void PathCPURenderThread::DirectLightSampling(
const float u0, const float u1, const float u2,
const float u3, const float u4,
const Spectrum &pathThrouput, const BSDF &bsdf,
const int depth, Spectrum *radiance) {
PathCPURenderEngine *engine = (PathCPURenderEngine *)renderEngine;
Scene *scene = engine->renderConfig->scene;
if (!bsdf.IsDelta()) {
// Pick a light source to sample
float lightPickPdf;
const LightSource *light = scene->SampleAllLights(u0, &lightPickPdf);
Vector lightRayDir;
float distance, directPdfW;
Spectrum lightRadiance = light->Illuminate(scene, bsdf.hitPoint,
u1, u2, u3, &lightRayDir, &distance, &directPdfW);
if (!lightRadiance.Black()) {
BSDFEvent event;
float bsdfPdfW;
Spectrum bsdfEval = bsdf.Evaluate(lightRayDir, &event, &bsdfPdfW);
if (!bsdfEval.Black()) {
const float epsilon = Max(MachineEpsilon::E(bsdf.hitPoint), MachineEpsilon::E(distance));
Ray shadowRay(bsdf.hitPoint, lightRayDir,
epsilon,
distance - epsilon);
RayHit shadowRayHit;
BSDF shadowBsdf;
Spectrum connectionThroughput;
// Check if the light source is visible
if (!scene->Intersect(device, false, u4, &shadowRay,
&shadowRayHit, &shadowBsdf, &connectionThroughput)) {
const float cosThetaToLight = AbsDot(lightRayDir, bsdf.shadeN);
const float directLightSamplingPdfW = directPdfW * lightPickPdf;
const float factor = cosThetaToLight / directLightSamplingPdfW;
if (depth >= engine->rrDepth) {
// Russian Roulette
bsdfPdfW *= Max(bsdfEval.Filter(), engine->rrImportanceCap);
}
// MIS between direct light sampling and BSDF sampling
const float weight = PowerHeuristic(directLightSamplingPdfW, bsdfPdfW);
*radiance += (weight * factor) * pathThrouput * connectionThroughput * lightRadiance * bsdfEval;
}
}
}
}
}
void SchlickScatter::Pdf(const HitPoint &hitPoint,
const Vector &localLightDir, const Vector &localEyeDir,
float *directPdfW, float *reversePdfW) const {
const Spectrum gValue = g->GetSpectrumValue(hitPoint).Clamp(-1.f, 1.f);
const Spectrum k = gValue * (Spectrum(1.55f) - .55f * gValue * gValue);
const float gFilter = k.Filter();
const float dotEyeLight = Dot(localEyeDir, localLightDir);
// 1+k*cos instead of 1-k*cos because localEyeDir is reversed compared to the
// standard phase function definition
const float compcostFilter = 1.f + gFilter * dotEyeLight;
const float pdf = (1.f - gFilter * gFilter) / (compcostFilter * compcostFilter * (4.f * M_PI));
if (directPdfW)
*directPdfW = pdf;
if (reversePdfW)
*reversePdfW = pdf;
}
Spectrum SchlickScatter::Sample(const HitPoint &hitPoint,
const Vector &localFixedDir, Vector *localSampledDir,
const float u0, const float u1, const float passThroughEvent,
float *pdfW, float *absCosSampledDir, BSDFEvent *event,
const BSDFEvent requestedEvent) const {
if (!(requestedEvent & (DIFFUSE | REFLECT)))
return Spectrum();
const Spectrum gValue = g->GetSpectrumValue(hitPoint).Clamp(-1.f, 1.f);
const Spectrum k = gValue * (Spectrum(1.55f) - .55f * gValue * gValue);
const float gFilter = k.Filter();
// Add a - because localEyeDir is reversed compared to the standard phase
// function definition
const float cost = -(2.f * u0 + gFilter - 1.f) / (2.f * gFilter * u0 - gFilter + 1.f);
Vector x, y;
CoordinateSystem(localFixedDir, &x, &y);
*localSampledDir = SphericalDirection(sqrtf(Max(0.f, 1.f - cost * cost)), cost,
2.f * M_PI * u1, x, y, localFixedDir);
// The - becomes a + because cost has been reversed above
const float compcost = 1.f + gFilter * cost;
*pdfW = (1.f - gFilter * gFilter) / (compcost * compcost * (4.f * M_PI));
if (*pdfW <= 0.f)
return Spectrum();
*absCosSampledDir = fabsf(localSampledDir->z);
*event = DIFFUSE | REFLECT;
Spectrum r = volume->SigmaS(hitPoint);
const Spectrum sigmaA = volume->SigmaA(hitPoint);
for (u_int i = 0; i < COLOR_SAMPLES; ++i) {
if (r.c[i] > 0.f)
r.c[i] /= r.c[i] + sigmaA.c[i];
else
r.c[i] = 1.f;
}
return r;
}
Spectrum SchlickScatter::Evaluate(const HitPoint &hitPoint,
const Vector &localLightDir, const Vector &localEyeDir, BSDFEvent *event,
float *directPdfW, float *reversePdfW) const {
Spectrum r = volume->SigmaS(hitPoint);
const Spectrum sigmaA = volume->SigmaA(hitPoint);
for (u_int i = 0; i < COLOR_SAMPLES; ++i) {
if (r.c[i] > 0.f)
r.c[i] /= r.c[i] + sigmaA.c[i];
else
r.c[i] = 1.f;
}
const Spectrum gValue = g->GetSpectrumValue(hitPoint).Clamp(-1.f, 1.f);
const Spectrum k = gValue * (Spectrum(1.55f) - .55f * gValue * gValue);
*event = DIFFUSE | REFLECT;
const float dotEyeLight = Dot(localEyeDir, localLightDir);
const float kFilter = k.Filter();
// 1+k*cos instead of 1-k*cos because localEyeDir is reversed compared to the
// standard phase function definition
const float compcostFilter = 1.f + kFilter * dotEyeLight;
const float pdf = (1.f - kFilter * kFilter) / (compcostFilter * compcostFilter * (4.f * M_PI));
if (directPdfW)
*directPdfW = pdf;
if (reversePdfW)
*reversePdfW = pdf;
// 1+k*cos instead of 1-k*cos because localEyeDir is reversed compared to the
// standard phase function definition
const Spectrum compcostValue = Spectrum(1.f) + k * dotEyeLight;
return r * (Spectrum(1.f) - k * k) / (compcostValue * compcostValue * (4.f * M_PI));
}
void LightCPURenderThread::RenderFunc() {
//SLG_LOG("[LightCPURenderThread::" << threadIndex << "] Rendering thread started");
//--------------------------------------------------------------------------
// Initialization
//--------------------------------------------------------------------------
LightCPURenderEngine *engine = (LightCPURenderEngine *)renderEngine;
RandomGenerator *rndGen = new RandomGenerator(engine->seedBase + threadIndex);
Scene *scene = engine->renderConfig->scene;
PerspectiveCamera *camera = scene->camera;
Film *film = threadFilm;
// Setup the sampler
double metropolisSharedTotalLuminance, metropolisSharedSampleCount;
Sampler *sampler = engine->renderConfig->AllocSampler(rndGen, film,
&metropolisSharedTotalLuminance, &metropolisSharedSampleCount);
const u_int sampleBootSize = 11;
const u_int sampleEyeStepSize = 4;
const u_int sampleLightStepSize = 5;
const u_int sampleSize =
sampleBootSize + // To generate the initial setup
engine->maxPathDepth * sampleEyeStepSize + // For each eye vertex
engine->maxPathDepth * sampleLightStepSize; // For each light vertex
sampler->RequestSamples(sampleSize);
//--------------------------------------------------------------------------
// Trace light paths
//--------------------------------------------------------------------------
vector<SampleResult> sampleResults;
while (!boost::this_thread::interruption_requested()) {
sampleResults.clear();
// Select one light source
float lightPickPdf;
const LightSource *light = scene->SampleAllLights(sampler->GetSample(2), &lightPickPdf);
// Initialize the light path
float lightEmitPdfW;
Ray nextEventRay;
Spectrum lightPathFlux = light->Emit(scene,
sampler->GetSample(3), sampler->GetSample(4), sampler->GetSample(5), sampler->GetSample(6),
&nextEventRay.o, &nextEventRay.d, &lightEmitPdfW);
if (lightPathFlux.Black()) {
sampler->NextSample(sampleResults);
continue;
}
lightPathFlux /= lightEmitPdfW * lightPickPdf;
assert (!lightPathFlux.IsNaN() && !lightPathFlux.IsInf());
// Sample a point on the camera lens
Point lensPoint;
if (!camera->SampleLens(sampler->GetSample(7), sampler->GetSample(8),
&lensPoint)) {
sampler->NextSample(sampleResults);
continue;
}
//----------------------------------------------------------------------
// I don't try to connect the light vertex directly with the eye
// because InfiniteLight::Emit() returns a point on the scene bounding
// sphere. Instead, I trace a ray from the camera like in BiDir.
// This is also a good why to test the Film Per-Pixel-Normalization and
// the Per-Screen-Normalization Buffers used by BiDir.
//----------------------------------------------------------------------
TraceEyePath(sampler, &sampleResults);
//----------------------------------------------------------------------
// Trace the light path
//----------------------------------------------------------------------
int depth = 1;
while (depth <= engine->maxPathDepth) {
const u_int sampleOffset = sampleBootSize + sampleEyeStepSize * engine->maxPathDepth +
(depth - 1) * sampleLightStepSize;
RayHit nextEventRayHit;
BSDF bsdf;
Spectrum connectionThroughput;
if (scene->Intersect(device, true, sampler->GetSample(sampleOffset),
&nextEventRay, &nextEventRayHit, &bsdf, &connectionThroughput)) {
// Something was hit
lightPathFlux *= connectionThroughput;
//--------------------------------------------------------------
// Try to connect the light path vertex with the eye
//--------------------------------------------------------------
ConnectToEye(sampler->GetSample(sampleOffset + 1),
bsdf, lensPoint, lightPathFlux, sampleResults);
if (depth >= engine->maxPathDepth)
break;
//--------------------------------------------------------------
// Build the next vertex path ray
//--------------------------------------------------------------
float bsdfPdf;
Vector sampledDir;
BSDFEvent event;
float cosSampleDir;
const Spectrum bsdfSample = bsdf.Sample(&sampledDir,
sampler->GetSample(sampleOffset + 2),
sampler->GetSample(sampleOffset + 3),
&bsdfPdf, &cosSampleDir, &event);
if (bsdfSample.Black())
break;
if (depth >= engine->rrDepth) {
// Russian Roulette
const float prob = Max(bsdfSample.Filter(), engine->rrImportanceCap);
if (sampler->GetSample(sampleOffset + 4) < prob)
bsdfPdf *= prob;
else
break;
}
lightPathFlux *= bsdfSample * (cosSampleDir / bsdfPdf);
assert (!lightPathFlux.IsNaN() && !lightPathFlux.IsInf());
nextEventRay = Ray(bsdf.hitPoint, sampledDir);
++depth;
} else {
// Ray lost in space...
break;
}
}
sampler->NextSample(sampleResults);
#ifdef WIN32
// Work around Windows bad scheduling
renderThread->yield();
#endif
}
delete sampler;
delete rndGen;
//SLG_LOG("[LightCPURenderThread::" << threadIndex << "] Rendering thread halted");
}
void PathCPURenderThread::RenderFunc() {
//SLG_LOG("[PathCPURenderEngine::" << threadIndex << "] Rendering thread started");
//--------------------------------------------------------------------------
// Initialization
//--------------------------------------------------------------------------
PathCPURenderEngine *engine = (PathCPURenderEngine *)renderEngine;
RandomGenerator *rndGen = new RandomGenerator(engine->seedBase + threadIndex);
Scene *scene = engine->renderConfig->scene;
PerspectiveCamera *camera = scene->camera;
Film * film = threadFilm;
const unsigned int filmWidth = film->GetWidth();
const unsigned int filmHeight = film->GetHeight();
// Setup the sampler
double metropolisSharedTotalLuminance, metropolisSharedSampleCount;
Sampler *sampler = engine->renderConfig->AllocSampler(rndGen, film,
&metropolisSharedTotalLuminance, &metropolisSharedSampleCount);
const unsigned int sampleBootSize = 4;
const unsigned int sampleStepSize = 9;
const unsigned int sampleSize =
sampleBootSize + // To generate eye ray
engine->maxPathDepth * sampleStepSize; // For each path vertex
sampler->RequestSamples(sampleSize);
//--------------------------------------------------------------------------
// Trace paths
//--------------------------------------------------------------------------
vector<SampleResult> sampleResults(1);
sampleResults[0].type = PER_PIXEL_NORMALIZED;
while (!boost::this_thread::interruption_requested()) {
float alpha = 1.f;
Ray eyeRay;
const float screenX = min(sampler->GetSample(0) * filmWidth, (float)(filmWidth - 1));
const float screenY = min(sampler->GetSample(1) * filmHeight, (float)(filmHeight - 1));
camera->GenerateRay(screenX, screenY, &eyeRay,
sampler->GetSample(2), sampler->GetSample(3));
int depth = 1;
bool lastSpecular = true;
float lastPdfW = 1.f;
Spectrum radiance;
Spectrum pathThrouput(1.f, 1.f, 1.f);
BSDF bsdf;
while (depth <= engine->maxPathDepth) {
const unsigned int sampleOffset = sampleBootSize + (depth - 1) * sampleStepSize;
RayHit eyeRayHit;
Spectrum connectionThroughput;
if (!scene->Intersect(device, false, sampler->GetSample(sampleOffset),
&eyeRay, &eyeRayHit, &bsdf, &connectionThroughput)) {
// Nothing was hit, look for infinitelight
DirectHitInfiniteLight(lastSpecular, pathThrouput * connectionThroughput, eyeRay.d,
lastPdfW, &radiance);
if (depth == 1)
alpha = 0.f;
break;
}
pathThrouput *= connectionThroughput;
// Something was hit
// Check if it is a light source
if (bsdf.IsLightSource()) {
DirectHitFiniteLight(lastSpecular, pathThrouput,
eyeRayHit.t, bsdf, lastPdfW, &radiance);
}
// Note: pass-through check is done inside SceneIntersect()
//------------------------------------------------------------------
// Direct light sampling
//------------------------------------------------------------------
DirectLightSampling(sampler->GetSample(sampleOffset + 1),
sampler->GetSample(sampleOffset + 2),
sampler->GetSample(sampleOffset + 3),
sampler->GetSample(sampleOffset + 4),
sampler->GetSample(sampleOffset + 5),
pathThrouput, bsdf, depth, &radiance);
//------------------------------------------------------------------
// Build the next vertex path ray
//------------------------------------------------------------------
Vector sampledDir;
BSDFEvent event;
float cosSampledDir;
const Spectrum bsdfSample = bsdf.Sample(&sampledDir,
sampler->GetSample(sampleOffset + 6),
sampler->GetSample(sampleOffset + 7),
&lastPdfW, &cosSampledDir, &event);
if (bsdfSample.Black())
break;
lastSpecular = ((event & SPECULAR) != 0);
if ((depth >= engine->rrDepth) && !lastSpecular) {
// Russian Roulette
const float prob = Max(bsdfSample.Filter(), engine->rrImportanceCap);
if (sampler->GetSample(sampleOffset + 8) < prob)
lastPdfW *= prob;
else
break;
}
pathThrouput *= bsdfSample * (cosSampledDir / lastPdfW);
assert (!pathThrouput.IsNaN() && !pathThrouput.IsInf());
eyeRay = Ray(bsdf.hitPoint, sampledDir);
++depth;
}
assert (!radiance.IsNaN() && !radiance.IsInf());
sampleResults[0].screenX = screenX;
sampleResults[0].screenY = screenY;
sampleResults[0].radiance = radiance;
sampleResults[0].alpha = alpha;
sampler->NextSample(sampleResults);
#ifdef WIN32
// Work around Windows bad scheduling
renderThread->yield();
#endif
}
delete sampler;
delete rndGen;
//SLG_LOG("[PathCPURenderEngine::" << threadIndex << "] Rendering thread halted");
}