gistfile1.txt

struct Renderable { virtual ~Renderable() {} };
struct SelfRenderable : Renderable {
    virtual void Render(Renderer& render) = 0;
};
class Renderer {
    com_ptr<ID3D10Device> device;
public:
    std::unordered_map<std::type_index, std::function<void(Renderer& renderer, const Renderable& renderable)>> rendering_functions;
    void Render(Renderable& renderable) {
        if (rendering_functions.find(typeid(renderable)) ! rendering_functions.end())
            return rendering_functions[typeid(renderable)](*this, renderable);
        if (auto self = dynamic_cast<SelfRenderable*>(&renderable))
            return self->Render(*this);
        assert(false);
    }
    void RenderText(std::string text, Rectangle where) { ... }
    void RenderImage(Image i, Rectangle where) { ... }
};