   Reflections/Refractions on a Projected Surface
  How do I reflect/refract on a planar projected surface?Basically, I have my planar mirrors that have a reflection and refraction texture.  So far, I can calculate the correct fresnel term for the surface, but I don't know how to calculate the reflection/refraction texture coordinates.At the moment, I am using projection (since my images are 2D view space images), I project the image onto the surface and it all works nice.  Since this is all in 2D, though, how do I take into account the surface normal to reflect/refract the surface?Thanks   
  Anyone?I have been messing with adding the normals to the texture coordinates and it produces interesting results (if nothing else, I can easily hack it using that method), but I'd prefer a more true method if one exists.   