iOS SceneKit：摄像机后面的TextNode

Question

我有一些SCNText节点，描述如下：

let newText = SCNText(string: "", extrusionDepth:0.1)
    newText.alignmentMode = kCAAlignmentCenter
    newText.font = UIFont (name: "Arial", size: 3)
    textNode = SCNNode(geometry: newText)
    self.addChildNode(textNode)

如何使文字始终看着相机？

Answer 1

textNode.constraints = [SCNBillboardConstraint（）]