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

Yes, Marshal.Copy is the way to go. I've answered a similar question here.

Here's a generic method to copy from struct[] to byte[] and vice versa

private static byte[] ToByteArray(T[] source) where T : struct
{
    GCHandle handle = GCHandle.Alloc(source, GCHandleType.Pinned);
    try
    {
        IntPtr pointer = handle.AddrOfPinnedObject();
        byte[] destination = new byte[source.Length * Marshal.SizeOf(typeof(T))];
        Marshal.Copy(pointer, destination, 0, destination.Length);
        return destination;
    }
    finally
    {
        if (handle.IsAllocated)
            handle.Free();
    }
}

private static T[] FromByteArray(byte[] source) where T : struct
{
    T[] destination = new T[source.Length / Marshal.SizeOf(typeof(T))];
    GCHandle handle = GCHandle.Alloc(destination, GCHandleType.Pinned);
    try
    {
        IntPtr pointer = handle.AddrOfPinnedObject();
        Marshal.Copy(source, 0, pointer, source.Length);
        return destination;
    }
    finally
    {
        if (handle.IsAllocated)
            handle.Free();
    }
}

Use it as:

[StructLayout(LayoutKind.Sequential)]
public struct Demo
{
    public double X;
    public double Y;
}

private static void Main()
{
    Demo[] array = new Demo[2];
    array[0] = new Demo { X = 5.6, Y = 6.6 };
    array[1] = new Demo { X = 7.6, Y = 8.6 };

    byte[] bytes = ToByteArray(array);
    Demo[] array2 = FromByteArray(bytes);
}