cocos2d/cocos2d-x — pull request #5534 by dabingnn (2014-03-04 07:43:48+00:00)
Title: Develop render texture improvement

This pull request add two features for RenderTexture
1. add `_keepMatrix`, if it is true, we will use current modelView and projection matrix instead of generate a new one.
2. add `setVirtualViewport` interface, we can only grab fullscreen RenderTexture by default, by using this interface, we can only grab part of screen to a texture.