可以用鲜红的SCNSpotlight画出清晰的SCNSphere吗？

Question

在过去的几天里，我对SceneKit有点纠结。我正在尝试绘制一个带有红色聚光灯的清晰/透明的SCNSphere。如果我将SCNSphere设置为透明/透明颜色，我的红色聚光灯似乎也变得透明。是否可以取消SCNLight节点与SCNSphereNode的链接，以便如果SCNSphere是透明的，则聚光灯的鲜红色保持不变？两个球体的图像都在代码下面。

我的代码：

func setupView() {
    scene = SCNScene()
    caliView.scene = scene
    caliView.allowsCameraControl = true
    caliView.backgroundColor = UIColor.clearColor()
    let clearMaterial = SCNMaterial()
    clearMaterial.diffuse.contents = UIColor(white: 0.9, alpha: 0.5)
    clearMaterial.locksAmbientWithDiffuse = true


    let shape = SCNSphere(radius: 5)
    shape.materials = [clearMaterial]
    let shapeNode = SCNNode(geometry: shape)

    let spotLight = SCNLight()
    spotLight.type = SCNLightTypeSpot
    spotLight.color = UIColor.init(colorLiteralRed: 180, green: 0, blue: 0, alpha: 0.0)
    let lightNode = SCNNode()
    lightNode.light = spotLight

    lightNode.position = SCNVector3(x: 0.0, y:0.0, z:15.0)
    lightNode.orientation = SCNQuaternion(x: 0.0, y:0, z:30, w:0.0)


    let ambientLight = SCNLight()
    ambientLight.type = SCNLightTypeAmbient
    ambientLight.color = UIColor(white: 0.8, alpha: 0.2)
    let ambientNode = SCNNode()
    ambientNode.light = ambientLight

    shapeNode.position = SCNVector3(x: 0.0, y: 0.0, z: 0.0)

    scene.rootNode.addChildNode(ambientNode)
    scene.rootNode.addChildNode(shapeNode)
    shapeNode.addChildNode(lightNode)


    }

带有鲜红色聚光灯的较暗球体：

​

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更透明的球体，带有柔和的红色聚光灯：

​

​

Answer 1

在这一行..。shapeNode.addChildNode(lightNode) ...you将灯光节点添加到球体节点。

如果要取消它们的链接，同时仍使它们一起移动，则可以创建一个空SCNNode，然后将另外两个SCNNode实例作为子实例添加到其中(一个用于灯光，另一个用于球体)：

func setupView() {
scene = SCNScene()
caliView.scene = scene
caliView.allowsCameraControl = true
caliView.backgroundColor = UIColor.clearColor()
let clearMaterial = SCNMaterial()
clearMaterial.diffuse.contents = UIColor(white: 0.9, alpha: 0.5)
clearMaterial.locksAmbientWithDiffuse = true

let emptyNode = SCNNode()

let shape = SCNSphere(radius: 5)
shape.materials = [clearMaterial]
let shapeNode = SCNNode(geometry: shape)

let spotLight = SCNLight()
spotLight.type = SCNLightTypeSpot
spotLight.color = UIColor.init(colorLiteralRed: 180, green: 0, blue: 0, alpha: 0.0)
let lightNode = SCNNode()
lightNode.light = spotLight

lightNode.position = SCNVector3(x: 0.0, y:0.0, z:15.0)
lightNode.orientation = SCNQuaternion(x: 0.0, y:0, z:30, w:0.0)

let ambientLight = SCNLight()
ambientLight.type = SCNLightTypeAmbient
ambientLight.color = UIColor(white: 0.8, alpha: 0.2)
let ambientNode = SCNNode()
ambientNode.light = ambientLight

shapeNode.position = SCNVector3(x: 0.0, y: 0.0, z: 0.0)

emptyNode.addChild(shapeNode)
emptyNode.addChild(lightNode)
scene.rootNode.addChildNode(emptyNode)
scene.rootNode.addChildNode(ambientNode)

}