Support for Gear, Deepoon, Google Cardboard and Oculus has been added. Read about VR in our [Programmers Guide](http://www.cocos2d-x.org/docs/programmers-guide/vr/index.html)
AudioEngine uses [OpenSL ES](https://developer.android.com/ndk/guides/audio/opensl-for-android.html) on Android, and it supports decoding audio source file to PCM data in codes since Android 4.2. Now AudioEngine uses this feature to fix the performance issue. The performane is the same as before if running on Android 4.1 or lower version. **Should preload first, or there is not performance improved for first time playing of the audio.**
In v3.12, we improved WebGL renderer in the web engine, this version have brought the dirty region algorithm to improve canvas renderer performance. Basically, it detect every region that have been changed between frames, then only render these parts instead of refresh the whole canvas. This technique is beneficial for many games in which the dynamic region is often limited, it can improve frame rate and reduce CPU usage, power consumation. It's desactivated by default, to activate it, you can do the following:
```
// Enable dirty region algorithm
if (cc._renderType === cc.game.RENDER_TYPE_CANVAS) {
cc.renderer.enableDirtyRegion(true);
// Maximum dirty region count to activate the partial rendering process
cocos2d-x switch to use clang in `v3.12`, but developers reported [some crash issue](https://github.com/cocos2d/cocos2d-x/issues/16244) that caused by using `clang+gnustl_static`, so we switch to use gcc 4.9. We will change to use `clang+c++_static` when `c++_static` is stable.
Because CURL has [a bug about connect to IPV4 numerical IP address in NAT64 environment](https://github.com/curl/curl/issues/863), and it is fixed in v7.50.0, so we upgrade to this version when v7.50.0 is released.
