Started on a terrain sample. The idea is to have the vertex shader set height based on heightmap data... not 100% sure how we'll go about calculating normals just yet, since we don't know which heightmap the terrain is set to use when its mesh is set (same actually is true for the terrain's width and height which should map to the size of the heightmap... Simplest solution that's half-way to the goal would be to do normal calculation in the vertex shader... but that's slow! Might just require that we have a normal map for the terrain along with the height map.