Importing bevy_pbr::mesh_view_types imples defining MAX_DIRECTIONAL_LIGHTS

[torsteingrindvik]

Bevy version

Main @ e954b8573

What you did

I did this in a shader:

#import bevy_pbr::mesh_view_types

Because I wanted the definition of the Globals struct to re-use in my own shader.

What went wrong

error: expected constant, found '#'
   ┌─ wgsl:59:49
   │
59 │     directional_lights: array<DirectionalLight, #{MAX_DIRECTIONAL_LIGHTS}u>,
   │                                                 ^ expected constant

Additional information

theories about what might be going wrong

Importing bevy_pbr::mesh_view_types implies that this value is defined.

workarounds that you used

1. I could redefine the Globals struct, but I would like to not repeat that.
2. I currently add

shader_defs: vec![ShaderDefVal::Int("MAX_DIRECTIONAL_LIGHTS".to_string(), 1)],

to my code and that works. But this feels like something I should not have to do.

[JMS55]

This happens because of the Lights struct in mesh_view_types.wgsl. Almost all importers of this file are not actually using the Lights struct. For now, I think we should hard-code MAX_DIRECTIONAL_LIGHTS to always be added to all shader defines. Eventually, this will be fixed by #5703.