Suppose you are holding an iphone/ipad vertically in front of you with the screen facing you, in portrait orientation. You tilt the device forward and backward keeping the screen facing you. I have the pitch value from CMMotion manager. I am facing issue with plotting the value of Y-axis accurately to the movement.
func setUpGyro() {
if motionManager.isGyroAvailable {
motionManager.deviceMotionUpdateInterval = 0.1;
motionManager.startDeviceMotionUpdates(to: OperationQueue.main, withHandler: {[weak self] (deviceMotion, NSError) -> Void in
self?.updatePitchMotion(deviceMotion!)
})
} else {
// gyro data is not available
}
}
private func updatePitchMotion(_ motion: CMDeviceMotion) {
let pitch = Double(round(motion.attitude.pitch.rad2deg()))
let maxDistance: CGFloat = 75 // line will not go over 75, as height of the superview is 150
let currentDistance = pitch / 90.0 * maxDistance
DispatchQueue.main.async {
// plotGreen changes the color of the line to green as line is red by default
pitch == -7 ? self.plotGreen() : self.plotRed()
pitch == -8 ? self.plotGreen() : self.plotRed()
pitch == -6 ? self.plotGreen() : self.plotRed()
self.pitchIndicatorLine.transform = CGAffineTransform(translationX: 0, y: currentDistance)
print(pitch)
}
}
I'm getting results from the above code for pitchIndicatorLine but the screen is facing in the upward direction (horizontally) and not facing myself (vertically), can anyone please correct the code for the device to work vertically.
Note: I think its more of a logic issue.
Related
I have a line (UIView with width = screen width and height = 2), I need to move this line up and down the screen with forward tilt and backward tilt. I know I need to use Gyroscope, how can I achieve this using MotionManager()?
var motionManager = CMMotionManager()
private func getGyroUpdates() {
if motionManager.isDeviceMotionAvailable == true {
motionManager.deviceMotionUpdateInterval = 0.1
let queue = OperationQueue()
motionManager.startDeviceMotionUpdates(to: queue, withHandler: { [weak self] motion, error in
// Get the attitude of the device
guard let motion = motion else { return }
let pitch = Double(round(motion.attitude.pitch.rad2deg()))
let length = sqrt(motion.gravity.x * motion.gravity.x + motion.gravity.y * motion.gravity.y + motion.gravity.z * motion.gravity.z)
// how to i get the value to be plotted in Y? do i use gravity? or pitch ?
DispatchQueue.main.async {
// frontBackMovement is the line view here
self?.frontBackMovement.transform = CGAffineTransform(translationX: 0, y: "what should be the value here??")
}
})
print("Device motion started")
}else {
print("Device motion unavailable")
}
}
line needs to move in the frame which is a uiview, I need to get value to put in the place of Y to put it in CGAffineTransform. so basically how do I map value I get from Motion object to plot it in Y. I tried the radian value I get from attitude.pitch but how do I convert that into Y? If I use gravity value how do I use it?
Thank you very much for your help in advance.
Depending on the effect you are trying to achieve you would want to get the pitch angle from motion.attitude.pitch. Then you need to calculate the y offset based on how far you want the line to move relative to the pitch angle.
Let's say you want the line to move 100 points up or down as the device is tilted between -90º and 90º.
You had the angle:
let pitch = Double(round(motion.attitude.pitch.rad2deg()))
So now calculate the distance:
let maxDistance = 100.0
let currentDistance = pitch / 90.0 * maxDistance
where maxDistance is the furthest you want the line to move. You probably need some extra checks to ensure pitch is kept between -90 and 90.
A much simpler approach than using CMMotionManager is to use UIInterpolatingMotionEffect. First setup your line to be in the center of its parent view. Then use the following code:
let maxDistance: Float = 100 // how far do you want the line to move
let eff = UIInterpolatingMotionEffect(keyPath: "center.y", type: .tiltAlongVerticalAxis)
eff.maximumRelativeValue = maxDistance
eff.minimumRelativeValue = -maxDistance
lineView.addMotionEffect(eff)
where maxDistance is the max distance you want the line to move as the device is tilted. In your case this sounds like it should be half the height of the line's parent view.
I want to rotate a SCNNode, which is a painting image.
I can rotate it on the floor, but I cannot rotate it correctly on wall.
(I am using UIRotationGestureRecognizer)
...
func addPainting(_ hitResult: ARHitTestResult, _ grid: Grid) {
...
// Add the painting
let newPaintingNode = SCNNode(geometry: planeGeometry)
newPaintingNode.transform = SCNMatrix4(hitResult.anchor!.transform)
newPaintingNode.eulerAngles = SCNVector3(newPaintingNode.eulerAngles.x + (-Float.pi / 2), newPaintingNode.eulerAngles.y, newPaintingNode.eulerAngles.z)
newPaintingNode.position = SCNVector3(hitResult.worldTransform.columns.3.x, hitResult.worldTransform.columns.3.y, hitResult.worldTransform.columns.3.z)
self.paintingNode = newPaintingNode
self.currentAngleY = newPaintingNode.eulerAngles.y
self.currentAngleZ = newPaintingNode.eulerAngles.z
augmentedRealityView.scene.rootNode.addChildNode(self.paintingNode!)
grid.removeFromParentNode()
}
...
#objc func rotateNode(_ gesture: UIRotationGestureRecognizer){
if let currentNode = self.paintingNode {
//1. Get The Current Rotation From The Gesture
let rotation = Float(gesture.rotation)
if self.paintingAlignment == "horizontal" {
log.verbose("rotate horizontal!")
//2. If The Gesture State Has Changed Set The Nodes EulerAngles.y
if gesture.state == .changed {
currentNode.eulerAngles.y = currentAngleY + rotation
}
//3. If The Gesture Has Ended Store The Last Angle Of The Cube
if(gesture.state == .ended) {
currentAngleY = currentNode.eulerAngles.y
}
} else if self.paintingAlignment == "vertical" {
log.verbose("rotate vertical!")
//2. If The Gesture State Has Changed Set The Nodes EulerAngles.z
if gesture.state == .changed {
currentNode.eulerAngles.z = currentAngleZ + rotation
}
//3. If The Gesture Has Ended Store The Last Angle Of The Cube
if(gesture.state == .ended) {
currentAngleZ = currentNode.eulerAngles.z
}
}
}
}
Does anyone know how can I rotate it correctly on wall? Thank you!
You're using eulerAngles instance property in your code:
var eulerAngles: SCNVector3 { get set }
According to Apple documentation:
SceneKit applies eulerAngles rotations relative to the node’s pivot property in the reverse order of the components: first roll (Z), then yaw (Y), then pitch (X).
...but three-component rotation can lead to Gimbal Lock.
Gimbal lock is the loss of one degree of freedom in a three-dimensional, three-gimbal mechanism that occurs when the axes of two of the three gimbals are driven into a parallel configuration, "locking" the system into rotation in a degenerate two-dimensional space.
So you need to use a four-component rotation property:
var rotation: SCNVector4 { get set }
The four-component rotation vector specifies the direction of the rotation axis in the first three components (XYZ) and the angle of rotation, expressed in radians, in the fourth (W).
currentNode.rotation = SCNVector4(x: 1,
y: 0,
z: 0,
w: -Float.pi / 2)
If you want to know more about SCNVector4 structure and four-component rotation (and its W component expressed in radians) look at THIS POST and THIS POST.
P.S.
In RealityKit framework instead of SCNVector4 structure you need to use SIMD4<Float> generic structure or simd_float4 type alias.
var rotation: simd_float4 { get set }
I tried SCNNode eulerAngles and SCNNode rotation and I have no luck...
I guess that is because I invoked SCNNode.transform() when I add the painting. When later I modify SCNNode.eulerAngles and invoke SCNNode.rotation(), they may have influence on the first transform.
I finally get it working using SCNMatrix4Rotate, not using eulerAngles and rotation.
func addPainting(_ hitResult: ARHitTestResult, _ grid: Grid) {
...
let newPaintingNode = SCNNode(geometry: planeGeometry)
newPaintingNode.transform = SCNMatrix4(hitResult.anchor!.transform)
newPaintingNode.transform = SCNMatrix4Rotate(newPaintingNode.transform, -Float.pi / 2.0, 1.0, 0.0, 0.0)
newPaintingNode.position = SCNVector3(hitResult.worldTransform.columns.3.x, hitResult.worldTransform.columns.3.y, hitResult.worldTransform.columns.3.z)
self.paintingNode = newPaintingNode
...
}
...
#objc func rotateNode(_ gesture: UIRotationGestureRecognizer){
if let _ = self.paintingNode {
// Get The Current Rotation From The Gesture
let rotation = Float(gesture.rotation)
if gesture.state == .began {
self.rotationZ = rotation
}
if gesture.state == .changed {
let diff = rotation - self.rotationZ
self.paintingNode?.transform = SCNMatrix4Rotate(self.paintingNode!.transform, diff, 0.0, 0.0, 1.0)
self.rotationZ = rotation
}
}
}
And the above code works on both vertical and horizontal plane.
I'm working with an AR app that uses Apple's Focus Square to guide user interaction on both vertical and horizontal surfaces. However, it's only designed to work on horizontal surfaces. I have modified the method that updates the square's rotation to account for vertical surfaces as well. However, using the method that they used only one rotation can be performed at a time, whereas in order to have the square positioned properly on a horizontal surface I need to have two rotations performed (one to apply the original yaw correction, and one to pitch the square vertically).
The relevant code is below, but the specific changes I made are only at the beginning and end.
// MARK: - Appearence
func update(for position: float3, planeAnchor: ARPlaneAnchor?, camera: ARCamera?) {
lastPosition = position
let thisAlignment = planeAnchor?.alignment ?? .horizontal
if thisAlignment != lastAlignment {
lastAlignment = thisAlignment
print("alignmentChanged")
recentFocusSquarePositions = []
}
if let anchor = planeAnchor {
close(flash: !anchorsOfVisitedPlanes.contains(anchor))
lastPositionOnPlane = position
anchorsOfVisitedPlanes.insert(anchor)
} else {
open()
}
updateTransform(for: position, alignment: thisAlignment, camera: camera)
}
private func updateTransform(for position: float3, alignment: ARPlaneAnchor.Alignment, camera: ARCamera?) {
// add to list of recent positions
recentFocusSquarePositions.append(position)
// remove anything older than the last 8
recentFocusSquarePositions.keepLast(8)
// move to average of recent positions to avoid jitter
if let average = recentFocusSquarePositions.average {
self.simdPosition = average
self.setUniformScale(scaleBasedOnDistance(camera: camera))
}
// Correct y rotation of camera square
if let camera = camera {
let tilt = abs(camera.eulerAngles.x)
let threshold1: Float = .pi / 2 * 0.65
let threshold2: Float = .pi / 2 * 0.75
let yaw = atan2f(camera.transform.columns.0.x, camera.transform.columns.1.x)
var angle: Float = 0
switch tilt {
case 0..<threshold1:
angle = camera.eulerAngles.y
case threshold1..<threshold2:
let relativeInRange = abs((tilt - threshold1) / (threshold2 - threshold1))
let normalizedY = normalize(camera.eulerAngles.y, forMinimalRotationTo: yaw)
angle = normalizedY * (1 - relativeInRange) + yaw * relativeInRange
default:
angle = yaw
}
if alignment == .vertical{
self.rotation = SCNVector4(0, 1, 1, Float.pi)
} else {
self.rotation = SCNVector4(0, 1, 0, angle)
}
}
}
My goal is to have both the rotations in the control statement at the end performed on the object. If the else statement is removed, only that rotation is applied and the square remains horizontal. I have tried making both modifications to the transform directly using SCNMatrix4MakeRotation(_:_:_:_:) but this caused the square to spin endlessly and position itself incorrectly. I also tried adjusting the node's Pivot but this resulted in no visible changes to the object.
I am trying to put SCNCylinder node in the scene on the touch point. I always want to show the cylinder shape diameter facing towards camera. Its working fine for horizontal scene but it have a problem in vertical scene. In vertical scene I can see the cylinder sides but I want to show the full diameter facing towards the camera no matter whats the camera orientation is. I know there is some transformation needs to be applied depending on the camera transform but don't know how. I am not using plane detection its the simple node which is directly added to the scene.
Vertical Image:
Horizontal Image:
The code to insert the node is as follows,
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
guard let touch = touches.first else {
return
}
let result = sceneView.hitTest(touch.location(in: sceneView), types: [ARHitTestResult.ResultType.featurePoint])
guard let hitResult = result.last else {
print("returning because couldn't find the touch point")
return
}
let hitTransform = SCNMatrix4(hitResult.worldTransform)
let position = SCNVector3Make(hitTransform.m41, hitTransform.m42, hitTransform.m43)
let ballShape = SCNCylinder(radius: 0.02, height: 0.01)
let ballNode = SCNNode(geometry: ballShape)
ballNode.position = position
sceneView.scene.rootNode.addChildNode(ballNode)
}
Any help would be appreciated.
I'm not certain this is the right way to handle what you need but here is something which may help you.
I think CoreMotion could be useful to help you determine if the device is at a horizontal or vertical angle.
This class has a property called attitude, which describes the rotation of our device in terms of roll, pitch, and yaw. If we are holding our phone in portrait orientation, the roll describes the angle of rotation about the axis that runs through the top and bottom of the phone. The pitch describes the angle of rotation about the axis that runs through the sides of your phone (where the volume buttons are). And finally, the yaw describes the angle of rotation about the axis that runs through the front and back of your phone. With these three values, we can determine how the user is holding their phone in reference to what would be level ground (Stephan Baker).
Begin by importing CoreMotion:
import CoreMotion
Then create the following variables:
let deviceMotionDetector = CMMotionManager()
var currentAngle: Double!
We will then create a function which will check the angle of our device like so:
/// Detects The Angle Of The Device
func detectDeviceAngle(){
if deviceMotionDetector.isDeviceMotionAvailable == true {
deviceMotionDetector.deviceMotionUpdateInterval = 0.1;
let queue = OperationQueue()
deviceMotionDetector.startDeviceMotionUpdates(to: queue, withHandler: { (motion, error) -> Void in
if let attitude = motion?.attitude {
DispatchQueue.main.async {
let pitch = attitude.pitch * 180.0/Double.pi
self.currentAngle = pitch
print(pitch)
}
}
})
}
else {
print("Device Motion Unavailable");
}
}
This only needs to be called once for example in viewDidLoad:
detectDeviceAngle()
In your touchesBegan method you can add this to the end:
//1. If We Are Holding The Device Above 60 Degress Change The Node
if currentAngle > 60 {
//2a. Get The X, Y, Z Values Of The Desired Rotation
let rotation = SCNVector3(1, 0, 0)
let vector3x = rotation.x
let vector3y = rotation.y
let vector3z = rotation.z
let degreesToRotate:Float = 90
//2b. Set The Position & Rotation Of The Object
sphereNode.rotation = SCNVector4Make(vector3x, vector3y, vector3z, degreesToRotate * 180 / .pi)
}else{
}
I am sure there are better ways to achieve what you need (and I would be very interested in hearing them too), but I hope it will get you started.
Here is the result:
I have a SceneKit SCNBox Cube that should follow all the movements of my iphone. So If my iphone rotate 90 or 360 degrees sideways should the cube also rotate 90 or 360 degrees and if I spin my phone forward the cube should spin like the phone.
I have tried with startDeviceMotionUpdatesUsingReferenceFrame, but it doesn't match the movements of my phone :(
motionManager.deviceMotionUpdateInterval = 1.0 / 60.0
motionManager.startDeviceMotionUpdatesUsingReferenceFrame(
CMAttitudeReferenceFrame.XArbitraryZVertical,
toQueue: NSOperationQueue.mainQueue(),
withHandler: { (motion: CMDeviceMotion!, error: NSError!) -> Void in
let currentAttitude = motion.attitude
let roll = Float(currentAttitude.roll)
let pitch = Float(currentAttitude.pitch)
let yaw = Float(currentAttitude.yaw)
self.arrRoll.append(roll)
self.arrPitch.append(pitch)
self.arrYaw.append(yaw)
cubeNode.eulerAngles = SCNVector3Make(roll, 0.0, 0.0)
cubeNode.eulerAngles = SCNVector3Make(0.0, 0.0, pitch)
cubeNode.eulerAngles = SCNVector3Make(0.0, yaw, 0.0)
})
Your code snippet is a little out of context, but one thing that strikes me off the bat is that you are (most likely unintentionally) overwriting the eulerAngles property of your node.
Why do you have 3 separate assignments (only the last of which will have an effect), instead of:
cubeNode.eulerAngles = SCNVector3Make(roll, yaw, pitch)
?