#graphics folks, I need some help.

[lisyarus@mastodon.gamedev.place]

#graphics folks, I need some help. Say I'm accumulating irradiance at some point simply by shooting rays randomly in a sphere. I'm also using these rays' intensity as weights in a reservoir which is updated after each sample.

How do I use the reservoir in the sampling itself? How do I compute the probability of the samples from the reservoir, given that they were initially generated using a uniform distribution?

[lisyarus@mastodon.gamedev.place]

Say I'm selecting either a new random ray or reusing the reservoir ray with 50/50 chance. What are the correct Monte-Carlo weights?

[1st_c_lord@mastodon.gamedev.place]

@lisyarus that's the beauty of reservoir sampling, uniform weighting would be 1/number of samples in the reservoir but in practice you'd want to a smarter algorithm for rejecting samples spatio-temporally. I really like this explanation of it here - https://samwho.dev/reservoir-sampling/