Unity Shader Lab

http://docs.unity3d.com/460/Documentation/Manual/SL-BuiltinValues.html

http://docs.unity3d.com/Manual/SL-BuiltinMacros.html

http://docs.unity3d.com/Manual/SL-DepthTextures.html

http://docs.unity3d.com/Manual/SL-CameraDepthTexture.html