The rubbersheet test computed the angle between a triangle's normal
and its position in word coordinates instead of in the frame of the
respective reference view.
This PR passes the reference view position to the shader and uses it to
transform world to ref. view coordinates.
The rubbersheet test computed the angle between a triangle's normal and its position in word coordinates instead of in the frame of the respective reference view.
This PR passes the reference view position to the shader and uses it to transform world to ref. view coordinates.