It is possible?

[ector]

It's possible, but you have to hack the gfx plugin to render to render everything twice to two render targets, then use a shader to combine them. Since the actual vertex positions must be different, you can't just use MRT to render to two render targets simultaneously, you have to buffer up the entire scene and render it again (HARD), or switch back and forth between two render targets really quickly (SLOW).

So, well, not for the faint-hearted.