# 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`.
		
	
			
		
			
				
	
	
		
			76 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			76 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! A simple scene to demonstrate picking events
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use bevy::{color::palettes::tailwind::CYAN_400, prelude::*};
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fn main() {
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    let mut app = App::new();
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    app.add_plugins(DefaultPlugins);
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    app.add_systems(Startup, setup);
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    app.run();
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}
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/// set up a simple 3D scene
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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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) {
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    commands
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        .spawn((
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            Text::new("Click Me to get a box"),
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            Style {
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                position_type: PositionType::Absolute,
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                top: Val::Percent(12.0),
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                left: Val::Percent(12.0),
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                ..default()
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            },
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        ))
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        .observe(
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            |_click: Trigger<Pointer<Click>>,
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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 num: Local<usize>| {
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                commands.spawn((
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                    Mesh3d(meshes.add(Cuboid::new(1.0, 1.0, 1.0))),
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                    MeshMaterial3d(materials.add(Color::srgb_u8(124, 144, 255))),
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                    Transform::from_xyz(0.0, 0.5 + 1.1 * *num as f32, 0.0),
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                ));
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                *num += 1;
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            },
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        )
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        .observe(
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            |evt: Trigger<Pointer<Out>>, mut texts: Query<&mut TextColor>| {
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                let mut color = texts.get_mut(evt.entity()).unwrap();
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                color.0 = Color::WHITE;
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            },
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        )
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        .observe(
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            |evt: Trigger<Pointer<Over>>, mut texts: Query<&mut TextColor>| {
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                let mut color = texts.get_mut(evt.entity()).unwrap();
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                color.0 = CYAN_400.into();
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            },
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        );
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    // circular base
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    commands.spawn((
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        Mesh3d(meshes.add(Circle::new(4.0))),
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        MeshMaterial3d(materials.add(Color::WHITE)),
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        Transform::from_rotation(Quat::from_rotation_x(-std::f32::consts::FRAC_PI_2)),
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    ));
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    // light
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    commands.spawn((
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        PointLight {
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            shadows_enabled: true,
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            ..default()
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        },
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        Transform::from_xyz(4.0, 8.0, 4.0),
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    ));
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    // camera
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    commands.spawn((
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        Camera3d::default(),
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        Transform::from_xyz(-2.5, 4.5, 9.0).looking_at(Vec3::ZERO, Vec3::Y),
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    ));
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}
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