ARKit - 如何将SCNText包含在另一个SCNNode中（语音气泡）

Question

我正在尝试使用ARKit创建带有简单文本的引用生成器。我可以显示带文本的对话框，但是文本总是从中间开始，并溢出到对话框外。任何帮助使其在对话框的左上角对齐并在对话框内换行的方法都将不胜感激。

类

class SpeechBubbleNode: SCNNode {
    private let textNode = TextNode()

    var string: String? {
        didSet {
            textNode.string = string
        }
    }

    override init() {
        super.init()

        // Speech Bubble
        let plane = SCNPlane(width: 200.0, height: 100.0)
        plane.cornerRadius = 4.0
        plane.firstMaterial?.isDoubleSided = true
        geometry = plane

        // Text Node
        textNode.position = SCNVector3(position.x, position.y, position.z + 1.0)
//        textNode.position = convertPosition(SCNVector3(0.0, 0.0, 1.0), to: textNode)
//        textNode.position = SCNVector3(0.0, 0.0, position.z + 1.0)
        addChildNode(textNode)
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
}

class TextNode: SCNNode {
    private let textGeometry = SCNText()

    var string: String? {
        didSet {
            updateTextContainerFrame()
            textGeometry.string = string
        }
    }

    override init() {
        super.init()

        textGeometry.truncationMode = CATextLayerTruncationMode.middle.rawValue
        textGeometry.isWrapped = true
        textGeometry.alignmentMode = CATextLayerAlignmentMode.left.rawValue

        let blackMaterial = SCNMaterial()
        blackMaterial.diffuse.contents = UIColor.black
        blackMaterial.locksAmbientWithDiffuse = true
        textGeometry.materials = [blackMaterial]

        geometry = textGeometry
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    private func updateTextContainerFrame() {
        let (min, max) = boundingBox
        let width = CGFloat(max.x - min.x)
        let height = CGFloat(max.y - min.y)
        print("width :",max.x - min.x,"height :",max.y - min.y,"depth :",max.z - min.z)
        textGeometry.containerFrame = CGRect(x: 0.0, y: 0.0, width: width, height: height)
//        textGeometry.containerFrame = CGRect(origin: .zero, size: CGSize(width: 1.0, height: 1.0))
    }
}

实现

private func makeSpeechBubbleNode(forBobbleheadNode bobbleheadNode: BobbleheadNode) {
    let node = SpeechBubbleNode()
    node.position = sceneView.scene.rootNode.convertPosition(bobbleheadNode.position, to: node)
    node.scale = SCNVector3(0.002, 0.002, 0.002)

    sceneView.scene.rootNode.addChildNode(speechBubbleNode)
    self.speechBubbleNode = speechBubbleNode

    speechBubbleNode.string = "Some random string that could be long and should wrap within speech bubble"
}

- JimmyJammed

Answer 1

我曾经遇到过同样的问题，最终我按照以下方法解决了它：

• Create a SCNText and add it as a geometry to SCNNode:

  let string = "Coverin text with a plane :)"
  let text = SCNText(string: string, extrusionDepth: 0.1)
  text.font = UIFont.systemFont(ofSize: 1)
  text.flatness = 0.005
  let textNode = SCNNode(geometry: text)
  let fontScale: Float = 0.01
  textNode.scale = SCNVector3(fontScale, fontScale, fontScale)
  

• Coordinate the text pivot form left bottom to center:

  let (min, max) = (text.boundingBox.min, text.boundingBox.max)
  let dx = min.x + 0.5 * (max.x - min.x)
  let dy = min.y + 0.5 * (max.y - min.y)
  let dz = min.z + 0.5 * (max.z - min.z)
  textNode.pivot = SCNMatrix4MakeTranslation(dx, dy, dz)
  

• Create a PlaneNode and add the textNode as a childNode of the PlaneNode:

  let width = (max.x - min.x) * fontScale
  let height = (max.y - min.y) * fontScale
  let plane = SCNPlane(width: CGFloat(width), height: CGFloat(height))
  let planeNode = SCNNode(geometry: plane)
  planeNode.geometry?.firstMaterial?.diffuse.contents = UIColor.green.withAlphaComponent(0.5)
  planeNode.geometry?.firstMaterial?.isDoubleSided = true
  planeNode.position = textNode.position
  textNode.eulerAngles = planeNode.eulerAngles
  planeNode.addChildNode(textNode)
  

• and at the end add the PlaneNode to sceneView:

  sceneView.scene.rootNode.addChildNode(planeNode)
  

这就是结果：

- Mina

Answer 2

如果你只需要在文本后面有一个白色的框，我通过在我的渲染函数中执行以下操作来实现它：

func renderer(_ renderer: SCNSceneRenderer, nodeFor anchor: ARAnchor) -> SCNNode? {

        let node = SCNNode()

        ............

        let testPlane = SCNPlane(width: someWidth, height: someHeight)


        let testScene = SKScene(size: CGSize(width: 900, height: 900))
        testScene.backgroundColor = UIColor.white

        let str = SKLabelNode(text: "This is just a test")
        str.color = UIColor.black
        str.fontColor = UIColor.black
        str.fontSize = 45.5

        str.position = CGPoint(x: stuff.size.width / 2,
                                 y: stuff.size.height / 2)
        testScene.addChild(str)

        testPlane.firstMaterial?.diffuse.contents = testScene
        testPlane.firstMaterial?.isDoubleSided = true
        testPlane.firstMaterial?.diffuse.contentsTransform = SCNMatrix4Translate(SCNMatrix4MakeScale(1, -1, 1), 0, 1, 0)

        let testNode = SCNNode(geometry: testPlane)


        testNode.eulerAngles.x = -.pi / 2
        testNode.position = SCNVector3Make(0.0,0.0,0.0)

        node.addChildNode(testNode)


}

- fannolo