http://aicdg.com/ue4-msaa-depth/
http://aicdg.com/vulkan-mass-shader-resolve/
ao两篇paper
分bake和realtime两部分
s2016_pbs_activision_occlusion(有GTAO).pdf
【2016年GTAO(Ground True Ambient Occlusion)】Practical-Realtime-Strategies-for-Accurate-Indirect-Occlusion
half resolution prepass
depth+normal rgba8
compute shader for ao
rgba8888 for blur
before base pass