add a bunch more debugging with VTK_REPORT_OPENGL_ERRORS
Have the OpenGLState object check for errors after every call and check state consistency before every call when VTK_REPORT_OPENGL_ERRORS is set which it commonly is for Debug builds
Have the OpenGLState object check for errors after every call and check state consistency before every call when VTK_REPORT_OPENGL_ERRORS is set which it commonly is for Debug builds