edu.mines.jtk.sgl.Point4 Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of edu-mines-jtk Show documentation
Java packages for science and engineering
There is a newer version: 1.1.0
/****************************************************************************
Copyright 2004, Colorado School of Mines and others.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
****************************************************************************/
package edu.mines.jtk.sgl;

/**
 * A point with four coordinates x, y, z, and w.
 * @author Dave Hale, Colorado School of Mines
 * @version 2005.05.19
 */
public class Point4 extends Tuple4 {

  /**
   * Constructs a point with coordinates (x,y,z) = 0 and w = 1.
   */
  public Point4() {
    super(0.0,0.0,0.0,1.0);
  }

  /**
   * Constructs a point with specified (x,y,z) coordinates and w = 1.
   * @param x the x coordinate.
   * @param y the y coordinate.
   * @param z the z coordinate.
   */
  public Point4(double x, double y, double z) {
    super(x,y,z,1.0);
  }

  /**
   * Constructs a point with specified coordinates.
   * @param x the x coordinate.
   * @param y the y coordinate.
   * @param z the z coordinate.
   * @param w the w coordinate.
   */
  public Point4(double x, double y, double z, double w) {
    super(x,y,z,w);
  }

  /**
   * Constructs a point from the specified 3-D point.
   * The (x,y,z,w) coordinates of the constructed point are (p.x,p.y,p.z,1).
   * @param p the 3-D point.
   */
  public Point4(Point3 p) {
    super(p.x,p.y,p.z,1.0);
  }

  /**
   * Constructs a copy of the specified point.
   * @param p the point.
   */
  public Point4(Point4 p) {
    super(p.x,p.y,p.z,p.w);
  }

  /**
   * Returns the homogenized point equivalent to this point.
   * Homogenization is division of the coordinates (x,y,z,w) by w.
   * @return the homogenized point.
   */
  public Point4 homogenize() {
    return new Point4(x/w,y/w,z/w,1.0);
  }

  /**
   * Homogenizes this point.
   * Homogenization is division of the coordinates (x,y,z,w) by w.
   * @return this homogenized point.
   */
  public Point4 homogenizeEquals() {
    x /= w;
    y /= w;
    z /= w;
    w = 1.0;
    return this;
  }

  /**
   * Returns the point q = p+v, for this point p and the specified vector v.
   * @param v the vector v.
   * @return the point q = p+v.
   */
  public Point4 plus(Vector3 v) {
    return new Point4(x+v.x,y+v.y,z+v.z,w);
  }

  /**
   * Returns the point q = p-v, for this point p and the specified vector v.
   * @param v the vector v.
   * @return the point q = p-v.
   */
  public Point4 minus(Vector3 v) {
    return new Point4(x-v.x,y-v.y,z-v.z,w);
  }

  /**
   * Moves this point p by adding the specified vector v.
   * @param v the vector v.
   * @return this point, p += v, moved.
   */
  public Point4 plusEquals(Vector3 v) {
    x += v.x;
    y += v.y;
    z += v.z;
    return this;
  }

  /**
   * Moves this point p by subtracting the specified vector v.
   * @param v the vector v.
   * @return this point, p -= v, moved.
   */
  public Point4 minusEquals(Vector3 v) {
    x -= v.x;
    y -= v.y;
    z -= v.z;
    return this;
  }

  /**
   * Returns an affine combination of this point p and the specified point q.
   * @param a the weight of the point q.
   * @param q the point q.
   * @return the affine combination (1-a)*p + a*q.
   */
  public Point4 affine(double a, Point4 q) {
    double b = 1.0-a;
    Point4 p = this;
    return new Point4(b*p.x+a*q.x,b*p.y+a*q.y,b*p.z+a*q.z,b*p.w+a*q.w);
  }
}