bevy/examples/shader/extended_material.rs
Gilles Henaux ca25a67d0d
Fix the extended_material example on WebGL2 (#18812)
# Objective

- Fixes #13872 (also mentioned in #17167)

## Solution

- Added conditional padding fields to the shader uniform

## Alternatives

### 1- Use a UVec4

Replace the `u32` field in `MyExtension` by a `UVec4` and only use the
`x` coordinate.

(This was the original approach, but for consistency with the rest of
the codebase, separate padding fields seem to be preferred)

### 2- Don't fix it, unlist it

While the fix is quite simple, it does muddy the waters a tiny bit due
to `quantize_steps` now being a UVec4 instead of a simple u32. We could
simply remove this example from the examples that support WebGL2.

## Testing

- Ran the example locally on WebGL2 (and native Vulkan) successfully
2025-07-07 19:34:12 +00:00

107 lines
3.3 KiB
Rust

//! Demonstrates using a custom extension to the `StandardMaterial` to modify the results of the builtin pbr shader.
use bevy::{
color::palettes::basic::RED,
pbr::{ExtendedMaterial, MaterialExtension, OpaqueRendererMethod},
prelude::*,
render::render_resource::*,
};
/// This example uses a shader source file from the assets subdirectory
const SHADER_ASSET_PATH: &str = "shaders/extended_material.wgsl";
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_plugins(MaterialPlugin::<
ExtendedMaterial<StandardMaterial, MyExtension>,
>::default())
.add_systems(Startup, setup)
.add_systems(Update, rotate_things)
.run();
}
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<ExtendedMaterial<StandardMaterial, MyExtension>>>,
) {
// sphere
commands.spawn((
Mesh3d(meshes.add(Sphere::new(1.0))),
MeshMaterial3d(materials.add(ExtendedMaterial {
base: StandardMaterial {
base_color: RED.into(),
// can be used in forward or deferred mode
opaque_render_method: OpaqueRendererMethod::Auto,
// in deferred mode, only the PbrInput can be modified (uvs, color and other material properties),
// in forward mode, the output can also be modified after lighting is applied.
// see the fragment shader `extended_material.wgsl` for more info.
// Note: to run in deferred mode, you must also add a `DeferredPrepass` component to the camera and either
// change the above to `OpaqueRendererMethod::Deferred` or add the `DefaultOpaqueRendererMethod` resource.
..Default::default()
},
extension: MyExtension::new(1),
})),
Transform::from_xyz(0.0, 0.5, 0.0),
));
// light
commands.spawn((
DirectionalLight::default(),
Transform::from_xyz(1.0, 1.0, 1.0).looking_at(Vec3::ZERO, Vec3::Y),
Rotate,
));
// camera
commands.spawn((
Camera3d::default(),
Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
));
}
#[derive(Component)]
struct Rotate;
fn rotate_things(mut q: Query<&mut Transform, With<Rotate>>, time: Res<Time>) {
for mut t in &mut q {
t.rotate_y(time.delta_secs());
}
}
#[derive(Asset, AsBindGroup, Reflect, Debug, Clone, Default)]
struct MyExtension {
// We need to ensure that the bindings of the base material and the extension do not conflict,
// so we start from binding slot 100, leaving slots 0-99 for the base material.
#[uniform(100)]
quantize_steps: u32,
// Web examples WebGL2 support: structs must be 16 byte aligned.
#[cfg(feature = "webgl2")]
#[uniform(100)]
_webgl2_padding_8b: u32,
#[cfg(feature = "webgl2")]
#[uniform(100)]
_webgl2_padding_12b: u32,
#[cfg(feature = "webgl2")]
#[uniform(100)]
_webgl2_padding_16b: u32,
}
impl MyExtension {
fn new(quantize_steps: u32) -> Self {
Self {
quantize_steps,
..default()
}
}
}
impl MaterialExtension for MyExtension {
fn fragment_shader() -> ShaderRef {
SHADER_ASSET_PATH.into()
}
fn deferred_fragment_shader() -> ShaderRef {
SHADER_ASSET_PATH.into()
}
}