bevy/examples/ui/ui_texture_atlas.rs
Alex a7be8a2655
Prefer UVec2 when working with texture dimensions (#11698)
# Objective

The physical width and height (pixels) of an image is always integers,
but for `GpuImage` bevy currently stores them as `Vec2` (`f32`).
Switching to `UVec2` makes this more consistent with the [underlying
texture data](https://docs.rs/wgpu/latest/wgpu/struct.Extent3d.html).

I'm not sure if this is worth the change in the surface level API. If
not, feel free to close this PR.

## Solution

- Replace uses of `Vec2` with `UVec2` when referring to texture
dimensions.
- Use integer types for the texture atlas dimensions and sections.


[`Sprite::rect`](a81a2d1da3/crates/bevy_sprite/src/sprite.rs (L29))
remains unchanged, so manually specifying a sub-pixel region of an image
is still possible.

---

## Changelog

- `GpuImage` now stores its size as `UVec2` instead of `Vec2`.
- Texture atlases store their size and sections as `UVec2` and `URect`
respectively.
- `UiImageSize` stores its size as `UVec2`.

## Migration Guide

- Change floating point types (`Vec2`, `Rect`) to their respective
unsigned integer versions (`UVec2`, `URect`) when using `GpuImage`,
`TextureAtlasLayout`, `TextureAtlasBuilder`,
`DynamicAtlasTextureBuilder` or `FontAtlas`.
2024-02-25 15:23:04 +00:00

85 lines
2.8 KiB
Rust

//! This example illustrates how to use `TextureAtlases` within ui
use bevy::{prelude::*, winit::WinitSettings};
fn main() {
App::new()
.add_plugins(DefaultPlugins.set(
// This sets image filtering to nearest
// This is done to prevent textures with low resolution (e.g. pixel art) from being blurred
// by linear filtering.
ImagePlugin::default_nearest(),
))
// 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, increment_atlas_index)
.run();
}
fn setup(
mut commands: Commands,
asset_server: Res<AssetServer>,
mut texture_atlases: ResMut<Assets<TextureAtlasLayout>>,
) {
// Camera
commands.spawn(Camera2dBundle::default());
let text_style = TextStyle {
font_size: 20.,
..default()
};
let texture_handle = asset_server.load("textures/rpg/chars/gabe/gabe-idle-run.png");
let texture_atlas = TextureAtlasLayout::from_grid(UVec2::splat(24), 7, 1, None, None);
let texture_atlas_handle = texture_atlases.add(texture_atlas);
// root node
commands
.spawn(NodeBundle {
style: Style {
width: Val::Percent(100.0),
height: Val::Percent(100.0),
flex_direction: FlexDirection::Column,
justify_content: JustifyContent::Center,
align_items: AlignItems::Center,
row_gap: Val::Px(text_style.font_size * 2.),
..default()
},
..default()
})
.with_children(|parent| {
parent.spawn(AtlasImageBundle {
style: Style {
width: Val::Px(256.),
height: Val::Px(256.),
..default()
},
texture_atlas: texture_atlas_handle.into(),
image: UiImage::new(texture_handle),
..default()
});
parent.spawn(TextBundle::from_sections([
TextSection::new("press ".to_string(), text_style.clone()),
TextSection::new(
"space".to_string(),
TextStyle {
color: LegacyColor::YELLOW,
..text_style.clone()
},
),
TextSection::new(" to advance frames".to_string(), text_style),
]));
});
}
fn increment_atlas_index(
mut atlas_images: Query<&mut TextureAtlas>,
keyboard: Res<ButtonInput<KeyCode>>,
) {
if keyboard.just_pressed(KeyCode::Space) {
for mut atlas_image in &mut atlas_images {
atlas_image.index = (atlas_image.index + 1) % 6;
}
}
}