opengl_error_break

Question

I'm developing a game for iPhone and is pretty far along, but one thing bugs me when using Instrument a see that something called opengl_error_break is taking LOTS of valueable time. The caller seems to be MBXGLEngine which is a part of the OpenGLES framework but I have no idea of what it does or how to debug it.

Does any one here have a clue about this? Here's a screen dump that can be of help.

Answer 1

It's a red herring. The time is actually spent in other OpenGL functions, but Instruments is confused.

In some OS/SDK versions, all OpenGL symbols are hidden except for opengl_error_break (which allows you to continue to set a breakpoint on it). This confuses Instruments (and Shark). Basically, Instruments knows the execution is in an OpenGL library, but since the only symbol it can find is opengl_error_break, it guesses (incorrectly) that opengl_error_break is executing.

This is explained by an Apple developer on the Apple Developer forums. A later reply goes into more detail.