87 lines
3.1 KiB
Rust
87 lines
3.1 KiB
Rust
use crate::TextureAtlas;
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use bevy_asset::Assets;
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use bevy_math::{IVec2, Rect, Vec2};
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use bevy_render::texture::{Image, TextureFormatPixelInfo};
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use guillotiere::{size2, Allocation, AtlasAllocator};
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/// Helper utility to update [`TextureAtlas`] on the fly.
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///
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/// Helpful in cases when texture is created procedurally,
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/// e.g: in a font glyph [`TextureAtlas`], only add the [`Image`] texture for letters to be rendered.
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pub struct DynamicTextureAtlasBuilder {
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atlas_allocator: AtlasAllocator,
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padding: i32,
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}
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impl DynamicTextureAtlasBuilder {
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/// Create a new [`DynamicTextureAtlasBuilder`]
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///
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/// # Arguments
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///
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/// * `size` - total size for the atlas
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/// * `padding` - gap added between textures in the atlas, both in x axis and y axis
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pub fn new(size: Vec2, padding: i32) -> Self {
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Self {
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atlas_allocator: AtlasAllocator::new(to_size2(size)),
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padding,
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}
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}
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/// Add a new texture to [`TextureAtlas`].
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/// It is user's responsibility to pass in the correct [`TextureAtlas`]
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pub fn add_texture(
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&mut self,
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texture_atlas: &mut TextureAtlas,
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textures: &mut Assets<Image>,
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texture: &Image,
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) -> Option<usize> {
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let allocation = self.atlas_allocator.allocate(size2(
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texture.texture_descriptor.size.width as i32 + self.padding,
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texture.texture_descriptor.size.height as i32 + self.padding,
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));
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if let Some(allocation) = allocation {
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let atlas_texture = textures.get_mut(&texture_atlas.texture).unwrap();
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self.place_texture(atlas_texture, allocation, texture);
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let mut rect: Rect = to_rect(allocation.rectangle);
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rect.max -= self.padding as f32;
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Some(texture_atlas.add_texture(rect))
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} else {
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None
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}
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}
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fn place_texture(
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&mut self,
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atlas_texture: &mut Image,
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allocation: Allocation,
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texture: &Image,
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) {
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let mut rect = allocation.rectangle;
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rect.max.x -= self.padding;
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rect.max.y -= self.padding;
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let atlas_width = atlas_texture.texture_descriptor.size.width as usize;
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let rect_width = rect.width() as usize;
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let format_size = atlas_texture.texture_descriptor.format.pixel_size();
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for (texture_y, bound_y) in (rect.min.y..rect.max.y).map(|i| i as usize).enumerate() {
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let begin = (bound_y * atlas_width + rect.min.x as usize) * format_size;
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let end = begin + rect_width * format_size;
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let texture_begin = texture_y * rect_width * format_size;
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let texture_end = texture_begin + rect_width * format_size;
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atlas_texture.data[begin..end]
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.copy_from_slice(&texture.data[texture_begin..texture_end]);
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}
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}
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}
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fn to_rect(rectangle: guillotiere::Rectangle) -> Rect {
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Rect {
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min: IVec2::new(rectangle.min.x, rectangle.min.y).as_vec2(),
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max: IVec2::new(rectangle.max.x, rectangle.max.y).as_vec2(),
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}
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}
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fn to_size2(vec2: Vec2) -> guillotiere::Size {
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guillotiere::Size::new(vec2.x as i32, vec2.y as i32)
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}
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