Do you have a brand new computer with a retina display and the latest OSX release?
I just started receiving messages like this yesterday. It appears that even though I followed all of Apple's development rules perfectly a year ago, they have since decided to change their API, thus breaking Cogs
I did some searching around and found that the problem isn't in my code, but rather in one of the toolkits that I'm using. I'll start trying to fix the problem immediately, but unfortuntaely, since I'm the only one maintaining this code and I have 2 much bigger projects that are demanding my time right now, I fear it will take a few weeks before I can get out a patch that will work on the new Macbook Pros with the retina display. This may sound like a small fix, but since Apple development rules change very quickly, I have to make a huge variety of changes to the game before Apple will approve a new version.
It's often the case that whenever Apple releases new hardware, there are temporary bugs that appear in many games until Apple releases a software patch for the graphics drivers. So this may fix itself next time you get an OS update.
I wish I had better news.
Thank you for the bug report. Without these kinds of hardware-specific bug reports, it would be impossible for me to make Cogs work on as many computers as possible.
Founder, Lazy 8 Studios