bevy/crates/bevy_sprite/src/texture_atlas.rs
Robbie Davenport 4aabe983ec
Switch usage of std HashMap/HashSet default hasher, to aHash algo (#258)
switch to ahash for HashMaps and HashSets via a new bevy_utils crate
2020-08-28 17:08:51 -07:00

120 lines
3.5 KiB
Rust

use crate::Rect;
use bevy_asset::Handle;
use bevy_core::Bytes;
use bevy_math::Vec2;
use bevy_render::{
color::Color,
renderer::{RenderResource, RenderResources},
texture::Texture,
};
use bevy_utils::HashMap;
/// An atlas containing multiple textures (like a spritesheet or a tilemap)
#[derive(RenderResources)]
pub struct TextureAtlas {
/// The handle to the texture in which the sprites are stored
pub texture: Handle<Texture>,
// TODO: add support to Uniforms derive to write dimensions and sprites to the same buffer
pub size: Vec2,
/// The specific areas of the atlas where each texture can be found
#[render_resources(buffer)]
pub textures: Vec<Rect>,
#[render_resources(ignore)]
pub texture_handles: Option<HashMap<Handle<Texture>, usize>>,
}
// NOTE: cannot do `unsafe impl Byteable` here because Vec3 takes up the space of a Vec4. If/when glam changes this we can swap out
// Bytes for Byteable as a micro-optimization. https://github.com/bitshifter/glam-rs/issues/36
#[derive(Bytes, RenderResources, RenderResource)]
#[render_resources(from_self)]
pub struct TextureAtlasSprite {
pub color: Color,
pub index: u32,
}
impl Default for TextureAtlasSprite {
fn default() -> Self {
Self {
index: 0,
color: Color::WHITE,
}
}
}
impl TextureAtlasSprite {
pub fn new(index: u32) -> TextureAtlasSprite {
Self {
index,
..Default::default()
}
}
}
impl TextureAtlas {
/// Create a new `TextureAtlas` that has a texture, but does not have
/// any individual sprites specified
pub fn new_empty(texture: Handle<Texture>, dimensions: Vec2) -> Self {
Self {
texture,
size: dimensions,
texture_handles: None,
textures: Vec::new(),
}
}
/// Generate a `TextureAtlas` by splitting a texture into a grid where each
/// cell of the grid is one of the textures in the atlas
pub fn from_grid(
texture: Handle<Texture>,
size: Vec2,
columns: usize,
rows: usize,
) -> TextureAtlas {
let texture_width = size.x() / columns as f32;
let texture_height = size.y() / rows as f32;
let mut sprites = Vec::new();
for y in 0..rows {
for x in 0..columns {
sprites.push(Rect {
min: Vec2::new(x as f32 * texture_width, y as f32 * texture_height),
max: Vec2::new(
(x + 1) as f32 * texture_width,
(y + 1) as f32 * texture_height,
),
})
}
}
TextureAtlas {
size,
textures: sprites,
texture,
texture_handles: None,
}
}
/// Add a sprite to the list of textures in the `TextureAtlas`
///
/// # Arguments
///
/// * `rect` - The section of the atlas that contains the texture to be added,
/// from the top-left corner of the texture to the bottom-right corner
pub fn add_texture(&mut self, rect: Rect) {
self.textures.push(rect);
}
/// How many textures are in the `TextureAtlas`
pub fn len(&self) -> usize {
self.textures.len()
}
pub fn is_empty(&self) -> bool {
self.textures.is_empty()
}
pub fn get_texture_index(&self, texture: Handle<Texture>) -> Option<usize> {
self.texture_handles
.as_ref()
.and_then(|texture_handles| texture_handles.get(&texture).cloned())
}
}