Add Useful methods to the diagram.

Implement Delaunay triangulation i the SK Demo

Author: Oleksandr Glagoliev

Demo/Demo/VoronoiView.swift

@@ -55,18 +55,18 @@ class VoronoiView: UIView {
 
     @objc func tap(_ gesture: UITapGestureRecognizer) {
 
-//        let seedPoint = gesture.location(in: self)
-//        drawNewPortionOfAxipoints(
-//            generateCircularPoints(
-//                center: Site(
-//                    x: Double(bounds.width / 2),
-//                    y: Double(bounds.height / 2)
-//                ).cgPoint,
-//                seedPoint: seedPoint,
-//                radius: center.distance(to: seedPoint),
-//                numberOfAxis: 1
-//            )
-//        )
+        let seedPoint = gesture.location(in: self)
+        drawNewPortionOfAxipoints(
+            generateCircularPoints(
+                center: Site(
+                    x: Double(bounds.width / 2),
+                    y: Double(bounds.height / 2)
+                ).cgPoint,
+                seedPoint: seedPoint,
+                radius: center.distance(to: seedPoint),
+                numberOfAxis: 10
+            )
+        )
 
 
 //        if axipoints.count > 4 {
@@ -76,7 +76,7 @@ class VoronoiView: UIView {
 
 //        drawRandomSites(200)
 
-        drawNextEdgeCase()
+//        drawNextEdgeCase()
     }
 
     private func generateCircularPoints(
@@ -179,7 +179,7 @@ class VoronoiView: UIView {
                 context.drawLine(
                     from: o.cgPoint,
                     to: d.cgPoint,
-                    color: UIColor.black.withAlphaComponent(0.05), lineWidth: 2.0
+                    color: UIColor.black.withAlphaComponent(1), lineWidth: 2.0
                 )
 
                 // Site
@@ -191,7 +191,7 @@ class VoronoiView: UIView {
 
 //            context.drawPolygonFromCCWPoints(points, color: UIColor.random().withAlphaComponent(0.2))
 
-            let hullVertices = points.map { $0.cgPoint }
+//            let hullVertices = points.map { $0.cgPoint }
 
 //            context.addPath(
 //                UIBezierPath.roundedCornersPath(hullVertices, 10).cgPath
@@ -201,11 +201,11 @@ class VoronoiView: UIView {
 //            context.addPath(
 //                UIBezierPath.roundedCornersPath(scaledHull, 10).cgPath
 //            )
-//
-            let paddedHull = paddedPolygon(hullVertices, padding: -15.0)
-            context.addPath(
-                UIBezierPath.roundedCornersPath(paddedHull, 10)!.cgPath
-            )
+
+//            let paddedHull = paddedPolygon(hullVertices, padding: -15.0)
+//            context.addPath(
+//                UIBezierPath.roundedCornersPath(paddedHull, 10)!.cgPath
+//            )
 
 //            for i in 0..<1 {
 //                let paddedHull = paddedPolygon(hullVertices, padding: CGFloat(-i) * 8)

Sources/FortunesAlgorithm/Diagram.swift

@@ -61,6 +61,47 @@ public class Cell {
     }
 }
 
+public extension Cell {
+    
+    
+    /// Returns hell vertices of the cell
+    func hullVerticesCCW() -> [Vertex] {
+        var vertices: [Vertex] = []
+        guard var he = outerComponent else {
+            return []
+        }
+        
+        var finish = false
+        while !finish {
+            vertices.append(he.origin!)
+            he = he.next!
+            finish = he === outerComponent
+        }
+        
+        return vertices
+    }
+    
+    
+    /// Returns all the neighbours of specific cell
+    func neighbours() -> [Cell] {
+        var neighbours = [Cell]()
+        guard var he = outerComponent else {
+            return []
+        }
+        
+        var finish = false
+        while !finish {
+            if let neighbour = he.twin?.incidentFace {
+                neighbours.append(neighbour)
+            }
+            he = he.next!
+            finish = he === outerComponent
+        }
+        return neighbours
+    }
+    
+}
+
 /// The half‐edge record of a half‐edge e stores pointer to:
 /// • Origin(e)
 /// • Twin of e, e.twin or twin(e)

SpriteKitDemo/SpriteKitDemo/GameScene.swift

@@ -33,36 +33,30 @@ class GameScene: SKScene {
             clippingRect: self.clippingRect
         )
 
-        self.diagram.cells.forEach { cell in
-            var points: [Site] = []
-            var he = cell.outerComponent
+        diagram.cells.forEach { cell in
+//            let hullVertices = cell
+//                .hullVerticesCCW()
+//                .map { $0.cgPoint }
 
-            var finish = false
-            while !finish {
-                
-                let o = he!.origin!
-                points.append(o)
-                
-                
-                he = he?.next
-                finish = he === cell.outerComponent
-            }
-            
-//                let hullVertices = points.map { $0.cgPoint }
-//                for i in 0..<hullVertices.count {
-//                    if i == 0 {
-//                        totalPath.move(to: hullVertices[i])
-//                    } else { totalPath.addLine(to: hullVertices[i])}
+//            let numRepeats = 1
+//            let radius: CGFloat = 0
+//            for i in 0..<numRepeats {
+//                let paddedHull = paddedPolygon(hullVertices, padding: CGFloat(-i) * 10)
+//                if let path = UIBezierPath.roundedCornersPath(paddedHull, radius) {
+//                    totalPath.append(path)
 //                }
-//                totalPath.close()
+//            }
 
-            let hullVertices = points.map { $0.cgPoint }
+//            let centroid = polygonCentroid(hullVertices)
+//
+//            for vtx in hullVertices {
+//                totalPath.move(to: centroid)
+//                totalPath.addLine(to: vtx)
+//            }
 
-            for i in 0..<1 {
-                let paddedHull = paddedPolygon(hullVertices, padding: CGFloat(-i) * 10)
-                if let path = UIBezierPath.roundedCornersPath(paddedHull, 10) {
-                    totalPath.append(path)
-                }
+            for n in cell.neighbours() {
+                totalPath.move(to: cell.site.cgPoint)
+                totalPath.addLine(to: n.site.cgPoint)
             }
         }
 
@@ -88,8 +82,8 @@ class GameScene: SKScene {
 
             let body = SKPhysicsBody(circleOfRadius: r)
             body.affectedByGravity = false
-            body.linearDamping = 0
-            body.mass = 0.0
+            body.linearDamping = 0.9
+            body.mass = 2.0
 
             point.physicsBody = body
             point.isHidden = false
@@ -148,17 +142,20 @@ class GameScene: SKScene {
     func touchMoved(toPoint pos : CGPoint) {
         let spriteAtPoint = atPoint(pos)
         if spriteAtPoint != diagramNode {
-            atPoint(pos).position = CGPoint(x: pos.x.rounded(), y: pos.y.rounded())
+            spriteAtPoint.position = CGPoint(x: pos.x.rounded(), y: pos.y.rounded())
+            
         }
-        redraw(Set<Site>(balls.map { $0.position.point }))
     }
 
     func touchUp(atPoint pos : CGPoint) {
         let ball = atPoint(pos)
         if ball == diagramNode { return }
-//        balls.removeAll(where: { $0 == ball})
-//        ball.removeFromParent()
-//        ball.physicsBody!.affectedByGravity = true
+        
+        let force = CGVector(
+            dx: CGFloat.random(in: -300...300),
+            dy: CGFloat.random(in: -300...300)
+        )
+        ball.physicsBody?.applyImpulse(force)
     }
 
     override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
@@ -178,7 +175,7 @@ class GameScene: SKScene {
     }
 
     override func update(_ currentTime: TimeInterval) {
-//        redraw(Set<Site>(balls.map { $0.position.point }))
+        redraw(Set<Site>(balls.map { $0.position.point }))
     }
 }