Point3f RealisticCamera::SampleExitPupil(const Point2f &pFilm,
const Point2f &lensSample,
Float *sampleBoundsArea) const {
// Find exit pupil bound for sample distance from film center
Float rFilm = std::sqrt(pFilm.x * pFilm.x + pFilm.y * pFilm.y);
int rIndex = rFilm / (film->diagonal / 2) * exitPupilBounds.size();
rIndex = std::min((int)exitPupilBounds.size() - 1, rIndex);
Bounds2f pupilBounds = exitPupilBounds[rIndex];
if (sampleBoundsArea) *sampleBoundsArea = pupilBounds.Area();
// Generate sample point inside exit pupil bound
Point2f pLens = pupilBounds.Lerp(lensSample);
// Return sample point rotated by angle of _pFilm_ with $+x$ axis
Float sinTheta = (rFilm != 0) ? pFilm.y / rFilm : 0;
Float cosTheta = (rFilm != 0) ? pFilm.x / rFilm : 1;
return Point3f(cosTheta * pLens.x - sinTheta * pLens.y,
sinTheta * pLens.x + cosTheta * pLens.y, LensRearZ());
}
// 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;
}
