gov/nasa/worldwind/geom/Triangle.java

   1 /*
   2 Copyright (C) 2001, 2006 United States Government
   3 as represented by the Administrator of the
   4 National Aeronautics and Space Administration.
   5 All Rights Reserved.
   6 */
   7 package gov.nasa.worldwind.geom;
   8
   9 import gov.nasa.worldwind.*;
  10
  11 /**
  12  * @author Eric Dalgliesh 30/11/2006
  13  * @version $Id: Triangle.java 1991 2007-06-09 23:27:42Z dcollins $
  14  */
  15 public class Triangle
  16 {
  17     private static final double EPSILON = 0.0000001; // used in intersects method
  18
  19     private final Vec4 a;
  20     private final Vec4 b;
  21     private final Vec4 c;
  22
  23     public Triangle(Vec4 a, Vec4 b, Vec4 c)
  24     {
  25         if (a == null || b == null || c == null)
  26         {
  27             String msg = WorldWind.retrieveErrMsg("nullValue.PointIsNull");
  28             WorldWind.logger().log(java.util.logging.Level.FINE, msg);
  29             throw new IllegalArgumentException(msg);
  30         }
  31
  32         this.a = a;
  33         this.b = b;
  34         this.c = c;
  35     }
  36
  37 //    private Plane getPlane()
  38 //    {
  39 //        Vector ab, ac;
  40 //        ab = new Vector(this.b.subtract(this.a)).normalize();
  41 //        ac = new Vector(this.c.subtract(this.a)).normalize();
  42 //
  43 //        Vector n = new Vector(new Point(ab.x(), ab.y(), ab.z(), ab.w()).cross(new Point(ac.x(), ac.y(), ac.z(), ac.w())));
  44 //
  45 //        return new gov.nasa.worldwind.geom.Plane(n);
  46 //    }
  47
  48 //    private Point temporaryIntersectPlaneAndLine(Line line, Plane plane)
  49 //    {
  50 //        Vector n = line.getDirection();
  51 //        Point v0 = Point.fromOriginAndDirection(plane.getDistance(), plane.getNormal(), Point.ZERO);
  52 //        Point p0 = line.getPointAt(0);
  53 //        Point p1 = line.getPointAt(1);
  54 //
  55 //        double r1 = n.dot(v0.subtract(p0))/n.dot(p1.subtract(p0));
  56 //        if(r1 >= 0)
  57 //            return line.getPointAt(r1);
  58 //        return null;
  59 //    }
  60 //
  61 //    private Triangle divide(double d)
  62 //    {
  63 //        d  = 1/d;
  64 //        return new Triangle(this.a.multiply(d), this.b.multiply(d), this.c.multiply(d));
  65 //    }
  66
  67 //    public Point intersect(Line line)
  68 //    {
  69 //        // taken from Moller and Trumbore
  70 //        // http://www.cs.virginia.edu/~gfx/Courses/2003/ImageSynthesis/papers/Acceleration/
  71 //        // Fast%20MinimumStorage%20RayTriangle%20Intersection.pdf
  72 //
  73 //        Point origin = line.getOrigin();
  74 //        Point dir = new Point(line.getDirection());
  75 //
  76 //        double u, v;
  77 //
  78 //        // find vectors for two edges sharing Point a
  79 //        Point edge1 = this.c.subtract(this.a);
  80 //        Point edge2 = this.b.subtract(this.a);
  81 //
  82 //        // start calculating determinant
  83 //        Point pvec = dir.cross(edge2);
  84 //
  85 //        // get determinant.
  86 //        double det = edge1.dot(pvec);
  87 //
  88 //        if (det > -EPSILON && det < EPSILON)
  89 //        {// If det is near zero, then ray lies on plane of triangle
  90 //            return null;
  91 //        }
  92 //
  93 //        double detInv = 1d / det;
  94 //
  95 //        // distance from vert0 to ray origin
  96 //        Point tvec = origin.subtract(this.a);
  97 //
  98 //        // calculate u parameter and test bounds
  99 //        u = tvec.dot(pvec) * detInv;
 100 //        if (u < 0 || u > 1)
 101 //        {
 102 //            return null;
 103 //        }
 104 //
 105 //        // prepare to test v parameter
 106 //        Point qvec = tvec.cross(edge1);
 107 //
 108 //        //calculate v parameter and test bounds
 109 //        v = dir.dot(qvec) * detInv;
 110 //        if (v < 0 || u + v > 1)
 111 //        {
 112 //            return null;
 113 //        }
 114 //
 115 //        double t = edge2.dot(qvec) * detInv;
 116 //        return Point.fromOriginAndDirection(t, line.getDirection(), line.getOrigin());
 117 //
 118 ////        return new Point(t, u, v);
 119 ////        return line.getPointAt(t);
 120 //    }
 121 }