SceneKit Custom Geometry Shape not showing up

Question

I am pretty new to Swift, and SceneKit, and my current problem is that the custom shape I am trying to create is not showing up, even though the primitive shapes in the framework show up fine.

I have been following the tutorial from https://www.raywenderlich.com/1261-scene-kit-tutorial-with-swift-part-1-getting-started.

I have also checked out the answer on SO: SceneKit – Custom geometry does not show up. I have looked at other answers on here but none work for me.

Here is my code:

import UIKit
import SceneKit
import QuartzCore

class GameViewController: UIViewController {
    var scnView: SCNView!
    var scnScene: SCNScene!
    var cameraNode: SCNNode!

    override func viewDidLoad() {
        super.viewDidLoad()
        setupView()
        setupScene()
        setupCamera()
        let lightNode0 = SCNNode()
        lightNode0.light = SCNLight()
        lightNode0.light!.type = .omni
        lightNode0.position = SCNVector3(x: 0, y: 10, z: 10)
        scnScene.rootNode.addChildNode(lightNode0)

        let lightNode1 = SCNNode()
        lightNode1.light = SCNLight()
        lightNode1.light!.type = .omni
        lightNode1.position = SCNVector3(5, -10, 0)
        scnScene.rootNode.addChildNode(lightNode1)
        spawnShape()
    }

    func shouldAutorotate() -> Bool {
        return true
    }

    func prefersStatusBarHidden() -> Bool {
        return true
    }
    func setupView() {
        scnView = self.view as! SCNView
        // 1
        scnView.showsStatistics = true
        // 2
        scnView.allowsCameraControl = true
        // 3
        scnView.autoenablesDefaultLighting = true
    }
    func setupScene() {
        scnScene = SCNScene()
        scnView.scene = scnScene
    }

    func setupCamera() {
        // 1
        cameraNode = SCNNode()
        // 2
        cameraNode.camera = SCNCamera()
        // 3
        cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)
        // 4
        scnScene.rootNode.addChildNode(cameraNode)
    }

And here is the function that produce the custom shape:

    func spawnShape() {
        // 1
        var geometry:SCNGeometry
        let positions = [
            SCNVector3(-2, 1.5, 0), //0
            SCNVector3(-2, 1.5, 0), //1
            SCNVector3(2, -1.5, 0), //2
            SCNVector3(2, 1.5, 0), //3
            SCNVector3(-2, 1.5, 0.4), //4
            SCNVector3(2, 1.5, 0.4) //5
        ]
        let source = SCNGeometrySource(vertices: positions)
        let indices:[CInt] = [
            0, 2, 1,
            0, 3, 2,
            0, 4, 5,
            0, 5 ,3,
            4, 1, 2,
            4, 2, 5
            ]
        let element = SCNGeometryElement(indices: indices, primitiveType:.triangles)

        // 4
        geometry = SCNGeometry(sources: [source], elements: [element])
        let geometryNode = SCNNode(geometry: geometry)

        // 5
        scnScene.rootNode.addChildNode(geometryNode)
    }
}

Answer 1

Try my light-weighting code (macOS version for quick testing).

It's working:

import SceneKit

class GameViewController: NSViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        let scene = SCNScene()
        let cameraNode = SCNNode()
        cameraNode.camera = SCNCamera()
        scene.rootNode.addChildNode(cameraNode)
        cameraNode.position = SCNVector3(x: 0, y: 0, z: 3)

        let geometry: SCNGeometry?
        let positions = [
            SCNVector3(0, 1, 0),
            SCNVector3(-0.5, 0, 0.5),
            SCNVector3(0.5, 0, 0.5),
            SCNVector3(0.5, 0, -0.5),
            SCNVector3(-0.5, 0, -0.5),
            SCNVector3(0, -1, 0),
        ]
        let source = SCNGeometrySource(vertices: positions)
        let indices: [UInt32] = [
            0, 1, 2,
            2, 3, 0,
            3, 4, 0,
            4, 1, 0,
            1, 5, 2,
            2, 5, 3,
            3, 5, 4,
            4, 5, 1
        ]
        let element = SCNGeometryElement(indices: indices, primitiveType:.triangles)
        geometry = SCNGeometry(sources: [source], elements: [element])
        geometry!.firstMaterial?.diffuse.contents = NSColor.red
        let geometryNode = SCNNode(geometry: geometry)
        scene.rootNode.addChildNode(geometryNode)

        let scnView = self.view as! SCNView
        scnView.scene = scene
        scnView.allowsCameraControl = true
        scnView.autoenablesDefaultLighting = true
        scnView.backgroundColor = NSColor.black
    }
}