iOS 6 Blues
Entry posted by Josh ·
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Apple's problems in iOS 6 aren't limited to maps. Their OpenGL drivers in iOS 6 are absolutely non-functional.
First I was experiencing a BAD_EXC_ACCESS error when rendering certain surfaces. Feedback on the Apple dev forum suggests I am not alone in this. I took a guess and switched my position vertex buffers to use vec4s instead of vec3s, and it appears to have solved that problem (even though both should be fine).
Second, all 3D objects just stopped appearing, completely. I've debugged it to the point of absolute barebones, and still can't get anything to show up...but only on the iPad 3 device itself. My iPhone 4 (also running iOS 6.01), the iOS simulator, and even my HTC Evo all appear fine, running the same code.
My guess is that the Apple driver team was given a directive to get the speed of their graphics chip up to be competitive with the latest 12-core NVidia Tegra, and that they gained speed by fine-tuning the drivers for specific applications they were testing with, at the expense of compliance with the OpenGL ES specification.
In a world where the graphics device performance between all targeted hardware can vary by 1000x, compliance with the OpenGL spec is paramount. Performance at the cost of reliability is not an option.
I also have come to the conclusion that OpenGL is just a fundamentally flawed API. Programmable shaders have been around since 2003-ish, and the vendors still can't write drivers that work. I take this as an indication that the OpenGL specification is just too complicated.
Anyways, this is one of my more emo blogs, and I will solve the problem, but that's where I'm at today. Considering the amount of non-working **** we deal with on both Android and iOS, it's clear to me that for most developers, cross-platform development is just infeasible. I'm glad we can figure this stuff all out for you, so you can just use our API and not worry about all the mistakes third parties make with their APIs, drivers, and tools.
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