CurlFunc.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.sqr;

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

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

  private static final String PARAM_C1 = "c1";
  private static final String PARAM_C2 = "c2";
  private static final String[] paramNames = { PARAM_C1, PARAM_C2 };

  private double c1 = 0.1;
  private double c2 = 0;

  @Override
  public void transform(FlameTransformationContext pContext, XForm pXForm, XYZPoint pAffineTP, XYZPoint pVarTP, double pAmount) {
    double re = 1 + c1 * pAffineTP.x + c2 * (sqr(pAffineTP.x) - sqr(pAffineTP.y));
    double im = c1 * pAffineTP.y + c2 * 2 * pAffineTP.x * pAffineTP.y;

    double r = pAmount / (sqr(re) + sqr(im));

    pVarTP.x += (pAffineTP.x * re + pAffineTP.y * im) * r;
    pVarTP.y += (pAffineTP.y * re - pAffineTP.x * im) * r;
    if (pContext.isPreserveZCoordinate()) {
  pVarTP.z += pAmount * pAffineTP.z;
}
  }

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

  @Override
  public Object[] getParameterValues() {
    return new Object[] { c1, c2 };
  }

  @Override
  public void setParameter(String pName, double pValue) {
    if (PARAM_C1.equalsIgnoreCase(pName))
      c1 = pValue;
    else if (PARAM_C2.equalsIgnoreCase(pName))
      c2 = pValue;
    else
      throw new IllegalArgumentException(pName);
  }

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

}