JacSnFunc.java

/*
  JWildfire - an image and animation processor written in Java 
  Copyright (C) 1995-2014 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.EPSILON;
import static org.jwildfire.base.mathlib.MathLib.sqr;
import static org.jwildfire.create.tina.variation.JacCnFunc.Jacobi_elliptic;

import org.jwildfire.create.tina.base.XForm;
import org.jwildfire.create.tina.base.XYZPoint;
import org.jwildfire.create.tina.variation.JacCnFunc.Jacobi_elliptic_result;

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

  private static final String PARAM_K = "k";

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

  private double k = 0.5;

  @Override
  public void transform(FlameTransformationContext pContext, XForm pXForm, XYZPoint pAffineTP, XYZPoint pVarTP, double pAmount) {
    // Jacobi-elliptic-SN by dark-beam, http://dark-beam.deviantart.com/art/Jacobi-elliptic-sn-cn-and-dn-Apoplugins-460783612
    double NumX, NumY, Denom;
    Jacobi_elliptic_result jac_x = new Jacobi_elliptic_result();
    Jacobi_elliptic(pAffineTP.x, k, jac_x);
    Jacobi_elliptic_result jac_y = new Jacobi_elliptic_result();
    Jacobi_elliptic(pAffineTP.y, 1.0 - k, jac_y);

    NumX = jac_x.sn * jac_y.dn;
    NumY = jac_x.cn * jac_x.dn * jac_y.cn * jac_y.sn;
    Denom = sqr(jac_x.sn) * sqr(jac_y.sn) * k + sqr(jac_y.cn);
    Denom = pAmount / (EPSILON + Denom);
    pVarTP.x += Denom * NumX;
    pVarTP.y += Denom * NumY;
    if (pContext.isPreserveZCoordinate()) {
  pVarTP.z += pAmount * pAffineTP.z;
}

  }

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

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

  @Override
  public void setParameter(String pName, double pValue) {
    if (PARAM_K.equalsIgnoreCase(pName))
      k = limitVal(pValue, -1.0, 1.0);
    else
      throw new IllegalArgumentException(pName);
  }

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

}