SceneKit / ARKit 中不可见阴影平面的问题

Question

有一段时间以来，我一直在四处寻找我的问题的答案，但找不到任何真正有帮助或解释正在发生的事情。我也一遍又一遍地检查了我在 SO 上找到的所有内容，但找不到答案。

在 AR 世界中显示对象时，问题不断发生。 iEx 我将一个物体放置在地板上的一个平面上，这是我不可见的阴影平面。然后，这完全取决于设备的视角。为了澄清，我添加了图像，它们的视角略有不同。看看阴影发生了什么：

我希望一直有一个好的影子，而不是你看到的那种人工制品。

注意：我已经尝试使用 shadowSampleCount、偏差和所有其他选项，这应该有助于获得适当的、低渲染成本的阴影。

这里是光照和平面的相关代码的摘录，Material，等等

对于SCNLight：

class func directionalLight() -> SCNLight {

    let light = SCNLight()

    light.type = .directional
    light.castsShadow = true
    light.color = UIColor.white
    light.shadowMode = .deferred
    light.shadowSampleCount = 8
    light.shadowRadius = 1
    // light.automaticallyAdjustsShadowProjection = false
    light.shadowColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.75)
    light.categoryBitMask = -1

    return light

}

以及我如何添加它：

func setupLights() {

    lightDirectionNode.light = Lighting.directionalLight()
    // lightDirectionNode.eulerAngles = SCNVector3(-66.degreesToRadians, 0, 0)
    lightDirectionNode.eulerAngles = SCNVector3(0, 90.degreesToRadians, 45.degreesToRadians)
    sceneView.scene.rootNode.addChildNode(lightDirectionNode)

}

对于SCNPlane:

class func shadowPlane() -> SCNNode {

    let objectShape = SCNPlane(width: 200, height: 200)
    objectShape.heightSegmentCount = 2
    objectShape.widthSegmentCount = 2
    objectShape.cornerRadius = 100
    objectShape.cornerSegmentCount = 16

    let objectNode = SCNNode(geometry: objectShape)

    objectNode.geometry?.firstMaterial?.diffuse.contents = UIColor(red: 1.0, green: 1.0, blue: 1.0, alpha: 1.0)
    objectNode.geometry?.firstMaterial?.colorBufferWriteMask = SCNColorMask(rawValue: 0)

    objectNode.physicsBody = Physics.floorPhysicsBody(shape: objectShape)
    objectNode.name = "floor"
    objectNode.renderingOrder = -10 // renderingOrder // 0

    return objectNode
}

以及我如何添加它：

func setupShadowPlane() {

    let shadowPlane = NodeFactory.shadowPlane()

    // Set the Node's properties
    shadowPlane.position = SCNVector3(x: (focusSquare.lastPosition?.x)!, y: (focusSquare.lastPosition?.y)!, z: (focusSquare.lastPosition?.z)!)
    shadowPlane.eulerAngles = SCNVector3(-90.degreesToRadians, 0.0, 0.0)
    sceneView.scene.rootNode.addChildNode(shadowPlane)

}

我做错了什么？有人可以帮忙吗？

Answer 1

还有 3 个实例属性需要考虑：

var shadowRadius: CGFloat { get set }
var shadowCascadeCount: Int { get set }
var shadowCascadeSplittingFactor: CGFloat { get set }

如果您不设置这些，它们肯定会导致渲染瑕疵。

let lightNode = SCNNode()
lightNode.light = SCNLight()
// POSITION OF DIRECTIONAL LIGHT ISN'T IMPORTANT.
// ONLY DIRECTION IS CRUCIAL FOR DIRECTIONAL LIGHTS.
lightNode.rotation = SCNVector4(x: 0, y: 0, z: 0, w: 1)
lightNode.light!.type = .directional
lightNode.light!.castsShadow = true
lightNode.light?.shadowMode = .deferred

/* THREE INSTANCE PROPERTIES TO SETUP */
lightNode.light?.shadowRadius = 3.25
lightNode.light?.shadowCascadeCount = 3
lightNode.light?.shadowCascadeSplittingFactor = 0.09

lightNode.light?.shadowColor = UIColor(white: 0, alpha: 0.75)
scene.rootNode.addChildNode(lightNode)

And one more thing – when Auto Adjust is off:

Light, like a camera, has near and far clipping planes for setup.

lightNode.light?.zNear = 0
lightNode.light?.zFar = 1000000    // Far Clipping Plane is important

希望对您有所帮助。

SceneKit / ARKit 中不可见阴影平面的问题

Issue with invisible Shadow Plane in SceneKit / ARKit

shadow

augmented-reality

scenekit

swift

arkit