Example for custom mesh attributes (#757)

example for custom attributes + changelog

CHANGELOG.md

@@ -13,8 +13,6 @@ to view all changes since the `0.2.1` release.
 ### Added
 
 - [Touch Input][696]
-- [Do not depend on spirv on wasm32 target][689]
-- [Another fast compile flag for macOS][552]
 - [Introduce Mouse capture API][679]
 - [`bevy_input::touch`: implement touch input][696]
 - [D-pad support on MacOS][653]
@@ -70,9 +68,10 @@ to view all changes since the `0.2.1` release.
   - New methods `Color::rgb_linear` and `Color::rgba_linear` will accept colors already in linear sRGB (the old behavior)
   - Individual color-components must now be accessed through setters and getters.
 - [`Mesh` overhaul with custom vertex attributes][599]
+  - Any vertex attribute can now be added over `mesh.attributes.insert()`.
+  - See `example/shader/mesh_custom_attribute.rs`
   - Removed `VertexAttribute`, `Vertex`, `AsVertexBufferDescriptor`.
   - For missing attributes (requested by shader, but not defined by mesh), Bevy will provide a zero-filled fallback buffer.
-  - Any vertex attribute can now be added over `mesh.attributes.insert()`. `mesh.attributes.insert(Cow::Borrowed(Mesh::ATTRIBUTE_POSITION), points.into())`
 - Despawning an entity multiple times causes a debug-level log message to be emitted instead of a panic: [#649][649], [#651][651]
 - [Migrated to Rodio 0.12][692]
   - New method of playing audio can be found in the examples.

Cargo.toml

@@ -254,6 +254,10 @@ path = "examples/scene/scene.rs"
 name = "properties"
 path = "examples/scene/properties.rs"
 
+[[example]]
+name = "mesh_custom_attribute"
+path = "examples/shader/mesh_custom_attribute.rs"
+
 [[example]]
 name = "shader_custom_material"
 path = "examples/shader/shader_custom_material.rs"

examples/shader/mesh_custom_attribute.rs

@@ -0,0 +1,156 @@
+use bevy::{
+    prelude::*,
+    render::{
+        mesh::{shape, VertexAttributeValues},
+        pipeline::{DynamicBinding, PipelineDescriptor, PipelineSpecialization, RenderPipeline},
+        render_graph::{base, AssetRenderResourcesNode, RenderGraph},
+        renderer::RenderResources,
+        shader::{ShaderStage, ShaderStages},
+    },
+    type_registry::TypeUuid,
+};
+
+/// This example illustrates how to add a custom attribute to a mesh and use it in a custom shader.
+fn main() {
+    App::build()
+        .add_default_plugins()
+        .add_asset::<MyMaterialWithVertexColorSupport>()
+        .add_startup_system(setup.system())
+        .run();
+}
+
+#[derive(RenderResources, Default, TypeUuid)]
+#[uuid = "0320b9b8-b3a3-4baa-8bfa-c94008177b17"]
+struct MyMaterialWithVertexColorSupport {}
+
+const VERTEX_SHADER: &str = r#"
+#version 450
+layout(location = 0) in vec3 Vertex_Position;
+layout(location = 1) in vec3 Vertex_Color;
+layout(location = 0) out vec3 v_color;
+
+layout(set = 0, binding = 0) uniform Camera {
+    mat4 ViewProj;
+};
+layout(set = 1, binding = 0) uniform Transform {
+    mat4 Model;
+};
+void main() {
+    gl_Position = ViewProj * Model * vec4(Vertex_Position, 1.0);
+    v_color = Vertex_Color;
+}
+"#;
+
+const FRAGMENT_SHADER: &str = r#"
+#version 450
+layout(location = 0) out vec4 o_Target;
+layout(location = 0) in vec3 v_color;
+
+void main() {
+    o_Target = vec4(v_color, 1.0);
+}
+"#;
+
+fn setup(
+    mut commands: Commands,
+    mut pipelines: ResMut<Assets<PipelineDescriptor>>,
+    mut shaders: ResMut<Assets<Shader>>,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<MyMaterialWithVertexColorSupport>>,
+    mut render_graph: ResMut<RenderGraph>,
+) {
+    // Create a new shader pipeline
+    let pipeline_handle = pipelines.add(PipelineDescriptor::default_config(ShaderStages {
+        vertex: shaders.add(Shader::from_glsl(ShaderStage::Vertex, VERTEX_SHADER)),
+        fragment: Some(shaders.add(Shader::from_glsl(ShaderStage::Fragment, FRAGMENT_SHADER))),
+    }));
+
+    // Add an AssetRenderResourcesNode to our Render Graph. This will bind MyMaterialWithVertexColorSupport resources to our shader
+    render_graph.add_system_node(
+        "my_material_with_vertex_color_support",
+        AssetRenderResourcesNode::<MyMaterialWithVertexColorSupport>::new(true),
+    );
+
+    // Add a Render Graph edge connecting our new "my_material" node to the main pass node. This ensures "my_material" runs before the main pass
+    render_graph
+        .add_node_edge(
+            "my_material_with_vertex_color_support",
+            base::node::MAIN_PASS,
+        )
+        .unwrap();
+
+    // Create a new material
+    let material = materials.add(MyMaterialWithVertexColorSupport {});
+
+    // create a generic cube
+    let mut cube_with_vertex_colors = Mesh::from(shape::Cube { size: 1.0 });
+
+    // insert our custom color attribute with some nice colors!
+    cube_with_vertex_colors.set_attribute(
+        // name of the attribute
+        "Vertex_Color",
+        // the vertex attributes, represented by `VertexAttributeValues`
+        // NOTE: the attribute count has to be consistent across all attributes, otherwise bevy will panic.
+        VertexAttributeValues::from(vec![
+            // top
+            [0.79, 0.73, 0.07],
+            [0.74, 0.14, 0.29],
+            [0.08, 0.55, 0.74],
+            [0.20, 0.27, 0.29],
+            // bottom
+            [0.79, 0.73, 0.07],
+            [0.74, 0.14, 0.29],
+            [0.08, 0.55, 0.74],
+            [0.20, 0.27, 0.29],
+            // right
+            [0.79, 0.73, 0.07],
+            [0.74, 0.14, 0.29],
+            [0.08, 0.55, 0.74],
+            [0.20, 0.27, 0.29],
+            // left
+            [0.79, 0.73, 0.07],
+            [0.74, 0.14, 0.29],
+            [0.08, 0.55, 0.74],
+            [0.20, 0.27, 0.29],
+            // front
+            [0.79, 0.73, 0.07],
+            [0.74, 0.14, 0.29],
+            [0.08, 0.55, 0.74],
+            [0.20, 0.27, 0.29],
+            // back
+            [0.79, 0.73, 0.07],
+            [0.74, 0.14, 0.29],
+            [0.08, 0.55, 0.74],
+            [0.20, 0.27, 0.29],
+        ]),
+    );
+    // Setup our world
+    commands
+        // cube
+        .spawn(MeshComponents {
+            mesh: meshes.add(cube_with_vertex_colors), // use our cube with vertex colors
+            render_pipelines: RenderPipelines::from_pipelines(vec![RenderPipeline::specialized(
+                pipeline_handle,
+                // NOTE: in the future you wont need to manually declare dynamic bindings
+                PipelineSpecialization {
+                    dynamic_bindings: vec![
+                        // Transform
+                        DynamicBinding {
+                            bind_group: 1,
+                            binding: 0,
+                        },
+                    ],
+                    ..Default::default()
+                },
+            )]),
+            transform: Transform::from_translation(Vec3::new(0.0, 0.0, 0.0)),
+            ..Default::default()
+        })
+        .with(material)
+        // camera
+        .spawn(Camera3dComponents {
+            transform: Transform::from_translation(Vec3::new(3.0, 5.0, -8.0))
+                .looking_at(Vec3::default(), Vec3::unit_y()),
+            ..Default::default()
+        });
+}