package ballworld;

/**
 * A utility class that can be used to create smoothly varying sinusoidal
 * numerical data.
 * Note that this is not a singleton class nor does it have static methods as
 * its behavior depends on the minimum, maximum and delta values given to 
 * its constructor.
 */
public class SineMaker {
  /**
   * The midpoint of the min and max values.
   */
  private double _mid;    
  /**
   * The amplitude of the sinusoidal output
   */
  private double _ampl;  
  /**
   * The amount that _theta is incremented each time, in radians.
   */
  private double _delta; 
  /**
   * The current angle used to generate the current
   * sinusoidal value.  Initialized to produce the minimum value.
   */
  private double _theta = -Math.PI/2.0;  
  
  /**
   * The constructor takes several values to control the object's behavior.
   * @param min The minimum and initial value to produce.
   * @param max The maximum value to produce.
   * @param delta The amount in radians that the generating angle is incremented each time
   * */
  public SineMaker(double min, double max, double delta) {
    _mid = (max+min)/2.0;
    _ampl = (max-min)/2.0;
    _delta = delta;
  }
  
  
  /**
   * Returns a different value each time it is called.  The value varies smoothly in a 
   * sinusoidal fashion, incrementing each time as per the above specified delta 
   * angle increase.
   */
  public double getDblVal() {
    double result = _mid + _ampl*Math.sin(_theta);
    _theta += _delta; // shorthand for _theta = _theta + _delta
    return result;
  }
  
  /**
   * Same as getDblVal, but returns the result rounded to the nearest integer.
   * Note that getDblVal and getIntVal are not independent as getIntVal merely calls
   * getDblVal.
   */
  public int getIntVal() {
    return (int) Math.round(getDblVal());
  }
}