bevy/examples/picking/simple_picking.rs
UkoeHB c2c19e5ae4
Text rework (#15591)
**Ready for review. Examples migration progress: 100%.**

# Objective

- Implement https://github.com/bevyengine/bevy/discussions/15014

## Solution

This implements [cart's
proposal](https://github.com/bevyengine/bevy/discussions/15014#discussioncomment-10574459)
faithfully except for one change. I separated `TextSpan` from
`TextSpan2d` because `TextSpan` needs to require the `GhostNode`
component, which is a `bevy_ui` component only usable by UI.

Extra changes:
- Added `EntityCommands::commands_mut` that returns a mutable reference.
This is a blocker for extension methods that return something other than
`self`. Note that `sickle_ui`'s `UiBuilder::commands` returns a mutable
reference for this reason.

## Testing

- [x] Text examples all work.

---

## Showcase

TODO: showcase-worthy

## Migration Guide

TODO: very breaking

### Accessing text spans by index

Text sections are now text sections on different entities in a
hierarchy, Use the new `TextReader` and `TextWriter` system parameters
to access spans by index.

Before:
```rust
fn refresh_text(mut query: Query<&mut Text, With<TimeText>>, time: Res<Time>) {
    let text = query.single_mut();
    text.sections[1].value = format_time(time.elapsed());
}
```

After:
```rust
fn refresh_text(
    query: Query<Entity, With<TimeText>>,
    mut writer: UiTextWriter,
    time: Res<Time>
) {
    let entity = query.single();
    *writer.text(entity, 1) = format_time(time.elapsed());
}
```

### Iterating text spans

Text spans are now entities in a hierarchy, so the new `UiTextReader`
and `UiTextWriter` system parameters provide ways to iterate that
hierarchy. The `UiTextReader::iter` method will give you a normal
iterator over spans, and `UiTextWriter::for_each` lets you visit each of
the spans.

---------

Co-authored-by: ickshonpe <david.curthoys@googlemail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2024-10-09 18:35:36 +00:00

75 lines
2.2 KiB
Rust

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