void SetLazyRendering(bool state = true) {m_lazy_rendering = state;}
bool UsingLazyRendering() const {return m_lazy_rendering;}
void SetLazyRendering(bool state = true) {m_lazy_rendering = state;}
bool UsingLazyRendering() const {return m_lazy_rendering;}
void PrepareRender(); // call when m_render_dirty is true
void UpdateObjBoundsVBO(unsigned first_obj, unsigned last_obj); // call when m_buffer_dirty is true
void PrepareRender(); // call when m_render_dirty is true
void UpdateObjBoundsVBO(unsigned first_obj, unsigned last_obj); // call when m_buffer_dirty is true