I am trying to make my node start at the same position that I tap in a game but I can't figure it out
here is my code for where to position the node. I get my location from the tap gesture recognizer by:
let myLocation = recognizer.location(in: self.view)
Then I get the x and y position into a float value:
let myx = Float(myLocation.x * 0.01)
let myy = Float(myLocation.y * 0.01)
Then I set the nodes position(the camera is set at 30)
shapeNode.position = SCNVector3(x:myx, y:myy, z: 30.0)
The position is off by a lot and I can't figure out why...
Someone please help
First you need to convert location from 2D on screen into 3D in real world using hittest() to place object in real world
Related
I have created a scnbox in SceneKit and am trying to add a circular plane on the face that is touched by the user.
I can add the SCNPlane as a child node at the touch point using the hittest but I’m struggling to orient the plane to the face that was touched.
The localnormal vector provided as part of hit test seems to be what I need but I’m nit sure how to use it. Normally I would orient using the EulerAngles property but localnormal looks to be a vector. I tried Look(at:) which takes a vector3 but that didn’t seem to work.
Any suggestions would be gratefully received. Code sample below which is taken from touchesBegan. "result" is the SCNHitTestResult:
//Draw circular plane, double sided
let circle = SCNPlane(width: 0.1, height: 0.1) //SCNSphere(radius: 0.1)
circle.cornerRadius = 0.5
circle.materials.first?.diffuse.contents = UIColor.black
circle.materials.first?.isDoubleSided = true
let circleNode = SCNNode(geometry: circle)
//Set position to hit test
circleNode.position = result.localCoordinates
let lookAtPoint = SCNVector3(result.localNormal.x * 100, result.localNormal.y * 100, result.localNormal.z * 100)
//Align to far point on normal
circleNode.look(at: lookAtPoint)
//Add to touched node
result.node.addChildNode(circleNode)
I'm building a UIPanGestureRecognizer so I can move nodes in 3D space.
Currently, I have something that works, but only when the camera is exactly perpendicular to the plane, my UIPanGestureRecognizer looks like this:
#objc func handlePan(_ sender:UIPanGestureRecognizer) {
let projectedOrigin = self.sceneView!.projectPoint(SCNVector3Zero)
let viewCenter = CGPoint(
x: self.view!.bounds.midX,
y: self.view!.bounds.midY
)
let touchlocation = sender.translation(in: self.view!)
let moveLoc = CGPoint(
x: CGFloat(touchlocation.x + viewCenter.x),
y: CGFloat(touchlocation.y + viewCenter.y)
)
let touchVector = SCNVector3(x: Float(moveLoc.x), y: Float(moveLoc.y), z: Float(projectedOrigin.z))
let worldPoint = self.sceneView!.unprojectPoint(touchVector)
let loc = SCNVector3( x: worldPoint.x, y: 0, z: worldPoint.z )
worldHandle?.position = loc
}
The problem happens when the camera is rotated, and the coordinates are effected by the perspective change. Here is you can see the touch position drifting:
Related SO post for which I used to get to this position:
How to use iOS (Swift) SceneKit SCNSceneRenderer unprojectPoint properly
It referenced these great slides: http://www.terathon.com/gdc07_lengyel.pdf
The tricky part of going from 2D touch position to 3D space is obviously the z-coordinate. Instead of trying to convert the touch position to an imaginary 3D space, map the 2D touch to a 2D plane in that 3D space using a hittest. Especially when movement is required only in two direction, for example like chess pieces on a board, this approach works very well. Regardless of the orientation of the plane and the camera settings (as long as the camera doesn't look at the plane from the side obviously) this will map the touch position to a 3D position directly under the finger of the touch and follow consistently.
I modified the Game template from Xcode with an example.
https://github.com/Xartec/PrecisePan/
The main parts are:
the pan gesture code:
// retrieve the SCNView
let scnView = self.view as! SCNView
// check what nodes are tapped
let p = gestureRecognize.location(in: scnView)
let hitResults = scnView.hitTest(p, options: [SCNHitTestOption.searchMode: 1, SCNHitTestOption.ignoreHiddenNodes: false])
if hitResults.count > 0 {
// check if the XZPlane is in the hitresults
for result in hitResults {
if result.node.name == "XZPlane" {
//NSLog("Local Coordinates on XZPlane %f, %f, %f", result.localCoordinates.x, result.localCoordinates.y, result.localCoordinates.z)
//NSLog("World Coordinates on XZPlane %f, %f, %f", result.worldCoordinates.x, result.worldCoordinates.y, result.worldCoordinates.z)
ship.position = result.worldCoordinates
ship.position.y += 1.5
return;
}
}
}
The addition of a XZ plane node in viewDidload:
let XZPlaneGeo = SCNPlane(width: 100, height: 100)
let XZPlaneNode = SCNNode(geometry: XZPlaneGeo)
XZPlaneNode.geometry?.firstMaterial?.diffuse.contents = UIImage(named: "grid")
XZPlaneNode.name = "XZPlane"
XZPlaneNode.rotation = SCNVector4(-1, 0, 0, Float.pi / 2)
//XZPlaneNode.isHidden = true
scene.rootNode.addChildNode(XZPlaneNode)
Uncomment the isHidden line to hide the helper plane and it will still work. The plane obviously needs to be large enough to fill the screen or at least the portion where the user is allowed to pan.
By setting a global var to hold a startWorldPosition of the pan (in state .began) and comparing it to the hit worldPosition in the state .change you can determine the delta/translation in world space and translate other objects accordingly.
I'm having a hard time setting boundaries and positioning camera properly inside my view after panning. So here's my scenario.
I have a node that is bigger than the screen and I want to let user pan around to see the full map. My node is 1000 by 1400 when the view is 640 by 1136. Sprites inside the map node have the default anchor point.
Then I've added a camera to the map node and set it's position to (0.5, 0.5).
Now I'm wondering if I should be changing the position of the camera or the map node when the user pans the screen ? The first approach seems to be problematic, since I can't simply add translation to the camera position because position is defined as (0.5, 0.5) and translation values are way bigger than that. So I tried multiplying/dividing it by the screen size but that doesn't seem to work. Is the second approach better ?
var map = Map(size: CGSize(width: 1000, height: 1400))
override func didMove(to view: SKView) {
(...)
let pan = UIPanGestureRecognizer(target: self, action: #selector(panned(sender:)))
view.addGestureRecognizer(pan)
self.anchorPoint = CGPoint.zero
self.cam = SKCameraNode()
self.cam.name = "camera"
self.camera = cam
self.addChild(map)
self.map.addChild(self.cam!)
cam.position = CGPoint(x: 0.5, y: 0.5)
}
var previousTranslateX:CGFloat = 0.0
func panned (sender:UIPanGestureRecognizer) {
let currentTranslateX = sender.translation(in: view!).x
//calculate translation since last measurement
let translateX = currentTranslateX - previousTranslateX
let xMargin = (map.nodeSize.width - self.frame.width)/2
var newCamPosition = CGPoint(x: cam.position.x, y: cam.position.y)
let newPositionX = cam.position.x*self.frame.width + translateX
// since the camera x is 320, our limits are 140 and 460 ?
if newPositionX > self.frame.width/2 - xMargin && newPositionX < self.frame.width - xMargin {
newCamPosition.x = newPositionX/self.frame.width
}
centerCameraOnPoint(point: newCamPosition)
//(re-)set previous measurement
if sender.state == .ended {
previousTranslateX = 0
} else {
previousTranslateX = currentTranslateX
}
}
func centerCameraOnPoint(point: CGPoint) {
if cam != nil {
cam.position = point
}
}
Your camera is actually at a pixel point 0.5 points to the right of the centre, and 0.5 points up from the centre. At (0, 0) your camera is dead centre of the screen.
I think the mistake you've made is a conceptual one, thinking that anchor point of the scene (0.5, 0.5) is the same as the centre coordinates of the scene.
If you're working in pixels, which it seems you are, then a camera position of (500, 700) will be at the top right of your map, ( -500, -700 ) will be at the bottom left.
This assumes you're using the midpoint anchor that comes default with the Xcode SpriteKit template.
Which means the answer to your question is: Literally move the camera as you please, around your map, since you'll now be confident in the knowledge it's pixel literal.
With one caveat...
a lot of games use constraints to stop the camera somewhat before it gets to the edge of a map so that the map isn't half off and half on the screen. In this way the map's edge is showing, but the furthest the camera travels is only enough to reveal that edge of the map. This becomes a constraints based effort when you have a player/character that can walk/move to the edge, but the camera doesn't go all the way out there.
I'm trying to rotate an SCNBox I created using swipe gestures. For example, when I swipe right the box should rotate 90degs in the Y-axis and -90degs when I swipe left. To achieve this I have been using the node's SCNAction.rotateByX method to perform the rotation animation. Now the problem I'm having is when rotating along either the X-axis or Z-axis after a rotation in the Y-axis and vice-versa is that the positions of the axes change.
What I have notice is that any rotation perform on either of the X,Y,Z axes changes the direction in which the other axes point.
Example: Default position
Then after a rotation in the Z-axis:
Of course this pose a problem because now when I swipe left or right I no longer get the desire effect because the X-axis and Y-axis have now swapped positions. What I would like to know is why does this happen? and is there anyway to perform the rotation animation without it affecting the other axes?
I apologize for my lack of understanding on this subject as this is my first go at 3d graphics.
Solution:
func swipeRight(recognizer: UITapGestureRecognizer) {
// rotation animation
let action = SCNAction.rotateByX(0, y: CGFloat(GLKMathDegreesToRadians(90)), z: 0, duration: 0.5)
boxNode.runAction(action)
//repositoning of the x,y,z axes after the rotation has been applied
let currentPivot = boxNode.pivot
let changePivot = SCNMatrix4Invert(boxNode.transform)
boxNode.pivot = SCNMatrix4Mult(changePivot, currentPivot)
boxNode.transform = SCNMatrix4Identity
}
I haven't ran into any problems yet but it may be safer to use a completion handler to ensure any changes to X,Y,Z axes are done before repositioning them.
I had the same issue, here's what I use to give the desired behavior:
func panGesture(sender: UIPanGestureRecognizer) {
let translation = sender.translationInView(sender.view!)
let pan_x = Float(translation.x)
let pan_y = Float(-translation.y)
let anglePan = sqrt(pow(pan_x,2)+pow(pan_y,2))*(Float)(M_PI)/180.0
var rotVector = SCNVector4()
rotVector.x = -pan_y
rotVector.y = pan_x
rotVector.z = 0
rotVector.w = anglePan
// apply to your model container node
boxNode.rotation = rotVector
if(sender.state == UIGestureRecognizerState.Ended) {
let currentPivot = boxNode.pivot
let changePivot = SCNMatrix4Invert(boxNode.transform)
boxNode.pivot = SCNMatrix4Mult(changePivot, currentPivot)
boxNode.transform = SCNMatrix4Identity
}
}
I am making a fist person camera in Scenekit and the character is not moving relative to the rotation. Instead it is moving relative to the world axis. I want my game to be so when the player swipes forward, the character moves forward on its own x axis. Not along the x axis of the world. I tried to compensate of this with sine and cosine but it did not work. Here is my code:
func lookGestureRecognized(gesture: UIPanGestureRecognizer) {
let velocity = gesture.velocityInView(sceneView)
let rotationAngle = heroNode.presentationNode().rotation.w * heroNode.presentationNode().rotation.y
var impulse = SCNVector3Make(Float(velocity.x)/50, 0, Float(velocity.y)/50)
impulse = SCNVector3(x: impulse.x * cos(rotationAngle), y: 0, z: impulse.z * sin(rotationAngle))
heroNode.physicsBody?.applyForce(impulse, impulse: true)
}
This is still making the character move in the wrong direction of the swipe. Does anyone know how to make the character move relative to its rotation?
Thanks, please ask for clarification if needed
the rotation property is made of a rotation axis and a rotation angle. If you want to retrieve the rotation along the x axis you can use the eulerAngles property.