Shader Editor 

<a href=http://shader.gamepoint.net/>Shader Editor Homepage</a></b><br><br>
"With the 'Shader Editor' you can create new or edit existing shaderfiles, new shaders and stages according to the specifications of the 'official' shaderdocs that were released by iD Software recently. Users can edit the supplied .def files that come with the editor to suit their own needs, although they contain all working attributes."<br><br>