package edu.berkeley.qfat.geom;
+import javax.media.opengl.*;
/** vector in 3-space; immutable */
public final class Vec {
public Vec cross(Vec v) { return new Vec(y*v.z-z*v.y, z*v.x-x*v.z, x*v.y-y*v.x); }
public Vec plus(Vec v) { return new Vec(x+v.x, y+v.y, z+v.z); }
public Vec norm() { return mag()==0 ? this : div(mag()); }
- public Vec times(Matrix m) { return m.apply(this); }
public float mag() { return (float)Math.sqrt(x*x+y*y+z*z); }
public float dot(Vec v) { return x*v.x + y*v.y + z*v.z; }
public Vec times(float mag) { return new Vec(x*mag, y*mag, z*mag); }
public Vec div(float mag) { return new Vec(x/mag, y/mag, z/mag); }
public String toString() { return "<"+x+","+y+","+z+">"; }
+ public void glNormal(GL gl) { gl.glNormal3f(x, y, z); }
+
+ /** fundamental error quadric for the plane with this normal passing through p */
+ public Matrix fundamentalQuadric(Point p) {
+ Vec n = this;
+ if (mag() != 1) n = norm();
+ float a = n.x;
+ float b = n.y;
+ float c = n.z;
+ float d = (-a * p.x) + (-b * p.y) + (-c * p.z);
+ return new Matrix(a*a, a*b, a*c, a*d,
+ a*b, b*b, b*c, b*d,
+ a*c, b*c, c*c, c*d,
+ a*d, b*d, c*d, d*d);
+ }
}