// MLT Method Definitions
Spectrum MLTIntegrator::L(const Scene &scene, MemoryArena &arena,
MLTSampler &sampler, int depth, Point2f *samplePos) {
sampler.SetStream(3, 0);
// Determine the number of available strategies and pick a specific one
int s, t, nStrategies;
if (depth == 0) {
nStrategies = 1;
s = 0;
t = 2;
} else {
nStrategies = depth + 2;
s = std::min((int)(sampler.Get1D() * nStrategies), nStrategies - 1);
t = nStrategies - s;
}
// Generate a camera subpath with exactly _t_ vertices
Vertex *cameraSubpath = (Vertex *)arena.Alloc<Vertex>(t);
Bounds2i sampleBounds = camera->film->GetSampleBounds();
Vector2i diag = sampleBounds.Diagonal();
*samplePos = Point2f(sampleBounds.pMin.x + diag.x * sampler.Get1D(),
sampleBounds.pMin.y + diag.y * sampler.Get1D());
if (GenerateCameraSubpath(scene, sampler, arena, t, *camera, *samplePos,
cameraSubpath) != t)
return Spectrum(0.f);
// Generate a light subpath with exactly _s_ vertices
sampler.SetStream(3, 1);
Vertex *lightSubpath = (Vertex *)arena.Alloc<Vertex>(s);
if (GenerateLightSubpath(scene, sampler, arena, s, cameraSubpath[0].time(),
*lightDistr, lightSubpath) != s)
return Spectrum(0.f);
// Execute connection strategy and return the radiance estimate
sampler.SetStream(3, 2);
Spectrum L = ConnectBDPT(scene, lightSubpath, cameraSubpath, s, t,
*lightDistr, *camera, sampler, samplePos);
arena.Reset();
return L * nStrategies;
}
// MLT Method Definitions
Spectrum MLTIntegrator::L(const Scene &scene, MemoryArena &arena,
const std::unique_ptr<Distribution1D> &lightDistr,
const std::unordered_map<const Light *, size_t> &lightToIndex,
MLTSampler &sampler, int depth, Point2f *pRaster) {
sampler.StartStream(cameraStreamIndex);
// Determine the number of available strategies and pick a specific one
int s, t, nStrategies;
if (depth == 0) {
nStrategies = 1;
s = 0;
t = 2;
} else {
nStrategies = depth + 2;
s = std::min((int)(sampler.Get1D() * nStrategies), nStrategies - 1);
t = nStrategies - s;
}
// Generate a camera subpath with exactly _t_ vertices
Vertex *cameraVertices = arena.Alloc<Vertex>(t);
Bounds2f sampleBounds = (Bounds2f)camera->film->GetSampleBounds();
*pRaster = sampleBounds.Lerp(sampler.Get2D());
if (GenerateCameraSubpath(scene, sampler, arena, t, *camera, *pRaster,
cameraVertices) != t)
return Spectrum(0.f);
// Generate a light subpath with exactly _s_ vertices
sampler.StartStream(lightStreamIndex);
Vertex *lightVertices = arena.Alloc<Vertex>(s);
if (GenerateLightSubpath(scene, sampler, arena, s, cameraVertices[0].time(),
*lightDistr, lightToIndex, lightVertices) != s)
return Spectrum(0.f);
// Execute connection strategy and return the radiance estimate
sampler.StartStream(connectionStreamIndex);
return ConnectBDPT(scene, lightVertices, cameraVertices, s, t, *lightDistr,
lightToIndex, *camera, sampler, pRaster) *
nStrategies;
}
