I am sick of non-deterministic memory management. So sick. This was the big promise of .NET wasn’t it, way back in the 00s? No more having to worry about reference counting, double-frees or leaks. Well all we’ve done is switched it for worrying about event handlers, garbage collector pauses and weak dictionaries.
If you don’t have to worry about memory in .NET applications, then why are there so many commercial tools for solving memory-related problems? I’m starting to yearn for the days of being able to put an instance on the stack for the length of a curly-bracketed scope, and knowing that after that, it’s gone. Continue reading Heisenmemory→
Oh man, I just wasted too many hours of my life trying to figure out why calls to glBlitFramebuffer in my iOS app were returning GL_INVALID_OPERATION. I was targeting iOS 7, so I should’ve been able to use OpenGL ES 3.0 calls, and after all, I’d built against the v3 headers and everything else was compiling and working… right?
Wrong. Well, I really should’ve RTFM. It turns out that ES 3.0 use is not determined just by the OS version, but by the hardware. So even if you’re running iOS 7, you can only use ES 3.0 if you’re on the latest gen: iPhone 5S, iPad Air etc. Check out the full compatibility matrix here.
Here are a few extra tips to help you avoid wasting your time like I did if you’re explicitly targeting OpenGL ES 3.0:
As well as running on the right hardware, you can also use the simulator, which supports emulation of v3.0.
Call glGetString(GL_VERSION) to get a report of which version you’re actually running.
Pass the appropriate parameter to EAGLContext initWithAPI, if you’re using it.
It’s pretty frustrating that you get no indication that the function’s not supported, as opposed to just having being passed bad state. But I guess that’s par-for-the-course with a bare-bones, down-to-the-metal API like Open GL.
On my recent iOS puzzler Wordz, I decided not to reinvent the wheel, and instead use an off-the-shelf 2d game framework. I settled on Cocos2d. It makes it very easy to put together sprite-based games or apps by providing all the basic pieces like a scene graph, animations and integration with a couple of physics engines. It’s built on OpenGL but, happily, hides all that away from you – unless you need it.
No sooner had I released it, than Apple came out and announced a new framework for 2d games: SpriteKit. And it’s remarkably similar to Cocos2d. Here I’ll take a look at a few places where they differ, so you know what to look out for if you’re considering migrating to SpriteKit. Continue reading SpriteKit for Cocos2D developers→
The push button. It’s truly the blunt instrument of UI design. While most other controls provide some indication of the type of operation they’re performing – sliders are adjusting a value, a switch is moving between two states – buttons just mean “do something”. What? The only way to tell is to press it and see. But this shouldn’t be the case. Continue reading A short (and round) history of the button→
Catchy title, eh? This little experiment came about as I’ve been working on an iOS app where I decided to use an embedded OpenGL view, via GLKit, for a bit more flexibility than a plain-old UIView. This found me falling head-first down a rabbit-hole of OpenGL ES shaders. I ended up putting together a little demo that emulates a lava lamp using a nifty bit of GLSL code. Continue reading An iOS Lava Lamp using OpenGL ES shaders→
Wow, it’s been a ridiculously long time since I’ve blogged. I think it’s time I put something up just to break the curse, and this seemed like a good, and hopefully useful, place to start. Time to polish some of these dusty drafts into published gems.
Ever been in that situation where you (or someone else) finds that Visual Studio just won’t set a breakpoint in some source code that you’re sure should be being used? You’ll see the hollow breakpoint icon and something like ‘The breakpoint will not currently be hit. No symbols have been loaded for this document’. Continue reading Examining PDB files with DBH→
In the second of an unknown number of parts in my series of Beginning F# posts, I’ll be talking about record types. They’re a useful and powerful F# feature that you’ll probably find yourself using very widely. I’ll take a look at what they are, how they’re used and how they integrate with the rest of the language. Continue reading Beginning F#: Records→
If, like me, you’re still squeezing yourself into 32-bit Windows processes, you’re probably, also like me, constantly keeping an eye on the virtual address space usage of your application. If you happen to have used something like vmmap to take a peek at your memory contents, maybe you’ve noticed something strange with some .NET assemblies: they’re loaded twice! What’s going on…? Continue reading .NET DLLs Loaded Twice→