Conversion of cocos world coordinates and relative coordinates

1. cocos provides 4 coordinate conversion methods
   convertToNodeSpace
   convertToWorldSpace
   convertToNodeSpaceAR
   convertToWorldSpaceAR

The yellow coordinates are world coordinates, and the brown coordinates are relative coordinates.

convertToWorldSpace

	var w_pos = this.node.convertToWorldSpace(cc.v2(0,0));
	cc.log(w_pos);
	//输出结果为：（430，270）