Explicit background for passes that clear the frame (e.g. RenderPass and
the OIT opaque clear). When set, the pass clears to this colour/alpha instead of
the renderer's current clear state, giving a single source of truth so the
background is identical regardless of which base pass renders the scene. When
null the pass falls back to the renderer's current clear colour/alpha.
Standalone FXAA post pass. Wraps a FxaaResolver and composites it in place into the shared pipeline buffer, so it works after any base pass (RenderPass or OITRenderPass) — unlike the OIT-internal SMAA / temporal modes it does not require order-independent transparency.
Insert it between the base pass and the OutputPass:
[base, new FXAAPass(), new OutputPass()].