// Sampling Function Definitions
void StratifiedSample1D(const RandomGenerator &rng, float *samp,
u_int nSamples, bool jitter)
{
float invTot = 1.f / nSamples;
for (u_int i = 0; i < nSamples; ++i) {
float delta = jitter ? rng.floatValue() : 0.5f;
*samp++ = (i + delta) * invTot;
}
}
void RejectionSampleDisk(const RandomGenerator &rng, float *x, float *y)
{
float sx, sy;
do {
sx = 1.f - 2.f * rng.floatValue();
sy = 1.f - 2.f * rng.floatValue();
} while (sx * sx + sy * sy > 1.f);
*x = sx;
*y = sy;
}
void StratifiedSample2D(const RandomGenerator &rng, float *samp,
u_int nx, u_int ny, bool jitter)
{
float dx = 1.f / nx, dy = 1.f / ny;
for (u_int y = 0; y < ny; ++y)
for (u_int x = 0; x < nx; ++x) {
float jx = jitter ? rng.floatValue() : 0.5f;
float jy = jitter ? rng.floatValue() : 0.5f;
*samp++ = (x + jx) * dx;
*samp++ = (y + jy) * dy;
}
}
void LatinHypercube(const RandomGenerator &rng, float *samples,
u_int nSamples, u_int nDim)
{
// Generate LHS samples along diagonal
float delta = 1.f / nSamples;
for (u_int i = 0; i < nSamples; ++i)
for (u_int j = 0; j < nDim; ++j)
samples[nDim * i + j] = (i + rng.floatValue()) * delta;
// Permute LHS samples in each dimension
for (u_int i = 0; i < nDim; ++i) {
for (u_int j = 0; j < nSamples; ++j) {
u_int other = rng.uintValue() % nSamples;
swap(samples[nDim * j + i],
samples[nDim * other + i]);
}
}
}
void BiDirVMCPURenderThread::RenderFuncVM() {
//SLG_LOG("[BiDirVMCPURenderThread::" << threadIndex << "] Rendering thread started");
//--------------------------------------------------------------------------
// Initialization
//--------------------------------------------------------------------------
BiDirVMCPURenderEngine *engine = (BiDirVMCPURenderEngine *)renderEngine;
RandomGenerator *rndGen = new RandomGenerator(engine->seedBase + threadIndex);
Scene *scene = engine->renderConfig->scene;
Camera *camera = scene->camera;
Film *film = threadFilm;
const u_int filmWidth = film->GetWidth();
const u_int filmHeight = film->GetHeight();
pixelCount = filmWidth * filmHeight;
// Setup the samplers
vector<Sampler *> samplers(engine->lightPathsCount, NULL);
const u_int sampleSize =
sampleBootSizeVM + // To generate the initial light vertex and trace eye ray
engine->maxLightPathDepth * sampleLightStepSize + // For each light vertex
engine->maxEyePathDepth * sampleEyeStepSize; // For each eye vertex
// metropolisSharedTotalLuminance and metropolisSharedSampleCount are
// initialized inside MetropolisSampler::RequestSamples()
double metropolisSharedTotalLuminance, metropolisSharedSampleCount;
for (u_int i = 0; i < samplers.size(); ++i) {
Sampler *sampler = engine->renderConfig->AllocSampler(rndGen, film,
&metropolisSharedTotalLuminance, &metropolisSharedSampleCount);
sampler->RequestSamples(sampleSize);
samplers[i] = sampler;
}
u_int iteration = 0;
vector<vector<SampleResult> > samplesResults(samplers.size());
vector<vector<PathVertexVM> > lightPathsVertices(samplers.size());
vector<Point> lensPoints(samplers.size());
HashGrid hashGrid;
const u_int haltDebug = engine->renderConfig->GetProperty("batch.haltdebug").Get<u_int>();
for(u_int steps = 0; !boost::this_thread::interruption_requested(); ++steps) {
// Clear the arrays
for (u_int samplerIndex = 0; samplerIndex < samplers.size(); ++samplerIndex) {
samplesResults[samplerIndex].clear();
lightPathsVertices[samplerIndex].clear();
}
// Setup vertex merging
float radius = engine->baseRadius;
radius /= powf(float(iteration + 1), .5f * (1.f - engine->radiusAlpha));
radius = Max(radius, DEFAULT_EPSILON_STATIC);
const float radius2 = radius * radius;
const float vmFactor = M_PI * radius2 * engine->lightPathsCount;
vmNormalization = 1.f / vmFactor;
const float etaVCM = vmFactor;
misVmWeightFactor = MIS(etaVCM);
misVcWeightFactor = MIS(1.f / etaVCM);
// Using the same time for all rays in the same pass is required by the
// current implementation (i.e. I can not mix paths with different
// times). However this is detrimental for the Metropolis sampler.
const float time = rndGen->floatValue();
//----------------------------------------------------------------------
// Trace all light paths
//----------------------------------------------------------------------
for (u_int samplerIndex = 0; samplerIndex < samplers.size(); ++samplerIndex) {
Sampler *sampler = samplers[samplerIndex];
// Sample a point on the camera lens
if (!camera->SampleLens(time, sampler->GetSample(3), sampler->GetSample(4),
&lensPoints[samplerIndex]))
continue;
TraceLightPath(time, sampler, lensPoints[samplerIndex],
lightPathsVertices[samplerIndex], samplesResults[samplerIndex]);
}
//----------------------------------------------------------------------
// Store all light path vertices in the k-NN accelerator
//----------------------------------------------------------------------
hashGrid.Build(lightPathsVertices, radius);
//cout << "==========================================\n";
//cout << "Iteration: " << iteration << " Paths: " << engine->lightPathsCount << " Light path vertices: "<< hashGrid.GetVertexCount() <<"\n";
//----------------------------------------------------------------------
// Trace all eye paths
//----------------------------------------------------------------------
for (u_int samplerIndex = 0; samplerIndex < samplers.size(); ++samplerIndex) {
Sampler *sampler = samplers[samplerIndex];
PathVertexVM eyeVertex;
SampleResult eyeSampleResult(Film::RADIANCE_PER_PIXEL_NORMALIZED | Film::ALPHA, 1);
eyeSampleResult.alpha = 1.f;
Ray eyeRay;
eyeSampleResult.filmX = min(sampler->GetSample(0) * filmWidth, (float)(filmWidth - 1));
eyeSampleResult.filmY = min(sampler->GetSample(1) * filmHeight, (float)(filmHeight - 1));
camera->GenerateRay(eyeSampleResult.filmX, eyeSampleResult.filmY, &eyeRay,
sampler->GetSample(9), sampler->GetSample(10), time);
eyeVertex.bsdf.hitPoint.fixedDir = -eyeRay.d;
eyeVertex.throughput = Spectrum(1.f);
const float cosAtCamera = Dot(scene->camera->GetDir(), eyeRay.d);
const float cameraPdfW = 1.f / (cosAtCamera * cosAtCamera * cosAtCamera *
scene->camera->GetPixelArea());
eyeVertex.dVCM = MIS(1.f / cameraPdfW);
eyeVertex.dVC = 1.f;
eyeVertex.dVM = 1.f;
eyeVertex.depth = 1;
while (eyeVertex.depth <= engine->maxEyePathDepth) {
const u_int sampleOffset = sampleBootSizeVM + engine->maxLightPathDepth * sampleLightStepSize +
(eyeVertex.depth - 1) * sampleEyeStepSize;
RayHit eyeRayHit;
Spectrum connectionThroughput, connectEmission;
const bool hit = scene->Intersect(device, false,
&eyeVertex.volInfo, sampler->GetSample(sampleOffset),
&eyeRay, &eyeRayHit, &eyeVertex.bsdf,
&connectionThroughput, NULL, NULL, &connectEmission);
// I account for volume emission only with path tracing (i.e. here and
// not in any other place)
eyeSampleResult.radiancePerPixelNormalized[0] += connectEmission;
if (!hit) {
// Nothing was hit, look for infinitelight
// This is a trick, you can not have a BSDF of something that has
// not been hit. DirectHitInfiniteLight must be aware of this.
eyeVertex.bsdf.hitPoint.fixedDir = -eyeRay.d;
eyeVertex.throughput *= connectionThroughput;
DirectHitLight(false, eyeVertex, &eyeSampleResult.radiancePerPixelNormalized[0]);
if (eyeVertex.depth == 1)
eyeSampleResult.alpha = 0.f;
break;
}
eyeVertex.throughput *= connectionThroughput;
// Something was hit
// Update MIS constants
const float factor = 1.f / MIS(AbsDot(eyeVertex.bsdf.hitPoint.shadeN, eyeVertex.bsdf.hitPoint.fixedDir));
eyeVertex.dVCM *= MIS(eyeRayHit.t * eyeRayHit.t) * factor;
eyeVertex.dVC *= factor;
eyeVertex.dVM *= factor;
// Check if it is a light source
if (eyeVertex.bsdf.IsLightSource())
DirectHitLight(true, eyeVertex, &eyeSampleResult.radiancePerPixelNormalized[0]);
// Note: pass-through check is done inside Scene::Intersect()
//--------------------------------------------------------------
// Direct light sampling
//--------------------------------------------------------------
DirectLightSampling(time,
sampler->GetSample(sampleOffset + 1),
sampler->GetSample(sampleOffset + 2),
sampler->GetSample(sampleOffset + 3),
sampler->GetSample(sampleOffset + 4),
sampler->GetSample(sampleOffset + 5),
eyeVertex, &eyeSampleResult.radiancePerPixelNormalized[0]);
if (!eyeVertex.bsdf.IsDelta()) {
//----------------------------------------------------------
// Connect vertex path ray with all light path vertices
//----------------------------------------------------------
const vector<PathVertexVM> &lightPathVertices = lightPathsVertices[samplerIndex];
for (vector<PathVertexVM>::const_iterator lightPathVertex = lightPathVertices.begin();
lightPathVertex < lightPathVertices.end(); ++lightPathVertex)
ConnectVertices(time,
eyeVertex, *lightPathVertex, &eyeSampleResult,
sampler->GetSample(sampleOffset + 6));
//----------------------------------------------------------
// Vertex Merging step
//----------------------------------------------------------
hashGrid.Process(this, eyeVertex, &eyeSampleResult.radiancePerPixelNormalized[0]);
}
//--------------------------------------------------------------
// Build the next vertex path ray
//--------------------------------------------------------------
if (!Bounce(time, sampler, sampleOffset + 7, &eyeVertex, &eyeRay))
break;
}
samplesResults[samplerIndex].push_back(eyeSampleResult);
}
//----------------------------------------------------------------------
// Splat all samples
//----------------------------------------------------------------------
for (u_int samplerIndex = 0; samplerIndex < samplers.size(); ++samplerIndex)
samplers[samplerIndex]->NextSample(samplesResults[samplerIndex]);
++iteration;
#ifdef WIN32
// Work around Windows bad scheduling
renderThread->yield();
#endif
//hashGrid.PrintStatistics();
if ((haltDebug > 0u) && (steps >= haltDebug))
break;
}
for (u_int samplerIndex = 0; samplerIndex < samplers.size(); ++samplerIndex)
delete samplers[samplerIndex];
delete rndGen;
//SLG_LOG("[BiDirVMCPURenderThread::" << renderThread->threadIndex << "] Rendering thread halted");
}
