Ennepers2Func.java

/*
  JWildfire - an image and animation processor written in Java 
  Copyright (C) 1995-2011 Andreas Maschke

  This is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser 
  General Public License as published by the Free Software Foundation; either version 2.1 of the 
  License, or (at your option) any later version.
 
  This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without 
  even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License along with this software; 
  if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jwildfire.create.tina.variation;

import static org.jwildfire.base.mathlib.MathLib.fabs;
import static org.jwildfire.base.mathlib.MathLib.sqr;
import static org.jwildfire.base.mathlib.MathLib.sqrt;

import org.jwildfire.create.tina.base.XForm;
import org.jwildfire.create.tina.base.XYZPoint;

public class Ennepers2Func extends VariationFunc {
  private static final long serialVersionUID = 1L;

  private static final String PARAM_A = "a";
  private static final String PARAM_B = "b";
  private static final String PARAM_C = "c";
  private static final String[] paramNames = { PARAM_A, PARAM_B, PARAM_C };

  private double a = 1.0;
  private double b = 0.3333;
  private double c = 0.075;

  @Override
  public void transform(FlameTransformationContext pContext, XForm pXForm, XYZPoint pAffineTP, XYZPoint pVarTP, double pAmount) {
    /* ennepers2 by dark-beam */
    double xx = pAffineTP.x;
    double yy = pAffineTP.y;
    double r2 = 1.0 / (sqr(xx) + sqr(yy));
    double dxy = (sqr(a * xx) - sqr(b * yy));

    pVarTP.x += pAmount * xx * (sqr(a) - dxy * r2 - c * sqrt(fabs(xx)));
    pVarTP.y += pAmount * yy * (sqr(b) - dxy * r2 - c * sqrt(fabs(yy)));
    pVarTP.z += pAmount * dxy * 0.5 * sqrt(r2);
  }

  @Override
  public String[] getParameterNames() {
    return paramNames;
  }

  @Override
  public Object[] getParameterValues() {
    return new Object[] { a, b, c };
  }

  @Override
  public void setParameter(String pName, double pValue) {
    if (PARAM_A.equalsIgnoreCase(pName))
      a = pValue;
    else if (PARAM_B.equalsIgnoreCase(pName))
      b = pValue;
    else if (PARAM_C.equalsIgnoreCase(pName))
      c = pValue;
    else
      throw new IllegalArgumentException(pName);
  }

  @Override
  public String getName() {
    return "ennepers2";
  }

}