- Changed to use the standard full-screen triangle drawing function instead of
one in the post processing utilities.
- Apply _Downsample at some points in the shader. Not it works.
- Small tweaks.
- Use R8 or RHalf for the AO buffer.
- Use globally bound texture ID (_MainDepthTexture).
- Reuse a command buffer between frames to avoid GC memory allocation.
- Use Hammersley2D (in ShaderLibrary) for hemispherical sampling.
- Use ComputeViewSapcePosition to reconstruct view position from depth.
- Remove unused variables.