Trying to flip screen in post process material

lpcstr

I'm trying to flip the screen horizontally and vertically in a post process material, but I am getting unexpected results.

return tex2D(SceneColorTexture, 1.0 - ScreenPos);

This should invert the Screen UVs and return the inverted image of the scene, but instead I'm getting this garbage:


http://s20.postimage.org/bgzte9dbf/Untitled_2.jpg