The Trees The Fork Maple Day20 - Sprites

Adding sprites to the 2d renderer


I've been thinking about my match 3 game a bit more recently after seeing my close friend's game Heavenscape make more progress. Its motivated me to work on my own game ideas a bit more.

Last I worked on my game, I was hitting some walls and frustration with typescript. I wrote it at the time because I knew that I could ship typescript wherever I might need it, but since then, both wgpu and rust have become significantly more cross platform, and I have written the majority of a 2d renderer that would work perfectly for a game like this.

Up till now my renderer (which I'm now calling Bedrock) has been built with Neovide rendering in mind. Though that is still a project I would like to push forward, I would love it if Bedrock could be used for other projects such as 2d rendering in games. The goal is to make something simple enough to integrate wherever it might be needed using a simple scene format as the common interface. Eventually I expect Vello to fit into this usecase much better as they have been doing it for much longer, but in the short run I benefit from understanding the full stack.

Sprite Rendering

Luckily for me much of the work for rendering textures from the gpu is identical to rendering glyphs which I have already done. The main difference is that I need to parse and pull the binary data from a file rather than rasterizing glyphs. To do so I parameterized the SpriteState struct (and by extension, the Renderer) by a type that implements the RustEmbed trait.

pub struct SpriteState<A: RustEmbed> {
    buffer: Buffer,
    atlas_texture: Texture,
    bind_group: BindGroup,

This way the end user of Bedrock can insert their own embedded files. Eventually I will make components of the renderer optional so that projects that don't need image rendering remove the extra compiled code. From here I followed the glyph code pretty closely using the Image crate to parse the texture paths taken from the scene, load them from the RustEmbed struct, and parse them into binary data.

pub fn upload_sprite(&mut self, queue: &Queue, sprite: &Sprite) -> InstancedSprite {
    let allocation_rectangle = if let Some(alloc_id) = self.image_lookup.get(&sprite.texture) {
    } else {
        let image_file = A::get(&sprite.texture).unwrap();
        let image = image::load_from_memory(image_file.as_ref()).unwrap();
        let data = image.to_rgba8();
        let (image_width, image_height) = image.dimensions();

        let allocation = self
            .allocate(size2(image_width as i32, image_height as i32))
            .expect("Could not allocate glyph to atlas");


            ImageCopyTexture {
                texture: &self.atlas_texture,
                mip_level: 0,
                origin: Origin3d {
                    x: allocation.rectangle.min.x as u32,
                    y: allocation.rectangle.min.y as u32,
                    z: 0,
                aspect: TextureAspect::All,
            ImageDataLayout {
                offset: 0,
                bytes_per_row: Some(4 * image_width as u32),
                rows_per_image: Some(image_height as u32),
            Extent3d {
                width: image_width as u32,
                height: image_height as u32,
                depth_or_array_layers: 1,


    InstancedSprite {
        top_left: sprite.top_left,
        size: sprite.size,
        atlas_top_left: vec2(
            allocation_rectangle.min.x as f32,
            allocation_rectangle.min.y as f32,
        atlas_size: vec2(
            allocation_rectangle.width() as f32,
            allocation_rectangle.height() as f32,
        color: sprite.color,

Not much to it. With that out of the way, I wrote a simple shader again matching the glyph code to take the InstancedSprites and draw them to quads sampling from the atlas for the image data. I modified the scene to draw one of the sprites from my old attempt to the screen as a test.

Working Sprite

In this image there's an issue I haven't figured out yet though. For some reason the blurred background from the test layer containing the path isn't being rendered. I didn't have time to track down why yet, but I need to address that. The other problem I haven't investigated fully is that the scene viewer crashes on my desktop machine which has an nvidia gpu. I think its possible it crashes due to a texture format mismatch, but I'm not positive yet and would like to address that as well.

Once I figure out those two issues, I plan on porting the old TARemake code to Rust and Bedrock pretty directly. Once ported over, I can start thinking about where to take the project next.

Till tomorrow, Kaylee