Hierarchical Depth Buffers

Overview A hierarchical depth buffer is a multi-level depth (Z) buffer used as an acceleration structure for depth queries. As with normal texture mip chains, the dimensions of each level are generally successive power-of-2 fractions of the full-resolution buffer’s dimensions. In this article I present two techniques for generating a hierarchical depth buffer from a full-resolution one. First I show how to generate the full mip chain for a depth buffer in a way that preserves depth query accuracy in texture coordinate (or NDC) space even for non-power-of-2 depth buffer dimensions.