bevy/examples/dev_tools/fps_overlay.rs
Carter Anderson 015f2c69ca
Merge Style properties into Node. Use ComputedNode for computed properties. (#15975)
# Objective

Continue improving the user experience of our UI Node API in the
direction specified by [Bevy's Next Generation Scene / UI
System](https://github.com/bevyengine/bevy/discussions/14437)

## Solution

As specified in the document above, merge `Style` fields into `Node`,
and move "computed Node fields" into `ComputedNode` (I chose this name
over something like `ComputedNodeLayout` because it currently contains
more than just layout info. If we want to break this up / rename these
concepts, lets do that in a separate PR). `Style` has been removed.

This accomplishes a number of goals:

## Ergonomics wins

Specifying both `Node` and `Style` is now no longer required for
non-default styles

Before:
```rust
commands.spawn((
    Node::default(),
    Style {
        width:  Val::Px(100.),
        ..default()
    },
));
```

After:

```rust
commands.spawn(Node {
    width:  Val::Px(100.),
    ..default()
});
```

## Conceptual clarity

`Style` was never a comprehensive "style sheet". It only defined "core"
style properties that all `Nodes` shared. Any "styled property" that
couldn't fit that mold had to be in a separate component. A "real" style
system would style properties _across_ components (`Node`, `Button`,
etc). We have plans to build a true style system (see the doc linked
above).

By moving the `Style` fields to `Node`, we fully embrace `Node` as the
driving concept and remove the "style system" confusion.

## Next Steps

* Consider identifying and splitting out "style properties that aren't
core to Node". This should not happen for Bevy 0.15.

---

## Migration Guide

Move any fields set on `Style` into `Node` and replace all `Style`
component usage with `Node`.

Before:
```rust
commands.spawn((
    Node::default(),
    Style {
        width:  Val::Px(100.),
        ..default()
    },
));
```

After:

```rust
commands.spawn(Node {
    width:  Val::Px(100.),
    ..default()
});
```

For any usage of the "computed node properties" that used to live on
`Node`, use `ComputedNode` instead:

Before:
```rust
fn system(nodes: Query<&Node>) {
    for node in &nodes {
        let computed_size = node.size();
    }
}
```

After:
```rust
fn system(computed_nodes: Query<&ComputedNode>) {
    for computed_node in &computed_nodes {
        let computed_size = computed_node.size();
    }
}
```
2024-10-18 22:25:33 +00:00

81 lines
2.4 KiB
Rust

//! Showcase how to use and configure FPS overlay.
use bevy::{
dev_tools::fps_overlay::{FpsOverlayConfig, FpsOverlayPlugin},
prelude::*,
text::FontSmoothing,
};
struct OverlayColor;
impl OverlayColor {
const RED: Color = Color::srgb(1.0, 0.0, 0.0);
const GREEN: Color = Color::srgb(0.0, 1.0, 0.0);
}
fn main() {
App::new()
.add_plugins((
DefaultPlugins,
FpsOverlayPlugin {
config: FpsOverlayConfig {
text_config: TextFont {
// Here we define size of our overlay
font_size: 42.0,
// If we want, we can use a custom font
font: default(),
// We could also disable font smoothing,
font_smoothing: FontSmoothing::default(),
},
// We can also change color of the overlay
text_color: OverlayColor::GREEN,
enabled: true,
},
},
))
.add_systems(Startup, setup)
.add_systems(Update, customize_config)
.run();
}
fn setup(mut commands: Commands) {
// We need to spawn a camera (2d or 3d) to see the overlay
commands.spawn(Camera2d);
// Instruction text
commands.spawn((
Text::new(concat!(
"Press 1 to toggle the overlay color.\n",
"Press 2 to decrease the overlay size.\n",
"Press 3 to increase the overlay size.\n",
"Press 4 to toggle the overlay visibility."
)),
Node {
position_type: PositionType::Absolute,
bottom: Val::Px(12.),
left: Val::Px(12.),
..default()
},
));
}
fn customize_config(input: Res<ButtonInput<KeyCode>>, mut overlay: ResMut<FpsOverlayConfig>) {
if input.just_pressed(KeyCode::Digit1) {
// Changing resource will affect overlay
if overlay.text_color == OverlayColor::GREEN {
overlay.text_color = OverlayColor::RED;
} else {
overlay.text_color = OverlayColor::GREEN;
}
}
if input.just_pressed(KeyCode::Digit2) {
overlay.text_config.font_size -= 2.0;
}
if input.just_pressed(KeyCode::Digit3) {
overlay.text_config.font_size += 2.0;
}
if input.just_pressed(KeyCode::Digit4) {
overlay.enabled = !overlay.enabled;
}
}