Debugging

Debugging graphics isn't easy. Figuring out where the problem is can be challenging because of the many aspects and components when it comes to graphics. The goal of this chapter is to show the tools and techniques that you can use to help with your investigation.

Let's oversimply things and consider that your graphics problems fall into one of two categories: the graphics stack hasn't initialized properly, or something isn't quite right when you run your application.

These tools and resources are at your disposal to help you debug your graphics problem, whether it's with initialization or application execution:

• the slog2info utility
• the screeninfo utility
• the Screen API (e.g., SCREEN_PROPERTY_METRICS, SCREEN_PROPERTY_DEBUG)
• /dev/screen
• the gltracelogger utility
• the gltraceprinter utility
• the screencmd utility

Most of the debugging approaches described in this chapter require Screen's debug module (screen-debug.so). You must remember to ensure that this, and other debugging tools, are available on your target image when you're debugging. Once your debugging is complete, this library and associated debugging tools, aren't required on your final image.