Fixes for WESL on Windows (bevyengine#18373)

# Objective

WESL was broken on windows.

## Solution

- Upgrade to `wesl_rs` 1.2.
- Fix path handling on windows.
- Improve example for khronos demo this week.

Author: tychedelia

assets/shaders/custom_material.wesl

@@ -1,4 +1,4 @@
-import super::shaders::util::make_polka_dots;
+import super::util::make_polka_dots;
 
 struct VertexOutput {
     @builtin(position) position: vec4<f32>,

assets/shaders/util.wesl

@@ -1,29 +1,44 @@
 fn make_polka_dots(pos: vec2<f32>, time: f32) -> vec4<f32> {
-    // Create repeating circles
     let scaled_pos = pos * 6.0;
     let cell = vec2<f32>(fract(scaled_pos.x), fract(scaled_pos.y));
-    let dist_from_center = distance(cell, vec2<f32>(0.5));
-    
-    // Make dots alternate between pink and purple
+    var dist_from_center = distance(cell, vec2<f32>(0.5));
+
     let is_even = (floor(scaled_pos.x) + floor(scaled_pos.y)) % 2.0;
 
     var dot_color = vec3<f32>(0.0);
+    var is_dot = 0.0;
+
     @if(!PARTY_MODE) {
         let color1 = vec3<f32>(1.0, 0.4, 0.8);  // pink
         let color2 = vec3<f32>(0.6, 0.2, 1.0);  // purple
         dot_color = mix(color1, color2, is_even);
-    }
-    // Animate the colors in party mode
-    @if(PARTY_MODE) {
-        let color1 = vec3<f32>(1.0, 0.2, 0.2);  // red
-        let color2 = vec3<f32>(0.2, 0.2, 1.0);  // blue
-        let oscillation = (sin(time * 10.0) + 1.0) * 0.5;
-        let animated_color1 = mix(color1, color2, oscillation);
-        let animated_color2 = mix(color2, color1, oscillation);
+        is_dot = step(dist_from_center, 0.3);
+    } @else {
+        let grid_x = floor(scaled_pos.x);
+        let grid_y = floor(scaled_pos.y);
+        let wave_speed = 3.0;
+        let wave_phase = time * wave_speed;
+
+        let diagonal_pos = (grid_x + grid_y) * 0.5;
+        let wave_value = sin(diagonal_pos + wave_phase);
+
+        let wave_normalized = (wave_value + 1.0) * 0.5;
+
+        let color1 = vec3<f32>(1.0, 0.3, 0.7);
+        let color2 = vec3<f32>(0.5, 0.1, 1.0);
+        let intense_color1 = vec3<f32>(1.0, 0.1, 0.9);
+        let intense_color2 = vec3<f32>(0.8, 0.0, 1.0);
+
+        let animated_color1 = mix(color1, intense_color1, wave_normalized);
+        let animated_color2 = mix(color2, intense_color2, wave_normalized);
+
         dot_color = mix(animated_color1, animated_color2, is_even);
+
+        let size_mod = 0.15 * wave_value;
+        dist_from_center = dist_from_center * (1.0 - size_mod);
+        // Animate whether something is a dot by position but also time
+        is_dot = step(dist_from_center, 0.3 + wave_normalized * 0.2);
     }
 
-    // Draw the dot
-    let is_dot = step(dist_from_center, 0.3);
     return vec4<f32>(dot_color * is_dot, is_dot);
 }

crates/bevy_render/Cargo.toml

@@ -113,7 +113,7 @@ tracing = { version = "0.1", default-features = false, features = ["std"] }
 indexmap = { version = "2" }
 fixedbitset = { version = "0.5" }
 bitflags = "2"
-wesl = { version = "0.1.0", optional = true }
+wesl = { version = "0.1.2", optional = true }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 # Omit the `glsl` feature in non-WebAssembly by default.

crates/bevy_render/src/render_resource/shader.rs

@@ -164,23 +164,34 @@ impl Shader {
         match import_path {
             ShaderImport::AssetPath(asset_path) => {
                 let asset_path = std::path::PathBuf::from(&asset_path);
-                // Resolve and normalize the path
-                let asset_path = asset_path.canonicalize().unwrap_or(asset_path);
-                // Strip the asset root
+
+                // Get the base path and canonicalize it to match the format of the asset path
                 let mut base_path = bevy_asset::io::file::FileAssetReader::get_base_path();
-                // TODO: integrate better with the asset system rather than hard coding this
                 base_path.push("assets");
-                let asset_path = asset_path
-                    .strip_prefix(&base_path)
-                    .unwrap_or_else(|_| &asset_path);
-                // Wesl paths are provided as absolute relative to the asset root
-                let asset_path = std::path::Path::new("/").join(asset_path);
-                // And with a striped file name
-                let asset_path = asset_path.with_extension("");
-                let asset_path = asset_path.to_str().unwrap_or_else(|| {
-                    panic!("Failed to convert path to string: {:?}", asset_path)
-                });
-                let import_path = ShaderImport::AssetPath(asset_path.to_string());
+                let base_path = base_path.canonicalize().unwrap_or(base_path);
+
+                // Try to make the path relative to the base path
+                let relative_path = match asset_path.canonicalize() {
+                    Ok(canonical_asset_path) => {
+                        match canonical_asset_path.strip_prefix(&base_path) {
+                            Ok(rel_path) => rel_path.to_path_buf(),
+                            Err(_) => canonical_asset_path,
+                        }
+                    }
+                    Err(_) => asset_path,
+                };
+
+                // Create the shader import path - always starting with "/"
+                let shader_path = std::path::Path::new("/").join(&relative_path);
+
+                // Convert to a string with forward slashes and without extension
+                let import_path_str = shader_path
+                    .with_extension("")
+                    .to_string_lossy()
+                    .replace('\\', "/");
+
+                let import_path = ShaderImport::AssetPath(import_path_str.to_string());
+
                 Shader {
                     path,
                     imports,

examples/shader/shader_material_wesl.rs

@@ -70,16 +70,20 @@ fn setup(
 
 fn update(
     time: Res<Time>,
-    mut query: Query<&MeshMaterial3d<CustomMaterial>>,
+    mut query: Query<(&MeshMaterial3d<CustomMaterial>, &mut Transform)>,
     mut materials: ResMut<Assets<CustomMaterial>>,
     keys: Res<ButtonInput<KeyCode>>,
 ) {
-    for material in query.iter_mut() {
+    for (material, mut transform) in query.iter_mut() {
         let material = materials.get_mut(material).unwrap();
         material.time = time.elapsed_secs();
         if keys.just_pressed(KeyCode::Space) {
             material.party_mode = !material.party_mode;
         }
+
+        if material.party_mode {
+            transform.rotate(Quat::from_rotation_y(0.005));
+        }
     }
 }