public KeystoningCorners(XmlNode xmlNode) : this()
{
corners[0] = XMLUtil.GetVector2FromXmlNode(xmlNode.SelectSingleNode("topLeft"));
corners[1] = XMLUtil.GetVector2FromXmlNode(xmlNode.SelectSingleNode("topRight"));
corners[2] = XMLUtil.GetVector2FromXmlNode(xmlNode.SelectSingleNode("bottomRight"));
corners[3] = XMLUtil.GetVector2FromXmlNode(xmlNode.SelectSingleNode("bottomLeft"));
}