0.14 Migration: Consolidate binned render phases changes

[rparrett]

The migration text for bevyengine/bevy#13277 is talking about types that didn't exist in Bevy 0.13. I think it needs to be consolidated with bevyengine/bevy#12453.

[alice-i-cecile]

Seconded by @djeedai here.

[djeedai]

There's another issue, which might be an actual code bug, or just a lack of documentation : I can't make BinnedRenderPhase<AlphaMask3d> to work with non-mesh items (particle effects for Hanabi). It seems that batching::sort_binned_render_phase() does run, but after that none of the GPU pre-processing / no-pre-processing prepare systems run, so the render phase items added are never rendered. I believe this is because they both have a render condition, based on a particular resource being present, but that part is not documented and I've yet to understand if/how I should add those resources.

CC: @pcwalton as I think you wrote all of that and know Hanabi very well, you probably know already the answer? :)

[rparrett]

It's possible you might find inspiration from bevy_ecs_tilemap's migration -- maybe a similar situation there where we're doing some very custom stuff with non-Meshs. (but uses a sorted phase)

I struggled with these particular changes myself and gave up, hence the ticket. CC also @ChristopherBiscardi who might be able to help with the migration guide.

[ChristopherBiscardi]

I can try to help, I won't be able to look into it until Tuesday though.

[djeedai]

Nope, that migration doesn't help, there's nothing about binned render phase.

[ChristopherBiscardi]

its looking like bevyengine/bevy#14029 will be included in this consolidation as well.

[BD103]

To summarize, the following migration guides need to be merged and improved:

• Make render phases render world resources instead of components. bevy#13277
• Improve performance by binning together opaque items instead of sorting them. bevy#12453
• Allow phase items not associated with meshes to be binned. bevy#14029

Feel free to ping me when you need a review, though I'll do more style than content checking. :)