cocos2d 坐标系

- (CGPoint)convertToNodeSpace:(CGPoint)worldPoint
{
	CGPoint ret;
	if( CC_CONTENT_SCALE_FACTOR() == 1 )
		ret = CGPointApplyAffineTransform(worldPoint, [self worldToNodeTransform]);
	else {
		ret = ccpMult( worldPoint, CC_CONTENT_SCALE_FACTOR() );
		ret = CGPointApplyAffineTransform(ret, [self worldToNodeTransform]);
		ret = ccpMult( ret, 1/CC_CONTENT_SCALE_FACTOR() );
	}
	
	return ret;
}

- (CGPoint)convertToWorldSpace:(CGPoint)nodePoint
{
	CGPoint ret;
	if( CC_CONTENT_SCALE_FACTOR() == 1 )
		ret = CGPointApplyAffineTransform(nodePoint, [self nodeToWorldTransform]);
	else {
		ret = ccpMult( nodePoint, CC_CONTENT_SCALE_FACTOR() );
		ret = CGPointApplyAffineTransform(ret, [self nodeToWorldTransform]);
		ret = ccpMult( ret, 1/CC_CONTENT_SCALE_FACTOR() );
	}
	
	return ret;
}

convertToWorldSpace方法可以把基于当前node的本地坐标系下的坐标转换到世界坐标系中。
convertToNodeSpace方法可以把世界坐标转换到当前node的本地坐标系中。

http://www.cnblogs.com/cppguru/archive/2011/05/10/2041835.html