This shader processes the depth map of the jit.freenect.grab external and outputs perspective-corrected x,y,z vertex coordinates for use with jit.gl.mesh and others. It expects jit.freenect.grab to output in mode 0 (raw). Based on the math at http://openkinect.org/wiki/Imaging_Information. Shader by Dieter Vandoren (http://dietervandoren.net). //