bevy/examples/2d/sprite_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

146 lines
4.4 KiB
Rust

//! Showcases sprite 9 slice scaling and tiling features, enabling usage of
//! sprites in multiple resolutions while keeping it in proportion
use bevy::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins.set(WindowPlugin {
primary_window: Some(Window {
resolution: (1350.0, 700.0).into(),
..default()
}),
..default()
}))
.add_systems(Startup, setup)
.run();
}
fn spawn_sprites(
commands: &mut Commands,
texture_handle: Handle<Image>,
mut position: Vec3,
slice_border: f32,
style: TextStyle,
gap: f32,
) {
let cases = [
// Reference sprite
(
"Original texture",
style.clone(),
Vec2::splat(100.0),
ImageScaleMode::default(),
),
// Scaled regular sprite
(
"Stretched texture",
style.clone(),
Vec2::new(100.0, 200.0),
ImageScaleMode::default(),
),
// Stretched Scaled sliced sprite
(
"Stretched and sliced",
style.clone(),
Vec2::new(100.0, 200.0),
ImageScaleMode::Sliced(TextureSlicer {
border: BorderRect::square(slice_border),
center_scale_mode: SliceScaleMode::Stretch,
..default()
}),
),
// Scaled sliced sprite
(
"Sliced and Tiled",
style.clone(),
Vec2::new(100.0, 200.0),
ImageScaleMode::Sliced(TextureSlicer {
border: BorderRect::square(slice_border),
center_scale_mode: SliceScaleMode::Tile { stretch_value: 0.5 },
sides_scale_mode: SliceScaleMode::Tile { stretch_value: 0.2 },
..default()
}),
),
// Scaled sliced sprite horizontally
(
"Sliced and Tiled",
style.clone(),
Vec2::new(300.0, 200.0),
ImageScaleMode::Sliced(TextureSlicer {
border: BorderRect::square(slice_border),
center_scale_mode: SliceScaleMode::Tile { stretch_value: 0.2 },
sides_scale_mode: SliceScaleMode::Tile { stretch_value: 0.3 },
..default()
}),
),
// Scaled sliced sprite horizontally with max scale
(
"Sliced and Tiled with corner constraint",
style,
Vec2::new(300.0, 200.0),
ImageScaleMode::Sliced(TextureSlicer {
border: BorderRect::square(slice_border),
center_scale_mode: SliceScaleMode::Tile { stretch_value: 0.1 },
sides_scale_mode: SliceScaleMode::Tile { stretch_value: 0.2 },
max_corner_scale: 0.2,
}),
),
];
for (label, text_style, size, scale_mode) in cases {
position.x += 0.5 * size.x;
commands
.spawn(SpriteBundle {
transform: Transform::from_translation(position),
texture: texture_handle.clone(),
sprite: Sprite {
custom_size: Some(size),
..default()
},
scale_mode,
..default()
})
.with_children(|builder| {
builder.spawn(Text2dBundle {
text: Text::from_section(label, text_style).with_justify(JustifyText::Center),
transform: Transform::from_xyz(0., -0.5 * size.y - 10., 0.0),
text_anchor: bevy::sprite::Anchor::TopCenter,
..default()
});
});
position.x += 0.5 * size.x + gap;
}
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
commands.spawn(Camera2dBundle::default());
let font = asset_server.load("fonts/FiraSans-Bold.ttf");
let style = TextStyle {
font: font.clone(),
font_size: 16.0,
color: Color::WHITE,
};
// Load textures
let handle_1 = asset_server.load("textures/slice_square.png");
let handle_2 = asset_server.load("textures/slice_square_2.png");
spawn_sprites(
&mut commands,
handle_1,
Vec3::new(-600.0, 200.0, 0.0),
200.0,
style.clone(),
50.,
);
spawn_sprites(
&mut commands,
handle_2,
Vec3::new(-600.0, -200.0, 0.0),
80.0,
style,
50.,
);
}