bevy/examples/stress_tests/many_buttons.rs
ira 992681b59b Make Resource trait opt-in, requiring #[derive(Resource)] V2 (#5577)
*This PR description is an edited copy of #5007, written by @alice-i-cecile.*
# Objective
Follow-up to https://github.com/bevyengine/bevy/pull/2254. The `Resource` trait currently has a blanket implementation for all types that meet its bounds.

While ergonomic, this results in several drawbacks:

* it is possible to make confusing, silent mistakes such as inserting a function pointer (Foo) rather than a value (Foo::Bar) as a resource
* it is challenging to discover if a type is intended to be used as a resource
* we cannot later add customization options (see the [RFC](https://github.com/bevyengine/rfcs/blob/main/rfcs/27-derive-component.md) for the equivalent choice for Component).
* dependencies can use the same Rust type as a resource in invisibly conflicting ways
* raw Rust types used as resources cannot preserve privacy appropriately, as anyone able to access that type can read and write to internal values
* we cannot capture a definitive list of possible resources to display to users in an editor
## Notes to reviewers
 * Review this commit-by-commit; there's effectively no back-tracking and there's a lot of churn in some of these commits.
   *ira: My commits are not as well organized :')*
 * I've relaxed the bound on Local to Send + Sync + 'static: I don't think these concerns apply there, so this can keep things simple. Storing e.g. a u32 in a Local is fine, because there's a variable name attached explaining what it does.
 * I think this is a bad place for the Resource trait to live, but I've left it in place to make reviewing easier. IMO that's best tackled with https://github.com/bevyengine/bevy/issues/4981.

## Changelog
`Resource` is no longer automatically implemented for all matching types. Instead, use the new `#[derive(Resource)]` macro.

## Migration Guide
Add `#[derive(Resource)]` to all types you are using as a resource.

If you are using a third party type as a resource, wrap it in a tuple struct to bypass orphan rules. Consider deriving `Deref` and `DerefMut` to improve ergonomics.

`ClearColor` no longer implements `Component`. Using `ClearColor` as a component in 0.8 did nothing.
Use the `ClearColorConfig` in the `Camera3d` and `Camera2d` components instead.


Co-authored-by: Alice <alice.i.cecile@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: devil-ira <justthecooldude@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2022-08-08 21:36:35 +00:00

111 lines
3.3 KiB
Rust

use bevy::{
diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
prelude::*,
window::PresentMode,
};
// For a total of 110 * 110 = 12100 buttons with text
const ROW_COLUMN_COUNT: usize = 110;
const FONT_SIZE: f32 = 7.0;
/// This example shows what happens when there is a lot of buttons on screen.
fn main() {
App::new()
.insert_resource(WindowDescriptor {
present_mode: PresentMode::Immediate,
..default()
})
.add_plugins(DefaultPlugins)
.add_plugin(FrameTimeDiagnosticsPlugin::default())
.add_plugin(LogDiagnosticsPlugin::default())
.init_resource::<UiFont>()
.add_startup_system(setup)
.add_system(button_system)
.run();
}
#[derive(Component)]
struct IdleColor(UiColor);
fn button_system(
mut interaction_query: Query<(&Interaction, &mut UiColor, &IdleColor), Changed<Interaction>>,
) {
for (interaction, mut material, IdleColor(idle_color)) in interaction_query.iter_mut() {
if matches!(interaction, Interaction::Hovered) {
*material = Color::ORANGE_RED.into();
} else {
*material = *idle_color;
}
}
}
#[derive(Resource)]
struct UiFont(Handle<Font>);
impl FromWorld for UiFont {
fn from_world(world: &mut World) -> Self {
let asset_server = world.get_resource::<AssetServer>().unwrap();
UiFont(asset_server.load("fonts/FiraSans-Bold.ttf"))
}
}
fn setup(mut commands: Commands, font: Res<UiFont>) {
let count = ROW_COLUMN_COUNT;
let count_f = count as f32;
let as_rainbow = |i: usize| Color::hsl((i as f32 / count_f) * 360.0, 0.9, 0.8);
commands.spawn_bundle(Camera2dBundle::default());
commands
.spawn_bundle(NodeBundle {
style: Style {
size: Size::new(Val::Percent(100.0), Val::Percent(100.0)),
..default()
},
..default()
})
.with_children(|commands| {
for i in 0..count {
for j in 0..count {
let color = as_rainbow(j % i.max(1)).into();
spawn_button(commands, font.0.clone_weak(), color, count_f, i, j);
}
}
});
}
fn spawn_button(
commands: &mut ChildBuilder,
font: Handle<Font>,
color: UiColor,
total: f32,
i: usize,
j: usize,
) {
let width = 90.0 / total;
commands
.spawn_bundle(ButtonBundle {
style: Style {
size: Size::new(Val::Percent(width), Val::Percent(width)),
position: UiRect {
bottom: Val::Percent(100.0 / total * i as f32),
left: Val::Percent(100.0 / total * j as f32),
..default()
},
align_items: AlignItems::Center,
position_type: PositionType::Absolute,
..default()
},
color,
..default()
})
.with_children(|commands| {
commands.spawn_bundle(TextBundle::from_section(
format!("{i}, {j}"),
TextStyle {
font,
font_size: FONT_SIZE,
color: Color::rgb(0.2, 0.2, 0.2),
},
));
})
.insert(IdleColor(color));
}