iPhone From Scratch pt. III

Last time I talked a bit about the implementation of OpenGL ES that Apple provides its developers and the restrictions that it imposes when writing an OpenGL app. This time we will walk through obeying those constraints and write a Plain-Jane app that sets the stage for the app to properly receive and handle OpenGL commands.

Road Map

The general idea here is that the simplest iPhone template gives us a Window. We will add a special View subclass to that Window in Interface Builder, then at the appointed time, initialize OpenGL with an appropriate framebuffer that conforms to Apple’s implementation.

iPhone From Scratch pt. II

Whenever I begin working with a new graphics API or a new environment, I like to spend time getting acquainted with fundamental issues like the coordinate system. Often times, the first thing I do is setup hardcoded vertex buffers to draw coordinate axes just to make sure that I’m not assuming anything. That’s what I’m going to start walkng through here, explaining next to near everything along the way.

Starting from Scratch

Last time, just to make sure our development environment was set-up, we used the OpenGL ES template. But I am more interested in seeing how that is itself built, so I am starting with the most basic iPhone Application possible.

iPhone From Scratch

So here, I wanted to post some of what I have found out while learning to make iPhone games. My hope is that by posting my results it may help others to get going faster and ultimately make a better community for iPhone coders.

The Baseline

I imagine that anyone who may be reading this probably knows how to get started, but for completeness, let’s start with the absolutely easiest thing. This is equivalent to Hello World, just a proof-of-concept to verify that everything works.