Volume Texel

In OGRE Engine, you should have a 3D texture and was implemnted in fixed function.

material Examples/VTDarkStuff
{
    technique
    {
        pass
        {
            diffuse 0.0 0.0 0.0
            ambient 0.1 0.1 0.15
            cull_hardware none
            lighting on
        }
      
    }
}