Bevy Render Rework: Postprocessing Effects

[james7132]

With the renderer rework slowly reaching production quality, it may be a good time to start looking at the standard gambit of postprocessing effects commonly seen across game engines. This initial post is to gather input/ideas/decisions. Here's an initial list of potential effects that might be useful, (* marks effects that will be required for a HDR workflow):

• Bloom*
• Color correction*
• Tonemapping (ACES?)*
• Depth of Field
• Chromatic Aberration
• White Balance
• Lens Distortion
• Lens Flare
• Film Grain
• Motion Blur
• Panini Projection
• Vignette
• Antialiasing (FXAA, SMAA, TXAA)

Important Points to Consider

• Ordering between each effect is important, Unity's Postprocessing notes that using DoF after Bloom adds notable artifacts
• Merging multiple similar effects into one shader as a ubereffect might be a good idea.
• Should we use a separate pass from this or just run it as the end of the main pass?

[mtsr]

I'd like to add a Composite step as required for Weighted Blended Order Independent Transparency (http://jcgt.org/published/0002/02/09/)

And I'm interested in the API. I did a pretty rough first implementation for the old renderer with FullscreenPassNode, but the new renderer is pretty different.