I’m trying to use a 3D texture for blending, so I upload four textures into the 3D Texture.
I would assume that I could use the third texture coordinate to switch between the different layers in the 3D texture. For instance if I wanted to use the first layer the third texture coordinate value would be 0.0f, and if wanted to use the last layer the coordinate would 1.0f is that not possible??? Or did I really miss something here.
For the behavior you want, I think you want to be clamping to the edge. If the texture is set to repeat, z=0 will be a blend between the top and bottom planes, I think.