Unlit materials cause shader panic

[aevyrie]

Bevy version

Commit e3435e5

Confirmed the breaking change happened in 73f4a9d

Operating system & version

Windows 10

What you did

Existing plugins that use unlit materials now panic as soon as meshes with that material are shown. Results in the following panic:

thread 'main' panicked at 'Shader compilation error:
glslang_shader_parse:
Info log:
ERROR: 0:293: 'getDistanceAttenuation' : no matching overloaded function found
ERROR: 0:293: '' : compilation terminated
ERROR: 2 compilation errors.  No code generated.

Lines in question appear to be in the pbr frag shader here:

bevy/crates/bevy_pbr/src/render_graph/pbr_pipeline/pbr.frag

Lines 291 to 292 in 73f4a9d

	float rangeAttenuation =
	getDistanceAttenuation(distance_square, light.lightParams.r);

[aevyrie]

I think I found the issue. Looks like a function that was previously only run if the material is not unlit, is now being run for unlit materials, and refers to the getDistanceAttenuation which is not defined for unlit materials.

Will PR solution.