Adapting the light pass

With the shadow maps rendered, it may be extremely tempting to try and sample them in our existing code, since the hard part is over, right? Well, not entirely. While we were extremely close with our previous approach, sadly, sampling of cubemap textures is the only thing that we couldn't do because of SFML. The sampling itself isn't really the problem, as much as binding the cubemap textures to be sampled is. Remember that sampling is performed by setting a uniform value of the sampler inside the shader to the texture unit ID that's bound to the texture in our C++ code. SFML resets these units each time something is rendered either onscreen, or to a render texture. The reason we haven't had this problem before is because we can set the uniforms of the shaders through SFML's sf::Shader class, which keeps track of references to textures and binds them to appropriate units when a shader is used for rendering. That's all fine and good, except for when the time comes...