gistfile1.txt

    let num_h_tiles = tile.sheet.sheet_size.0;
    let tile_w = tile.sheet.tile_size.0;
    let tile_h = tile.sheet.tile_size.1;
    let src_x = tile.index % num_h_tiles * tile_w;
    let src_y = tile.index / num_h_tiles * tile_h;
    let image = Image::new()
        .src_rect([src_x as i32,
                   src_y as i32,
                   tile_w as i32,
                   tile_h as i32])
        .rect([(x * tile_w) as f64, (y * tile_h) as f64, tile_w as f64, tile_h as f64])
    let transform = c.transform.scale(SCALE, SCALE);
    image.draw(texture, &Default::default(), transform, gl);