CDT work

src/org/poly2tri/Poly2Tri.scala

@@ -55,12 +55,17 @@ object Poly2Tri {
 
 class Poly2TriDemo extends BasicGame("Poly2Tri") {
   
-  var tesselator: Triangulator = null
+  // Sedidel Triangulator
+  var seidel: Triangulator = null
   var segments: ArrayBuffer[Segment] = null
   
+  // EarClip Triangulator
   val earClip = new EarClip
   var earClipResults: Array[poly2tri.earClip.Triangle] = null
   
+  // Sweep Line Constraied Delauney Triangulator (CDT)
+  var slCDT: CDT = null
+  
   var polyX: ArrayBuffer[Float] = null
   var polyY: ArrayBuffer[Float] = null
     
@@ -71,6 +76,7 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
   var hiLighter = 0
   var drawEarClip = false
   var hertelMehlhorn = false
+  var drawCDT = false
   
   val nazcaMonkey = "data/nazca_monkey.dat"
   val bird = "data/bird.dat"
@@ -79,7 +85,7 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
   val strange = "data/strange.dat"
   val i18 = "data/i.18"
   
-  var currentModel = nazcaMonkey
+  var currentModel = star
   
   def init(container: GameContainer) {
     selectModel(currentModel)
@@ -102,7 +108,7 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
     val yellow = new Color(1f, 1f, 0f)
     
    if(debug) {
-	   val draw = if(drawMap) tesselator.trapezoidMap else tesselator.trapezoids
+	   val draw = if(drawMap) seidel.trapezoidMap else seidel.trapezoids
 	   for(t <- draw) {
 	     val polygon = new Polygon()
 	     for(v <- t.vertices) {
@@ -121,14 +127,14 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
    
    if(!debug && !drawEarClip) {
     var i = 0
-    for(t <- tesselator.polygons) {
+    for(t <- seidel.polygons) {
         val poly = new Polygon
         t.foreach(p => poly.addPoint(p.x, p.y))
         g.setColor(red)
         g.draw(poly)
       }
    } else if (debug && drawMap && !drawEarClip){
-    for(mp <- tesselator.monoPolies) {
+    for(mp <- seidel.monoPolies) {
       val poly = new Polygon
       mp.foreach(p => poly.addPoint(p.x, p.y))
       g.setColor(yellow)
@@ -146,6 +152,17 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
 	      g.draw(triangle)
 	    })
    
+   if(drawCDT) {
+	   slCDT.mesh.map.foreach( t => {
+	     val triangle = new Polygon
+		 triangle.addPoint(t.points(0).x, t.points(0).y)
+		 triangle.addPoint(t.points(1).x, t.points(1).y)
+		 triangle.addPoint(t.points(2).x, t.points(2).y)
+		 g.setColor(red)
+		 g.draw(triangle) 
+	   })
+   }
+   
    if(drawSegs) {
      g.setColor(green)
      for(i <- 0 until segments.size) {
@@ -165,16 +182,17 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
     // UP
     if(key == 200) {
       hiLighter += 1
-      if (hiLighter == tesselator.polygons.size)
+      if (hiLighter == seidel.polygons.size)
         hiLighter = 0
     }
     // DOWN
     if(key == 208) {
       hiLighter -= 1
       if (hiLighter == -1)
-        hiLighter = tesselator.polygons.size-1
+        hiLighter = seidel.polygons.size-1
     }
     if(c == 'm') drawMap = !drawMap 
+    //if(c == 'c') drawCDT = !drawCDT
     if(c == '1') selectModel(nazcaMonkey)
     if(c == '2') selectModel(bird)
     if(c == '3') selectModel(strange)
@@ -235,7 +253,7 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
       segments += new Segment(points(i), points(i+1))
     segments += new Segment(points.first, points.last)
     
-    //val cdt = CDT.init(points)
+    //slCDT = CDT.init(points)
     
     println("Number of points = " + polyX.size)
     println
@@ -243,15 +261,15 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
     if(!drawEarClip) {  
       
 	    // Sediel triangulation
-	    tesselator = new Triangulator(segments)
+	    seidel = new Triangulator(segments)
-        tesselator.buildTriangles = hertelMehlhorn
+        seidel.buildTriangles = hertelMehlhorn
         
 	    val t1 = System.nanoTime
-	    tesselator.process
+	    seidel.process
 	    val runTime = System.nanoTime - t1
 	
 	    println("Poly2Tri average (ms) =  " + runTime*1e-6)
-	    println("Number of triangles = " + tesselator.polygons.size)
+	    println("Number of triangles = " + seidel.polygons.size)
      
     } else {
       

src/org/poly2tri/cdt/AFront.scala

@@ -36,28 +36,61 @@ import shapes.{Point, Triangle}
 class AFront(iTriangle: Triangle) {
 
   // Doubly linked list
+  // TODO: Replace with a Red-Black Tree for better performance
   var head = new Node(iTriangle.points(1), iTriangle)
-  var tail = new Node(iTriangle.points(2), iTriangle)
-  
   head.next = new Node(iTriangle.points(0), iTriangle)
+  var tail = new Node(iTriangle.points(2), null)
+  
   head.next.next = tail
   tail.prev = head.next
   
-  def locate(point: Point): Tuple2[List[Point], Triangle] = {
+  def locate(point: Point): Node = {
     var node = head
     while(node != tail) {
-      if(point.x > node.point.x && point.x < node.next.point.x)
+      if(point.x >= node.point.x && point.x <= node.next.point.x)
-        return (List(node.point, node.next.point), node.triangle)
+        return node
       node = node.next
     }
-    null
+    throw new Exception("Advancing front error")
   }
   
+  def +=(tuple: Tuple3[Point, Triangle, Node]) = {
+    val (point, triangle, nNode) = tuple
+    val node = new Node(point, triangle)
+    // Update pointer
+    nNode.triangle = triangle
+    // Insert new node into advancing front
+    nNode.next.prev = node
+    node.next = nNode.next
+    node.prev = nNode
+    nNode.next = node
+    node
+  }
+  
+  def -=(tuple: Tuple3[Node, Node, Triangle]) {
+    val (node, kNode, triangle) = tuple
+    kNode.next.prev = node
+    node.next = kNode.next
+    node.triangle = triangle
+  }
+  
+  def -==(tuple: Tuple3[Node, Node, Triangle]) {
+    val (node, kNode, triangle) = tuple
+    kNode.prev.next = node
+    node.prev = kNode.prev
+    node.prev.triangle = triangle
+  }
   
 }
 
-class Node(val point: Point, val triangle: Triangle) {
+class Node(val point: Point, var triangle: Triangle) {
 
   var next: Node = null
   var prev: Node = null
+  
+  def printDebug {
+    println("Point: " + point)
+    if(triangle != null)
+      println("Triangle points: " + triangle.points)
+  }
 }

src/org/poly2tri/cdt/CDT.scala

@@ -68,8 +68,11 @@ object CDT {
     
     val segments = initSegments(points)
     val sortedPoints = pointSort(points)
-    val initialTriangle = new Triangle(Array(sortedPoints(0), p1, p2), null)
+    
-    new CDT(sortedPoints, segments, initialTriangle)
+    val noNeighbors = new Array[Triangle](3)
+    val tPoints = Array(sortedPoints(0), p1, p2)
+    val iTriangle = new Triangle(tPoints, noNeighbors)
+    new CDT(sortedPoints, segments, iTriangle)
   }
   
     // Create segments and connect end points; update edge event pointer
@@ -89,11 +92,11 @@ object CDT {
   // Insertion sort is one of the fastest algorithms for sorting arrays containing 
   // fewer than ten elements, or for lists that are already mostly sorted.
   // Merge sort: O(n log n)
-  private def pointSort(pts: ArrayBuffer[Point]): List[Point] = {
+  private def pointSort(points: ArrayBuffer[Point]): List[Point] = {
-    if(pts.size < 10) 
+    if(points.size < 10) 
-      Util.insertSort((p1: Point, p2: Point) => p1 > p2)(pts).toList
+      Util.insertSort((p1: Point, p2: Point) => p1 > p2)(points).toList
     else
-      Util.msort((p1: Point, p2: Point) => p1 > p2)(pts.toList)
+      Util.msort((p1: Point, p2: Point) => p1 > p2)(points.toList)
   }
   
   // Prevents any two distinct endpoints from lying on a common horizontal line, and avoiding
@@ -103,60 +106,99 @@ object CDT {
   
 }
 
-class CDT(val points: List[Point], val segments: List[Segment], initialTriangle: Triangle) {
+class CDT(val points: List[Point], val segments: List[Segment], iTriangle: Triangle) {
   
   // The triangle mesh
-  val mesh = new Mesh(initialTriangle)
+  val mesh = new Mesh(iTriangle)
   // Advancing front
-  val aFront = new AFront(initialTriangle)
+  val aFront = new AFront(iTriangle)
   
   // Sweep points; build mesh
   sweep
   // Finalize triangulation
   finalization
   
-  // Implement sweep-line paradigm
+  // Implement sweep-line 
   private def sweep {
     
     for(i <- 1 until points.size) {
       val point = points(i)
-      pointEvent(point)
+      val triangle = pointEvent(point)
-      legalization
+      edgeEvent(point, triangle)
-      edgeEvent(point)
     }
+    
   }  
   
   // Point event
-  private def pointEvent(point: Point) {
+  private def pointEvent(point: Point): Triangle = {
     
+    val node = aFront.locate(point)
     // Neightbor points (ccw & cw) and triangle(i)
-    val (nPts, nTri) = aFront.locate(point)
+    val cwPoint = node.next.point
-    val pts = Array(point, nPts(0),  nPts(1))
+    val ccwPoint = node.point
+    val nTri = node.triangle
+    
+    val pts = Array(point, ccwPoint,  cwPoint)
     val neighbors = Array(nTri, null, null)
     val triangle = new Triangle(pts, neighbors)
     mesh.map += triangle
+    triangle.legalize
     
-    // Update neighbor's pointers
+    nTri.updateNeighbors(ccwPoint, cwPoint, triangle)
-    if(nPts(0) == nTri.points(1) && nPts(1) == nTri.points(2)) 
-      nTri.neighbors(2) = triangle 
-    else if(nPts(0) == nTri.points(2) && nPts(1) == nTri.points(1))
-      nTri.neighbors(1) = triangle
-    else 
-      throw new Exception("CDT Error!")
-    
-  }
-  
-  private def legalization {
-    
-  }
-  
-  private def legalizeEdge {
     
+    // Update advancing front
+    march(aFront += (point, triangle, node))
+    triangle
   }
   
   // EdgeEvent
-  private def edgeEvent(point: Point) {
+  private def edgeEvent(point: Point, triangle: Triangle) {
+    mesh.addEdge(point, triangle)
+  }
   
+  def march(n: Node) {
+    
+    var node = n
+    /*
+    // Update right
+    if(node.next != aFront.tail) {
+      var a = (node.point - node.next.point)
+      var b = (node.next.next.point - node.next.point)
+      var angle = Math.atan2(a cross b, a dot b)
+      while(node != aFront.tail && angle > -Math.Pi*0.5f) {
+	      if(angle >= -Math.Pi*0.5f) {
+	        val points = Array(node.next.point, node.next.next.point, node.point)
+	        val neighbors = Array(null, node.triangle, node.next.triangle)
+	        val triangle = new Triangle(points, neighbors)
+	        mesh.map += triangle
+	        aFront -= (node, node.next, triangle)
+	      }
+          node = node.next
+          a = (node.point - node.next.point)
+          b = (node.next.next.point - node.next.point)
+          angle = Math.atan2(a cross b, a dot b)
+      }
+    }
+    */
+    node = n
+    
+    // Update left
+    if(node.prev != aFront.head) {
+      var angle = 0.0
+      while(node != aFront.head.next && angle < Math.Pi*0.5f) {
+	      val a = (node.point - node.prev.point)
+		  val b = (node.prev.prev.point - node.prev.point)
+	      angle = Math.abs(Math.atan2(a cross b, a dot b))
+	      if(angle <= Math.Pi*0.5f) {
+	        val points = Array(node.prev.point, node.prev.prev.point, node.point)
+	        val neighbors = Array(null, node.triangle, node.prev.triangle)
+	        val triangle = new Triangle(points, neighbors)
+	        mesh.map += triangle
+	        aFront -== (node, node.prev, triangle)
+	      }
+          node = node.prev
+      }
+    }
   }
   
   private def finalization {

src/org/poly2tri/cdt/Mesh.scala

@@ -39,4 +39,11 @@ class Mesh(initialTriangle: Triangle) {
   // Triangles that constitute the mesh
   val map = HashSet(initialTriangle)
   
+  def addEdge(point:Point, triangle: Triangle) {
+    val p = point.eEvent.p
+    if(!triangle.contains(p)) {
+      
+    }
+    
+  }
 }

src/org/poly2tri/shapes/Triangle.scala

@@ -38,4 +38,44 @@ class Triangle(val points: Array[Point], val neighbors: Array[Triangle]) {
   // Flags to determine if an edge is the final Delauney edge
   val edges = new Array[Boolean](3)
   
+  def contains(point: Point) = {
+    if(point == points(0) || point == points(1) || point == points(2))
+      true
+    else 
+      false
+  }
+  
+  def legalize {
+    
+  }
+  
+  // Update neighbor pointers
+  def updateNeighbors(ccwPoint: Point, cwPoint: Point, triangle: Triangle) {
+    if(ccwPoint == points(2) && cwPoint == points(1)) 
+      neighbors(0) = triangle 
+    else if(ccwPoint == points(0) && cwPoint == points(2))
+      neighbors(1) = triangle
+    else 
+      neighbors(2) = triangle
+  }
+  
+  // Fast point in triangle test
+  def pointIn(point: Point): Boolean = {
+    
+    val ab = points(1) - points(0)
+	val bc = points(2) - points(1)
+	val ca = points(0) - points(2)
+
+    val pab = (point - points(0)).cross(ab)
+    val pbc = (point - points(1)).cross(bc)
+	var sameSign = Math.signum(pab) == Math.signum(pbc)
+    if (!sameSign) return false
+
+	val pca = (point - points(2)).cross(ca)
+	sameSign = Math.signum(pab) == Math.signum(pca)
+    if (!sameSign) return false
+    
+    true
+}
+
 }