loop.c

    while(running)
    {
        glClear(GL_COLOR_BUFFER_BIT);
        
        glDisable(GL_DEPTH_TEST);
        
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        glOrtho(0.0,1024,768,0,-1.0,1.0);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
        
        //2d rendering
        statemgr_render(mgrState);
        
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        gluPerspective(90,(float)1024/(float)768,10,100);
        glMatrixMode(GL_MODELVIEW);
        glViewport(0,0,1024,768);
        glLoadIdentity();
        glEnable(GL_DEPTH_TEST);
        
        //3d rendering
        
        glfwSwapBuffers();
        running=!glfwGetKey(GLFW_KEY_ESC)&&glfwGetWindowParam(GLFW_OPENED);
    }