I'd say instead that it doesn't NEED to slow you down. But if you store your entire scene graph on the native side, but do all the manipulation of it on the Java side, with a lot of Java->Java calls dispatched by the JNI layer in between, and lots of arrays getting locked or copied -- I guarantee you'll regret it.
But if you start with an intelligent architecture, so you're not just replacing lots of Java calls to trivial code with JNI calls to trivial code, you will usually be OK. Chris Pruett's strategy as he outlined it in this talk: http://code.google.com/events/io/2009/sessions/WritingRealTimeGamesAndroid.html I find to be a very solid strategy. BTW, the argument against moving things *unnecessarily* to JNI is not just one of performance. It is also negatively affects how quickly you can modify the code, how well you can test it, and how many bugs you'll ship with. But so will doing weird things in Java to try to get it fast enough. There's a point where it makes sense to move a body of code to JNI. It's somewhere after you benchmark and think about the problem for a bit, and before you drive yourself nuts or fail to get your product to market. If you've done that, and choose a reasonably cohesive chunk, than in most cases I wouldn't expect the JNI overhead to be an issue. If it is, well, you ARE analyzing your trace data, right? You'll figure it out, and what to do about it. Just never do "performance optimization" blindly. On Mar 17, 8:31 am, niko20 <nikolatesl...@yahoo.com> wrote: > Personally through my experience this "JNI layer overhead" is so > small that its effect is negligible. In my apps using NDK with JNI has > alway increased my speed immensly regardless of any JNI method call > overhead. It's just simply not true that the JNI will slow you down. -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
