I am new to Unity 3D, and I am trying to learn how to do my own opengl rendering in a plugin for iOS. Luckily there is such an official sample project here:
However, as I open it up in unity pro (4.1.2f1) under Mac OS, build and run it successfully, a blue window is appearing on my iPad 2, not the advertised rotating triangle.
Does anyone know what can be wrong? Maybe the sample is not updated for the latest Unity 3D, or am I missing some manual steps needed or something else obvious? 
Anyone? Or is there some other working sample showing how to achieve this?
Just an update: It appears the plugin sample is not working on iOS, only on Windows and Mac OSX. I thought the OpenGL version would be OK for iOS, but turns out not.
I thought most developers these days are targeting mobile devices with Unity3D, why make a Windows and MacOS only sample? 
The iOS Plugin example is located here: Unity - Manual: Native plug-ins for iOS
But there is no custom rendering example, though.