src/edu/berkeley/qfat/geom/Triangle.java

   1 package edu.berkeley.qfat.geom;
   2 import javax.media.opengl.*;
   3
   4 public abstract class Triangle {
   5     public abstract Point p1();
   6     public abstract Point p2();
   7     public abstract Point p3();
   8
   9     public Vec norm() {
  10         return p2().minus(p1()).cross(p3().minus(p1())).norm();
  11     }
  12     public float area() {
  13         return
  14             (float)Math.abs(0.5*p1().distance(p2())
  15                             * new Vec(p1(), p2()).norm().dot(new Vec(p2(), p3())));
  16     }
  17     public void glVertices(GL gl) {
  18         p1().glVertex(gl);
  19         p2().glVertex(gl);
  20         p3().glVertex(gl);
  21     }
  22     public Point centroid() {
  23         return new Point((p1().x+p2().x+p3().x)/3,
  24                          (p1().y+p2().y+p3().y)/3,
  25                          (p1().z+p2().z+p3().z)/3);
  26     }
  27     public float diameter() {
  28         // FIXME: what is this supposed to be?
  29         return Math.max(Math.max(p1().distance(p2()),
  30                                  p2().distance(p3())),
  31                         p3().distance(p1())) / 2;
  32     }
  33
  34     public float aspect() {
  35         float max = Math.max(Math.max(p1().distance(p2()),
  36                                       p2().distance(p3())),
  37                              p3().distance(p1())) / 2;
  38         return 1/(1+area()/(max*max));
  39     }
  40     public float aspect0() {
  41         float max = Math.max(Math.max(p1().distance(p2()),
  42                                       p2().distance(p3())),
  43                              p3().distance(p1())) / 2;
  44         return (area()/(max*max));
  45     }
  46
  47 }