垂直和水平将平面节点添加到ARKit场景

Question

我希望我的应用将节点放置在可以是垂直或水平的表面上。但是，节点始终是垂直的。这是一张图片，这些节点放置不正确。

@objc func didTapAddButton() {
    let screenCentre = CGPoint(x: self.sceneView.bounds.midX, y: self.sceneView.bounds.midY)
    let arHitTestResults: [ARHitTestResult] = sceneView.hitTest(screenCentre, types: [.featurePoint]) // Alternatively, we could use '.existingPlaneUsingExtent' for more grounded hit-test-points.
    if let closestResult = arHitTestResults.first {
        let transform: matrix_float4x4 = closestResult.worldTransform
        let worldCoord: SCNVector3 = SCNVector3Make(transform.columns.3.x, transform.columns.3.y, transform.columns.3.z)
        if let node = createNode() {
            sceneView.scene.rootNode.addChildNode(node)
            node.position = worldCoord
        }
    }
}

func createNode() -> SCNNode? {
    guard let theView = myView else {
        print("Failed to load view")
        return nil
    }

    let plane = SCNPlane(width: 0.06, height: 0.06)
    let imageMaterial = SCNMaterial()
    imageMaterial.isDoubleSided = true
    imageMaterial.diffuse.contents = theView.asImage()
    plane.materials = [imageMaterial]
    let node = SCNNode(geometry: plane)
    return node
}

该应用程序可以看到地面，但节点仍与我们平行。我该如何解决？

编辑：我认为我可以使用node.eulerAngles.x = -.pi / 2，这可以确保平面水平放置，但在垂直面上也仍然是水平的。

Answer 1

解决了！始终使视图与摄像机平行的方法如下：

let yourNode = SCNNode()

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

或

guard let currentFrame = sceneView.session.currentFrame else {return nil}
let camera = currentFrame.camera
let transform = camera.transform
var translationMatrix = matrix_identity_float4x4
translationMatrix.columns.3.z = -0.1
let modifiedMatrix = simd_mul(transform, translationMatrix)
let node = SCNNode(geometry: plane)
node.simdTransform = modifiedMatrix