bevy/examples/shader/extended_material.rs
robtfm c99351f7c2
allow extensions to StandardMaterial (#7820)
# Objective

allow extending `Material`s (including the built in `StandardMaterial`)
with custom vertex/fragment shaders and additional data, to easily get
pbr lighting with custom modifications, or otherwise extend a base
material.

# Solution

- added `ExtendedMaterial<B: Material, E: MaterialExtension>` which
contains a base material and a user-defined extension.
- added example `extended_material` showing how to use it
- modified AsBindGroup to have "unprepared" functions that return raw
resources / layout entries so that the extended material can combine
them

note: doesn't currently work with array resources, as i can't figure out
how to make the OwnedBindingResource::get_binding() work, as wgpu
requires a `&'a[&'a TextureView]` and i have a `Vec<TextureView>`.

# Migration Guide

manual implementations of `AsBindGroup` will need to be adjusted, the
changes are pretty straightforward and can be seen in the diff for e.g.
the `texture_binding_array` example.

---------

Co-authored-by: Robert Swain <robert.swain@gmail.com>
2023-10-17 21:28:08 +00:00

93 lines
3.0 KiB
Rust

//! Demonstrates using a custom extension to the `StandardMaterial` to modify the results of the builtin pbr shader.
use bevy::reflect::TypePath;
use bevy::{
pbr::{ExtendedMaterial, MaterialExtension, OpaqueRendererMethod},
prelude::*,
render::render_resource::*,
};
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(MaterialMeshBundle {
mesh: meshes.add(
Mesh::try_from(shape::Icosphere {
radius: 1.0,
subdivisions: 5,
})
.unwrap(),
),
transform: Transform::from_xyz(0.0, 0.5, 0.0),
material: materials.add(ExtendedMaterial {
base: StandardMaterial {
base_color: Color::RED,
// 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 { quantize_steps: 3 },
}),
..default()
});
// light
commands.spawn((PointLightBundle::default(), Rotate));
// camera
commands.spawn(Camera3dBundle {
transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
..default()
});
}
#[derive(Component)]
struct Rotate;
fn rotate_things(mut q: Query<&mut Transform, With<Rotate>>, time: Res<Time>) {
for mut t in q.iter_mut() {
t.translation = Vec3::new(
time.elapsed_seconds().sin(),
0.5,
time.elapsed_seconds().cos(),
) * 4.0;
}
}
#[derive(Asset, AsBindGroup, TypePath, Debug, Clone)]
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,
}
impl MaterialExtension for MyExtension {
fn fragment_shader() -> ShaderRef {
"shaders/extended_material.wgsl".into()
}
fn deferred_fragment_shader() -> ShaderRef {
"shaders/extended_material.wgsl".into()
}
}