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I have created measure demo which allow to put multiple points and show distance between them. which works fine
I want to show preview that what so far has been drawn in real world to the UIView using UIBezierPath . Just like http://armeasure.com/
I have tried many things to achieve this but I couldn't find any right way to do it.
if self.linkList.count == 1 {
bezierPath.removeAllPoints()
bezierPath.move(to: CGPoint(x: 10,y: 10))
} else {
guard self.linkList.count > 1 ,let object2 = self.linkList.lastNode, let object1 = self.linkList.lastNode?.previous else {return}
let value = self.getMeasurementXandYBetween(vector1: object1.node.mainNode.position, and: object2.node.mainNode.position)
print(value)
let x = Double((object1.node.mainNode.position.x + value ) * 377.9527559055 )
let y = Double((object1.node.mainNode.position.y + value) * 377.9527559055)
let pointCoordinates = CGPoint(x: x , y: y)
print("x : Y ",x,y)
bezierPath.addLine(to: pointCoordinates)
}
shapeLayer.removeFromSuperlayer()
shapeLayer.path = bezierPath.cgPath
shapeLayer.lineWidth = 0.5
shapeLayer.fillColor = UIColor.clear.cgColor
shapeLayer.strokeColor = UIColor.red.cgColor
shapeLayer.position = CGPoint(x: 0, y: 0)
self.viewToDraw.layer.addSublayer(shapeLayer)
func getMeasurementXandYBetween(vector1:SCNVector3, and vector2:SCNVector3) -> Float {
return sqrtf((vector1.x - vector2.x) * (vector1.x - vector2.x) + (vector1.y - vector2.y) * (vector1.y - vector2.y))
}
The logic I used (which is not working is) Location of previous node + distance I got from getMeasurementXandYBetween multiply by 377.
Please suggest a hint or any other solution
You can get the coordinates of any point in screen-space by using the projectPoint() on your SCNSceneRenderer.
This will give you a vector with 3 elements, build your CGPoint using the first two and build your shape from those points.
I have a flying aircraft which I am following and I am also showing the path the aircraft has followed. I am drawing cylinders as a line for drawing the path. Its kind of drawing a line between 2 points. I have a cameraNode which is set to (0,200,200) initially. At that point I can see the aircraft. But when I start my flight. It goes out of the screen. I want 2 things :
Follow just the aircraft (Path won't matter).
Show whole path and also the aircraft.
I tried finding the min ad max x,y and z and taking average but it din't work. If you see below gif its too zoomed and aircraft has moved out of the screen
Here is how I set my camera:
- (void)setUpCamera {
SCNScene *workingScene = [self getWorkingScene];
_cameraNode = [[SCNNode alloc] init];
_cameraNode.camera = [SCNCamera camera];
_cameraNode.camera.zFar = 500;
_cameraNode.position = SCNVector3Make(0, 60, 50);
[workingScene.rootNode addChildNode:_cameraNode];
SCNNode *frontCameraNode = [SCNNode node];
frontCameraNode.position = SCNVector3Make(0, 100, 50);
frontCameraNode.camera = [SCNCamera camera];
frontCameraNode.camera.xFov = 75;
frontCameraNode.camera.zFar = 500;
[_assetActivity addChildNode:frontCameraNode]; //_assetActivity is the aircraft node.
}
Here is how I am changing camera position which is not working:
- (void)showRealTimeFlightPath {
DAL3DPoint *point = [self.aircraftLocation convertCooridnateTo3DPoint];
DAL3DPoint *previousPoint = [self.previousAircraftLocation convertCooridnateTo3DPoint];
self.minCoordinate = [self.minCoordinate findMinPoint:self.minCoordinate currentPoint:point];
self.maxCoordinate = [self.minCoordinate findMaxPoint:self.maxCoordinate currentPoint:point];
DAL3DPoint *averagePoint = [[DAL3DPoint alloc] init];
averagePoint = [averagePoint averageBetweenCoordiantes:self.minCoordinate maxPoint:self.maxCoordinate];
SCNVector3 positions[] = {
SCNVector3Make(point.x,point.y,point.z) ,
SCNVector3Make(previousPoint.x,previousPoint.y,previousPoint.z)
};
SCNScene *workingScene = [self getWorkingScene];
DALLineNode *lineNodeA = [[DALLineNode alloc] init];
[lineNodeA init:workingScene.rootNode v1:positions[0] v2:positions[1] radius:0.1 radSegementCount:6 lineColor:[UIColor greenColor]] ;
[workingScene.rootNode addChildNode:lineNodeA];
self.previousAircraftLocation = [self.aircraftLocation mutableCopy];
self.cameraNode.position = SCNVector3Make(averagePoint.x, averagePoint.y, z);
self.pointOfView = self.cameraNode;
}
Code in swift or objective c are welcomed.
Thanks!!
The first behavior you describe would most easily be achieved by chaining a look-at constraint and a distance constraint, both targeting the aircraft.
let lookAtConstraint = SCNLookAtConstraint(target: aircraft)
let distanceConstraint = SCNDistanceConstraint(target: aircraft)
distanceConstraint.minimumDistance = 10 // set to whatever minimum distance between the camera and aircraft you'd like
distanceConstraint.maximumDistance = 10 // set to whatever maximum distance between the camera and aircraft you'd like
camera.constraints = [lookAtConstraint, distanceConstraint]
For iOS 10 and earlier, you can implement a distance constraint using SCNTransformConstraint. Here's a basic (though slightly ugly 😛) implementation that uses linear interpolation to update the node's position.
func normalize(_ value: Float, in range: ClosedRange<Float>) -> Float {
return (value - range.lowerBound) / (range.upperBound - range.lowerBound)
}
func interpolate(from start: Float, to end: Float, alpha: Float) -> Float {
return (1 - alpha) * start + alpha * end
}
let target = airplane
let minimumDistance: Float = 10
let maximumDistance: Float = 15
let distanceConstraint = SCNTransformConstraint(inWorldSpace: false) { (node, transform) -> SCNMatrix4 in
let distance = abs(sqrt(pow(target.position.x - node.position.x, 2) + pow(target.position.y - node.position.y, 2) + pow(target.position.z - node.position.z, 2)))
let normalizedDistance: Float
switch distance {
case ...minimumDistance:
normalizedDistance = self.normalize(minimumDistance, in: 0 ... distance)
case maximumDistance...:
normalizedDistance = self.normalize(maximumDistance, in: 0 ... distance)
default:
return transform
}
node.position.x = self.interpolate(from: target.position.x, to: node.position.x, alpha: normalizedDistance)
node.position.y = self.interpolate(from: target.position.y, to: node.position.y, alpha: normalizedDistance)
node.position.z = self.interpolate(from: target.position.z, to: node.position.z, alpha: normalizedDistance)
return transform
}
The second behavior could be implemented by determining the bounding box of your aircraft and all of its path segments in the camera's local coordinate space, then updating the camera's distance from the center of that bounding box to frame all of those nodes in the viewport. frameNodes(_:), a convenience method that implements this functionality, was introduced in iOS 11 and is defined on SCNCameraController. I'd recommend using it if possible, unless you want to dive into the trigonometry yourself. You could use your scene view's default camera controller or create a temporary instance, whichever suits the needs of your app.
You need to calculate the angle of the velocity so that the camera points in the direction of the moving SCNNode.
This code will point you in the right direction.
func renderer(_ aRenderer: SCNSceneRenderer, didSimulatePhysicsAtTime time: TimeInterval) {
// get velocity angle using velocity of vehicle
var degrees = convertVectorToAngle(vector: vehicle.chassisBody.velocity)
// get rotation of current camera on X and Z axis
let eX = cameraNode.eulerAngles.x
let eZ = cameraNode.eulerAngles.z
// offset rotation on y axis by 90 degrees
// this needs work, buggy
let ninety = deg2rad(90)
// default camera Y Euler angle facing north at 0 degrees
var eY : Float = 0.0
if degrees != 0 {
eY = Float(-degrees) - Float(ninety)
}
// rotate camera direction using cameraNode.eulerAngles and direction of velocity as eY
cameraNode.eulerAngles = SCNVector3Make(eX, eY, eZ)
// put camera 25 points behind vehicle facing direction of velocity
let dir = calculateCameraDirection(cameraNode: vehicleNode)
let pos = pointInFrontOfPoint(point: vehicleNode.position, direction:dir, distance: 25)
// camera follows driver view from 25 points behind, and 10 points above vehicle
cameraNode.position = SCNVector3Make(pos.x, vehicleNode.position.y + 10, pos.z)
}
func convertVectorToAngle(vector: SCNVector3) -> CGFloat {
let degrees = atan2(vector.z, vector.x)
return CGFloat(degrees)
}
func pointInFrontOfPoint(point: SCNVector3, direction: SCNVector3, distance: Float) -> SCNVector3 {
var x = Float()
var y = Float()
var z = Float()
x = point.x + distance * direction.x
y = point.y + distance * direction.y
z = point.z + distance * direction.z
let result = SCNVector3Make(x, y, z)
return result
}
func calculateCameraDirection(cameraNode: SCNNode) -> SCNVector3 {
let x = -cameraNode.rotation.x
let y = -cameraNode.rotation.y
let z = -cameraNode.rotation.z
let w = cameraNode.rotation.w
let cameraRotationMatrix = GLKMatrix3Make(cos(w) + pow(x, 2) * (1 - cos(w)),
x * y * (1 - cos(w)) - z * sin(w),
x * z * (1 - cos(w)) + y*sin(w),
y*x*(1-cos(w)) + z*sin(w),
cos(w) + pow(y, 2) * (1 - cos(w)),
y*z*(1-cos(w)) - x*sin(w),
z*x*(1 - cos(w)) - y*sin(w),
z*y*(1 - cos(w)) + x*sin(w),
cos(w) + pow(z, 2) * ( 1 - cos(w)))
let cameraDirection = GLKMatrix3MultiplyVector3(cameraRotationMatrix, GLKVector3Make(0.0, 0.0, -1.0))
return SCNVector3FromGLKVector3(cameraDirection)
}
func deg2rad(_ number: Double) -> Double {
return number * .pi / 180
}
I'm trying to draw a simple Parabola shape using UIBezierPath. I have a maxPoint and a boundingRect of which I'm basing the width and stretch of the parabola.
Here's the function I made to draw the parabola (I draw the parabola in a container view, rect will be container.bounds):
func addParabolaWithMax(maxPoint: CGPoint, inRect boundingRect: CGRect) {
let path = UIBezierPath()
let p1 = CGPointMake(1, CGRectGetMaxY(boundingRect)-1)
let p3 = CGPointMake(CGRectGetMaxX(boundingRect)-1, CGRectGetMaxY(boundingRect)-1)
path.moveToPoint(p1)
path.addQuadCurveToPoint(p3, controlPoint: maxPoint)
// Drawing code
...
}
My problem is, that I want the maxPoint that I send in the function to be the actual extreme point in the parabola itself. So for example, if I send in (CGRectGetMidX(container.bounds), 0), The maximum point should be at the top-most center. But in using this function with this particular point, this is what the result looks like:
So what exactly the path does here? Or in other words, how can I get from the controlPoint to the actual max point that I need? I've tried adding and subtracting different values from the y value, based on the height of the boundingRect, but I couldn't quite find the right combination, as in different points with different y values it behaves differently. There seem to be some kind of multiplier being added in, how can I solve it?
For may applications adam.wulf's solution is fine, but it doesn't actually create a parabola. To create a parabola, we need to compute the control point given the midpoint of the quadratic curve. Bézier paths are just math; we can compute this quite easily. We just need to invert the Bézier function and solve it for t=0.5.
The Bézier solution at 0.5 (the midpoint) is derived nicely at Draw a quadratic Bézier curve through three given points.
2*Pc - P0/2 - P2/2
Where Pc is the point we want to go through and P0 and P2 are the end points.
(Computing the Bézier at other points is not very intuitive. The value at t=0.25 is not "a quarter of the way along the path." But luckily for our purposes, t=0.5 matches quite nicely to our intuition of "the midpoint" on a quadratic.)
Given our solution, we can write our code. Forgive the translation to Swift 3; my copy of Xcode 7.3 isn't very happy with iOS playgrounds, but it should be easy to convert to 2.2.
func addParabolaWithMax(maxPoint: CGPoint, inRect boundingRect: CGRect) -> UIBezierPath {
func halfPoint1D(p0: CGFloat, p2: CGFloat, control: CGFloat) -> CGFloat {
return 2 * control - p0 / 2 - p2 / 2
}
let path = UIBezierPath()
let p0 = CGPoint(x: 0, y: boundingRect.maxY)
let p2 = CGPoint(x: boundingRect.maxX, y: boundingRect.maxY)
let p1 = CGPoint(x: halfPoint1D(p0: p0.x, p2: p2.x, control: maxPoint.x),
y: halfPoint1D(p0: p0.y, p2: p2.y, control: maxPoint.y))
path.move(to: p0)
path.addQuadCurve(to: p2, controlPoint: p1)
return path
}
The halfPoint1D function is the the one-dimensional implementation of our solution. For our two-dimentional CGPoint, we just have to call it twice.
If I could recommend just one resource for understanding Bézier curves, it would probably be the "Constructing Bézier curves" section from Wikipedia. Studying the little animations that show how the curves come about I find very enlightening. The "Specific Cases" section is useful as well. For a deep exploration of the topic (and one that I recommend all developers have a passing familiarity with), I like A Primer on Bézier Curves. It's ok to skim it and just read the parts that interest you at the moment. But a basic understanding of this group of functions will go a long way to removing the magic from drawing in Core Graphics and make UIBezierPath a tool rather than a black box.
let path = UIBezierPath()
let p1 = CGPointMake(0,self.view.frame.height/2)
let p3 = CGPointMake(self.view.frame.width,self.view.frame.height/2)
path.moveToPoint(p1)
path.addQuadCurveToPoint(p3, controlPoint: CGPoint(x: self.view.frame.width/2, y: -self.view.frame.height/2))
let line = CAShapeLayer()
line.path = path.CGPath;
line.strokeColor = UIColor.blackColor().CGColor
line.fillColor = UIColor.redColor().CGColor
view.layer.addSublayer(line)
this is the reason: https://cdn.tutsplus.com/mobile/authors/legacy/Akiel%20Khan/2012/10/15/bezier.png you should have to consider the tangent concept
The trick is to split the curve into two pieces so that you can control which points the curve passes through. As mentioned in Eduardo's answer, control points handle tangent, and end points are on the curve. This lets you have a curve from the bottom left to top center, then from top center to bottom right:
let p1 = CGPointMake(0,self.view.frame.height/2)
let p3 = CGPointMake(self.view.frame.width,self.view.frame.height/2)
let ctrlRight = CGPointMake(self.view.frame.width,0)
let ctrlLeft = CGPointZero
let bezierPath = UIBezierPath()
bezierPath.moveToPoint(p1)
bezierPath.addCurveToPoint(maxPoint, controlPoint1: p1, controlPoint2: ctrlLeft)
bezierPath.addCurveToPoint(p3, controlPoint1: ctrlRight, controlPoint2: p3)
UIColor.blackColor().setStroke()
bezierPath.lineWidth = 1
bezierPath.stroke()
I needed to do something similar where I wanted to have a UIBezierPath that exactly matched a specific parabola definition. So I made this little class that creates a parabola based on the focus and directrix or the a, b, c of the general equation. I threw in a convenience init which can use your boundingRect and maxPoint concepts. Either adapt those or the init where the upper corners of the box are its 1 and 2 and the middle of the bottom edge is the vertex.
Use the xform to scale and translate as needed. You can create/draw the path based on any two points on the parabola. They don't have to have the same y-value. The resulting shape will still exactly match the specified parabola.
This is not completely general in terms of rotation but it's a start.
class Parabola
{
var focus: CGPoint
var directrix: CGFloat
var a, b, c: CGFloat
init(_ f: CGPoint, _ y: CGFloat)
{
focus = f
directrix = y
let dy = f.y - y
a = 1 / (2*dy)
b = -f.x / dy
c = (f.x*f.x + f.y*f.y - y*y) / (2*dy)
}
init(_ a: CGFloat, _ b: CGFloat, _ c: CGFloat)
{
self.a = a
self.b = b
self.c = c
focus = CGPoint(x: -b / (2*a), y: (4*a*c - b*b + 1) / (4*a))
directrix = (4*a*c - b*b - 1) / (4*a)
}
convenience init(_ v: CGPoint,
_ pt1: CGPoint,
_ pt2: CGPoint)
{
let a = (pt2.y - v.y) / (pt2.x - v.x) / (pt2.x - v.x)
self.init(CGPoint(x: v.x, y: v.y + 1/(4*a)),
v.y - 1/(4*a))
}
func f(of x: CGFloat) -> CGFloat
{
a*x*x + b*x + c
}
func path(_ x1: CGFloat, _ x2: CGFloat,
_ xform: CGAffineTransform? = .identity) -> UIBezierPath
{
let pt1 = CGPoint(x1, f(of: x1))
let pt2 = CGPoint(x2, f(of: x2))
let x = (x1 + x2) / 2
let y = (2*a * x1 + b) * (x - x1) + pt1.y
let path = UIBezierPath()
path.move(to: pt1)
path.addQuadCurve(to: pt2, controlPoint: CGPoint(x: x, y: y))
path.apply(xform!)
return path
}
}
I've been trying to draw a cylinder between two points on the outer edge of a sphere using SceneKit. I have already produced a line between these two points using primitive geometry and openGL with SCNRendering Delegate, but now I need to produce a cylinder between these two (well, not just two, but any two 3D vectors that sit on the surface of the sphere). I've been working on this for about 3 days straight now, and I've gone through everything I could find on implementing Quaternions to make this happen, but as it stands, I can't get it to work. Academic articles, scientific studies, and nothing, nothing is working to realign a cylinder between two fixed points. I need an algorithm to do this.
Anyway, here's my most recent code that doesn't work, but this is just a small snippet of nearly 2k lines of code I've worked through so far without the intended result. I know I can move to something more advanced like building my own SCNProgram and/or SCNRenderer to then access GLSL, OpenGL, and Metal complexity, but this seems like something that should be possible using Scenekit and converting between GLKit vector structs to and from SCNVector structs, but so far it's impossible:
Code:
The following code ingests Longitude and Latitude coordinates and projects them onto the surface of a 3D sphere. These coordinates are returned through a proprietary function I build where I received a SCNVector3 of {x,y,z} coordinates that display accurately on my 3D sphere. I draw a line between two sets of Longitude and Latitude coordinates where the lines that are drawn using primitives shoot through the center of the sphere. So, as I mentioned above, I want this same functionality but with cylinders, not lines (by the way, the longitude and latitude coordinates listed here are bogus, they are randomly generated but both fall on the Earth's surface).
drawLine = [self lat1:37.76830 lon1:-30.40096 height1:tall lat2:3.97620 lon2:63.73095 height2:tall];
float cylHeight = GLKVector3Distance(SCNVector3ToGLKVector3(cooridnateSetOne.position), SCNVector3ToGLKVector3(coordinateSetTwo.position));
SCNCylinder * cylTest = [SCNCylinder cylinderWithRadius:0.2 height:cylHeight];
SCNNode * test = [SCNNode nodeWithGeometry:cylTest];
SCNMaterial *material = [SCNMaterial material];
[[material diffuse] setContents:[SKColor whiteColor]];
material.diffuse.intensity = 60;
material.emission.contents = [SKColor whiteColor];
material.lightingModelName = SCNLightingModelConstant;
[cylTest setMaterials:#[material]];
GLKVector3 u = SCNVector3ToGLKVector3(cooridnateSetOne.position);
GLKVector3 v = SCNVector3ToGLKVector3(cooridnateSetTwo.position);
GLKVector3 w = GLKVector3CrossProduct(u, v);
GLKQuaternion q = GLKQuaternionMakeWithAngleAndVector3Axis(GLKVector3DotProduct(u,v), GLKVector3Normalize(w));
q.w += GLKQuaternionLength(q);
q = GLKQuaternionNormalize(q);
SCNVector4 final = SCNVector4FromGLKVector4(GLKVector4Make(q.x, q.y, q.z, q.w));
test.orientation = final;
Other code I've tried includes this same sort of method, in fact, I even built my own SCNVector3 and SCNVector4 Math libraries in Objective-C to see if my math methods produced different values than using GLKit maths, but I get the same results with both methods. Any help would be awesome, but for now, I'm not looking to jump into anything more complicated than SceneKit. I won't be diving into Metal and/or OpenGL for another month or two. Thanks!
EDIT:
The variables "cooridnateSetOne" and "cooridnateSetTwo" are SCNNodes that are produced by another function that forces a primitive line geometry into this node and then returns it to a subclass implementation of SCNScene.
Here's a quick demo using node hierarchy (to get the cylinder situated such that its end is at one point and its length is along the local z-axis) and a constraint (to make that z-axis look at another point).
let root = view.scene!.rootNode
// visualize a sphere
let sphere = SCNSphere(radius: 1)
sphere.firstMaterial?.transparency = 0.5
let sphereNode = SCNNode(geometry: sphere)
root.addChildNode(sphereNode)
// some dummy points opposite each other on the sphere
let rootOneThird = CGFloat(sqrt(1/3.0))
let p1 = SCNVector3(x: rootOneThird, y: rootOneThird, z: rootOneThird)
let p2 = SCNVector3(x: -rootOneThird, y: -rootOneThird, z: -rootOneThird)
// height of the cylinder should be the distance between points
let height = CGFloat(GLKVector3Distance(SCNVector3ToGLKVector3(p1), SCNVector3ToGLKVector3(p2)))
// add a container node for the cylinder to make its height run along the z axis
let zAlignNode = SCNNode()
zAlignNode.eulerAngles.x = CGFloat(M_PI_2)
// and position the zylinder so that one end is at the local origin
let cylinder = SCNNode(geometry: SCNCylinder(radius: 0.1, height: height))
cylinder.position.y = -height/2
zAlignNode.addChildNode(cylinder)
// put the container node in a positioning node at one of the points
p2Node.addChildNode(zAlignNode)
// and constrain the positioning node to face toward the other point
p2Node.constraints = [ SCNLookAtConstraint(target: p1Node) ]
Sorry if you were looking for an ObjC-specific solution, but it was quicker for me to prototype this in an OS X Swift playground. (Also, less CGFloat conversion is needed in iOS, because the element type of SCNVector3 is just Float there.)
Just for reference a more elegant SCNCyclinder implementation to connect a start and end position with a given radius:
func makeCylinder(from: SCNVector3, to: SCNVector3, radius: CGFloat) -> SCNNode
{
let lookAt = to - from
let height = lookAt.length()
let y = lookAt.normalized()
let up = lookAt.cross(vector: to).normalized()
let x = y.cross(vector: up).normalized()
let z = x.cross(vector: y).normalized()
let transform = SCNMatrix4(x: x, y: y, z: z, w: from)
let geometry = SCNCylinder(radius: radius,
height: CGFloat(height))
let childNode = SCNNode(geometry: geometry)
childNode.transform = SCNMatrix4MakeTranslation(0.0, height / 2.0, 0.0) *
transform
return childNode
}
Needs the following extension:
extension SCNVector3 {
/**
* Calculates the cross product between two SCNVector3.
*/
func cross(vector: SCNVector3) -> SCNVector3 {
return SCNVector3Make(y * vector.z - z * vector.y, z * vector.x - x * vector.z, x * vector.y - y * vector.x)
}
func length() -> Float {
return sqrtf(x*x + y*y + z*z)
}
/**
* Normalizes the vector described by the SCNVector3 to length 1.0 and returns
* the result as a new SCNVector3.
*/
func normalized() -> SCNVector3 {
return self / length()
}
}
extension SCNMatrix4 {
public init(x: SCNVector3, y: SCNVector3, z: SCNVector3, w: SCNVector3) {
self.init(
m11: x.x,
m12: x.y,
m13: x.z,
m14: 0.0,
m21: y.x,
m22: y.y,
m23: y.z,
m24: 0.0,
m31: z.x,
m32: z.y,
m33: z.z,
m34: 0.0,
m41: w.x,
m42: w.y,
m43: w.z,
m44: 1.0)
}
}
/**
* Divides the x, y and z fields of a SCNVector3 by the same scalar value and
* returns the result as a new SCNVector3.
*/
func / (vector: SCNVector3, scalar: Float) -> SCNVector3 {
return SCNVector3Make(vector.x / scalar, vector.y / scalar, vector.z / scalar)
}
func * (left: SCNMatrix4, right: SCNMatrix4) -> SCNMatrix4 {
return SCNMatrix4Mult(left, right)
}
Thank you, Rickster! I have taken it a little further and made a class out of it:
class LineNode: SCNNode
{
init( parent: SCNNode, // because this node has not yet been assigned to a parent.
v1: SCNVector3, // where line starts
v2: SCNVector3, // where line ends
radius: CGFloat, // line thicknes
radSegmentCount: Int, // number of sides of the line
material: [SCNMaterial] ) // any material.
{
super.init()
let height = v1.distance(v2)
position = v1
let ndV2 = SCNNode()
ndV2.position = v2
parent.addChildNode(ndV2)
let ndZAlign = SCNNode()
ndZAlign.eulerAngles.x = Float(M_PI_2)
let cylgeo = SCNCylinder(radius: radius, height: CGFloat(height))
cylgeo.radialSegmentCount = radSegmentCount
cylgeo.materials = material
let ndCylinder = SCNNode(geometry: cylgeo )
ndCylinder.position.y = -height/2
ndZAlign.addChildNode(ndCylinder)
addChildNode(ndZAlign)
constraints = [SCNLookAtConstraint(target: ndV2)]
}
override init() {
super.init()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
}
I have tested this class successfully in an iOS app, using this function,
which draws 100 lines (oops cylinders :o).
func linesTest3()
{
let mat = SCNMaterial()
mat.diffuse.contents = UIColor.whiteColor()
mat.specular.contents = UIColor.whiteColor()
for _ in 1...100 // draw 100 lines (as cylinders) between random points.
{
let v1 = SCNVector3( x: Float.random(min: -50, max: 50),
y: Float.random(min: -50, max: 50),
z: Float.random(min: -50, max: 50) )
let v2 = SCNVector3( x: Float.random(min: -50, max: 50),
y: Float.random(min: -50, max: 50),
z: Float.random(min: -50, max: 50) )
// Just for testing, add two little spheres to check if lines are drawn correctly:
// each line should run exactly from a green sphere to a red one:
root.addChildNode(makeSphere(v1, radius: 0.5, color: UIColor.greenColor()))
root.addChildNode(makeSphere(v2, radius: 0.5, color: UIColor.redColor()))
// Have to pass the parentnode because
// it is not known during class instantiation of LineNode.
let ndLine = LineNode(
parent: scene.rootNode, // ** needed
v1: v1, // line (cylinder) starts here
v2: v2, // line ends here
radius: 0.2, // line thickness
radSegmentCount: 6, // hexagon tube
material: [mat] ) // any material
root.addChildNode(ndLine)
}
}
Regards. (btw. I can only see 3D objects.. I have never seen a "line" in my life :o)
i use SCNVector3 extensions with:
func cylVector(from : SCNVector3, to : SCNVector3) -> SCNNode {
let vector = to - from,
length = vector.length()
let cylinder = SCNCylinder(radius: cylsRadius, height: CGFloat(length))
cylinder.radialSegmentCount = 6
cylinder.firstMaterial = material
let node = SCNNode(geometry: cylinder)
node.position = (to + from) / 2
node.eulerAngles = SCNVector3Make(CGFloat(Double.pi/2), acos((to.z-from.z)/length), atan2((to.y-from.y), (to.x-from.x) ))
return node
}
Here's an entire method using Objective-C
First, here's how you use it:
SCNNode * testNode = [self lat1:-35 lon1:108 height1:tall lat2:-35 lon2:30 height2:0];
Inputs:
1rst location
lat1 = latitude of 1rst location
lon1 = longitude of 1rst location
height1 = distance from earth for 1rst location
lat2 = latitude of 2nd location
lon2 = latitude of 2nd location
height2 = distance from earth for 2nd location
The second method creates the SCNVector3 points for each location in question above:
-(SCNNode *)lat1:(double)lat1 lon1:(double)lon1 height1:(float)height1 lat2:(double)lat2 lon2:(double)lon2 height2:(float)height2 {
SCNVector3 positions[] = {[self lat:lat1 lon:lon1 height:height1], [self lat:lat2 lon:lon2 height:height2]};
float cylHeight = GLKVector3Distance(SCNVector3ToGLKVector3(positions[0]), SCNVector3ToGLKVector3(positions[1]))/4;
SCNCylinder * masterCylinderNode = [SCNCylinder cylinderWithRadius:0.05 height:cylHeight];
SCNMaterial *material = [SCNMaterial material];
[[material diffuse] setContents:[SKColor whiteColor]];
material.lightingModelName = SCNLightingModelConstant;
material.emission.contents = [SKColor whiteColor];
[masterCylinderNode setMaterials:#[material]];
SCNNode *mainLocationPointNodeTestA = [mainLocationPointNode clone];
SCNNode *mainLocationPointNodeTestB = [mainLocationPointNode clone];
mainLocationPointNodeTestA.position = positions[0];
mainLocationPointNodeTestB.position = positions[1];
SCNNode * mainParentNode = [SCNNode node];
SCNNode * tempNode2 =[SCNNode nodeWithGeometry:masterCylinderNode];
[mainParentNode addChildNode:mainLocationPointNodeTestA];
[mainParentNode addChildNode:mainLocationPointNodeTestB];
[mainParentNode addChildNode:tempNode2];
[mainParentNode setName:#"parentToLineNode"];
tempNode2.position = SCNVector3Make((positions[0].x+positions[1].x)/2, (positions[0].y+positions[1].y)/2, (positions[0].z+positions[1].z)/2);
tempNode2.pivot = SCNMatrix4MakeTranslation(0, cylHeight*1.5, 0);
GLKVector3 normalizedVectorStartingPosition = GLKVector3Make(0.0, 1.0, 0.0);
GLKVector3 magicAxis = GLKVector3Normalize(GLKVector3Subtract(GLKVector3Make(positions[0].x/2, positions[0].y/2, positions[0].z/2), GLKVector3Make(positions[1].x/2, positions[1].y/2, positions[1].z/2)));
GLKVector3 rotationAxis = GLKVector3CrossProduct(normalizedVectorStartingPosition, magicAxis);
CGFloat rotationAngle = GLKVector3DotProduct(normalizedVectorStartingPosition, magicAxis);
GLKVector4 rotation = GLKVector4MakeWithVector3(rotationAxis, acos(rotationAngle));
tempNode2.rotation = SCNVector4FromGLKVector4(rotation);
return mainParentNode;
}
This second method uses hard coded numbers for earth's radius and curvature, I'm showing this just to show the numbers required for total 100% accuracy, this is how it works. You'll want to change this to the correct dimensions for your scene, obviously, but here's the method. This is an adaptation of methods used by Link. An explanation an be found here: Link. I put this together very quickly but it works and is accurate, feel free to change the number formats to your liking.
-(SCNVector3)lat:(double)lat lon:(double)lon height:(float)height {
double latd = 0.0174532925;
double latitude = latd*lat;
double longitude = latd*lon;
Float64 rad = (Float64)(6378137.0);
Float64 f = (Float64)(1.0/298.257223563);
double cosLat = cos(latitude);
double sinLat = sin(latitude);
double FF = pow((1.0-f), 2);
double C = 1/(sqrt(pow(cosLat,2) + FF * pow(sinLat,2)));
double S = C * FF;
double x = ((rad * C)*cosLat * cos(longitude))/(1000000/(1+height));
double y = ((rad * C)*cosLat * sin(longitude))/(1000000/(1+height));
double z = ((rad * S)*sinLat)/(1000000/(1+height));
return SCNVector3Make(y+globeNode.position.x, z+globeNode.position.y, x+globeNode.position.z);
}
I have been looking for a solution to make cylinder between two points and thanks to rickster, I have used his answer to make SCNNode extension. There, I have added missing conditions for a possible cylinder orientation to avoid its wrong opposite direction.
func makeCylinder(positionStart: SCNVector3, positionEnd: SCNVector3, radius: CGFloat , color: NSColor, transparency: CGFloat) -> SCNNode
{
let height = CGFloat(GLKVector3Distance(SCNVector3ToGLKVector3(positionStart), SCNVector3ToGLKVector3(positionEnd)))
let startNode = SCNNode()
let endNode = SCNNode()
startNode.position = positionStart
endNode.position = positionEnd
let zAxisNode = SCNNode()
zAxisNode.eulerAngles.x = CGFloat(M_PI_2)
let cylinderGeometry = SCNCylinder(radius: radius, height: height)
cylinderGeometry.firstMaterial?.diffuse.contents = color
let cylinder = SCNNode(geometry: cylinderGeometry)
cylinder.position.y = -height/2
zAxisNode.addChildNode(cylinder)
let returnNode = SCNNode()
if (positionStart.x > 0.0 && positionStart.y < 0.0 && positionStart.z < 0.0 && positionEnd.x > 0.0 && positionEnd.y < 0.0 && positionEnd.z > 0.0)
{
endNode.addChildNode(zAxisNode)
endNode.constraints = [ SCNLookAtConstraint(target: startNode) ]
returnNode.addChildNode(endNode)
}
else if (positionStart.x < 0.0 && positionStart.y < 0.0 && positionStart.z < 0.0 && positionEnd.x < 0.0 && positionEnd.y < 0.0 && positionEnd.z > 0.0)
{
endNode.addChildNode(zAxisNode)
endNode.constraints = [ SCNLookAtConstraint(target: startNode) ]
returnNode.addChildNode(endNode)
}
else if (positionStart.x < 0.0 && positionStart.y > 0.0 && positionStart.z < 0.0 && positionEnd.x < 0.0 && positionEnd.y > 0.0 && positionEnd.z > 0.0)
{
endNode.addChildNode(zAxisNode)
endNode.constraints = [ SCNLookAtConstraint(target: startNode) ]
returnNode.addChildNode(endNode)
}
else if (positionStart.x > 0.0 && positionStart.y > 0.0 && positionStart.z < 0.0 && positionEnd.x > 0.0 && positionEnd.y > 0.0 && positionEnd.z > 0.0)
{
endNode.addChildNode(zAxisNode)
endNode.constraints = [ SCNLookAtConstraint(target: startNode) ]
returnNode.addChildNode(endNode)
}
else
{
startNode.addChildNode(zAxisNode)
startNode.constraints = [ SCNLookAtConstraint(target: endNode) ]
returnNode.addChildNode(startNode)
}
return returnNode
}
I have 2 objects and when I move one, I want to get the angle from the other.
For example:
Object1X = 211.000000, Object1Y = 429.000000
Object2X = 246.500000, Object2Y = 441.500000
I have tried the following and every variation under the sun:
double radians = ccpAngle(Object1,Object2);
double degrees = ((radians * 180) / Pi);
But I just get 2.949023 returned where I want something like 45 degrees etc.
Does this other answer help?
How to map atan2() to degrees 0-360
I've written it like this:
- (CGFloat) pointPairToBearingDegrees:(CGPoint)startingPoint secondPoint:(CGPoint) endingPoint
{
CGPoint originPoint = CGPointMake(endingPoint.x - startingPoint.x, endingPoint.y - startingPoint.y); // get origin point to origin by subtracting end from start
float bearingRadians = atan2f(originPoint.y, originPoint.x); // get bearing in radians
float bearingDegrees = bearingRadians * (180.0 / M_PI); // convert to degrees
bearingDegrees = (bearingDegrees > 0.0 ? bearingDegrees : (360.0 + bearingDegrees)); // correct discontinuity
return bearingDegrees;
}
Running the code:
CGPoint p1 = CGPointMake(10, 10);
CGPoint p2 = CGPointMake(20,20);
CGFloat f = [self pointPairToBearingDegrees:p1 secondPoint:p2];
And this returns 45.
Hope this helps.
Here's how I'm doing it in Swift for those interested, it's based on #bshirley's answer above w/ a few modifications to help match to the calayer rotation system:
extension CGFloat {
var degrees: CGFloat {
return self * CGFloat(180) / .pi
}
}
extension CGPoint {
func angle(to comparisonPoint: CGPoint) -> CGFloat {
let originX = comparisonPoint.x - x
let originY = comparisonPoint.y - y
let bearingRadians = atan2f(Float(originY), Float(originX))
var bearingDegrees = CGFloat(bearingRadians).degrees
while bearingDegrees < 0 {
bearingDegrees += 360
}
return bearingDegrees
}
}
This provides a coordinate system like this:
90
180 0
270
Usage:
point.angle(to: point2)
CGPoint.zero.angle(to: CGPoint(x: 0, y: 1)) // 90
I modified #tomas' solution to be streamlined. It's likely (it was for me) that this math is going to be called frequently.
In my incarnation, you have to perform the difference between the two points yourself (or if you're lucky, (0,0) is already one of your points). The value being calculated is the direction of the point from (0,0). Yes, that's simple enough and you could inline it if you really want to. My preference is for more readable code.
I also converted it to a function call:
CGFloat CGPointToDegree(CGPoint point) {
// Provides a directional bearing from (0,0) to the given point.
// standard cartesian plain coords: X goes up, Y goes right
// result returns degrees, -180 to 180 ish: 0 degrees = up, -90 = left, 90 = right
CGFloat bearingRadians = atan2f(point.y, point.x);
CGFloat bearingDegrees = bearingRadians * (180. / M_PI);
return bearingDegrees;
}
If you don't want negative values, you need to convert it yourself. Negative values were fine for me - no need to make unneeded calculations.
I was using this in a cocos2d environment, this is how I call it: (Mathematically, we are translating the plane to make p0 the origin. Thus subtracting p0 from p1 (p0 - p0 = {0,0}). The angles are unchanged when the plane is translated.)
CGPoint p0 = self.position;
CGPoint p1 = other.position;
CGPoint pnormal = ccpSub(p1, p0);
CGFloat angle = CGPointToDegree(pnormal);
ccpSub is provided by cocos2d, it's subtraction of a tuple - you can do that yourself if you don't have that available
aside: it's generally not polite style to name the method as above with the CG___ naming scheme, which identifies the function as part of CoreGraphics - so if you want to rename it to MyConvertCGPointToBearing() or FredLovesWilma() then you should do that.
Tomas' answer in Swift 5
func angle(between starting: CGPoint, ending: CGPoint) -> CGFloat {
let center = CGPoint(x: ending.x - starting.x, y: ending.y - starting.y)
let radians = atan2(center.y, center.x)
let degrees = radians * 180 / .pi
return degrees > 0 ? degrees : 360 + degrees
}
There is no angle between two points. If you want to know the angle between the vectors from the origin (0,0) to the objects, use the scalar (dot) product:
theta = arccos ( (veca dot vecb) / ( |veca| * |vecb| )
The math std lib of the language your are using surely provides functions for arcus cosine, scalar product and length.
The vertex of the angle is the point (0,0).
Consider object1X=x1 ....object2Y=y2.
Angle(object1-object2) =
90 * ( (1 + sign(x1)) * (1 - sign(y1^2))
- (1 + sign(x2)) * (1 - sign(y2^2)) )
+ 45 * ( (2 + sign(x1)) * sign(y1)
- (2 + sign(x2)) * sign(y2) )
+ 180/pi() * sign(x1*y1) * atan( (abs(x1) - abs(y1)) / (abs(x1) + abs(y1)) )
- 180/pi() * sign(x2*y2) * atan( (abs(x2) - abs(y2)) / (abs(x2) + abs(y2)) )
Will leave it here. Corrected code, plus with rotation of the axis by 90 degrees counterclockwise. I've used it for touches. viewCenter is just center of the view
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first {
let location = touch.location(in: self)
guard let viewCenter = self.viewCenter else { return }
let angle = angle(between: CGPoint(x: location.x, y: location.y) , ending:viewCenter)
print(angle)
}
}
func angle(between starting: CGPoint, ending: CGPoint) -> CGFloat {
let center = CGPoint(x: ending.x - starting.x, y: ending.y - starting.y)
let angle90 = deg2rad(90)
//Rotate axis by 90 degrees counter clockwise
let rotatedX = center.x * cos(angle90) + center.y * sin(angle90)
let rotatedY = -center.x * sin(angle90) + center.y * cos(angle90)
let radians = atan2(rotatedY, rotatedX)
let degrees = radians * 180 / .pi
return degrees > 0 ? degrees : degrees + 360
}
func deg2rad(_ number: CGFloat) -> CGFloat {
return number * .pi / 180
}