MC3D – Platform Agnostic 3D Foundation
Sorry for the lack of posts recently. Things have been, well… you know. Same old story. Super busy. Which is good, but it’s murder on blog post frequency.
I’ve recently had to port some OpenGL ES work I did from iOS to Android. It used to be that doing so would have been insanely painful (as opposed to just painful). I would have had to convert the Objective-C code to Java, and then maintain completely distinct sets of code that do the same exact thing. Fortunately, the Android NDK (Native Development Kit) allows you to write code for Android in C/C++. The version of the NDK supported on 2.2 still requires part of the Activity (Android’s counterpart to an iOS view controller) to be written in Java, but does allow you to call C/C++ code using JNI. In 2.3 and 3.0, you can do entire activities in C or C++.
This is a huge step forward for Android for those of us who do performance-critical work on multiple platforms, but it’s not without some pain. Debugging across the JNI bridge is… less than easy. But, being able to share code across platforms is a huge win, and being able to get native speeds in the process is teh awseome.
During these projects, I’ve been taking a lot of my 3D-related code and creating a new set of platform-agnostic C functions and types. I’ve been cleaning up and making names consistent, and placing appropriate pre-compiler macros to make sure the code compiles correctly everywhere. On iOS, the library will take advantage of the Accelerate Framework in places, but doesn’t require Accelerate to function.
I’ve chosen C because I don’t like mixing C++ and Objective-C. The object models are two different for my tastes. But I’ve also made sure to include proper ifdef’d extern statements so that you can import the MC3D header files from C++ without hassle.
I’ve dubbed this set of functions MC3D, and I’m making it open source under a simplified version of the simplified BSD license (simplified simplified BSD license?). I’ve taken out the attribution requirement, so the only requirement is that if you re-distribute the source code, you have to leave the copyright and license text intact. That’s it. Otherwise, you can use it for free in any project, commercial or otherwise, without paying anything, without attributing, and without asking (no really, you don’t need to ask).
MC3D is still very much a work in progress, and I’m only adding code to the repository that I feel is ready for public consumption. Much of what’s in MC3D has been posted here before, sometimes with different names or in slightly different form.
I have other code that I plan to add in the future, including higher-level functionality like model loading, scene management, and skeletal animation, but I won’t add anything until its both solid and platform agnostic.
Currently, documentation is very sparse, and I currently can’t offer any support or help with using it, so caveat emptor! I will gladly accept contributions, bug fixes, and new functionality back into the MC3D codeline.
Link fixed, sorry about that
http://iphonedevelopment.blogspot.com
Dealloc
Last week there was a bit of a Twitter in-fight in the iOS community over the “right” way to release your instance variables in dealloc. I think Rob actually started it, to be honest, but I probably shouldn’t be bringing that up.
Basically, several developers were claiming that there’s never a reason to set an instance variable to nil in dealloc, while others were arguing that you should always do so.
To me, there didn’t seem to be a clear and compelling winner between the two approaches. I’ve used both in my career. However, since we’re in the process of trying to decide which approach to use in the next edition of Beginning iPhone Development, I reached out to Apple’s Developer Tools Evangelist, Michael Jurewitz, to see if there was an official or recommended approach to handling instance variables in dealloc.
Other than the fact that you should never, ever use mutators in dealloc (or init, for that matter), Apple does not have an official recommendation on the subject.
However, Michael and Matt Drance of Bookhouse Software and a former Evangelist himself, had discussed this issue extensively last week. They kindly shared their conclusions with me and said it was okay for me to turn it into a blog post. So, here it is. Hopefully, I’ve captured everything correctly.
MGSplitViewController for iPad
MGSplitViewController is an open source replacement for UISplitViewController, with various useful enhancements.
Here’s a demonstration video hosted on YouTube. It’s better if you watch it in full HD.
Donations
I wrote MGSplitViewController for my own use, but I’m making it available (as usual) for the benefit of the iOS developer community, because I care about this community and about the platform.