You can use the Source Texture and Mask to supply the height data for the function. Increase the Pre-Smoothing value to smooth the heightmap.

Where light is, there's also shadow. Soften the edges between the illuminated parts and the shadows by increasing the Smooth Radius parameter (Image 1).

The Primary Color supplies the color of the light source. Ambient light is colored by the Secondary Color. Setting the ambient light color to White allows you to only brighten the texture without shadows.