bevy_shader

Shader assets. Defines the Shader type and asset loaders for WGSL, SPIR-V, GLSL (when enabled), and Bevy's own .wgsl import syntax.

Purpose

Shaders are first-class assets in Bevy. The renderer doesn't bake shader bytes into the binary — it loads Shader assets through AssetServer, processes Bevy-flavored imports (#import bevy_pbr::pbr_functions), and feeds the result to wgpu. Hot reloading works on shader assets too.

Directory layout

crates/bevy_shader/src/
├── lib.rs       # ShaderPlugin, Shader asset
├── loader.rs    # Asset loader for .wgsl / .spv / .vert / .frag
└── compose.rs   # Imports / shader def processing (via naga_oil)

Key abstractions

Type	File	Description
Shader	crates/bevy_shader/src/lib.rs	Asset; the un-processed source code.
ShaderImport	crates/bevy_shader/src/lib.rs	Names that other shaders can #import.
ShaderDefVal	crates/bevy_shader/src/lib.rs	Compile-time constant or boolean used for shader specialization.
ShaderPlugin	crates/bevy_shader/src/lib.rs	Registers the asset and loader.

How it works

Shaders are stored as Shader assets. When a pipeline asks for a fragment-shader handle plus a list of shader defs, the renderer (via naga_oil) composes the imports, applies defs, and produces a complete naga::Module that goes to wgpu. The composer caches by (handle, defs) so identical specializations don't recompile.

Integration points

• Depends on: bevy_app, bevy_asset, bevy_reflect, naga_oil.
• Depended on by: bevy_render, bevy_pbr, every renderer crate.

Entry points for modification

• New shader format: add an AssetLoader in loader.rs. Already supported: .wgsl, .spv, .glsl (gated).
• Custom import resolver: compose.rs.

See also

• bevy_render — pipeline cache.
• bevy_pbr — the canonical consumer.
• naga_oil documentation for the import syntax.