Bevy: Now that we have Changed<T>, optimize all the things

[cart]

We should be using Changed<T> everywhere we can to avoid doing redundant work:

• Transforms
• Parents/Children
• Labels
• Render Nodes
  
  
  
  • lights
  
  
  • camera
  
  
  • render_resources (potentially a _huge_ win here)
  
  
• Cameras
• ShaderDefs
• Sprites
• UI update system (only update "dirty" parts of the tree)
• Pipeline Compiler (only run when RenderPipelines component has changed)

[tristanpemble]

I was looking into doing this for the transforms systems. For transform_translation_rotation_scale_system, the current query is:

Query<Without<LocalTransform, Without<NonUniformScale, (&mut Transform, &Translation, &Rotation, &Scale)>>>

ideally we could do something like

Query<Without<LocalTransform, Without<NonUniformScale, (&mut Transform, &Translation, &Rotation, &Scale, Any<Changed<Translation>, Changed<Rotation>, Changed<Scale>>)>>>

the idea being we want to run this system on anything that has Transform, Rotation and Scale, and at least one of those was changed.

I asked in Discord and it seems like this is not currently possible (tldr queries are and only, no or right now)

[tristanpemble]

@cart it may be worth changing your list into checkboxes so we can track status

[Axighi]

What's left for this task?