78 lines
2.3 KiB
Rust
78 lines
2.3 KiB
Rust
//! A shader that uses the GLSL shading language.
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use bevy::{
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prelude::*,
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reflect::TypePath,
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render::render_resource::{AsBindGroup, ShaderRef},
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sprite::{AlphaMode2d, Material2d, Material2dPlugin},
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window::PrimaryWindow,
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};
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const SHADER_ASSET_PATH: &str = "shaders/default.wgsl";
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fn main() {
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App::new()
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.add_plugins((
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DefaultPlugins,
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Material2dPlugin::<CustomMaterial>::default(),
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))
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.add_systems(Startup, setup)
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.add_systems(Update, resize_fullscreen_quad)
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.run();
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}
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/// set up a simple 2D-screen-like surface
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fn setup(
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mut commands: Commands,
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mut meshes: ResMut<Assets<Mesh>>,
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mut materials: ResMut<Assets<CustomMaterial>>,
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primary_window: Single<&Window, With<PrimaryWindow>>,
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) {
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// camera
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commands.spawn(Camera2d);
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// quad that fills the whole window
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let size = Vec2::new(
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primary_window.resolution.width(),
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primary_window.resolution.height(),
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);
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commands.spawn((
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Mesh2d(meshes.add(Rectangle::default())),
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MeshMaterial2d(materials.add(CustomMaterial {})),
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Transform::from_scale(Vec3::new(size.x, size.y, 1.0)),
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FullscreenQuad,
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));
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}
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/// Marker component for the fullscreen quad so we can update it on window resize
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#[derive(Component)]
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struct FullscreenQuad;
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/// Update fullscreen quad transforms when the primary window is resized.
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fn resize_fullscreen_quad(
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primary_window: Single<&Window, With<PrimaryWindow>>,
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mut transform: Single<&mut Transform, With<FullscreenQuad>>,
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) {
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let size = Vec2::new(
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primary_window.resolution.width(),
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primary_window.resolution.height(),
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);
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transform.scale = Vec3::new(size.x, size.y, 1.0);
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}
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// This is the struct that will be passed to your shader
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#[derive(Asset, TypePath, AsBindGroup, Clone)]
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struct CustomMaterial {}
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/// The Material2d trait is very configurable, but comes with sensible defaults for all methods.
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/// You only need to implement functions for features that need non-default behavior. See the Material2d api docs for details!
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impl Material2d for CustomMaterial {
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fn fragment_shader() -> ShaderRef {
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SHADER_ASSET_PATH.into()
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}
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fn alpha_mode(&self) -> AlphaMode2d {
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AlphaMode2d::Opaque
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}
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}
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