Enable Parallax Quality for improved texture rendering

[sgi]

For more fun and power demanding stuff you can change the render type:
GBufferType="0"
to
GBufferType="1"

Should make shadows follow according to the offset in texture.

It was a while since I tested it, but it should work.

You forgot that you've got this line commented
//gl_FragData[2].xyz += vScreenNormal * fHeight * $VirtualPositionAddScale;