http://www.xdtech.net/construct/3dscroll.zip
(WASD camera control) (Construct .993)
Distort map is "Negative shift" only (Below zero in mesh editor) then using Sprite Z elevation to bring it closer to the camera. The issue i'm seeing is pretty obvious - theres a popping of the distorted sprites that seems to occur when the center of the distorted mesh is too far out of the view frustum of the camera.