I try to make my character "fall" to the next level on the floor. I tried to do it with physicsBody. When I do it with a box it works great but when I try with a 3D model it doesn't work at all. It moves weirdly in all directions instead of falling in a straight line...
Do you know how to do it correctly?
Here is my code.
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3(0, 1, 15)
cameraNode.eulerAngles.x = 50
scene.rootNode.addChildNode(cameraNode)
let floor = SCNFloor()
floor.reflectionFalloffEnd = 0
floor.firstMaterial?.diffuse.contents = UIColor.red
let floorNode = SCNNode(geometry: floor)
scene.rootNode.addChildNode(floorNode)
let modelScene = SCNScene(named: "Art.scnassets/max.scn")!
let modelNode = modelScene.rootNode.childNode(withName: "Max_rootNode",
recursively: true)!
modelNode.position = SCNVector3(0, 5, 0)
scene.rootNode.addChildNode(modelNode)
modelNode.physicsBody = SCNPhysicsBody(type: .dynamic, shape: nil)
try to study how Apple does move a character as presented on WWDC 2016. The Fox example app. They use a kinematic physicsBody, which is controlled by the updateAtTime function entirely.
https://developer.apple.com/library/archive/samplecode/Fox/Introduction/Intro.html#//apple_ref/doc/uid/TP40016154
(Character.swift, the walkInDirection() function - also handles a fall)
PS: A dynamic physicsBody cannot be controlled directly in a proper way. It is designed to be moved by the physics engine only.
Related
I put some objects in AR space using ARKit and SceneKit. That works well. Now I'd like to add an additional camera (SCNCamera) that is placed elsewhere in the scene attached and positioned by a common SCNNode. It is oriented to show me the current scene from an other (fixed) perspective.
Now I'd like to show this additional SCNCamera feed on i.Ex. a SCNPlane (as the diffuse first material) - Like a TV screen. Of course I am aware that it will only display the SceneKit content which stays in the camera focus and not rest of the ARKit image (which is only possible by the main camera of course). A simple colored background then would be fine.
I have seen tutorials that describes, how to play a video file on a virtual display in ARSpace, but I need a realtime camera feed from my own current scene.
I defined this objects:
let camera = SCNCamera()
let cameraNode = SCNNode()
Then in viewDidLoad I do this:
camera.usesOrthographicProjection = true
camera.orthographicScale = 9
camera.zNear = 0
camera.zFar = 100
cameraNode.camera = camera
sceneView.scene.rootNode.addChildNode(cameraNode)
Then I call my setup function to place the virtual Display next to all my AR stuff, position the cameraNode as well (pointing in the direction where objects stay in the scene)
cameraNode.position = SCNVector3(initialStartPosition.x, initialStartPosition.y + 0.5, initialStartPosition.z)
let cameraPlane = SCNNode(geometry: SCNPlane(width: 0.5, height: 0.3))
cameraPlane.geometry?.firstMaterial?.diffuse.contents = cameraNode.camera
cameraPlane.position = SCNVector3(initialStartPosition.x - 1.0, initialStartPosition.y + 0.5, initialStartPosition.z)
sceneView.scene.rootNode.addChildNode(cameraPlane)
Everything compiles and loads... The display shows up at the given position, but it stays entirely gray. Nothing is displayed at all from the SCNCamera I put in the scene. Everything else in the AR scene works well, I just don't get any feed from that camera.
Hay anyone an approach to get this scenario working?
To even better visualize, I add some more print screens.
The following shows the Image trough the SCNCamera according to ARGeo's input. But it takes the whole screen, instead of displaying its contents on a SCNPlane, like I need.
The next Print screen actually shows the current ARView result as I got it using my posted code. As you can see, the gray Display-Plane remains gray - it shows nothing.
The last print screen is a photomontage, showing the expected result, as I'd like to get.
How could this be realized? Am I missing something fundamental here?
After some research and sleep, I came to the following, working solution (including some inexplainable obstacles):
Currently, the additional SCNCamera feed is not linked to a SCNMaterial on a SCNPlane, as it was the initial idea, but I will use an additional SCNView (for the moment)
In the definitions I add an other view like so:
let overlayView = SCNView() // (also tested with ARSCNView(), no difference)
let camera = SCNCamera()
let cameraNode = SCNNode()
then, in viewDidLoad, I setup the stuff like so...
camera.automaticallyAdjustsZRange = true
camera.usesOrthographicProjection = false
cameraNode.camera = camera
cameraNode.camera?.focalLength = 50
sceneView.scene.rootNode.addChildNode(cameraNode) // add the node to the default scene
overlayView.scene = scene // the same scene as sceneView
overlayView.allowsCameraControl = false
overlayView.isUserInteractionEnabled = false
overlayView.pointOfView = cameraNode // this links the new SCNView to the created SCNCamera
self.view.addSubview(overlayView) // don't forget to add as subview
// Size and place the view on the bottom
overlayView.frame = CGRect(x: 0, y: 0, width: self.view.bounds.width * 0.8, height: self.view.bounds.height * 0.25)
overlayView.center = CGPoint(x: self.view.bounds.width * 0.5, y: self.view.bounds.height - 175)
then, in some other function, I place the node containing the SCNCamera to my desired position and angle.
// (exemplary)
cameraNode.position = initialStartPosition + SCNVector3(x: -0.5, y: 0.5, z: -(Float(shiftCurrentDistance * 2.0 - 2.0)))
cameraNode.eulerAngles = SCNVector3(-15.0.degreesToRadians, -15.0.degreesToRadians, 0.0)
The result, is a kind of window (the new SCNView) at the bottom of the screen, displaying the same SceneKit content as in the main sceneView, viewed trough the perspective of the SCNCamera plus its node position, and that very nicely.
In a common iOS/Swift/ARKit project, this construct generates some side effects, that one may struggle into.
1) Mainly, the new SCNView shows SceneKit content from the desired perspective, but the background is always the actual physical camera feed. I could not figure out, how to make the background a static color, by still displaying all the SceneKit content. Changing the new scene's background property affects also the whole main scene, what is actually NOT desired.
2) It might sound confusing, but as soon as the following code get's included (which is essential to make it work):
overlayView.scene = scene
the animation speed of the entire scenes (both) DOUBLES! (Why?)
I got this corrected by adding/changing the following property, which restores the animation speed behavour almost like normal (default):
// add or change this in the scene setup
scene.physicsWorld.speed = 0.5
3) If there are actions like SCNAction.playAudio in the project, all the effects will no longer play - as long as I don't do this:
overlayView.scene = nil
Of course, the additional SCNView stops working but everything else gets gets back to its normal.
Use this code (as a starting point) to find out how to setup a virtual camera.
Just create a default ARKit project in Xcode and copy-paste my code:
import UIKit
import SceneKit
import ARKit
class ViewController: UIViewController, ARSCNViewDelegate {
#IBOutlet var sceneView: ARSCNView!
override func viewDidLoad() {
super.viewDidLoad()
sceneView.delegate = self
sceneView.showsStatistics = true
let scene = SCNScene(named: "art.scnassets/ship.scn")!
sceneView.scene = scene
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3(0, 0, 1)
cameraNode.camera?.focalLength = 70
cameraNode.camera?.categoryBitMask = 1
scene.rootNode.addChildNode(cameraNode)
sceneView.pointOfView = cameraNode
sceneView.allowsCameraControl = true
sceneView.backgroundColor = UIColor.darkGray
let plane = SCNNode(geometry: SCNPlane(width: 0.8, height: 0.45))
plane.position = SCNVector3(0, 0, -1.5)
// ASSIGN A VIDEO STREAM FROM SCENEKIT-RECORDER TO YOUR MATERIAL
plane.geometry?.materials.first?.diffuse.contents = capturedVideoFromSceneKitRecorder
scene.rootNode.addChildNode(plane)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
let configuration = ARWorldTrackingConfiguration()
sceneView.session.run(configuration)
}
}
UPDATED:
Here's a SceneKit Recorder App that you can tailor to your needs (you don't need to write a video to disk, just use a CVPixelBuffer stream and assign it as a texture for a diffuse material).
Hope this helps.
I'm a little late to the party, but I've had a similar issue recently.
As far as I can tell, you cannot directly connect a camera to a node's material. You can, however, use a scene's layer as a texture for a node.
The code below is not verified, but should be more or less ok:
class MyViewController: UIViewController {
override func loadView() {
let projectedScene = createProjectedScene()
let receivingScene = createReceivingScene()
let projectionPlane = receivingScene.scene?.rootNode.childNode(withName: "ProjectionPlane", recursively: true)!
// Here's the important part:
// You can't directly connect a camera to a material's diffuse texture.
// But you can connect a scene's layer as a texture.
projectionPlane.geometry?.firstMaterial?.diffuse.contents = projectedScene.layer
projectedScene.layer.contentsScale = 1
// Note how we only need to connect the receiving view to the controller.
// The projected view is not directly connected as a subview,
// but updates in projectedScene will still be reflected in receivingScene.
self.view = receivingScene
}
func createProjectedScene() -> SCNView {
let view = SCNView()
// ... set up scene ...
return view
}
func createReceivingScene() -> SCNView {
let view = SCNView()
// ... set up scene ...
let projectionPlane = SCNNode(geometry: SCNPlane(width: 2, height: 2)
projectionPlane.name = "ProjectionPlane"
view.scene.rootNode.addChildNode(projectionPlane)
return view
}
}
I am trying to attach an object in front of the camera, but the issue is that it is always in relation to the initial camera direction. How can I adjust/get the SCNVector3 position to place the object in front, even if the direction of the camera is up or down?
This is how I do it now:
let ballShape = SCNSphere(radius: 0.03)
let ballNode = SCNNode(geometry: ballShape)
let viewPosition = sceneView.pointOfView!.position
ballNode.position = SCNVector3Make(viewPosition.x, viewPosition.y, viewPosition.z - 0.4)
sceneView.scene.rootNode.addChildNode(ballNode)
Edited to better answer the question now that it's clarified in a comment
New Answer:
You are using only the position of the camera, so if the camera is rotated, it doesn't affect the ball.
What you can do is get the transform matrix of the ball and multiply it by the transform matrix of the camera, that way the ball position will be relative to the full transformation of the camera, including rotation.
e.g.
let ballShape = SCNSphere(radius: 0.03)
let ballNode = SCNNode(geometry: ballShape)
ballNode.position = SCNVector3Make(0.0, 0.0, -0.4)
let ballMatrix = ballNode.transform
let cameraMatrix = sceneView.pointOfView!.transform
let newBallMatrix = SCNMatrix4Mult(ballMatrix, cameraMatrix)
ballNode.transform = newBallMatrix
sceneView.scene.rootNode.addChildNode(ballNode)
Or if you only want the SCNVector3 position, to answer exactly to your question (this way the ball will not rotate):
...
let newBallMatrix = SCNMatrix4Mult(ballMatrix, cameraMatrix)
let newBallPosition = SCNVector3Make(newBallMatrix.m41, newBallMatrix.m42, newBallMatrix.m43)
ballNode.position = newBallPosition
sceneView.scene.rootNode.addChildNode(ballNode)
Old Answer:
You are using only the position of the camera, so when the camera rotates, it doesn't affect the ball.
SceneKit uses a hierarchy of nodes, so when a node is "child" of another node, it follows the position, rotation and scale of its "parent". The proper way of attaching an object to another object, in this case the camera, is to make it "child" of the camera.
Then, when you set the position, rotation or any other aspect of the transform of the "child" node, you are setting it relative to its parent. So if you set the position to SCNVector3Make(0.0, 0.0, -0.4), it's translated -0.4 units in Z on top of its "parent" translation.
So to make what you want, it should be:
let ballShape = SCNSphere(radius: 0.03)
let ballNode = SCNNode(geometry: ballShape)
ballNode.position = SCNVector3Make(0.0, 0.0, -0.4)
let cameraNode = sceneView.pointOfView
cameraNode?.addChildNode(ballNode)
This way, when the camera rotates, the ball follows exactly its rotation, but separated -0.4 units from the camera.
Usually I instantiate SCNParticleSystems by using the file initializer like this:
var stars = SCNParticleSystem(named: "Stars.sncp", inDirectory: nil)
However this project requires a Swift Playground and when I try to use that init function with systems stored in the playground's Resources folder it returns nil (even if I change the specified directory to "Resources" or "/Resources" etc. etc. ).
Are Playground resource paths handled differently to normal apps or am I making a really stupid filenaming mistake?
In Xcode 11 and later there's no preconfigured .scnp Particle System file. Instead you can use Particle System object coming directly from Xcode library.
Or, as always, you can create a particle system in Xcode Playground programmatically.
About Swift Playgrounds for iPad read here.
Here's a code:
import PlaygroundSupport
import SceneKit
let rectangle = CGRect(x: 0, y: 0, width: 1000, height: 200)
var sceneView = SCNView(frame: rectangle)
var scene = SCNScene()
sceneView.scene = scene
sceneView.backgroundColor = .black
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position.z = 70
sceneView.scene!.rootNode.addChildNode(cameraNode)
let particleSystem = SCNParticleSystem()
particleSystem.birthRate = 500
particleSystem.particleLifeSpan = 0.5
particleSystem.particleColor = .systemIndigo
particleSystem.speedFactor = 7
particleSystem.emittingDirection = SCNVector3(1,1,1)
particleSystem.emitterShape = .some(SCNSphere(radius: 15))
let particlesNode = SCNNode()
particlesNode.scale = SCNVector3(2,2,2)
particlesNode.addParticleSystem(particleSystem)
sceneView.scene!.rootNode.addChildNode(particlesNode)
PlaygroundPage.current.liveView = sceneView
I think you're doing a mistake in filename extension. It is .scnp and not .sncp.
Either try without any extension -
var stars = SCNParticleSystem(named: "Stars", inDirectory: nil)
or try with correct extension -
var stars = SCNParticleSystem(named: "Stars.scnp", inDirectory: nil)
I have the following code that creates a SCNBox and shoots it on the screen. This works but as soon as I turn the phone in any other direction then the force impulse does not get updated and it always shoots the box in the same old position.
Here is the code:
#objc func tapped(recognizer :UIGestureRecognizer) {
guard let currentFrame = self.sceneView.session.currentFrame else {
return
}
/
let box = SCNBox(width: 0.2, height: 0.2, length: 0.2, chamferRadius: 0)
let material = SCNMaterial()
material.diffuse.contents = UIColor.red
material.lightingModel = .constant
var translation = matrix_identity_float4x4
translation.columns.3.z = -0.01
let node = SCNNode()
node.geometry = box
node.geometry?.materials = [material]
print(currentFrame.camera.transform)
node.physicsBody = SCNPhysicsBody(type: .dynamic, shape: nil)
node.simdTransform = matrix_multiply(currentFrame.camera.transform, translation)
node.physicsBody?.applyForce(SCNVector3(0,2,-10), asImpulse: true)
self.sceneView.scene.rootNode.addChildNode(node)
}
Line 26 is where I apply the force but it does not take into account the user's current phone orientation. How can I fix that?
On line 26 you're passing a constant vector to applyForce. That method takes a vector in world space, so passing a constant vector means you're always applying a force in the same direction — if you want a direction that's based on the direction the camera or something else is pointing, you'll need to calculate a vector based on that direction.
The (new) SCNNode property worldFront might prove helpful here — it gives you the direction a node is pointing, automatically converted to world space, so it's useful with physics methods. (Though you might want to scale it.)
I would like to know how I am supposed to extract the SCNRenderer from an instantiated SceneKit scene. I am trying to get the AVAudioEngine which lies in the SCNRenderer so that I can apply audio filters to my nodes.
Here is the override didFinishLaunching part reduced to relevant code:
override func awakeFromNib() {
// create a new scene
let scene = SCNScene()
// create and add a camera to the scene
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
scene.rootNode.addChildNode(cameraNode)
// place the camera
cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)
// set the scene to the view
self.gameView!.scene = scene
gameView.delegate = self
}
Please if someone can give me a pointer, I would really appreciate it as I was able to run sounds in positional but now am stuck with using the AVEngine graph to do stuff like:
AVAudioInput > AVAudioUnitDistortion > AVAudioOutput and start doing some fun mixing.
Edit:
This is what I had in mind for the engine:
distortion = AVAudioUnitDistortion()
let URL = NSURL(fileURLWithPath: dataPath+"/welcome.aiff")
if(NSFileManager.defaultManager().fileExistsAtPath(dataPath+"/welcome.aiff")){
let source = SCNAudioSource(URL: URL)!
source.volume = 30.0
source.reverbBlend = 50.0
source.rate = 0.9
let clip = SCNAudioPlayer(source: source)
engine = clip.audioNode!.engine
distortion.loadFactoryPreset(AVAudioUnitDistortionPreset.SpeechRadioTower)
engine.attachNode(distortion)
engine.connect(clip.audioNode!, to: distortion, format: nil)
engine.connect(self.distortion, to: engine.outputNode, format: nil)
return clip
But I am now having a null pointer exception over the distortion AVAudioUnitDistortion instance.
Where am I going wrong ?
audioEngine is a property on the SCNSceneRenderer protocol, not on the SCNRenderer class. Since SCNScene conforms to SCNSceneRenderer, scene.audioEngine will work.
edit:
Since SCNView conforms to SCNSceneRenderer, gameView.audioEngine will work.