Copy array to struct array as fast as possible in C#

Question

I am working with Unity 4.5, grabbing images as bytes arrays (each byte represent a channel, taking 4 bytes per pixel (rgba) and displaying them on a texture converting the

Answer 1

I haven't profiled it, but using fixed to ensure your memory doesn't get moved around and to remove bounds checks on array accesses might provide some benefit:

img = new Color32[byteArray.Length / nChannels]; //nChannels being 4
fixed (byte* ba = byteArray)
{
    fixed (Color32* c = img)
    {
        byte* byteArrayPtr = ba;
        Color32* colorPtr = c;
        for (int i = 0; i < img.Length; i++)
        {
            (*colorPtr).r = *byteArrayPtr++;
            (*colorPtr).g = *byteArrayPtr++;
            (*colorPtr).b = *byteArrayPtr++;
            (*colorPtr).a = *byteArrayPtr++;
            colorPtr++;
        }
    }
}

It might not provide much more benefit on 64-bit systems - I believe that the bounds checking is is more highly optimized. Also, this is an unsafe operation, so take care.