bevy/examples/ui/ui_texture_slice.rs
Félix Lescaudey de Maneville ab16f5ed6a
UI Texture 9 slice (#11600)
> Follow up to #10588 
> Closes #11749 (Supersedes #11756)

Enable Texture slicing for the following UI nodes:
- `ImageBundle`
- `ButtonBundle`

<img width="739" alt="Screenshot 2024-01-29 at 13 57 43"
src="https://github.com/bevyengine/bevy/assets/26703856/37675681-74eb-4689-ab42-024310cf3134">

I also added a collection of `fantazy-ui-borders` from
[Kenney's](www.kenney.nl) assets, with the appropriate license (CC).
If it's a problem I can use the same textures as the `sprite_slice`
example

# Work done

Added the `ImageScaleMode` component to the targetted bundles, most of
the logic is directly reused from `bevy_sprite`.
The only additional internal component is the UI specific
`ComputedSlices`, which does the same thing as its spritee equivalent
but adapted to UI code.

Again the slicing is not compatible with `TextureAtlas`, it's something
I need to tackle more deeply in the future

# Fixes

* [x] I noticed that `TextureSlicer::compute_slices` could infinitely
loop if the border was larger that the image half extents, now an error
is triggered and the texture will fallback to being stretched
* [x] I noticed that when using small textures with very small *tiling*
options we could generate hundred of thousands of slices. Now I set a
minimum size of 1 pixel per slice, which is already ridiculously small,
and a warning will be sent at runtime when slice count goes above 1000
* [x] Sprite slicing with `flip_x` or `flip_y` would give incorrect
results, correct flipping is now supported to both sprites and ui image
nodes thanks to @odecay observation

# GPU Alternative

I create a separate branch attempting to implementing 9 slicing and
tiling directly through the `ui.wgsl` fragment shader. It works but
requires sending more data to the GPU:
- slice border
- tiling factors

And more importantly, the actual quad *scale* which is hard to put in
the shader with the current code, so that would be for a later iteration
2024-02-07 20:07:53 +00:00

88 lines
3.3 KiB
Rust

//! This example illustrates how to create a button that has its image sliced
//! and kept in proportion instead of being stretched by the button dimensions
use bevy::{prelude::*, winit::WinitSettings};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
// Only run the app when there is user input. This will significantly reduce CPU/GPU use.
.insert_resource(WinitSettings::desktop_app())
.add_systems(Startup, setup)
.add_systems(Update, button_system)
.run();
}
fn button_system(
mut interaction_query: Query<(&Interaction, &Children), (Changed<Interaction>, With<Button>)>,
mut text_query: Query<&mut Text>,
) {
for (interaction, children) in &mut interaction_query {
let mut text = text_query.get_mut(children[0]).unwrap();
match *interaction {
Interaction::Pressed => {
text.sections[0].value = "Press".to_string();
}
Interaction::Hovered => {
text.sections[0].value = "Hover".to_string();
}
Interaction::None => {
text.sections[0].value = "Button".to_string();
}
}
}
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
let image = asset_server.load("textures/fantasy_ui_borders/panel-border-010.png");
let slicer = TextureSlicer {
border: BorderRect::square(22.0),
center_scale_mode: SliceScaleMode::Stretch,
sides_scale_mode: SliceScaleMode::Stretch,
max_corner_scale: 1.0,
};
// ui camera
commands.spawn(Camera2dBundle::default());
commands
.spawn(NodeBundle {
style: Style {
width: Val::Percent(100.0),
height: Val::Percent(100.0),
align_items: AlignItems::Center,
justify_content: JustifyContent::Center,
..default()
},
..default()
})
.with_children(|parent| {
for [w, h] in [[150.0, 150.0], [300.0, 150.0], [150.0, 300.0]] {
parent
.spawn(ButtonBundle {
style: Style {
width: Val::Px(w),
height: Val::Px(h),
// horizontally center child text
justify_content: JustifyContent::Center,
// vertically center child text
align_items: AlignItems::Center,
margin: UiRect::all(Val::Px(20.0)),
..default()
},
image: image.clone().into(),
scale_mode: ImageScaleMode::Sliced(slicer.clone()),
..default()
})
.with_children(|parent| {
parent.spawn(TextBundle::from_section(
"Button",
TextStyle {
font: asset_server.load("fonts/FiraSans-Bold.ttf"),
font_size: 40.0,
color: Color::rgb(0.9, 0.9, 0.9),
},
));
});
}
});
}