void start();
void button_press(float, float, unsigned);
void pointer_motion(float, float);
virtual void render(Msp::GL::Renderer &, const Msp::GL::Tag &) const;
private:
void update_mesh();
void start();
void button_press(float, float, unsigned);
void pointer_motion(float, float);
virtual void render(Msp::GL::Renderer &, const Msp::GL::Tag &) const;
private:
void update_mesh();