All of the OSX platform layers I've seen use OpenGL which is kind of not the same as hand-rolling a software renderer from scratch, no?
Would Quartz2D be about as low as you can go on OSX?
I'm sure resurrecting this old thread is poor forum etiquette, but it looks to be very relevant to my interests. Jeff (or anyone else who can help), I'm curious what the simplest version of your platform layer is i.e. what would the analogous OSX implementation be to what Casey had running under windows on say, day 5, where there was just one file and a couple hundred lines of code?
OpenGL is actually the closest to the metal that you can currently get on OS X. It sits below Quartz. On iOS, you could drop down to Apple's Metal API, but that won't be coming to OS X any time soon.