# Objective
Closes#15799.
Many rendering people and maintainers are in favor of reverting default
mesh materials added in #15524, especially as the migration to required
component is already large and heavily breaking.
## Solution
Revert default mesh materials, and adjust docs accordingly.
- Remove `extract_default_materials`
- Remove `clear_material_instances`, and move the logic back into
`extract_mesh_materials`
- Remove `HasMaterial2d` and `HasMaterial3d`
- Change default material handles back to pink instead of white
- 2D uses `Color::srgb(1.0, 0.0, 1.0)`, while 3D uses `Color::srgb(1.0,
0.0, 0.5)`. Not sure if this is intended.
There is now no indication at all about missing materials for `Mesh2d`
and `Mesh3d`. Having a mesh without a material renders nothing.
## Testing
I ran `2d_shapes`, `mesh2d_manual`, and `3d_shapes`, with and without
mesh material components.
c1a4b82762