title: calculate intersection area of two triangle
body: <p>I have been trying to find an algorithm which computes the intersecting area of two triangles but I failed to find any. Can anybody give a clue how to write this algorithm?</p>
  
  <p>I would like something like:</p>
  
  <pre><code>  double getAreaOfIntersection(Vector2 p1,Vector2 p2, Vector2 p3,Vector2 p4,Vector2 p5,Vector2 p6 )
  </code></pre>
  
  <p>where pX represents the 2 triangles. </p>