I want to ask what is a best way to do custom postprocessing in UE4.
What I want to do (I’m from unity world - that’s why I ask how to do it in UE4-way):

  1. Get scene texture (after all the solid objects are drawn, BEFORE tonemapping/transparent objects) and mask (co called ‘custom depth’ in UE4)
  2. Create new rendertarget (half the resolution of screen) and output white pixel to it if the masked object is visible (custom depth >= scene depth I assume) and black if not
  3. Downsample the original scene color x2 and place the values computed in #2 in alpha
  4. Using texture created in #3 as an input launch some fancy pixel shader kernel to do some calculations (realy need to launch it few times in ping-pong manner)
    5] Use this calculated texture to blend-in some effects into scene texture.

Is there an easy way to do this in UE4 (without modifying engine source) ? Or the only way is to play with FPostProcessing class ?