/*
  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.cos;
import static org.jwildfire.base.mathlib.MathLib.exp;
import static org.jwildfire.base.mathlib.MathLib.log;
import static org.jwildfire.base.mathlib.MathLib.sin;

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

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

  private static final String PARAM_BETA = "beta";

  private static final String[] paramNames = { PARAM_BETA };

  private double beta = 0.30;

  @Override
  public void transform(FlameTransformationContext pContext, XForm pXForm, XYZPoint pAffineTP, XYZPoint pVarTP, double pAmount) {
    /* Escher in the Apophysis Plugin Pack */

    double a = pAffineTP.getPrecalcAtanYX();
    double lnr = 0.5 * log(pAffineTP.getPrecalcSumsq());

    double seb = sin(beta);
    double ceb = cos(beta);

    double vc = 0.5 * (1.0 + ceb);
    double vd = 0.5 * seb;

    double m = pAmount * exp(vc * lnr - vd * a);
    double n = vc * a + vd * lnr;

    double sn = sin(n);
    double cn = cos(n);

    pVarTP.x += m * cn;
    pVarTP.y += m * sn;
    if (pContext.isPreserveZCoordinate()) {
  pVarTP.z += pAmount * pAffineTP.z;
}
  }

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

  @Override
  public Object[] getParameterValues() {
    return new Object[] { beta };
  }

  @Override
  public void setParameter(String pName, double pValue) {
    if (PARAM_BETA.equalsIgnoreCase(pName))
      beta = pValue;
    else
      throw new IllegalArgumentException(pName);
  }

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

}