Struct widgetry::backend_glow::SpriteTexture

pub struct SpriteTexture {
    texture_bytes: Vec<u8>,
    sprite_width: u32,
    sprite_height: u32,
    sprite_count: u32,
}

Uploads a sprite sheet of textures to the GPU so they can be used by Fill::Texture and friends to paint shapes.

path - image file which is a grid of images. sprite_length - the width and height of an individual cell in the image grid

The image file can have any number of sprites, but they must all be the same size.

Once uploaded, textures are addressed by their id, starting from 1, from left to right, top to bottom, like so:

┌─┬─┬─┐ │1│2│3│ ├─┼─┼─┤ │4│5│6│ ├─┼─┼─┤ │7│8│9│ └─┴─┴─┘

Texture(0) is reserved for a pure white (no-op) texture.

Implementation is based on the the description of ArrayTextures from: https://www.khronos.org/opengl/wiki/Array_Texture.

OpenGL texture arrays expect each texture’s bytes to be contiguous, but it’s conventional to store textures in a grid within a single spritesheet image, where a row and column traverses multiple sprites.

For example, if we had 6 textures, A-F, the input spritesheet bytes would be like: [[AAA, BBB, CCC], [AAA, BBB, CCC] [AAA, BBB, CCC], [DDD, EEE, FFF], [DDD, EEE, FFF], [DDD, EEE, FFF]]

Which we need to convert to: [[AAAAAAAAA], [BBBBBBBBB], [CCCCCCCCC], [DDDDDDDDD], [EEEEEEEEE], [FFFFFFFFF]]

Fields

texture_bytes: Vec<u8>

sprite_width: u32

sprite_height: u32

sprite_count: u32

Implementations

impl SpriteTexture

pub fn new( sprite_bytes: Vec<u8>, sprite_width: u32, sprite_height: u32 ) -> Result<Self>

fn upload_gl2(&self, gl: &Context) -> Result<()>