Just found yet another AR library for Android called ARmsk. The description sounds promising. But the demo video is kind of shocking. They have like half a frame per second. The code looks like they used a lot of examples, like the OpenGL Cube renderer from the Android API demos and some stuff from the OpenCV-Android examples.
Last updates were in January this year, so quite up-to-date actually.
Oh, btw, guys why can't I find you when I search for "AR Android". I mean seriously, take care of your website keywords
AndEngine is a 2D OpenGL Engine. Actually a game engine. But it has also some small AR extension. I've stumbled upon this project a little while ago but then somehow forgot about it and now rediscovered it. So far it looks promising (even though I already found some kind of "lazy bug" which prevents the AR example to run ). Especially the the animation stuff and sensor helpers look great.
Hopefully this can boost my project a little.Will see.
From the Android NDK example "bitmap-plasma":
We're going to perform computations for every pixel of the target bitmap. floating-point operations are very slow on ARMv5, and not too bad on ARMv7 with the exception of trigonometric functions. For better performance on all platforms, we're going to use fixed-point arithmetic and all kinds of tricks
I stumbled upon this one or two times before. So it really seems like this is an issue needed to be addressed, since I want to do lots of heavy pixel-by-pixel computation stuff (a.k.a. image processing). Maybe there is a better way to do this: instead of translating everything from floating-point to fixed-point operations or even finding and implementing "all kind of tricks", I could do everything with OpenGL. Android 1.6 supports OpenGL ES 1.1 and from Android 2.0 and up OpenGL ES 2.0 is supported. Such OpenGL-operation are probably performed on the same CPU, but I assume if OpenGL is doing some floating-to-fixed-point translation this is more effective than I could do.