Re: Core Data with OpenGL
Re: Core Data with OpenGL
- Subject: Re: Core Data with OpenGL
- From: Erik Buck <email@hidden>
- Date: Tue, 13 Oct 2009 06:58:59 -0700 (PDT)
For a variety of reasons, I use Core Data with OpenGL all of the time. One of my presentations this weekend at "Voices That Matter: iPhone Developers Conference" uses a Core Data application with two different Views as an example of the MVC design pattern. One View presents information about the Model using Core Graphics/Quartz. The other View presents information using OpenGL ES.
I think that the Core Data model and any generated classes should be left untouched because you may want to regenerate the classes later.
I use Categories to add View specific drawing methods to the objects that represent Core Data entities. There are different categories with different methods in each View. E.g. there are -drawInOpenGLContext: methods added to entity objects within the OpenGL View subsystem and there are -drawWithCoreGraphics methods added in the Core Graphics View subsystem.
There is ample precedent for adding View specific capabilities to Model objects via categories. AppKit adds string drawing methods to NSString.
You definitely don't want your View subsystem constantly asking Model objects what kind they are in order to present information. If you have ifs or switches based on the class of objects or even based on an attribute of an Entity, you are doing it wrong.
It is much cleaner to use the built in language polymorphism. Just keep View related code implementation within the View.
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