On Mon, Jul 9, 2012 at 6:16 PM, Nobu Games <[email protected]> wrote: > As far as I know that allocated array > resides on the native heap until it is released and copied back to Java. > That probably only happens when you alter the pixel data from Java. Which > means that the get and setPixel methods must be really slow because in worst > case they can cause heavy copy operations between JVM and native code for > each access.
I tried in the meantime to fill my large Bitmap by calling setPixel() on each of its pixels and the running time is in the order of tens seconds. > The only other option that comes to my mind for speeding up things would be > writing some NDK code and using a PNG library for encoding the pixel data in > native code. Passing that int array to that native code is straightforward. > With a trick you can even access the original Java int array directly > without waiting for a copy. This is possible with the JNI function > GetPrimitiveArrayCritical. There is no guarantee, though that direct access > works in any case. The documentation of that function explains the limits > pretty well. I don't use NDK in this app, was meant to be pure Java, however as there are other (performance) problems with bulk GL data handling that apparently cannot be solved without native code, I might consider NDK as well. -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
