Painting individual pixels on dynamically generated sprites

[pmorim]

For context, I'm trying to build a tech demo for a 2D pixel-art game.
The world would be infinite and divided into dynamically created 32x32 chunks with each of their pixels painted according to some world-gen rules.

My idea was to generate a sprite for each chunk and paint its pixels accordingly.
But I cannot figure out how to create a sprite with the generated pixels.

const CHUNK_SIZE = 32;

// Multiply by 4 for RGBA channels?
let mut pixel_data = Vec::with_capacity(CHUNK_SIZE * CHUNK_SIZE);

for y in 0..CHUNK_SIZE {
    for x in 0..CHUNK_SIZE {
          // Fancy algorithm
          // Push pixel to vec
    }
}

// Add pixel data to sprite 👈
// Spawn sprite

Any ideas?

[Aiden2207]

You can create a texture from a dynamic Image. You'd probably want something like this:

pub fn setup_graphics(mut commands: Commands, mut images: ResMut<Assets<Image>>) {
    const CHUNK_SIZE = 32;
    let mut pixels = Vec::with_capacity(CHUNK_SIZE * CHUNK_SIZE * 4);
    for y in 0..CHUNK_SIZE {
        for x in 0..CHUNK_SIZE {
              // Fancy algorithm
              // Push pixel to vec
              // Bear in mind, pixels are 4 bytes long, at least the way things are set up below
        }
    }

    let size = Extent3d {
        width: 32,
        height: 32,
        ..default()
    };
    let mut image = Image {
        data: pixels,
        texture_descriptor: TextureDescriptor {
            size,
            label: None,
            dimension: TextureDimension::D2,
            format: TextureFormat::Bgra8UnormSrgb, // obviously, if you use a different color scale put the appropriate one here 
            mip_level_count: 1,
            sample_count: 1,
            usage: TextureUsages::RENDER_ATTACHMENT //I think these flags are right, but no promises
                | TextureUsages::COPY_SRC
                | TextureUsages::TEXTURE_BINDING,
            view_formats: &[TextureFormat::Bgra8UnormSrgb], // best to keep this one the same as `format` unless you know what you are doing
        },
        ..default()
    };

    let image_handle = images.add(image); //now the image is an asset and can be used in textures

    // Spawns the sprite at the origin, obviously, you probably want to add some other components, move it, or maybe even just stash the image handle for later
    commands 
        .spawn(SpriteBundle {  
            texture: image_handle.clone(),
            transform: Transform::from_xyz(0.0, 0.0, 0.0),
            ..default()
        });
}

[pmorim]

Thank you. It worked perfectly.