Couriersud fixed bug #603 Using the following sequence SDL_Init(..:) SDL_CreateWindow(..., SDL_WINDOW_OPENGL) SDL_DestroyWindow SDL_CreateWindow(..., SDL_WINDOW_OPENGL) SDL will crash in X11_GL_GetVisual. This is due to the fact that during SDL_DestroyWindow X11_GL_Shutdown was called because the last window has been closed. On the next call to SDL_CreateWindow the library is still loaded and only the memory is reinitialized. Function pointers such as gl_data->glXChooseVisual will not be reinitialized. Consequently, SDL will crash due to a NULL pointer access. The attached patch corrects the behaviour.