Swift: ARKit place a rectangle based on 2 nodes - swift

Question

My idea is that i want to place 2 sphere nodes at selected locations. From that point i basically want to draw a rectangle that will adjust the height with a slider. Basically that means that the 2 spheres will represent all 4 corners in the beginning. But when testing the code i use 1 meter height as a test.
The problem i have is that i cant seem to place the rectangle at the correct location as illustrated in the image below:
the rectangle in the image has a higher y-point than the points, it's rotated slightly and its center point is above node 2 and not in between the nodes. I don't want to use node.rotation as it wont work dynamically.
This is the code i use to place the 2 nodes and draw + add the rectangle.
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
guard let location = touches.first?.location(in: sceneView) else {return}
let hitTest = sceneView.hitTest(location, types: [ARHitTestResult.ResultType.featurePoint])
guard let result = hitTest.last else {return}
// Converts the matrix_float4x4 to an SCNMatrix4 to be used with SceneKit
let transform = SCNMatrix4.init(result.worldTransform)
// Creates an SCNVector3 with certain indexes in the matrix
let vector = SCNVector3Make(transform.m41, transform.m42, transform.m43)
let node = addSphere(withPosition: vector)
nodeArray.append(node)
sceneView.scene.rootNode.addChildNode(node)
if nodeArray.count == 2 {
let node1 = sceneView.scene.rootNode.childNodes[0]
let node2 = sceneView.scene.rootNode.childNodes[1]
let bezeierPath = UIBezierPath()
bezeierPath.lineWidth = 0.01
bezeierPath.move(to: CGPoint(x: CGFloat(node1.position.x), y: CGFloat(node1.position.y)))
bezeierPath.addLine(to: CGPoint(x: CGFloat(node2.position.x), y: CGFloat(node2.position.y)))
bezeierPath.addLine(to: CGPoint(x: CGFloat(node2.position.x), y: CGFloat(node2.position.y+1.0)))
bezeierPath.addLine(to: CGPoint(x: CGFloat(node1.position.x), y: CGFloat(node1.position.y+1.0)))
bezeierPath.close()
bezeierPath.fill()
let shape = SCNShape(path: bezeierPath, extrusionDepth: 0.02)
shape.firstMaterial?.diffuse.contents = UIColor.red.withAlphaComponent(0.8)
let node = SCNNode.init(geometry: shape)
node.position = SCNVector3(CGFloat(abs(node1.position.x-node2.position.x)/2), CGFloat(abs((node1.position.y)-(node2.position.y))/2), CGFloat(node1.position.z))
sceneView.scene.rootNode.addChildNode(node)
}
}
Also note that this is not my final code. It will be refactored once i get everything working :).

Answer 1

This is currently working. I used the wrong calculation to set it in the middle of the 2 points.
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
// Check if a window is placed already and fetch location in sceneView
guard debugMode, let location = touches.first?.location(in: sceneView) else {return}
// Fetch targets at the current location
let hitTest = sceneView.hitTest(location, types: [ARHitTestResult.ResultType.featurePoint])
guard let result = hitTest.last else {return}
// Create sphere are position. getPosition() is an extension
createSphere(withPosition: result.getPosition())
// When 2 nodes has been placed, create a window and hide the spheres
if nodeArray.count == 2 {
let firstNode = nodeArray[nodeArray.count-1]
let secondNode = nodeArray[nodeArray.count-2]
firstNode.isHidden = true
secondNode.isHidden = true
createWindow(firstNode: firstNode, secondNode: secondNode)
sceneView.debugOptions = []
}
}
func createSphere(withPosition position: SCNVector3) {
// Create an geometry which you will apply materials to and convert to a node
let object = SCNSphere(radius: 0.01)
let material = SCNMaterial()
material.diffuse.contents = UIColor.red
object.materials = [material]
let node = SCNNode(geometry: object)
node.position = position
nodeArray.append(node)
sceneView.scene.rootNode.addChildNode(node)
}
func createWindow(firstNode: SCNNode, secondNode: SCNNode) {
// Create an geometry which you will apply materials to and convert to a node
let shape = SCNBox(width: CGFloat(abs(firstNode.worldPosition.x-secondNode.worldPosition.x)), height: 0.01, length: 0.02, chamferRadius: 0)
let material = SCNMaterial()
material.diffuse.contents = UIColor.red.withAlphaComponent(0.8)
// Each side of a cube can have different materials
// https://stackoverflow.com/questions/27509092/scnbox-different-colour-or-texture-on-each-face
shape.materials = [material]
let node = SCNNode(geometry: shape)
let minX = min(firstNode.worldPosition.x, secondNode.worldPosition.x)
let maxX = max(firstNode.worldPosition.x, secondNode.worldPosition.x)
// The nodes pivot Y-axis should be split in half of the nodes height, this will cause the node to
// only scale in one direction, when scaling it
// https://stackoverflow.com/questions/42568420/scenekit-understanding-the-pivot-property-of-scnnode/42613002#42613002
node.position = SCNVector3(((maxX-minX)/2)+minX, firstNode.worldPosition.y, firstNode.worldPosition.z)
node.pivot = SCNMatrix4MakeTranslation(0, 0.005, 0)
node.scale = SCNVector3Make(1, -50, 1)
node.name = "window"
sceneView.scene.rootNode.addChildNode(node)
}
Also added:
#objc func resetSceneView() {
// Clear all the nodes
sceneView.scene.rootNode.enumerateHierarchy { (node, stop) in
node.childNodes.forEach({
$0.removeFromParentNode()
})
node.removeFromParentNode()
}
// Reset the session
sceneView.session.pause()
sceneView.debugOptions = [ARSCNDebugOptions.showFeaturePoints]
sceneView.session.run(configuration, options: .resetTracking)
let matrix = sceneView.session.currentFrame!.camera.transform
sceneView.session.setWorldOrigin(relativeTransform: matrix)
nodeArray = []
}
To make sure that the world alignment is reset to your camera position