6f7d0e5725
# Objective
Currently text is recomputed unnecessarily on any changes to its color,
which is extremely expensive.
## Solution
Split up `TextStyle` into two separate components `TextFont` and
`TextColor`.
## Testing
I added this system to `many_buttons`:
```rust
fn set_text_colors_changed(mut colors: Query<&mut TextColor>) {
for mut text_color in colors.iter_mut() {
text_color.set_changed();
}
}
```
reports ~4fps on main, ~50fps with this PR.
## Migration Guide
`TextStyle` has been renamed to `TextFont` and its `color` field has
been moved to a separate component named `TextColor` which newtypes
`Color`.
129 lines
3.6 KiB
Rust
129 lines
3.6 KiB
Rust
//! Shows how to render UI to a texture. Useful for displaying UI in 3D space.
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use std::f32::consts::PI;
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use bevy::{
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color::palettes::css::GOLD,
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prelude::*,
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render::{
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camera::RenderTarget,
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render_asset::RenderAssetUsages,
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render_resource::{Extent3d, TextureDimension, TextureFormat, TextureUsages},
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},
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};
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins)
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.add_systems(Startup, setup)
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.add_systems(Update, rotator_system)
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.run();
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}
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// Marks the cube, to which the UI texture is applied.
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#[derive(Component)]
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struct Cube;
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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<StandardMaterial>>,
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mut images: ResMut<Assets<Image>>,
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) {
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let size = Extent3d {
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width: 512,
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height: 512,
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..default()
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};
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// This is the texture that will be rendered to.
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let mut image = Image::new_fill(
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size,
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TextureDimension::D2,
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&[0, 0, 0, 0],
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TextureFormat::Bgra8UnormSrgb,
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RenderAssetUsages::default(),
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);
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// You need to set these texture usage flags in order to use the image as a render target
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image.texture_descriptor.usage =
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TextureUsages::TEXTURE_BINDING | TextureUsages::COPY_DST | TextureUsages::RENDER_ATTACHMENT;
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let image_handle = images.add(image);
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// Light
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commands.spawn(DirectionalLight::default());
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let texture_camera = commands
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.spawn((
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Camera2d,
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Camera {
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target: RenderTarget::Image(image_handle.clone()),
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..default()
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},
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))
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.id();
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commands
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.spawn((
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NodeBundle {
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style: Style {
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// Cover the whole image
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width: Val::Percent(100.),
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height: Val::Percent(100.),
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flex_direction: FlexDirection::Column,
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justify_content: JustifyContent::Center,
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align_items: AlignItems::Center,
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..default()
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},
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background_color: GOLD.into(),
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..default()
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},
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TargetCamera(texture_camera),
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))
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.with_children(|parent| {
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parent.spawn((
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Text::new("This is a cube"),
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TextFont {
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font_size: 40.0,
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..default()
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},
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TextColor::BLACK,
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));
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});
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let cube_size = 4.0;
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let cube_handle = meshes.add(Cuboid::new(cube_size, cube_size, cube_size));
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// This material has the texture that has been rendered.
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let material_handle = materials.add(StandardMaterial {
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base_color_texture: Some(image_handle),
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reflectance: 0.02,
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unlit: false,
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..default()
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});
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// Cube with material containing the rendered UI texture.
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commands.spawn((
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Mesh3d(cube_handle),
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MeshMaterial3d(material_handle),
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Transform::from_xyz(0.0, 0.0, 1.5).with_rotation(Quat::from_rotation_x(-PI / 5.0)),
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Cube,
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));
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// The main pass camera.
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commands.spawn((
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Camera3d::default(),
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Transform::from_xyz(0.0, 0.0, 15.0).looking_at(Vec3::ZERO, Vec3::Y),
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));
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}
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const ROTATION_SPEED: f32 = 0.5;
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fn rotator_system(time: Res<Time>, mut query: Query<&mut Transform, With<Cube>>) {
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for mut transform in &mut query {
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transform.rotate_x(1.0 * time.delta_seconds() * ROTATION_SPEED);
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transform.rotate_y(0.7 * time.delta_seconds() * ROTATION_SPEED);
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}
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}
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