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`.
93 lines
3.0 KiB
Rust
93 lines
3.0 KiB
Rust
//! Showcases the [`RelativeCursorPosition`] component, used to check the position of the cursor relative to a UI node.
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use bevy::{
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prelude::*, render::camera::Viewport, ui::RelativeCursorPosition, winit::WinitSettings,
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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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// Only run the app when there is user input. This will significantly reduce CPU/GPU use.
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.insert_resource(WinitSettings::desktop_app())
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.add_systems(Startup, setup)
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.add_systems(Update, relative_cursor_position_system)
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.run();
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}
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fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
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commands.spawn((
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Camera2d,
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Camera {
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// Cursor position will take the viewport offset into account
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viewport: Some(Viewport {
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physical_position: [200, 100].into(),
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physical_size: [600, 600].into(),
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..default()
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}),
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..default()
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},
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));
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commands
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.spawn(NodeBundle {
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style: Style {
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width: Val::Percent(100.),
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height: Val::Percent(100.0),
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align_items: AlignItems::Center,
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justify_content: JustifyContent::Center,
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flex_direction: FlexDirection::Column,
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..default()
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},
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..default()
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})
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.with_children(|parent| {
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parent
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.spawn(NodeBundle {
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style: Style {
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width: Val::Px(250.),
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height: Val::Px(250.),
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margin: UiRect::bottom(Val::Px(15.)),
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..default()
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},
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background_color: Color::srgb(235., 35., 12.).into(),
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..default()
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})
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.insert(RelativeCursorPosition::default());
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parent.spawn((
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Text::new("(0.0, 0.0)"),
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TextFont {
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font: asset_server.load("fonts/FiraSans-Bold.ttf"),
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font_size: 33.0,
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..default()
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},
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TextColor(Color::srgb(0.9, 0.9, 0.9)),
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));
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});
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}
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/// This systems polls the relative cursor position and displays its value in a text component.
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fn relative_cursor_position_system(
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relative_cursor_position_query: Query<&RelativeCursorPosition>,
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mut output_query: Query<(&mut Text, &mut TextColor)>,
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) {
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let relative_cursor_position = relative_cursor_position_query.single();
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let (mut output, mut text_color) = output_query.single_mut();
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**output = if let Some(relative_cursor_position) = relative_cursor_position.normalized {
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format!(
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"({:.1}, {:.1})",
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relative_cursor_position.x, relative_cursor_position.y
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)
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} else {
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"unknown".to_string()
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};
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text_color.0 = if relative_cursor_position.mouse_over() {
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Color::srgb(0.1, 0.9, 0.1)
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} else {
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Color::srgb(0.9, 0.1, 0.1)
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};
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}
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