CODEWITHSUNDEEP
openglgraphics3dglslshadow
Basti
Basti

Reputation: 392

How to get completely rid of shadow acne and erroneous self shadowing?

I'm doing Simple Shadow Mapping and have problems with handling shadow acne and erroneous self shadowing and just can't get rid of it. I already tried adding a bias to the depth value and rendering back faces to the depth buffer, but it doesn't remove all artifacts. I also have problems choosing the right bias which leads to Peter Panning.

Here I have some screenshots.

So my questions are:

  1. Is there a robust (and easy) way to completely eliminate shadow acne and erroneous self shadowing?

  2. How to choose the perfect bias?

Upvotes: 3

Views: 4477

Answers (1)

comingstorm
comingstorm

Reputation: 26117

There's a technique called variance shadow maps which is subject to its own peculiar artifacts, but which is very good at eliminating shadow acne and erroneous self-shadowing. It was designed as a nonlinear filter for shadow maps, to avoid jaggies due to low resolution.

Briefly, it estimates the variance of the depth map, and uses that to find a smooth, conservative estimate of shadowing vs. depth. You need to be careful about buffer precision, as most implementations seem to evaluate the variance in ways that abuse their dynamic range.

Upvotes: 1

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