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//! Image operations for textures.

/// Flips the image vertically.
pub fn flip_vertical(memory: &[u8], size: [u32; 2], channels: u8) -> Vec<u8> {
    let (width, height, channels) = (size[0] as usize, size[1] as usize,
        channels as usize);
    let mut res = vec![0; width * height];
    let stride = width * channels;
    for y in 0..height {
        for x in 0..width {
            for c in 0..channels {
                res[(c + x * channels + (height - 1 - y) * stride) as usize] =
                    memory[(c + x * channels + y * stride) as usize];
            }
        }
    }
    res
}

/// Converts from alpha to rgba8.
pub fn alpha_to_rgba8(memory: &[u8], size: [u32; 2]) -> Vec<u8> {
    let (width, height) = (size[0] as usize, size[1] as usize);
    let capacity = width * height * 4;
    let stride = width;
    let mut res = Vec::with_capacity(capacity);
    for y in 0..height {
        for x in 0..width {
            res.push(255);
            res.push(255);
            res.push(255);
            res.push(memory[x + y * stride]);
        }
    }
    res
}