Bevy Toon Shader 调研

Date: 2026-05-13 Topic: Bevy Engine Cartoon/Toon Shader Implementation Bevy Version: 0.18 Status: Existing crates lag behind; custom Material implementation required

Existing Crates

bevy_toon_material

Author: AndrewDanial
Repo: https://github.com/AndrewDanial/bevy_toon_material
crates.io: https://crates.io/crates/bevy_toon_material
Bevy Support: 0.15 only (v0.1)
Features: Toon shading, specular highlight, rim effects, banding
Limitations: No shadow receiving, single light source, no existing texture support
Implementation: Custom Material with AsBindGroup, internal WGSL asset
License: MIT/Apache-2.0

bevy_toon_shader

Author: tbillington
Repo: https://github.com/tbillington/bevy_toon_shader
crates.io: https://crates.io/crates/bevy_toon_shader
Bevy Support: up to 0.12
Status: Outdated, unmaintained
Note: Referenced as prior art by bevy_toon_material

bevy_shader_mtoon

Repo: https://github.com/kayh/bevy_shader_mtoon (via bevy_vrm)
crates.io: https://crates.io/crates/bevy_shader_mtoon
Bevy Support: up to ~0.14
Features: MToon shader (VRM standard) implementation
Downloads: 15,930+ all time

bevy_wind_waker_shader

Docs: https://docs.rs/bevy_wind_waker_shader
Style: Two-color toon (highlight/shadow) with slight gradient edge

Bevy 0.18 Built-in Shader APIs

Custom Material (Material Trait)

Example: https://bevy.org/examples/shaders/shader-material/
Source: https://github.com/bevyengine/bevy/blob/main/examples/shader/shader_material.rs
Key Traits: Material, AsBindGroup, TypePath
WGSL Imports: bevy_pbr::forward_io::VertexOutput, #{MATERIAL_BIND_GROUP} macro
Bindings: @group(#{MATERIAL_BIND_GROUP}) @binding(N)

Extended Material (MaterialExtension)

Example: https://bevy.org/examples/shaders/extended-material/
Source: https://github.com/bevyengine/bevy/blob/main/examples/shader/extended_material.rs
Key Traits: MaterialExtension + ExtendedMaterial<Base, Extension>
Binding Offset: Extension bindings must start at slot 100
Use Case: Extend StandardMaterial without rewriting PBR pipeline
Deferred Support: Requires deferred_fragment_shader() override

Reference: bevy_toon_material WGSL Shader

Source: https://github.com/AndrewDanial/bevy_toon_material/blob/main/src/toon.wgsl (raw)

Key techniques observed:

VertexOutput with world_normal, world_position, uv
Banding: round(n_dot_l * band_count) / band_count
Smooth fallback: smoothstep(0.0, 0.01, n_dot_l)
Specular: Blinn-Phong with pow(n_dot_h * light_intensity, glossiness^2)
Rim: smoothstep(rim_amount - 0.01, rim_amount + 0.01, rim_dot * pow(n_dot_l, rim_threshold))
UV fallback pattern for meshes without UVs

Reference URLs

Resource	URL
bevy_toon_material GitHub	https://github.com/AndrewDanial/bevy_toon_material
bevy_toon_material WGSL raw	https://raw.githubusercontent.com/AndrewDanial/bevy_toon_material/main/src/toon.wgsl
bevy_toon_material lib.rs raw	https://raw.githubusercontent.com/AndrewDanial/bevy_toon_material/main/src/lib.rs
bevy_toon_shader GitHub	https://github.com/tbillington/bevy_toon_shader
bevy_shader_mtoon crates.io	https://crates.io/crates/bevy_shader_mtoon
Bevy Material Example	https://bevy.org/examples/shaders/shader-material/
Bevy Extended Material Example	https://bevy.org/examples/shaders/extended-material/
Bevy 0.18 Release Notes	https://bevy.org/news/bevy-0-18/
Roy Stan Toon Shader Tutorial (Unity)	https://roystan.net/articles/toon-shader/