Dragging SCNNode in ARKit Face Tracking - ios

I want to be able to drag SCNNode on the face in real-time.
I try to map the touch position from the screen to the face's position but the node doesn't move as expected. The node moves slower than a finger and doesn't follow when I drag outside the user's face.
When dragging SCNNode to the left or the right, it seems to stick and can go further than just about half the face.
My current code:
#objc private func handleTouchGesture(_ sender: UIPanGestureRecognizer) {
let location = sender.location(in: arView)
switch sender.state {
case .began:
guard let nodeHitTest = arView.hitTest(location, options: nil).first
else { return }
lastDragPosition = nodeHitTest.localCoordinates
draggingNode = nodeHitTest.node
panStartZ = CGFloat(arView.projectPoint(nodeHitTest.node.position).z)
case .changed:
guard let lastDragPosition = lastDragPosition,
let draggingNode = draggingNode,
let panStartZ = panStartZ
else { return }
let localTouchPosition = arView.unprojectPoint(SCNVector3(location.x, location.y, panStartZ))
let movementVector = SCNVector3(
(localTouchPosition.x * -1.0) - lastDragPosition.x,
(localTouchPosition.y * -1.0),
0.0
)
draggingNode.localTranslate(by: movementVector)
self.lastDragPosition = localTouchPosition
case .ended:
(lastDragPosition, draggingNode, panStartZ) = (nil, nil, nil)
default:
break
}
}
I'm not sure if the issue is about the movementVector or not. I also try using several approaches but still not working.
Any help would be highly appreciated.
Thank you.

Related

SceneKit finger panning becomes inaccurate as it moves away from center

In my ARSCNView, I'm drawing a SCNPlane with a grid inside. It is a child of sceneView.pointOfView. When you drag your finger across it, you can connect the dots in the grid. This works almost perfectly, except something subtly strange is happening: The edge of the tragged line SHOULD track accurately with the finger, but it actually falls ahead or behind depending on how far above or below the center it is respectively.
#objc func handlePan(gesture: UIPanGestureRecognizer) {
print("panned")
let location = gesture.location(in: sceneView)
let projectedOriginUI = sceneView.projectPoint(SCNVector3(0, 0, gridCon.grid.position.z))
let placeOnUI = sceneView.unprojectPoint(SCNVector3(location.x, location.y, CGFloat(projectedOriginUI.z)))
let rootNode: SCNNode = sceneView.scene.rootNode
let positionOnGrid = rootNode.convertPosition(placeOnUI, to: gridCon.grid)
let state = gesture.state
let hitVertex = gridCon.hitVertex(location: location, sceneView: sceneView)
if (state == UIGestureRecognizer.State.began) {
print("began")
if (hitVertex != nil) {
let edge = EdgeController.createEdge()
edge.position.x = hitVertex?.position.x ?? 0
edge.position.y = hitVertex?.position.y ?? 0
gridCon.grid.addChildNode(edge)
draggedLine = edge
startVertex = hitVertex
print("Edge added!")
}
}
if (state == UIGestureRecognizer.State.ended) {
draggedLine = nil
startVertex = nil
}
if (draggedLine != nil && startVertex !== nil) {
print("line height changed")
let _draggedLine = draggedLine!
let geo: SCNPlane = _draggedLine.geometry as! SCNPlane
let between = startVertex!.position.y - positionOnGrid.y
geo.height = CGFloat(between)
_draggedLine.position.y = startVertex!.position.y - (between/2)
}
}
Why is my finger tracking slightly off here?

How to scale and move all nodes at once? ARKit Swift

I got these functions that scale and move the 3D object displayed on the screen when tapping on it. The problem consists that if I move or scale the node (3D object) it will only make bigger or smaller one part of the node and I want to scale everything.
I know one solution is to join the 3D object in Blender as one but, later on, I want to add specific animation to specific nodes and that's why I don't want to join them.
Here are the code that I'm using for scaling and moving the objects:
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return
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let translation = recognizer.translation(in: sceneView)
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And this one:
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{
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{
return
}
}
let touch = recognizer.location(in: sceneView)
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if let hitTest = hitTestResults.first
{
let planeNode = hitTest.node
let pinchScaleX = Float(recognizer.scale) * planeNode.scale.x
let pinchScaleY = Float(recognizer.scale) * planeNode.scale.y
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I don't know if this helps, but here is an image of the nodes:
Image of the nodes
Thanks in advance!
In order to achieve the "grouping" you are looking for you have to create an empty scene node that will be the root to all other nodes.
let myRootNode : SCNNode = SCNNode()
sceneView.scene.rootNode.addChildNode(myRootNode)
Next append all new nodes in the scene to myRootNode so all your models are parented to the same node.
let newChildNode : SCNNode = SCNNode()
myRootNode.addChildNode(newChildNode)
Then you can apply translations to the myRootNode to move it along with all child nodes. Also the child nodes remain separate models that can be moved (translated/rotated) individually or as a single group.
Within your hit test you should be scaling and rotating the myRootNode instead of the individual model.

How to swipe/slide go into the 3D Object

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This is the code i used for rotate based Y axis,
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guard var originalRotation = originalRotation else { return }
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default:
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To rotate in all direction using UIPanGestureRecognizer, this is the code i have added,
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let x = Float(translation.x)
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rotationVector.z = 0
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if(gestureRecognize.state == UIGestureRecognizerState.ended) {
//
let currentPivot = homeNode?.pivot
let changePivot = SCNMatrix4Invert( (homeNode?.transform)!)
homeNode?.pivot = SCNMatrix4Mult(changePivot, currentPivot!)
homeNode?.transform = SCNMatrix4Identity
}
}
Perhaps there is another way of doing this, Can someone suggest a way..Thanks..

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if !isRotating{
//1. Get The Current Touch Point
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if gesture.state == .began {
guard let nodeHitTest = self.sceneView.hitTest(currentTouchPoint, options: nil).first else {return}
let nodeHit = nodeHitTest.node
currentNode = nodeHit
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if gesture.state == .changed {
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guard let hitTest = self.sceneView.hitTest(currentTouchPoint, types: .existingPlane).first else { return }
//3. Convert To World Coordinates
let worldTransform = hitTest.worldTransform
//4. Set The New Position
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guard let _ = sceneView.session.currentFrame
else { return }
guard let scnView = sceneView else { return }
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What you probably can try is the logic below (hitResults are the results of your hitTest):
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