[Merged by Bors] - Add support for vertex colors

Cargo.toml

@@ -196,6 +196,10 @@ path = "examples/3d/parenting.rs"
 name = "pbr"
 path = "examples/3d/pbr.rs"
 
+[[example]]
+name = "render_to_texture"
+path = "examples/3d/render_to_texture.rs"
+
 [[example]]
 name = "shadow_biases"
 path = "examples/3d/shadow_biases.rs"
@@ -212,10 +216,6 @@ path = "examples/3d/spherical_area_lights.rs"
 name = "texture"
 path = "examples/3d/texture.rs"
 
-[[example]]
-name = "render_to_texture"
-path = "examples/3d/render_to_texture.rs"
-
 [[example]]
 name = "two_passes"
 path = "examples/3d/two_passes.rs"
@@ -224,6 +224,10 @@ path = "examples/3d/two_passes.rs"
 name = "update_gltf_scene"
 path = "examples/3d/update_gltf_scene.rs"
 
+[[example]]
+name = "vertex_colors"
+path = "examples/3d/vertex_colors.rs"
+
 [[example]]
 name = "wireframe"
 path = "examples/3d/wireframe.rs"

crates/bevy_gltf/src/loader.rs

@@ -269,12 +269,12 @@ async fn load_gltf<'a, 'b>(
                 mesh.insert_attribute(Mesh::ATTRIBUTE_UV_0, uvs);
             }
 
-            // if let Some(vertex_attribute) = reader
-            //     .read_colors(0)
-            //     .map(|v| VertexAttributeValues::Float32x4(v.into_rgba_f32().collect()))
-            // {
-            //     mesh.insert_attribute(Mesh::ATTRIBUTE_COLOR, vertex_attribute);
-            // }
+            if let Some(vertex_attribute) = reader
+                .read_colors(0)
+                .map(|v| VertexAttributeValues::Float32x4(v.into_rgba_f32().collect()))
+            {
+                mesh.insert_attribute(Mesh::ATTRIBUTE_COLOR, vertex_attribute);
+            }
 
             if let Some(iter) = reader.read_joints(0) {
                 let vertex_attribute = VertexAttributeValues::Uint16x4(iter.into_u16().collect());

crates/bevy_pbr/src/render/mesh.rs

@@ -560,6 +560,11 @@ impl SpecializedMeshPipeline for MeshPipeline {
             vertex_attributes.push(Mesh::ATTRIBUTE_TANGENT.at_shader_location(3));
         }
 
+        if layout.contains(Mesh::ATTRIBUTE_COLOR) {
+            shader_defs.push(String::from("VERTEX_COLORS"));
+            vertex_attributes.push(Mesh::ATTRIBUTE_COLOR.at_shader_location(4));
+        }
+
         // TODO: consider exposing this in shaders in a more generally useful way, such as:
         // # if AVAILABLE_STORAGE_BUFFER_BINDINGS == 3
         // /* use storage buffers here */
@@ -577,8 +582,8 @@ impl SpecializedMeshPipeline for MeshPipeline {
             && layout.contains(Mesh::ATTRIBUTE_JOINT_WEIGHT)
         {
             shader_defs.push(String::from("SKINNED"));
-            vertex_attributes.push(Mesh::ATTRIBUTE_JOINT_INDEX.at_shader_location(4));
-            vertex_attributes.push(Mesh::ATTRIBUTE_JOINT_WEIGHT.at_shader_location(5));
+            vertex_attributes.push(Mesh::ATTRIBUTE_JOINT_INDEX.at_shader_location(5));
+            vertex_attributes.push(Mesh::ATTRIBUTE_JOINT_WEIGHT.at_shader_location(6));
             bind_group_layout.push(self.skinned_mesh_layout.clone());
         } else {
             bind_group_layout.push(self.mesh_layout.clone());

crates/bevy_pbr/src/render/mesh.wgsl

@@ -8,9 +8,12 @@ struct Vertex {
 #ifdef VERTEX_TANGENTS
     [[location(3)]] tangent: vec4<f32>;
 #endif
+#ifdef VERTEX_COLORS
+    [[location(4)]] color: vec4<f32>;
+#endif
 #ifdef SKINNED
-    [[location(4)]] joint_indices: vec4<u32>;
-    [[location(5)]] joint_weights: vec4<f32>;
+    [[location(5)]] joint_indices: vec4<u32>;
+    [[location(6)]] joint_weights: vec4<f32>;
 #endif
 };
 
@@ -22,6 +25,9 @@ struct VertexOutput {
 #ifdef VERTEX_TANGENTS
     [[location(3)]] world_tangent: vec4<f32>;
 #endif
+#ifdef VERTEX_COLORS
+    [[location(4)]] color: vec4<f32>;
+#endif
 };
 
 [[group(2), binding(0)]]
@@ -60,6 +66,9 @@ fn vertex(vertex: Vertex) -> VertexOutput {
     );
 #endif
 #endif
+#ifdef VERTEX_COLORS
+    out.color = vertex.color;
+#endif 
 
     out.uv = vertex.uv;
     out.clip_position = view.view_proj * out.world_position;
@@ -74,9 +83,16 @@ struct FragmentInput {
 #ifdef VERTEX_TANGENTS
     [[location(3)]] world_tangent: vec4<f32>;
 #endif
+#ifdef VERTEX_COLORS
+    [[location(4)]] color: vec4<f32>;
+#endif
 };
 
 [[stage(fragment)]]
 fn fragment(in: FragmentInput) -> [[location(0)]] vec4<f32> {
+#ifdef VERTEX_COLORS
+    return in.color;
+#else
     return vec4<f32>(1.0, 0.0, 1.0, 1.0);
-}
+#endif
+}

crates/bevy_pbr/src/render/pbr.wgsl

@@ -465,11 +465,17 @@ struct FragmentInput {
 #ifdef VERTEX_TANGENTS
     [[location(3)]] world_tangent: vec4<f32>;
 #endif
+#ifdef VERTEX_COLORS
+    [[location(4)]] color: vec4<f32>;
+#endif 
 };
 
 [[stage(fragment)]]
 fn fragment(in: FragmentInput) -> [[location(0)]] vec4<f32> {
     var output_color: vec4<f32> = material.base_color;
+    #ifdef VERTEX_COLORS
+    output_color = output_color * in.color;
+    #endif
     if ((material.flags & STANDARD_MATERIAL_FLAGS_BASE_COLOR_TEXTURE_BIT) != 0u) {
         output_color = output_color * textureSample(base_color_texture, base_color_sampler, in.uv);
     }

crates/bevy_render/src/mesh/mesh/mod.rs

@@ -73,7 +73,7 @@ impl Mesh {
 
     /// Per vertex coloring. Use in conjunction with [`Mesh::insert_attribute`]
     pub const ATTRIBUTE_COLOR: MeshVertexAttribute =
-        MeshVertexAttribute::new("Vertex_Color", 4, VertexFormat::Uint32);
+        MeshVertexAttribute::new("Vertex_Color", 4, VertexFormat::Float32x4);
 
     /// Per vertex joint transform matrix weight. Use in conjunction with [`Mesh::insert_attribute`]
     pub const ATTRIBUTE_JOINT_WEIGHT: MeshVertexAttribute =

crates/bevy_sprite/src/mesh2d/mesh.rs

@@ -295,6 +295,11 @@ impl SpecializedMeshPipeline for Mesh2dPipeline {
             vertex_attributes.push(Mesh::ATTRIBUTE_TANGENT.at_shader_location(3));
         }
 
+        if layout.contains(Mesh::ATTRIBUTE_COLOR) {
+            shader_defs.push(String::from("VERTEX_COLORS"));
+            vertex_attributes.push(Mesh::ATTRIBUTE_COLOR.at_shader_location(4));
+        }
+
         #[cfg(feature = "webgl")]
         shader_defs.push(String::from("NO_ARRAY_TEXTURES_SUPPORT"));
 

examples/2d/mesh2d_manual.rs

@@ -4,7 +4,7 @@ use bevy::{
     prelude::*,
     reflect::TypeUuid,
     render::{
-        mesh::Indices,
+        mesh::{Indices, MeshVertexAttribute},
         render_asset::RenderAssets,
         render_phase::{AddRenderCommand, DrawFunctions, RenderPhase, SetItemPipeline},
         render_resource::{
@@ -72,7 +72,10 @@ fn star(
     // And a RGB color attribute as well
     let mut v_color: Vec<u32> = vec![Color::BLACK.as_linear_rgba_u32()];
     v_color.extend_from_slice(&[Color::YELLOW.as_linear_rgba_u32(); 10]);
-    star.insert_attribute(Mesh::ATTRIBUTE_COLOR, v_color);
+    star.insert_attribute(
+        MeshVertexAttribute::new("Vertex_Color", 1, VertexFormat::Uint32),
+        v_color,
+    );
 
     // Now, we specify the indices of the vertex that are going to compose the
     // triangles in our star. Vertices in triangles have to be specified in CCW

examples/3d/vertex_colors.rs

@@ -0,0 +1,59 @@
+use bevy::{prelude::*, render::mesh::VertexAttributeValues};
+
+fn main() {
+    App::new()
+        .insert_resource(Msaa { samples: 4 })
+        .add_plugins(DefaultPlugins)
+        .add_startup_system(setup)
+        .run();
+}
+
+/// set up a simple 3D scene
+fn setup(
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+) {
+    // plane
+    commands.spawn_bundle(PbrBundle {
+        mesh: meshes.add(Mesh::from(shape::Plane { size: 5.0 })),
+        material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
+        ..default()
+    });
+    // cube
+    // Assign vertex colors based on vertex positions
+    let mut colorful_cube = Mesh::from(shape::Cube { size: 1.0 });
+    if let Some(VertexAttributeValues::Float32x3(positions)) =
+        colorful_cube.attribute(Mesh::ATTRIBUTE_POSITION)
+    {
+        let colors: Vec<[f32; 4]> = positions
+            .iter()
+            .map(|[r, g, b]| [(1. - *r) / 2., (1. - *g) / 2., (1. - *b) / 2., 1.])
+            .collect();
+        colorful_cube.insert_attribute(Mesh::ATTRIBUTE_COLOR, colors);
+    }
+    commands.spawn_bundle(PbrBundle {
+        mesh: meshes.add(colorful_cube),
+        // This is the default color, but note that vertex colors are
+        // multiplied by the base color, so you'll likely want this to be
+        // white if using vertex colors.
+        material: materials.add(Color::rgb(1., 1., 1.).into()),
+        transform: Transform::from_xyz(0.0, 0.5, 0.0),
+        ..default()
+    });
+    // light
+    commands.spawn_bundle(PointLightBundle {
+        point_light: PointLight {
+            intensity: 1500.0,
+            shadows_enabled: true,
+            ..default()
+        },
+        transform: Transform::from_xyz(4.0, 8.0, 4.0),
+        ..default()
+    });
+    // camera
+    commands.spawn_bundle(PerspectiveCameraBundle {
+        transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
+        ..default()
+    });
+}

examples/README.md

@@ -115,6 +115,7 @@ Example | File | Description
 `spherical_area_lights` | [`3d/spherical_area_lights.rs`](./3d/spherical_area_lights.rs) | Demonstrates how point light radius values affect light behavior.
 `texture` | [`3d/texture.rs`](./3d/texture.rs) | Shows configuration of texture materials
 `update_gltf_scene` | [`3d/update_gltf_scene.rs`](./3d/update_gltf_scene.rs) | Update a scene from a gltf file, either by spawning the scene as a child of another entity, or by accessing the entities of the scene
+`vertex_colors` | [`3d/vertex_colors.rs`](./3d/vertex_colors.rs) | Shows the use of vertex colors
 `wireframe` | [`3d/wireframe.rs`](./3d/wireframe.rs) | Showcases wireframe rendering
 
 ## Animation