Initial commit for historical purposes

src/main/java/com/aaaaahhhhhhh/bananapuncher714/tess4j/HalfWing.java

@@ -0,0 +1,105 @@
+package com.aaaaahhhhhhh.bananapuncher714.tess4j;
+
+public class HalfWing {
+    protected HalfWing sym;
+    protected HalfWing prev;
+    protected HalfWing next;
+    
+    protected Vertex origin;
+    
+    public HalfWing() {
+        init();
+        
+        new HalfWing( this );
+    }
+    
+    private HalfWing( HalfWing o ) {
+        init();
+        
+        sym = o;
+        o.sym = this;
+        
+        next = o;
+        o.next = this;
+    }
+    
+    private void init() {
+        origin = new Vertex( this );
+        prev = this;
+    }
+    
+    public Vertex getOrigin() {
+        return origin;
+    }
+    
+    public HalfWing setOrigin( Vertex vert ) {
+        origin = vert;
+        return this;
+    }
+    
+    public HalfWing getSym() {
+        return sym;
+    }
+    
+    public HalfWing getPrev() {
+        return prev;
+    }
+    
+    public HalfWing setPrev( HalfWing wing ) {
+        this.prev = wing;
+        return this;
+    }
+    
+    public HalfWing getNext() {
+        return next;
+    }
+    
+    public HalfWing setNext( HalfWing wing ) {
+        this.next = wing;
+        return this;
+    }
+    
+    public Vertex getDest() {
+        return sym.origin;
+    }
+    
+    public Vector2d toVector2d() {
+        return getDest().getPosition().subtracted( getOrigin().getPosition() );
+    }
+    
+    public boolean isZero() {
+        return getOrigin().equals( getDest() );
+    }
+    
+    // Split this edge in half, and return the new edge
+    public HalfWing split() {
+        HalfWing wing = new HalfWing();
+        
+        splice( wing, getNext() );
+        
+        splice( getSym(), getNext() );
+        splice( getSym(), wing.getSym() );
+        
+        wing.setOrigin( getDest() );
+        wing.getOrigin().setWing( wing );
+        
+        getSym().setOrigin( wing.getDest() );
+        getDest().setWing( getSym() );
+        
+        wing.getOrigin().update();
+        wing.getDest().update();
+        
+        return wing.getSym();
+    }
+    
+    public static void splice( HalfWing a, HalfWing b ) {
+        HalfWing ap = a.prev;
+        HalfWing bp = b.prev;
+        
+        a.prev = bp;
+        b.prev = ap;
+        
+        ap.sym.next = b;
+        bp.sym.next = a;
+    }
+}