Add uv_transform to ColorMaterial (bevyengine#17879)

# Objective

Implements and closes bevyengine#17515

## Solution

Add `uv_transform` to `ColorMaterial`

## Testing

Create a example similar to `repeated_texture` but for `Mesh2d` and
`MeshMaterial2d<ColorMaterial>`

## Showcase


![image](https://github.com/user-attachments/assets/72943b9b-59a6-489a-96a2-f9c245f0dd53)

## Migration Guide

Add `uv_transform` field to constructors of `ColorMaterial`

Author: hukasu

Cargo.toml

@@ -783,6 +783,17 @@ description = "Used to test alpha modes with mesh2d"
 category = "2D Rendering"
 wasm = true
 
+[[example]]
+name = "mesh2d_repeated_texture"
+path = "examples/2d/mesh2d_repeated_texture.rs"
+doc-scrape-examples = true
+
+[package.metadata.example.mesh2d_repeated_texture]
+name = "Mesh2d Repeated Texture"
+description = "Showcase of using `uv_transform` on the `ColorMaterial` of a `Mesh2d`"
+category = "2D Rendering"
+wasm = true
+
 [[example]]
 name = "pixel_grid_snap"
 path = "examples/2d/pixel_grid_snap.rs"

crates/bevy_sprite/src/mesh2d/color_material.rs

@@ -3,7 +3,7 @@ use bevy_app::{App, Plugin};
 use bevy_asset::{load_internal_asset, weak_handle, Asset, AssetApp, Assets, Handle};
 use bevy_color::{Alpha, Color, ColorToComponents, LinearRgba};
 use bevy_image::Image;
-use bevy_math::Vec4;
+use bevy_math::{Affine2, Mat3, Vec4};
 use bevy_reflect::prelude::*;
 use bevy_render::{render_asset::RenderAssets, render_resource::*, texture::GpuImage};
 
@@ -45,6 +45,7 @@ impl Plugin for ColorMaterialPlugin {
 pub struct ColorMaterial {
     pub color: Color,
     pub alpha_mode: AlphaMode2d,
+    pub uv_transform: Affine2,
     #[texture(1)]
     #[sampler(2)]
     pub texture: Option<Handle<Image>>,
@@ -61,6 +62,7 @@ impl Default for ColorMaterial {
     fn default() -> Self {
         ColorMaterial {
             color: Color::WHITE,
+            uv_transform: Affine2::default(),
             texture: None,
             // TODO should probably default to AlphaMask once supported?
             alpha_mode: AlphaMode2d::Blend,
@@ -117,6 +119,7 @@ impl ColorMaterialFlags {
 #[derive(Clone, Default, ShaderType)]
 pub struct ColorMaterialUniform {
     pub color: Vec4,
+    pub uv_transform: Mat3,
     pub flags: u32,
     pub alpha_cutoff: f32,
 }
@@ -140,6 +143,7 @@ impl AsBindGroupShaderType<ColorMaterialUniform> for ColorMaterial {
         };
         ColorMaterialUniform {
             color: LinearRgba::from(self.color).to_f32_array().into(),
+            uv_transform: self.uv_transform.into(),
             flags: flags.bits(),
             alpha_cutoff,
         }

crates/bevy_sprite/src/mesh2d/color_material.wgsl

@@ -9,6 +9,7 @@
 
 struct ColorMaterial {
     color: vec4<f32>,
+    uv_transform: mat3x3<f32>,
     // 'flags' is a bit field indicating various options. u32 is 32 bits so we have up to 32 options.
     flags: u32,
     alpha_cutoff: f32,
@@ -34,8 +35,10 @@ fn fragment(
     output_color = output_color * mesh.color;
 #endif
 
+    let uv = (material.uv_transform * vec3(mesh.uv, 1.0)).xy;
+
     if ((material.flags & COLOR_MATERIAL_FLAGS_TEXTURE_BIT) != 0u) {
-        output_color = output_color * textureSample(texture, texture_sampler, mesh.uv);
+        output_color = output_color * textureSample(texture, texture_sampler, uv);
     }
 
     output_color = alpha_discard(material, output_color);

examples/2d/mesh2d_alpha_mode.rs

@@ -34,6 +34,7 @@ fn setup(
             color: WHITE.into(),
             alpha_mode: AlphaMode2d::Opaque,
             texture: Some(texture_handle.clone()),
+            ..default()
         })),
         Transform::from_xyz(-400.0, 0.0, 0.0),
     ));
@@ -43,6 +44,7 @@ fn setup(
             color: BLUE.into(),
             alpha_mode: AlphaMode2d::Opaque,
             texture: Some(texture_handle.clone()),
+            ..default()
         })),
         Transform::from_xyz(-300.0, 0.0, 1.0),
     ));
@@ -52,6 +54,7 @@ fn setup(
             color: GREEN.into(),
             alpha_mode: AlphaMode2d::Opaque,
             texture: Some(texture_handle.clone()),
+            ..default()
         })),
         Transform::from_xyz(-200.0, 0.0, -1.0),
     ));
@@ -67,6 +70,7 @@ fn setup(
             color: WHITE.into(),
             alpha_mode: AlphaMode2d::Mask(0.5),
             texture: Some(texture_handle.clone()),
+            ..default()
         })),
         Transform::from_xyz(200.0, 0.0, 0.0),
     ));
@@ -76,6 +80,7 @@ fn setup(
             color: BLUE.with_alpha(0.7).into(),
             alpha_mode: AlphaMode2d::Blend,
             texture: Some(texture_handle.clone()),
+            ..default()
         })),
         Transform::from_xyz(300.0, 0.0, 1.0),
     ));
@@ -85,6 +90,7 @@ fn setup(
             color: GREEN.with_alpha(0.7).into(),
             alpha_mode: AlphaMode2d::Blend,
             texture: Some(texture_handle),
+            ..default()
         })),
         Transform::from_xyz(400.0, 0.0, -1.0),
     ));

examples/2d/mesh2d_repeated_texture.rs

@@ -0,0 +1,107 @@
+//! By default Bevy loads images to textures that clamps the image to the edges
+//! This example shows how to configure it to repeat the image instead.
+
+use bevy::{
+    audio::AudioPlugin,
+    image::{ImageAddressMode, ImageLoaderSettings, ImageSampler, ImageSamplerDescriptor},
+    math::Affine2,
+    prelude::*,
+};
+
+/// How much to move some rectangles away from the center
+const RECTANGLE_OFFSET: f32 = 250.0;
+/// Length of the sides of the rectangle
+const RECTANGLE_SIDE: f32 = 200.;
+/// How much to move the label away from the rectangle
+const LABEL_OFFSET: f32 = (RECTANGLE_SIDE / 2.) + 25.;
+
+fn main() {
+    App::new()
+        .add_plugins(DefaultPlugins.build().disable::<AudioPlugin>())
+        .add_systems(Startup, setup)
+        .run();
+}
+
+fn setup(
+    mut commands: Commands,
+    asset_server: Res<AssetServer>,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<ColorMaterial>>,
+) {
+    // #11111: We use a duplicated image so that it can be load with and without
+    // settings
+    let image_with_default_sampler =
+        asset_server.load("textures/fantasy_ui_borders/panel-border-010.png");
+    let image_with_repeated_sampler = asset_server.load_with_settings(
+        "textures/fantasy_ui_borders/panel-border-010-repeated.png",
+        |s: &mut _| {
+            *s = ImageLoaderSettings {
+                sampler: ImageSampler::Descriptor(ImageSamplerDescriptor {
+                    // rewriting mode to repeat image,
+                    address_mode_u: ImageAddressMode::Repeat,
+                    address_mode_v: ImageAddressMode::Repeat,
+                    ..default()
+                }),
+                ..default()
+            }
+        },
+    );
+
+    // central rectangle with not repeated texture
+    commands.spawn((
+        Mesh2d(meshes.add(Rectangle::new(RECTANGLE_SIDE, RECTANGLE_SIDE))),
+        MeshMaterial2d(materials.add(ColorMaterial {
+            texture: Some(image_with_default_sampler.clone()),
+            ..default()
+        })),
+        Transform::from_translation(Vec3::ZERO),
+        children![(
+            Text2d::new("Control"),
+            Transform::from_xyz(0., LABEL_OFFSET, 0.),
+        )],
+    ));
+
+    // left rectangle with repeated texture
+    commands.spawn((
+        Mesh2d(meshes.add(Rectangle::new(RECTANGLE_SIDE, RECTANGLE_SIDE))),
+        MeshMaterial2d(materials.add(ColorMaterial {
+            texture: Some(image_with_repeated_sampler),
+            // uv_transform used here for proportions only, but it is full Affine2
+            // that's why you can use rotation and shift also
+            uv_transform: Affine2::from_scale(Vec2::new(2., 3.)),
+            ..default()
+        })),
+        Transform::from_xyz(-RECTANGLE_OFFSET, 0.0, 0.0),
+        children![(
+            Text2d::new("Repeat On"),
+            Transform::from_xyz(0., LABEL_OFFSET, 0.),
+        )],
+    ));
+
+    // right rectangle with scaled texture, but with default sampler.
+    commands.spawn((
+        Mesh2d(meshes.add(Rectangle::new(RECTANGLE_SIDE, RECTANGLE_SIDE))),
+        MeshMaterial2d(materials.add(ColorMaterial {
+            // there is no sampler set, that's why
+            // by default you see only one small image in a row/column
+            // and other space is filled by image edge
+            texture: Some(image_with_default_sampler),
+
+            // uv_transform used here for proportions only, but it is full Affine2
+            // that's why you can use rotation and shift also
+            uv_transform: Affine2::from_scale(Vec2::new(2., 3.)),
+            ..default()
+        })),
+        Transform::from_xyz(RECTANGLE_OFFSET, 0.0, 0.0),
+        children![(
+            Text2d::new("Repeat Off"),
+            Transform::from_xyz(0., LABEL_OFFSET, 0.),
+        )],
+    ));
+
+    // camera
+    commands.spawn((
+        Camera2d,
+        Transform::default().looking_at(Vec3::ZERO, Vec3::Y),
+    ));
+}

examples/README.md

@@ -114,6 +114,7 @@ Example | Description
 [Mesh 2D](../examples/2d/mesh2d.rs) | Renders a 2d mesh
 [Mesh 2D With Vertex Colors](../examples/2d/mesh2d_vertex_color_texture.rs) | Renders a 2d mesh with vertex color attributes
 [Mesh2d Alpha Mode](../examples/2d/mesh2d_alpha_mode.rs) | Used to test alpha modes with mesh2d
+[Mesh2d Repeated Texture](../examples/2d/mesh2d_repeated_texture.rs) | Showcase of using `uv_transform` on the `ColorMaterial` of a `Mesh2d`
 [Move Sprite](../examples/2d/move_sprite.rs) | Changes the transform of a sprite
 [Pixel Grid Snapping](../examples/2d/pixel_grid_snap.rs) | Shows how to create graphics that snap to the pixel grid by rendering to a texture in 2D
 [Sprite](../examples/2d/sprite.rs) | Renders a sprite

examples/stress_tests/bevymark.rs

@@ -613,6 +613,7 @@ fn init_materials(
         color: Color::WHITE,
         texture: textures.first().cloned(),
         alpha_mode,
+        ..default()
     }));
 
     // We're seeding the PRNG here to make this example deterministic for testing purposes.
@@ -625,6 +626,7 @@ fn init_materials(
                 color: Color::srgb_u8(color_rng.r#gen(), color_rng.r#gen(), color_rng.r#gen()),
                 texture: textures.choose(&mut texture_rng).cloned(),
                 alpha_mode,
+                ..default()
             })
         })
         .take(capacity - materials.len()),