[Merged by Bors] - Refactor Globals and View structs into separate shaders

[torsteingrindvik]

fixes #6799

Objective

We should be able to reuse the Globals or View shader struct definitions from anywhere (including third party plugins) without needing to worry about defining unrelated shader defs.
Also we'd like to refactor these structs to not be repeatedly defined.

Solution

Refactor both Globals and View into separate importable shaders.
Use the imports throughout.

[torsteingrindvik]

As a note: This change does not introduce any change in the engine itself since mesh_view_types includes the new importable shader.
But from a third-party plugin's perspective they may now directly import the new shader.

[IceSentry]

I don't think this is the right direction. If you are using the default Globals struct you need to use it through the mesh view bindings. If you just want the struct definition, but bind the data yourself then you are probably doing something different and should probably just define your own struct.

I'm not sure I understand when this would be useful.

[IceSentry]

Oh, also, if the goal is to import only the global struct I think #5703 is a much better solution for granular imports

[torsteingrindvik]

@IceSentry the use case is a third party plugin that has its own shader(s). Like you say I bind it myself.

I think it's reasonable to expect other users to want to reuse the data found in Globals too, and allowing the definition import makes it quite frictionless since I don't need to keep my own local definition up to date and I can just bind it via the render world resource which is already there.

I haven't look at #5703 yet.

[superdump]

I think I agree with @torsteingrindvik - custom code should be able to reuse bindings and data from core. You don't have to use mesh_view_bindings to want to use the Globals uniform buffer. Same for View. Indeed, I would like a PR that separates out View into a shader import that is shared across bevy_pbr, bevy_sprite and anywhere else it is used. I think this would be a good place for the Globals too.

EDIT: That's not to say that #5703 isn't a better solution. I too need to look into the details of how that works.

[torsteingrindvik]

I tried doing the refactor to include View, don't have time to test it right now but I'll polish this tomorrow.

[torsteingrindvik]

After the changes I tried some examples which all work, it also works for my plugin.

Waiting on review.

[torsteingrindvik]

Adding 0.10 since I'd like to know if this should be in or closed before 0.10 so I know what to do with the linked issue in my plugin.

[superdump]

Minor changes but looks good. Have you tested everything continues to work correctly? So each of the renderers using View (pbr, sprite, mesh2d, ui) and something using the Globals (I think maybe there's a shader material example using the time for animation.)

[torsteingrindvik]

@superdump
Applied your suggestions, and tried:

• many_sprites
• ui
• animate_shader
• pbr

all of which work well.

[superdump]

I just tested the mesh2d example as well and it works fine.

@robtfm has approved the PR on Discord noting that they want this to be merged regardless of their shader import / view bind group slot efforts. Noting this as it removes the possible controversiality raised by @IceSentry .

[superdump]

bors r+

[bors]

Pull request successfully merged into main.

Build succeeded:

• build-and-install-on-iOS
• build-android
• build (macos-latest)
• build (ubuntu-latest)
• build-wasm
• build (windows-latest)
• build-without-default-features (bevy)
• build-without-default-features (bevy_ecs)
• build-without-default-features (bevy_reflect)
• check-compiles
• check-doc
• check-missing-examples-in-docs
• ci
• markdownlint
• msrv
• run-examples
• run-examples-on-wasm
• run-examples-on-windows-dx12