Thank you all very much for the great information available in this forum. Without your help, I would never have been able to accomplish what I have so far with shaders. I have been able to use the shader code provided (without really understanding it) and have amazed myself with the results.

Now I have a few questions that I need to ask for clarification, and to make sure that I understand correctly. I will try to word my questions as clearly as possible. Since I am still a newbie as far as shaders are concerned, I apologize if I am not as clear as I would like to be. I have actually gotten quite confused trying to digest all of the technical information.

My questions deal with the alpha channel and how exactly it is used by pixel and vertex shaders to multi-texture terrains. I have looked at people's sample TGA files and I am trying to digest how exactly they work.

1) The alpha channel is always greyscale, right?
2) Does the transparency value of the alpha channel determine the level of shading and the blending used?
3) When you create a TGA image and give it an alpha channel, are the RGB values used at all by the shader? If so, how does this work?

It is just an assumption on my part, but it seems like the red channel controls one texture, the green controls another, and the blue yet another. Then the transparency values control the actual shading.

How far off am I?

Many thanks to any who can assist me in understanding this.