Clément Foucault
b43b62191c
This new implementation does all downsampling in a single compute shader dispatch, removing a lot of complexity from the previous recursive downsampling. This is heavilly inspired by the Single-Pass-Downsampler from GPUOpen: https://github.com/GPUOpen-Effects/FidelityFX-SPD However I do not implement all the optimization bits as they require vulkan (GL_KHR_shader_subgroup) and is not as versatile (it is only for HiZ). Timers inside renderdoc report ~0.4ms of saving on a 2048*1024 render for the whole downsampling. Note that the previous implementation only processed 6 mips where the new one processes 8 mips. ``` EEVEE ~1.0ms EEVEE-Next ~0.6ms ``` Padding has been bumped to be of 128px for processing 8 mips. A new debug option has been added (debug value 2) to validate the HiZ.