void Grid::SetForcedFirstScatterPos(Photon& p, const RNG& rng) const { cfloat tEdgeMax = GetMaxOpticalDepth(p); cfloat photonWgt = 1.0f - expf(-tEdgeMax); cfloat tRunMax = -logf(1.0f - (rng.FUniformRandom() * photonWgt)); Integrate(p, tRunMax, IM_FORCED); }