http://stackoverflow.com/questions/10614876/rotate-sprite-to-face-a-point-cocos2d

http://stackoverflow.com/questions/7785089/cocos2d-angle-confusion

 

 

 

 

 

 

 

http://www.nipic.com/show/4/79/4807200k6e741f91.html

http://www.nipic.com/show/4/79/4311521kd4be8f0a.html