Custom material always requires vertex position, normal and UV

[afonsolage]

Bevy version

0.7

What you did

Created a custom material without using Vertex_UV attribute

What went wrong

The custom material requires vertex POSITION, NORMAL and UV attributes to be set on Mesh even if the custom material layout doesn't specifies so. This seems to be a requirement of the mesh pipeline.

Additional information

This was first reported and discussed here

superdump

This passes the mesh layout into the mesh pipeline specialization function: https://github.com/bevyengine/bevy/blob/9eb69282efe57b9e3922e66ade887e6239bff175/crates/bevy_pbr/src/material.rs#L263 Which requires these attributes: https://github.com/bevyengine/bevy/blob/9eb69282efe57b9e3922e66ade887e6239bff175/crates/bevy_pbr/src/render/mesh.rs#L576 So even if you want to override the vertex attributes and layout, that code already required them and if your mesh doesn’t have them, it will fail

cart

Gotcha that makes sense. Fixing that will probably require some design work. Ex: do we build an api to let people override vertex layouts (specifically), or add a lifecycle hook that allows people to specialize the mesh pipeline. Do we add another generic to MeshPipeline that lets users plug their custom logic in or take a more retroactive approach?

[kulkalkul]

I also encountered this, alternative to this is writing a pipeline, which is a lot boilerplate. Here it is for reference: https://discord.com/channels/691052431525675048/970964103516532746/970998522679816222

[nicopap]

Seems to be fixed in 0.10. Am I mistaken? in mesh.wgsl I see all vertex attributes are conditionally added.

struct Vertex {
#ifdef VERTEX_POSITIONS
    @location(0) position: vec3<f32>,
#endif
#ifdef VERTEX_NORMALS
    @location(1) normal: vec3<f32>,
#endif
#ifdef VERTEX_UVS
    @location(2) uv: vec2<f32>,
#endif
#ifdef VERTEX_TANGENTS
    @location(3) tangent: vec4<f32>,
#endif
#ifdef VERTEX_COLORS
    @location(4) color: vec4<f32>,
#endif
#ifdef SKINNED
    @location(5) joint_indices: vec4<u32>,
    @location(6) joint_weights: vec4<f32>,
#endif
};