For parallax mapping, we need three textures: a height map texture, a normal map texture, and a color texture. We could combine the height map and normal map into a single texture, storing the height values in the alpha channel and the normal in the R, G, and B. This is a common technique and saves a significant amount of disk and memory space. In this recipe, we'll treat them as separate textures.
We also need a mesh with tangent vectors as well so that we can transform into tangent space. For more information on tangent space, see the previous recipe.
