added new circumcenter test

src/org/poly2tri/Poly2Tri.scala

@@ -210,6 +210,13 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
 		 g.draw(triangle) 
 	   })
     
+	   //slCDT.cList.foreach(c => {
+       for(i <- 0 until 7) {
+	     val circ = new Circle(slCDT.cList(i).x, slCDT.cList(i).y, 0.5f)
+	     g.setColor(blue); g.draw(circ); g.fill(circ)
+       }
+       //})
+       
    }
    
    if(drawSegs) {
@@ -243,6 +250,11 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
     mousePressed = true
     mousePosOld = mousePos
     mousePos = Point(x, y)
+    /*
+    val point = mousePos/scaleFactor + Point(deltaX, deltaY)
+    slCDT.addPoint(point)
+    slCDT.triangulate
+    */
   }
   
   /**
@@ -424,6 +436,15 @@ class Poly2TriDemo extends BasicGame("Poly2Tri") {
         slCDT triangulate
 	    val runTime = System.nanoTime - t1
         
+        if(slCDT.cList.size > 1) {
+          //slCDT.addPoint(slCDT.cList(0))
+          //slCDT.addPoint(slCDT.cList(1))
+          println(slCDT.cList.size)
+          for(i <- 0 until 7) 
+            slCDT.addPoint(slCDT.cList(i))
+          slCDT.triangulate
+        }
+        
 	    println("CDT average (ms) =  " + runTime*1e-6)
 		println("Number of triangles = " + slCDT.triangles.size)
 	    println

src/org/poly2tri/cdt/CDT.scala

@@ -53,6 +53,9 @@ class CDT(polyLine: Array[Point], clearPoint: Point) {
   def triangleMesh = mesh.map
   def debugTriangles = mesh.debug
   
+  val cList = new ArrayBuffer[Point]
+  var refine = false
+  
   // Initialize edges
   initEdges(polyLine)
   
@@ -62,9 +65,20 @@ class CDT(polyLine: Array[Point], clearPoint: Point) {
     points = points ++ holePolyLine.toList
   }
   
+  // Add an internal point
+  // Good for manually refining the mesh. Use this when you want to eliminate
+  // skinny triangles
+  def addPoint(point: Point) {
+    points = point :: points
+  }
+  
   // Triangulate simple polygon with holes
   def triangulate {
     
+    mesh.map.clear
+    mesh.triangles.clear
+    mesh.debug.clear
+    
     var xmax, xmin = points.first.x
     var ymax, ymin = points.first.y
     
@@ -125,7 +139,6 @@ class CDT(polyLine: Array[Point], clearPoint: Point) {
 	    if(p1.x > p2.x) {
 	      return List(p2, p1)
 	    } else if(p1.x == p2.x) {
-	      println(p1 + "," + p2)
           throw new Exception("Duplicate point")
         }
 	  }
@@ -139,8 +152,10 @@ class CDT(polyLine: Array[Point], clearPoint: Point) {
   
   // Implement sweep-line 
   private def sweep {
+    // 48 67
+    val size = if(refine) 68 else points.size
     
-    for(i <- 1 until points.size) {
+    for(i <- 1 until size) {
       
       val point = points(i)
       // Process Point event
@@ -167,6 +182,17 @@ class CDT(polyLine: Array[Point], clearPoint: Point) {
     })
     // Collect interior triangles constrained by edges
     mesh clean cleanTri
+    
+    mesh.triangles.foreach(t => {
+      if(t.thin) {
+        val center = Util.circumcenter(t.points(0), t.points(1), t.points(2))
+        cList += center
+        refine = true
+        //addPoint(center)
+        //mesh.debug += t
+      }
+    })
+    
   }
   
   // Point event
@@ -286,12 +312,24 @@ class CDT(polyLine: Array[Point], clearPoint: Point) {
       nTriangles += pNode.triangle
       pNode = pNode.next
       
-	  while(pNode.point != point2 && edge > pNode.point) {
+	  while(pNode.point != point2) {
 		points += pNode.point
         nTriangles += pNode.triangle
 		pNode = pNode.next
 	  }
       
+      val s = new Segment(first.point, first.next.point)
+      if(s > point1) {
+        mesh.map -= first.triangle
+        first.triangle = first.triangle.neighborCW(first.point)
+        val t = first.triangle.neighborAcross(first.point)
+        val n = new Node(point1, t)
+        first.next = n
+        n.prev = first
+        n.next = first.next.next
+        n.next.prev = n
+      }
+      
       // Triangulate empty areas.
       val T = new ArrayBuffer[Triangle]
       triangulate(points.toArray, List(point1, point2), T)
@@ -305,6 +343,11 @@ class CDT(polyLine: Array[Point], clearPoint: Point) {
       // Mark constrained edge
       T.last markEdge(point1, point2)
       
+      if(pNode.point != edge.p) {
+        println("span")
+        //edgeEvent(edge, pNode)
+      }
+      
     } else if(firstTriangle.contains(edge.q, edge.p)) { 
       // Constrained edge lies on the side of a triangle
       // Mark constrained edge

src/org/poly2tri/shapes/Triangle.scala

@@ -353,7 +353,8 @@ class Triangle(val points: Array[Point]) {
     
     val b = points(0).x - points(1).x
     val h = points(2).y - points(1).y
-    (b*h*0.5f)
+    
+    Math.abs((b*h*0.5f))
   }
   
   def centroid: Point = {
@@ -363,4 +364,18 @@ class Triangle(val points: Array[Point]) {
     Point(cx, cy)
   }
   
+  def thin: Boolean = {
+     val a1 = (points(1) - points(0))
+	 val b1 = (points(2) - points(0))
+     val a2 = (points(0) - points(1))
+     val b2 = (points(2) - points(1))
+	 val angle1 = Math.abs(Math.atan2(a1 cross b1, a1 dot b1))
+     val angle2 = Math.abs(Math.atan2(a2 cross b2, a2 dot b2))
+	 val angle3 = Math.Pi - angle1 - angle2
+     // 30 degrees
+     val minAngle = Math.Pi/6
+     //println(angle1 + "," + angle2 + "," + angle3)
+     (angle1 <= minAngle || angle2 <= minAngle || angle3 <= minAngle)
+  } 
+  
 }

src/org/poly2tri/utils/Util.scala

@@ -133,6 +133,30 @@ object Util {
 
    }
    
+   // Original by Jonathan Shewchuk
+   // http://www.ics.uci.edu/~eppstein/junkyard/circumcenter.html
+   def circumcenter(a: Point, b: Point, c: Point): Point = {
+
+     /* Use coordinates relative to point `a' of the triangle. */
+     val xba = b.x - a.x
+     val yba = b.y - a.y
+     val xca = c.x - a.x
+     val yca = c.y - a.y
+     /* Squares of lengths of the edges incident to `a'. */
+     val balength = xba * xba + yba * yba
+     val calength = xca * xca + yca * yca
+
+     /* Calculate the denominator of the formulae. */
+     val denominator = 0.5 / orient2d(b, c, a)
+
+     /* Calculate offset (from `a') of circumcenter. */
+     val xcirca = (yca * balength - yba * calength) * denominator
+     val ycirca = (xba * calength - xca * balength) * denominator
+     
+     a + Point(xcirca.toFloat, ycirca.toFloat)
+
+  }
+
    // Returns triangle circumcircle point and radius
    def circumCircle(a: Point, b: Point, c: Point): Tuple2[Point, Float] = {