Today I set out to replace the old SSR implementation in the toy engine with AMD’s FidelityFX’s one but in the end I got distracted and spent the day studying how it works instead. This is a modern SSR solution that implements a lot of good practices so I’ve gathered my notes in a blog post in case someone finds it of interest. This is not intended as an exhaustive description of the technique, more like a few interesting observations.
The technique takes as an input the main rendertarget, the worldspace normal buffer, a roughness buffer, a hierarchical depth buffer and an environment cubemap. The hierarchical depth buffer is a mip chain where each mip level pixel is the minimum of the previous level’s 2×2 area depths (mip 0 corresponds to the screen-sized, original depth buffer). It will used later to speed up raymarching but can also used in many other techniques, like GPU occlusion culling.Continue reading “Notes on screenspace reflections with FidelityFX SSSR”