Code review / Q&A request - colored wireframes

[LightAndLight]

Bevy's current wireframe plugin hard-codes the wireframe color. I wanted per-entity wireframe colors, so I created my own plugin based on the one in bevy_pbr.

I've got it working, but suspect there's a nicer way to do it. There are also a few Bevy renderer things that I copied from the original plugin that I don't understand.

If you're feeling generous with your time, I'd love to hear your feedback. I also have some specific questions, in case you don't want to peruse my code.

My plugin:

• colored_wireframe.rs
• wireframe.wgsl

Specific questions:

• colored_wireframe.rs#L61-L75 - Is there a better place to create and store the bind group layout?

• colored_wireframe.rs#L80-L103, colored_wireframe.rs#L219, colored_wireframe.rs#L233, colored_wireframe.rs#L241-L257, colored_wireframe.rs#L296 - What is pipeline specialization and why do I need to use it?

  • Since I didn't set up imports (wireframe.wgsl#L1-L2, wireframe.wgsl#L10, wireframe.wgsl#L17), preprocessor variables (wireframe.wgsl#L7), vertex input locations (wireframe.wgsl#L19-L25), or the first two bind groups (wireframe.wgsl#L4-L5, wireframe.wgsl#L8-L9), I assume this are defined in the mesh pipeline and "inherited" by my custom pipeline when I specialize. I think I can figure out how it all works by reading the code. I'd appreciate a prose explanation to prime me first, though.
  • Related resources:
    • Pipeline specialization - https://bevyengine.org/news/bevy-0-6/#pipeline-specialization
    • Mesh pipeline specialization - https://bevyengine.org/news/bevy-0-7/#flexible-mesh-vertex-layouts

• colored_wireframe.rs#L94-L99 - This feels janky. Is there a better way to add a bind group layout to the layout I inherited from the mesh pipeline?

• colored_wireframe.rs#L154-L172 - Is it expensive to re-create a bind group each frame? The DynamicUniformBuffer I'm using might allocate new graphics buffers without me knowing, and binding every frame was the easiest way to make things work.

[LegNeato]

I'm not a member of the project, but it is likely better to just put it up as a draft PR.