if (light->IsDeltaLight())
Ld += f * Li * AbsDot(wi, n);
else {
bsdfPdf = bsdf->Pdf(wo, wi);
//float weight = PowerHeuristic(1, lightPdf, 1, bsdfPdf);
Ld += f * Li * AbsDot(wi, n)*bsdfPdf;
}
}
}
}/*
// Sample BSDF with multiple importance sampling
if (!light->IsDeltaLight()) {
BxDFType flags = BxDFType(BSDF_ALL & ~BSDF_SPECULAR & ~BSDF_FLUORESCENT);
if(bsdf->NumComponents(BSDF_FLUORESCENT) > 0)
{
Bispectrum * fluoro = (Bispectrum*)bsdf->Sample_f_ptr(wo, &wi, bs1, bs2, bcs, &bsdfPdf, BxDFType(BSDF_FLUORESCENT));
if (bsdfPdf > 0.) {
lightPdf = light->Pdf(p, n, wi);
if (lightPdf > 0.) {
// Add light contribution from BSDF sampling
float weight = PowerHeuristic(1, bsdfPdf, 1, lightPdf);
Intersection lightIsect;
Spectrum Li(0.f);
RayDifferential ray(p, wi);
if (scene->Intersect(ray, &lightIsect)) {
if (lightIsect.primitive->GetAreaLight() == light)
Li = lightIsect.Le(-wi);
}
else
Li = light->Le(ray);
if (!Li.Black()) {
Li *= scene->Transmittance(ray);
Ld += fluoro->output(Li, true, false) * AbsDot(wi, n)* weight / bsdfPdf;
}
}
}
}else{
Spectrum f = bsdf->Sample_f(wo, &wi, bs1, bs2, bcs, &bsdfPdf, flags);
if (!f.Black() && bsdfPdf > 0.) {
lightPdf = light->Pdf(p, n, wi);
if (lightPdf > 0.) {
// Add light contribution from BSDF sampling
float weight = PowerHeuristic(1, bsdfPdf, 1, lightPdf);
Intersection lightIsect;
Spectrum Li(0.f);
RayDifferential ray(p, wi);
if (scene->Intersect(ray, &lightIsect)) {
if (lightIsect.primitive->GetAreaLight() == light)
Li = lightIsect.Le(-wi);
}
else
Li = light->Le(ray);
if (!Li.Black()) {
Li *= scene->Transmittance(ray);
Ld += f * Li * AbsDot(wi, n) * weight / bsdfPdf;
}
}
}
}
}*/
return Ld;
}
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 DipoleSubsurfaceIntegrator::Preprocess(const Scene *scene,
const Camera *camera, const Renderer *renderer) {
if (scene->lights.size() == 0) return;
vector<SurfacePoint> pts;
// Get _SurfacePoint_s for translucent objects in scene
if (filename != "") {
// Initialize _SurfacePoint_s from file
vector<float> fpts;
if (ReadFloatFile(filename.c_str(), &fpts)) {
if ((fpts.size() % 8) != 0)
Error("Excess values (%d) in points file \"%s\"", int(fpts.size() % 8),
filename.c_str());
for (u_int i = 0; i < fpts.size(); i += 8)
pts.push_back(SurfacePoint(Point(fpts[i], fpts[i+1], fpts[i+2]),
Normal(fpts[i+3], fpts[i+4], fpts[i+5]),
fpts[i+6], fpts[i+7]));
}
}
if (pts.size() == 0) {
Point pCamera = camera->CameraToWorld(camera->shutterOpen,
Point(0, 0, 0));
FindPoissonPointDistribution(pCamera, camera->shutterOpen,
minSampleDist, scene, &pts);
}
// Compute irradiance values at sample points
RNG rng;
MemoryArena arena;
PBRT_SUBSURFACE_STARTED_COMPUTING_IRRADIANCE_VALUES();
ProgressReporter progress(pts.size(), "Computing Irradiances");
for (uint32_t i = 0; i < pts.size(); ++i) {
SurfacePoint &sp = pts[i];
Spectrum E(0.f);
for (uint32_t j = 0; j < scene->lights.size(); ++j) {
// Add irradiance from light at point
const Light *light = scene->lights[j];
Spectrum Elight = 0.f;
int nSamples = RoundUpPow2(light->nSamples);
uint32_t scramble[2] = { rng.RandomUInt(), rng.RandomUInt() };
uint32_t compScramble = rng.RandomUInt();
for (int s = 0; s < nSamples; ++s) {
float lpos[2];
Sample02(s, scramble, lpos);
float lcomp = VanDerCorput(s, compScramble);
LightSample ls(lpos[0], lpos[1], lcomp);
Vector wi;
float lightPdf;
VisibilityTester visibility;
Spectrum Li = light->Sample_L(sp.p, sp.rayEpsilon,
ls, camera->shutterOpen, &wi, &lightPdf, &visibility);
if (Dot(wi, sp.n) <= 0.) continue;
if (Li.IsBlack() || lightPdf == 0.f) continue;
Li *= visibility.Transmittance(scene, renderer, NULL, rng, arena);
if (visibility.Unoccluded(scene))
Elight += Li * AbsDot(wi, sp.n) / lightPdf;
}
E += Elight / nSamples;
}
if (E.y() > 0.f)
{
irradiancePoints.push_back(IrradiancePoint(sp, E));
PBRT_SUBSURFACE_COMPUTED_IRRADIANCE_AT_POINT(&sp, &E);
}
arena.FreeAll();
progress.Update();
}
progress.Done();
PBRT_SUBSURFACE_FINISHED_COMPUTING_IRRADIANCE_VALUES();
// Create octree of clustered irradiance samples
octree = octreeArena.Alloc<SubsurfaceOctreeNode>();
for (uint32_t i = 0; i < irradiancePoints.size(); ++i)
octreeBounds = Union(octreeBounds, irradiancePoints[i].p);
for (uint32_t i = 0; i < irradiancePoints.size(); ++i)
octree->Insert(octreeBounds, &irradiancePoints[i], octreeArena);
octree->InitHierarchy();
}
Spectrum EstimateDirect(const Interaction &it, const Point2f &uScattering,
const Light &light, const Point2f &uLight,
const Scene &scene, Sampler &sampler,
MemoryArena &arena, bool handleMedia, bool specular) {
BxDFType bsdfFlags =
specular ? BSDF_ALL : BxDFType(BSDF_ALL & ~BSDF_SPECULAR);
Spectrum Ld(0.f);
// Sample light source with multiple importance sampling
Vector3f wi;
Float lightPdf = 0, scatteringPdf = 0;
VisibilityTester visibility;
Spectrum Li = light.Sample_Li(it, uLight, &wi, &lightPdf, &visibility);
if (lightPdf > 0 && !Li.IsBlack()) {
// Compute BSDF or phase function's value for light sample
Spectrum f;
if (it.IsSurfaceInteraction()) {
// Evaluate BSDF for light sampling strategy
const SurfaceInteraction &isect = (const SurfaceInteraction &)it;
f = isect.bsdf->f(isect.wo, wi, bsdfFlags) *
AbsDot(wi, isect.shading.n);
scatteringPdf = isect.bsdf->Pdf(isect.wo, wi, bsdfFlags);
} else {
// Evaluate phase function for light sampling strategy
const MediumInteraction &mi = (const MediumInteraction &)it;
Float p = mi.phase->p(mi.wo, wi);
f = Spectrum(p);
scatteringPdf = p;
}
if (!f.IsBlack()) {
// Compute effect of visibility for light source sample
if (handleMedia)
Li *= visibility.Tr(scene, sampler);
else if (!visibility.Unoccluded(scene))
Li = Spectrum(0.f);
// Add light's contribution to reflected radiance
if (!Li.IsBlack()) {
if (IsDeltaLight(light.flags))
Ld += f * Li / lightPdf;
else {
Float weight =
PowerHeuristic(1, lightPdf, 1, scatteringPdf);
Ld += f * Li * weight / lightPdf;
}
}
}
}
// Sample BSDF with multiple importance sampling
if (!IsDeltaLight(light.flags)) {
Spectrum f;
bool sampledSpecular = false;
if (it.IsSurfaceInteraction()) {
// Sample scattered direction for surface interactions
BxDFType sampledType;
const SurfaceInteraction &isect = (const SurfaceInteraction &)it;
f = isect.bsdf->Sample_f(isect.wo, &wi, uScattering, &scatteringPdf,
bsdfFlags, &sampledType);
f *= AbsDot(wi, isect.shading.n);
sampledSpecular = sampledType & BSDF_SPECULAR;
} else {
// Sample scattered direction for medium interactions
const MediumInteraction &mi = (const MediumInteraction &)it;
Float p = mi.phase->Sample_p(mi.wo, &wi, uScattering);
f = Spectrum(p);
scatteringPdf = p;
}
if (!f.IsBlack() && scatteringPdf > 0) {
// Account for light contributions along sampled direction _wi_
Float weight = 1;
if (!sampledSpecular) {
lightPdf = light.Pdf_Li(it, wi);
if (lightPdf == 0) return Ld;
weight = PowerHeuristic(1, scatteringPdf, 1, lightPdf);
}
// Find intersection and compute transmittance
SurfaceInteraction lightIsect;
Ray ray = it.SpawnRay(wi);
Spectrum Tr(1.f);
bool foundSurfaceInteraction =
handleMedia ? scene.IntersectTr(ray, sampler, &lightIsect, &Tr)
: scene.Intersect(ray, &lightIsect);
// Add light contribution from material sampling
Spectrum Li(0.f);
if (foundSurfaceInteraction) {
if (lightIsect.primitive->GetAreaLight() == &light)
Li = lightIsect.Le(-wi);
} else
Li = light.Le(ray);
if (!Li.IsBlack()) Ld += f * Li * Tr * weight / scatteringPdf;
}
}
return Ld;
}
Spectrum ConnectBDPT(
const Scene &scene, Vertex *lightVertices, Vertex *cameraVertices, int s,
int t, const Distribution1D &lightDistr,
const std::unordered_map<const Light *, size_t> &lightToIndex,
const Camera &camera, Sampler &sampler, Point2f *pRaster,
Float *misWeightPtr) {
Spectrum L(0.f);
// Ignore invalid connections related to infinite area lights
if (t > 1 && s != 0 && cameraVertices[t - 1].type == VertexType::Light)
return Spectrum(0.f);
// Perform connection and write contribution to _L_
Vertex sampled;
if (s == 0) {
// Interpret the camera subpath as a complete path
const Vertex &pt = cameraVertices[t - 1];
if (pt.IsLight()) L = pt.Le(scene, cameraVertices[t - 2]) * pt.beta;
DCHECK(!L.HasNaNs());
} else if (t == 1) {
// Sample a point on the camera and connect it to the light subpath
const Vertex &qs = lightVertices[s - 1];
if (qs.IsConnectible()) {
VisibilityTester vis;
Vector3f wi;
Float pdf;
Spectrum Wi = camera.Sample_Wi(qs.GetInteraction(), sampler.Get2D(),
&wi, &pdf, pRaster, &vis);
if (pdf > 0 && !Wi.IsBlack()) {
// Initialize dynamically sampled vertex and _L_ for $t=1$ case
sampled = Vertex::CreateCamera(&camera, vis.P1(), Wi / pdf);
L = qs.beta * qs.f(sampled, TransportMode::Importance) * sampled.beta;
if (qs.IsOnSurface()) L *= AbsDot(wi, qs.ns());
DCHECK(!L.HasNaNs());
// Only check visibility after we know that the path would
// make a non-zero contribution.
if (!L.IsBlack()) L *= vis.Tr(scene, sampler);
}
}
} else if (s == 1) {
// Sample a point on a light and connect it to the camera subpath
const Vertex &pt = cameraVertices[t - 1];
if (pt.IsConnectible()) {
Float lightPdf;
VisibilityTester vis;
Vector3f wi;
Float pdf;
int lightNum =
lightDistr.SampleDiscrete(sampler.Get1D(), &lightPdf);
const std::shared_ptr<Light> &light = scene.lights[lightNum];
Spectrum lightWeight = light->Sample_Li(
pt.GetInteraction(), sampler.Get2D(), &wi, &pdf, &vis);
if (pdf > 0 && !lightWeight.IsBlack()) {
EndpointInteraction ei(vis.P1(), light.get());
sampled =
Vertex::CreateLight(ei, lightWeight / (pdf * lightPdf), 0);
sampled.pdfFwd =
sampled.PdfLightOrigin(scene, pt, lightDistr, lightToIndex);
L = pt.beta * pt.f(sampled, TransportMode::Radiance) * sampled.beta;
if (pt.IsOnSurface()) L *= AbsDot(wi, pt.ns());
// Only check visibility if the path would carry radiance.
if (!L.IsBlack()) L *= vis.Tr(scene, sampler);
}
}
} else {
// Handle all other bidirectional connection cases
const Vertex &qs = lightVertices[s - 1], &pt = cameraVertices[t - 1];
if (qs.IsConnectible() && pt.IsConnectible()) {
L = qs.beta * qs.f(pt, TransportMode::Importance) * pt.f(qs, TransportMode::Radiance) * pt.beta;
VLOG(2) << "General connect s: " << s << ", t: " << t <<
" qs: " << qs << ", pt: " << pt << ", qs.f(pt): " << qs.f(pt, TransportMode::Importance) <<
", pt.f(qs): " << pt.f(qs, TransportMode::Radiance) << ", G: " << G(scene, sampler, qs, pt) <<
", dist^2: " << DistanceSquared(qs.p(), pt.p());
if (!L.IsBlack()) L *= G(scene, sampler, qs, pt);
}
}
++totalPaths;
if (L.IsBlack()) ++zeroRadiancePaths;
ReportValue(pathLength, s + t - 2);
// Compute MIS weight for connection strategy
Float misWeight =
L.IsBlack() ? 0.f : MISWeight(scene, lightVertices, cameraVertices,
sampled, s, t, lightDistr, lightToIndex);
VLOG(2) << "MIS weight for (s,t) = (" << s << ", " << t << ") connection: "
<< misWeight;
DCHECK(!std::isnan(misWeight));
L *= misWeight;
if (misWeightPtr) *misWeightPtr = misWeight;
return L;
}
// WhittedIntegrator Method Definitions
Spectrum WhittedIntegrator::Li(const Scene *scene,
const RayDifferential &ray, const Sample *sample,
float *alpha) const {
Intersection isect;
Spectrum L(0.);
bool hitSomething;
// Search for ray-primitive intersection
hitSomething = scene->Intersect(ray, &isect);
if (!hitSomething) {
// Handle ray with no intersection
if (alpha) *alpha = 0.;
for (u_int i = 0; i < scene->lights.size(); ++i)
L += scene->lights[i]->Le(ray);
if (alpha && !L.Black()) *alpha = 1.;
return L;
}
else {
// Initialize _alpha_ for ray hit
if (alpha) *alpha = 1.;
// Compute emitted and reflected light at ray intersection point
// Evaluate BSDF at hit point
BSDF *bsdf = isect.GetBSDF(ray);
// Initialize common variables for Whitted integrator
const Point &p = bsdf->dgShading.p;
const Normal &n = bsdf->dgShading.nn;
Vector wo = -ray.d;
// Compute emitted light if ray hit an area light source
L += isect.Le(wo);
// Add contribution of each light source
Vector wi;
for (u_int i = 0; i < scene->lights.size(); ++i) {
VisibilityTester visibility;
Spectrum Li = scene->lights[i]->Sample_L(p, &wi, &visibility);
if (Li.Black()) continue;
Spectrum f = bsdf->f(wo, wi);
if (!f.Black() && visibility.Unoccluded(scene))
L += f * Li * AbsDot(wi, n) * visibility.Transmittance(scene);
}
if (rayDepth++ < maxDepth) {
// Trace rays for specular reflection and refraction
Spectrum f = bsdf->Sample_f(wo, &wi,
BxDFType(BSDF_REFLECTION | BSDF_SPECULAR));
if (!f.Black() && AbsDot(wi, n) > 0.f) {
// Compute ray differential _rd_ for specular reflection
RayDifferential rd(p, wi);
rd.hasDifferentials = true;
rd.rx.o = p + isect.dg.dpdx;
rd.ry.o = p + isect.dg.dpdy;
// Compute differential reflected directions
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.rx.d - wo, dwody = -ray.ry.d - wo;
float dDNdx = Dot(dwodx, n) + Dot(wo, dndx);
float dDNdy = Dot(dwody, n) + Dot(wo, dndy);
rd.rx.d = wi -
dwodx + 2 * Vector(Dot(wo, n) * dndx +
dDNdx * n);
rd.ry.d = wi -
dwody + 2 * Vector(Dot(wo, n) * dndy +
dDNdy * n);
L += scene->Li(rd, sample) * f * AbsDot(wi, n);
}
f = bsdf->Sample_f(wo, &wi,
BxDFType(BSDF_TRANSMISSION | BSDF_SPECULAR));
if (!f.Black() && AbsDot(wi, n) > 0.f) {
// Compute ray differential _rd_ for specular transmission
RayDifferential rd(p, wi);
rd.hasDifferentials = true;
rd.rx.o = p + isect.dg.dpdx;
rd.ry.o = 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.rx.d - wo, dwody = -ray.ry.d - 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.rx.d = wi + eta * dwodx - Vector(mu * dndx + dmudx * n);
rd.ry.d = wi + eta * dwody - Vector(mu * dndy + dmudy * n);
L += scene->Li(rd, sample) * f * AbsDot(wi, n);
}
}
--rayDepth;
}
return L;
}
Spectrum ConnectBDPT(const Scene &scene, Vertex *lightVertices,
Vertex *cameraVertices, int s, int t,
const Distribution1D &lightDistr, const Camera &camera,
Sampler &sampler, Point2f *pRaster, Float *misWeightPtr) {
Spectrum L(0.f);
// Ignore invalid connections related to infinite area lights
if (t > 1 && s != 0 && cameraVertices[t - 1].type == VertexType::Light)
return Spectrum(0.f);
// Perform connection and write contribution to _L_
Vertex sampled;
if (s == 0) {
// Interpret the camera subpath as a complete path
const Vertex &pt = cameraVertices[t - 1];
if (pt.IsLight()) L = pt.Le(scene, cameraVertices[t - 2]) * pt.beta;
} else if (t == 1) {
// Sample a point on the camera and connect it to the light subpath
const Vertex &qs = lightVertices[s - 1];
if (qs.IsConnectible()) {
VisibilityTester vis;
Vector3f wi;
Float pdf;
Spectrum Wi = camera.Sample_Wi(qs.GetInteraction(), sampler.Get2D(),
&wi, &pdf, pRaster, &vis);
if (pdf > 0 && !Wi.IsBlack()) {
// Initialize dynamically sampled vertex and _L_ for $t=1$ case
sampled = Vertex::CreateCamera(&camera, vis.P1(), Wi / pdf);
L = qs.beta * qs.f(sampled) * vis.Tr(scene, sampler) *
sampled.beta;
if (qs.IsOnSurface()) L *= AbsDot(wi, qs.ns());
}
}
} else if (s == 1) {
// Sample a point on a light and connect it to the camera subpath
const Vertex &pt = cameraVertices[t - 1];
if (pt.IsConnectible()) {
Float lightPdf;
VisibilityTester vis;
Vector3f wi;
Float pdf;
int lightNum =
lightDistr.SampleDiscrete(sampler.Get1D(), &lightPdf);
const std::shared_ptr<Light> &light = scene.lights[lightNum];
Spectrum lightWeight = light->Sample_Li(
pt.GetInteraction(), sampler.Get2D(), &wi, &pdf, &vis);
if (pdf > 0 && !lightWeight.IsBlack()) {
EndpointInteraction ei(vis.P1(), light.get());
sampled =
Vertex::CreateLight(ei, lightWeight / (pdf * lightPdf), 0);
sampled.pdfFwd = sampled.PdfLightOrigin(scene, pt, lightDistr);
L = pt.beta * pt.f(sampled) * vis.Tr(scene, sampler) *
sampled.beta;
if (pt.IsOnSurface()) L *= AbsDot(wi, pt.ns());
}
}
} else {
// Handle all other bidirectional connection cases
const Vertex &qs = lightVertices[s - 1], &pt = cameraVertices[t - 1];
if (qs.IsConnectible() && pt.IsConnectible()) {
L = qs.beta * qs.f(pt) * pt.f(qs) * pt.beta;
if (!L.IsBlack()) L *= G(scene, sampler, qs, pt);
}
}
// Compute MIS weight for connection strategy
Float misWeight =
L.IsBlack() ? 0.f : MISWeight(scene, lightVertices, cameraVertices,
sampled, s, t, lightDistr);
L *= misWeight;
if (misWeightPtr) *misWeightPtr = misWeight;
return L;
}
Spectrum ConnectBDPT(const Scene &scene, Vertex *lightSubpath,
Vertex *cameraSubpath, int s, int t,
const Distribution1D &lightDistr, const Camera &camera,
Sampler &sampler, Point2f *rasterPos, Float *misWeight) {
Spectrum weight(0.f);
// Ignore invalid connections related to infinite area lights
if (t > 1 && s != 0 && cameraSubpath[t - 1].type == VertexType::Light)
return Spectrum(0.f);
// Perform connection and write contribution to _weight_
Vertex sampled;
if (s == 0) {
// Interpret the camera subpath as a complete path
const Vertex &pt = cameraSubpath[t - 1];
if (pt.IsLight()) {
const Vertex &ptMinus = cameraSubpath[t - 2];
weight = pt.Le(scene, ptMinus) * pt.weight;
}
} else if (t == 1) {
// Sample a point on the camera and connect it to the light subpath
const Vertex &qs = lightSubpath[s - 1];
if (qs.IsConnectible()) {
VisibilityTester vis;
Vector3f wi;
Float pdf;
Spectrum cameraWeight =
camera.Sample_We(qs.GetInteraction(), sampler.Get2D(), &wi,
&pdf, rasterPos, &vis);
if (pdf > 0 && !cameraWeight.IsBlack()) {
// Initialize dynamically sampled vertex and _weight_
sampled = Vertex(VertexType::Camera,
EndpointInteraction(vis.P1(), &camera),
cameraWeight);
weight = qs.weight * qs.f(sampled) * vis.T(scene, sampler) *
sampled.weight;
if (qs.IsOnSurface())
weight *= AbsDot(wi, qs.GetShadingNormal());
}
}
} else if (s == 1) {
// Sample a point on a light and connect it to the camera subpath
const Vertex &pt = cameraSubpath[t - 1];
if (pt.IsConnectible()) {
Float lightPdf;
VisibilityTester vis;
Vector3f wi;
Float pdf;
int lightNum =
lightDistr.SampleDiscrete(sampler.Get1D(), &lightPdf);
const std::shared_ptr<Light> &light = scene.lights[lightNum];
Spectrum lightWeight = light->Sample_L(
pt.GetInteraction(), sampler.Get2D(), &wi, &pdf, &vis);
if (pdf > 0 && !lightWeight.IsBlack()) {
sampled = Vertex(VertexType::Light,
EndpointInteraction(vis.P1(), light.get()),
lightWeight / (pdf * lightPdf));
sampled.pdfFwd = sampled.PdfLightOrigin(scene, pt, lightDistr);
weight = pt.weight * pt.f(sampled) * vis.T(scene, sampler) *
sampled.weight;
if (pt.IsOnSurface())
weight *= AbsDot(wi, pt.GetShadingNormal());
}
}
} else {
// Handle all other cases
const Vertex &qs = lightSubpath[s - 1], &pt = cameraSubpath[t - 1];
if (qs.IsConnectible() && pt.IsConnectible()) {
weight = qs.weight * qs.f(pt) *
GeometryTerm(scene, sampler, qs, pt) * pt.f(qs) *
pt.weight;
}
}
// Compute MIS weight for connection strategy
*misWeight =
weight.IsBlack() ? 0.f : MISWeight(scene, lightSubpath, cameraSubpath,
sampled, s, t, lightDistr);
return weight;
}
// WhittedIntegrator [ surface integrator ] Method Definitions
Spectrum WhittedIntegrator::Li(const Scene *scene,
const Renderer *renderer, const RayDifferential &ray,
const Intersection &isect, const Sample *sample, RNG &rng,
MemoryArena &arena) const {
Spectrum L(0.);
// Compute emitted and reflected light at ray intersection point
// Evaluate BSDF at hit point
BSDF *bsdf = isect.GetBSDF(ray, arena); // return BSDF of the material of the hit primitive
// Initialize common variables for Whitted integrator
const pbrt::Point &p = bsdf->dgShading.p;
const Normal &n = bsdf->dgShading.nn;
Vector wo = -ray.d;
// Compute emitted light at the intersection point. The emiited light exists if
// the intersection occured at an area light source; otherwise, it is zero.
L += isect.Le(wo);
// Add contribution of each light source
for (uint32_t i = 0; i < scene->lights.size(); ++i) {
Vector wi;
float pdf;
VisibilityTester visibility;
Spectrum Li = scene->lights[i]->Sample_L(p, isect.rayEpsilon,
LightSample(rng), ray.time, &wi, &pdf, &visibility);
// if light is a delta light, then "reflection" direction wi is set to the light direction with pdf =1
if (Li.IsBlack() || pdf == 0.f) continue;
Spectrum f = bsdf->f(wo, wi);
//
// compute the fraction of light to be reflected from wi to wo.
// ONLY non-delta BXDF, e.g. Lambertian (diffuse reflection) contributes to f here.
if (!f.IsBlack() && visibility.Unoccluded(scene))
// bsdf indicates that some of the incident
// light from direction wi is in fact scattered to the direction wo
L += f * Li * AbsDot(wi, n) *
visibility.Transmittance(scene, renderer,
sample, rng, arena) / pdf;
}
// consider the specular reflection and the specular transmission;
// you can get this component only when the light sources are NOT delta distribution.
// there's no possible way that the peaks of the two delta distributions (the glass
// and the point light) match. it is not possible
// to get a highlight of a point light source in a mirror.
if (ray.depth + 1 < maxDepth) {
// 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;
}
Color3f Li(const Scene *scene, Sampler *sampler, const Ray3f &ray) const {
/* Find the surface that is visible in the requested direction */
Intersection its;
//check if the ray intersects the scene
if (!scene->rayIntersect(ray, its)) {
//check if a distant disk light is set
const Emitter* distantsDisk = scene->getDistantEmitter();
if(distantsDisk == nullptr ) return Color3f(0.0f);
//sample the distant disk light
Vector3f d = ray.d;
return distantsDisk->sampleL(d);
}
//get the Number of lights from the scene
const std::vector<Emitter *> lights = scene->getEmitters();
uint32_t nLights = lights.size();
Color3f tp(1.0f, 1.0f, 1.0f);
Color3f L(0.0f, 0.0f, 0.0f);
Ray3f pathRay(ray.o, ray.d);
bool deltaFlag = true;
while(true) {
if (its.mesh->isEmitter() && deltaFlag) {
const Emitter* areaLightEM = its.mesh->getEmitter();
const areaLight* aEM = static_cast<const areaLight *> (areaLightEM);
L += tp * aEM->sampleL(-pathRay.d, its.shFrame.n, its);
}
//Light sampling
//randomly select a lightsource
uint32_t var = uint32_t(std::min(sampler->next1D()*nLights, float(nLights) - 1.0f));
//init the light color
Color3f Li(0.0f, 0.0f, 0.0f);
Color3f Ld(1.0f, 1.0f, 1.0f);
//create a sample for the light
const BSDF* curBSDF = its.mesh->getBSDF();
const Point2f lightSample = sampler->next2D();
VisibilityTester vis;
Vector3f wo;
float lightpdf;
float bsdfpdf;
Normal3f n = its.shFrame.n;
deltaFlag = curBSDF->isDeltaBSDF();
//sample the light
{
Li = lights[var]->sampleL(its.p, Epsilon, lightSample , &wo, &lightpdf, &vis);
lightpdf /= float(nLights);
//check if the pdf of the sample is greater than 0 and if the color is not black
if(lightpdf > 0 && Li.maxCoeff() != 0.0f) {
//calculate the cosine term wi in my case the vector to the light
float cosTerm = std::abs(n.dot(wo));
const BSDFQueryRecord queryEM = BSDFQueryRecord(its.toLocal(- pathRay.d), its.toLocal(wo), EMeasure::ESolidAngle, sampler);
Color3f f = curBSDF->eval(queryEM);
if(f.maxCoeff() > 0.0f && f.minCoeff() >= 0.0f && vis.Unoccluded(scene)) {
bsdfpdf = curBSDF->pdf(queryEM);
float weight = BalanceHeuristic(float(1), lightpdf, float(1), bsdfpdf);
if(curBSDF->isDeltaBSDF()) weight = 1.0f;
if(bsdfpdf > 0.0f) {
Ld = (weight * f * Li * cosTerm) / lightpdf;
L += tp * Ld;
} else {
//cout << "bsdfpdf = " << bsdfpdf << endl;
//cout << "f = " << f << endl;
}
}
}
}
//Material part
BSDFQueryRecord queryMats = BSDFQueryRecord(its.toLocal(-pathRay.d), Vector3f(0.0f), EMeasure::ESolidAngle, sampler);
Color3f fi = curBSDF->sample(queryMats, sampler->next2D());
bsdfpdf = curBSDF->pdf(queryMats);
lightpdf = 0.0f;
if(fi.maxCoeff() > 0.0f && fi.minCoeff() >= 0.0f) {
if(bsdfpdf > 0.0f) {
Ray3f shadowRay(its.p, its.toWorld(queryMats.wo));
Intersection lightIsect;
if (scene->rayIntersect(shadowRay, lightIsect)) {
if(lightIsect.mesh->isEmitter()){
const Emitter* areaLightEMcur = lightIsect.mesh->getEmitter();
const areaLight* aEMcur = static_cast<const areaLight *> (areaLightEMcur);
Li = aEMcur->sampleL(-shadowRay.d, lightIsect.shFrame.n, lightIsect);
lightpdf = aEMcur->pdf(its.p, (lightIsect.p - its.p).normalized(), lightIsect.p, Normal3f(lightIsect.shFrame.n));
}
} else {
const Emitter* distantsDisk = scene->getDistantEmitter();
if(distantsDisk != nullptr ) {
//check if THIS is right!
Li = distantsDisk->sampleL(lightIsect.toWorld(queryMats.wo));
lightpdf = distantsDisk->pdf(Point3f(0.0f), wo, Point3f(0.0f), Normal3f(0.0f));
}
}
lightpdf /= float(nLights);
//calculate the weights
float weight = BalanceHeuristic(float(1), bsdfpdf, float(1), lightpdf);
//check if the lightcolor is not black
if(Li.maxCoeff() > 0.0f && lightpdf > 0.0f ) {
//wo in my case the vector to the light
Ld = weight * Li * fi;
L += tp * Ld;
}
}
tp *= fi;
} else {
break;
}
wo = its.toWorld(queryMats.wo);
pathRay = Ray3f(its.p, wo);
if (!scene->rayIntersect(pathRay, its)) {
const Emitter* distantsDisk = scene->getDistantEmitter();
if(distantsDisk != nullptr ) {
//sample the distant disk light
Vector3f d = pathRay.d;
L += tp * distantsDisk->sampleL(d);
}
break;
}
float maxCoeff = tp.maxCoeff();
float q = std::min(0.99f, maxCoeff);
if(q < sampler->next1D()){
break;
}
tp /= q;
}
return L;
}
Spectrum Path::estimateDirectLighting( const RayIntersection i_intersection, RenderablePtr i_light, const Sampler &i_sampler, const SceneData &i_scene )
{
// Direct contribution
Spectrum Ld = Spectrum::black();
float lightPdf = 0.0f;
float surfacePdf = 0.0f;
vec3f wiWorld;
const vec3f &woWorld = -i_intersection.dir;
const vec3f &woLocal = i_intersection.worldToSurface( woWorld );
const vec3f &normal = i_intersection.getSurfacePoint().normal;
const shading::BSDF &bsdf = i_intersection.getBSDF();
/* ==================== */
/* Sample Light */
/* ==================== */
{
VisibilityTester visibilityTester;
const vec3f &uLight = i_sampler.sample3D();
Spectrum Li = i_light->sampleIncidenceRadiance( i_intersection, uLight, &wiWorld, &lightPdf, &visibilityTester );
// Convert to local (surface) coords
const vec3f &wiLocal = i_intersection.worldToSurface( wiWorld );
// Sample light
if ( !Li.isBlack() && lightPdf > 0.0f ) {
const Spectrum &f = bsdf.computeF( woLocal, wiLocal ) * absDot( wiWorld, normal );
surfacePdf = bsdf.pdf( woLocal, wiLocal );
if ( !f.isBlack() ) {
// Ray is in shadow
if ( visibilityTester.isOccluded( i_scene ) ) {
Li = Spectrum::black();
}
if ( !Li.isBlack() ) {
// Weight with MIS
float misWeight = powerHeuristic( lightPdf, surfacePdf );
Ld += ( Li * f * misWeight ) / lightPdf;
}
}
}
}
/* ==================== */
/* Sample BSDF */
/* ==================== */
{
const vec2f &uSurface = i_sampler.sample2D();
vec3f wiLocal;
const Spectrum &f = bsdf.sampleF( woLocal, &wiLocal, uSurface, &surfacePdf ) * absDot( wiWorld, normal );
if ( !f.isBlack() && surfacePdf > 0.0f ) {
// TODO computer light PDF
lightPdf = 0.0;
// No contribution, return
if ( lightPdf == 0.0 ) {
return Ld;
}
// Convert to local (surface) coords
vec3f wiWorld = i_intersection.surfaceToWorld( wiLocal );
const Ray bsdfRay = Ray( i_intersection.getSurfacePoint().pos, wiWorld );
RayIntersection lightIntersection;
bool foundIntersection = i_scene.intersect( bsdfRay, lightIntersection );
Spectrum Li = Spectrum::black();
if ( foundIntersection ) {
if ( lightIntersection.m_shapeId == i_light->getIdentifier() ) {
Li = i_light->computeRadiance( lightIntersection.getSurfacePoint(), wiWorld );
}
}
if ( !Li.isBlack() ) {
// Weight with MIS
float misWeight = powerHeuristic( lightPdf, surfacePdf );
Ld += ( Li * f * misWeight ) / surfacePdf;
}
}
}
return Ld;
}
Color3f Li(const Scene *scene, Sampler *sampler, const Ray3f &ray) const {
/* Find the surface that is visible in the requested direction */
Intersection its;
if (!scene->rayIntersect(ray, its))
return Color3f(0.0f);
//get the Normal at the intersection point
Vector3f n = Vector3f(its.shFrame.n);
//get the Number of lights from the scene
const std::vector<Emitter *> lights = scene->getEmitters();
uint32_t nLights = lights.size();
//check for lights
if(nLights > 0) {
//get the asigned BSDF
const BSDF* curBSDF = its.mesh->getBSDF();
if(curBSDF) {
Color3f totalLight(0.0f);
//uterated over all lights
//std::cout << "start light comp" << std::endl;
for (uint32_t var = 0; var < nLights; ++var) {
VisibilityTester vis;
Vector3f wi;
float pdf;
const Point2f ls;
//sample the light
Color3f Ld =lights[var]->sampleL(its.p, Epsilon, ls, &wi, &pdf, &vis);
//check if the light is visible
if(vis.Unoccluded(scene)) {
//create a query for the brdf
Vector3f wo = - ray.d;
//calculate the abs value of n dot wi
float costerm = n.dot(wi);
//transform to the local frame
wo = its.toLocal(wo);
wi = its.toLocal(wi);
const BSDFQueryRecord query = BSDFQueryRecord(wi, wo, EMeasure::ESolidAngle);
//calculate the BSDF
Color3f f = curBSDF->eval(query);
//add the light up
totalLight += (Ld * f * std::abs(costerm));
}
}
return totalLight;
}
}
return Color3f(0.0f);
}
