/*
  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.atan2;
import static org.jwildfire.base.mathlib.MathLib.cos;
import static org.jwildfire.base.mathlib.MathLib.sin;
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 CirclesplitFunc extends VariationFunc {
  private static final long serialVersionUID = 1L;
  private static final String PARAM_CS_RADIUS = "cs_radius";
  private static final String PARAM_CS_SPLIT = "cs_split";
  private static final String[] paramNames = { PARAM_CS_RADIUS, PARAM_CS_SPLIT };
  private double cs_radius = 1.0;
  private double cs_split = 0.5;

  @Override
  public void transform(FlameTransformationContext pContext, XForm pXForm, XYZPoint pAffineTP, XYZPoint pVarTP, double pAmount) {
    // "circlesplit" variation created by Tatyana Zabanova implemented into JWildfire by Brad Stefanov

    double x0 = pAffineTP.x;
    double y0 = pAffineTP.y;

    double r = sqrt(sqr(x0) + sqr(y0));

    double x1;
    double y1;

    if (r < cs_radius - cs_split) {
      x1 = x0;
      y1 = y0;
    }
    else {
      double a = atan2(y0, x0);
      double len = r + cs_split;
      x1 = cos(a) * len;
      y1 = sin(a) * len;
    }

    pVarTP.x += pAmount * x1;
    pVarTP.y += pAmount * y1;
    if (pContext.isPreserveZCoordinate()) {
      pVarTP.z += pAmount * pAffineTP.z;
    }
  }

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

  @Override
  public Object[] getParameterValues() {
    return new Object[] { cs_radius, cs_split };
  }

  @Override
  public void setParameter(String pName, double pValue) {
    if (PARAM_CS_RADIUS.equalsIgnoreCase(pName))
      cs_radius = pValue;
    else if (PARAM_CS_SPLIT.equalsIgnoreCase(pName))
      cs_split = pValue;
    else
      throw new IllegalArgumentException(pName);
  }

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