How to add Shadow on surface plane? - ios

Question

I Have one problem, In ARView Display Shadow on the object but did not display on the surface, I have attached try code? It is working Display shadow on the object but does not display on the surface.
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Code :
var light2 = SCNLight()
var lightNodeb2 = SCNNode()
light2.castsShadow = true
light2.automaticallyAdjustsShadowProjection = true
light2.maximumShadowDistance = 40.0
light2.orthographicScale = 1
light2.type = .directional
light2.shadowMapSize = CGSize(width: 2048, height: 2048)
light2.shadowMode = .forward
light2.shadowSampleCount = 128
light2.shadowRadius = 3
light2.shadowBias = 32
light2.zNear=1;
light2.zFar=1000;
lightNodeb2.light = light2
lightNodeb2.position = SCNVector3(x: -1, y: 10, z: 1)
lightNodeb2.rotation = SCNVector4Make(2, 0, 0, -Float.pi / 3)
self.sceneView.scene.rootNode.addChildNode(lightNodeb2)

Answer 1

I see here 2 possible problems:
Your light's settings are OK. I think the first problem is following: you use programmatic light with "non-programmatic" 3D objects in Scene graph.
Check it. In this code all objects are programmatic:
let sphereNode1 = SCNNode(geometry: SCNSphere(radius: 1))
sphereNode1.position = SCNVector3(x: 0, y: 5, z: 3)
scene.rootNode.addChildNode(sphereNode1)
let sphereNode2 = SCNNode(geometry: SCNSphere(radius: 3))
sphereNode2.position = SCNVector3(x: 0, y: 1, z: 0)
scene.rootNode.addChildNode(sphereNode2)
let boxNode = SCNNode(geometry: SCNBox(width: 20, height: 0.1, length: 20, chamferRadius: 0))
boxNode.position = SCNVector3(x: 0, y: -3, z: 0)
scene.rootNode.addChildNode(boxNode)
let light2 = SCNLight()
let lightNodeb2 = SCNNode()
light2.castsShadow = true
light2.automaticallyAdjustsShadowProjection = true
light2.maximumShadowDistance = 40.0
light2.orthographicScale = 1
light2.type = .directional
light2.shadowMapSize = CGSize(width: 2048, height: 2048)
light2.shadowMode = .deferred // Renders shadows in a postprocessing pass
light2.shadowSampleCount = 128
light2.shadowRadius = 3
light2.shadowBias = 32
light2.zNear = 1
light2.zFar = 1000
lightNodeb2.light = light2
// DIRECTIONAL LIGHT POSITION doesn't matter. Matters only its direction.
// lightNodeb2.position = SCNVector3(x: -1, y: 10, z: 1)
lightNodeb2.rotation = SCNVector4(2, 0, 0, -Float.pi/3)
scene.rootNode.addChildNode(lightNodeb2)
All objects Shadow castings are On by default.
First problem's Solution:
To make your 3D model to become accessible for virtual programmatic lights use the following approach:
func childNode(withName name: String, recursively: Bool) -> SCNNode? {
return SCNNode()
}
let geometryNode = childNode(withName: "art.scnassets/your3Dmodel",
recursively: true)!
scene.rootNode.addChildNode(geometryNode)
Second problem's Solution:
And if you wanna have a hidden plane with a shadow use this code:
hiddenPlaneNode.castsShadow = false
hiddenPlaneNode.geometry?.firstMaterial?.lightingModel = .constant
hiddenPlaneNode.geometry?.firstMaterial?.isDoubleSided = true
hiddenPlaneNode.geometry?.firstMaterial?.readsFromDepthBuffer = true
hiddenPlaneNode.geometry?.firstMaterial?.writesToDepthBuffer = true
hiddenPlaneNode.geometry?.firstMaterial?.colorBufferWriteMask = []
light2.shadowMode = .deferred