Some platforms have high resolution screens such as the iPad, this function determines how those platforms display their content. You have the choice of mode=1 which will use a full resolution frame buffer that will look better, or mode=0 that will use a smaller resolution frame buffer (usually half sized) which is then scaled to fit the screen, and will run faster. This does not affect low resolution devices that will always use a low resolution frame buffer.
SetResolutionMode( mode )