Record render diagnostics for all engine passes

[JMS55]

https://dev-docs.bevyengine.org/bevy_render/diagnostic/struct.RenderDiagnosticsPlugin.html

Ideally we nest the diagnostics so that each view has it's own diagnostic subpath, although we'll have to figure out how shadow passes fit into that, as well as non-view-specific nodes like MeshPreprocessing.

Also would be nice to further group by category, e.g. prepass/gbuffer, mainpass, post processing, etc.

Total path would look like /render/view_<NameOrEntityId>/main3d/opaque/gpu_time, using the Name component of the view if it's available, else the entity ID.

• Bloom
• MainOpaquePass2d
• MainTransparentPass2d
• MainOpaquePass3d
• MainTransparentPass3d
• Prepass
• ShadowPass
• AutoExposure
• RCAS
• MainTransmissivePass3d
• DeferredGBufferPrepass (+CopyDeferredLightingId?)
• DeferredOpaquePass3dPbrLighting
• DepthOfField
• FXAA
• MotionBlur
• OITResolve
• PostProcessing stack
• SMAA
• TAA
• MSAAWriteback
• Upscale
• Meshlet
  • MeshletVisibilityBufferRasterPass (+subpass timings)
  • MeshletMainOpaquePass3d, MeshletPrepass, MeshletDeferredGBufferPrepass
• SSAO
• SSR
• VolumetricFog
• GpuPreprocess
• UI
• Tonemapping
• CameraDriver(?)

[jf908]

I'm interested in implementing this.

Any ideas on how to implement the nesting? I'm not immediately seeing any easy way to propagate the timestamps up to form groups. Would it be fine to just do the passes individually for now deal with the nesting in a follow up?

[JMS55]

It's been a bit since I've looked, but I think that nesting works automatically for Bevy render diagnostics, i.e. what goes into bevy_diagnostics and later gets printed out to the terminal with log diagnostics plugin or whatever.

For the tracy GPU integration, I think I was able to get nesting working, but it just looked a little weird.

Honestly can't really remember, you'll just have to play around with it and see what works or not.

Totally fine to leave nesting as a followup (or for someone else to do in the future) though!

[JMS55]

Some other comments:

• Be aware that the list I wrote above is not complete. E.g. since that time we've added atmosphere rendering.
• Code for converting render diagnostics -> bevy diagnostics is here if you need to see the internal details
  

  bevy/crates/bevy_render/src/diagnostic/internal.rs

  Line 490 in 732b2e0

  fn run_mapped_callback(&mut self, timestamp_period_ns: f32) -> bool {