ios - 如何使用 ARKit 将 SCNNode 的方向更改为相机

Question

下面的代码将 SCNPlane 放置在触摸点上，但该平面定向(旋转)到应用程序启动时手机所在的位置。理想情况下，我希望将节点定向到物理墙或相机的当前方向。这是如何使用 ARKit 完成的？

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    guard let touch = touches.first else {return}
    let result = sceneView.hitTest(touch.location(in: sceneView), types: [ARHitTestResult.ResultType.featurePoint])
    guard let hitResult = result.last else {return}
    let hitTransform = SCNMatrix4.init(hitResult.worldTransform)

    let hitVector = SCNVector3Make(hitTransform.m41, hitTransform.m42, hitTransform.m43)
    createPlane(position: hitVector)
}

func createPlane(position: SCNVector3) {

    let background = SCNNode()
    background.geometry = SCNPlane.init(width: 0.12, height: 0.10) // better set its size
    background.geometry?.firstMaterial?.diffuse.contents = "odinBW2.jpeg"
    background.position = position

    sceneView.scene.rootNode.addChildNode(background)

}

Answer 1

如果你想将你的节点与相机的方向对齐，只需使用 SCNBillboardConstraint .

let yourNode = SCNNode()

let billboardConstraint = SCNBillboardConstraint()
billboardConstraint.freeAxes = [.X, .Y, .Z]
yourNode.constraints = [billboardConstraint]