/*
  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.M_PI;
import static org.jwildfire.base.mathlib.MathLib.M_2PI;
import static org.jwildfire.base.mathlib.MathLib.M_PI_4;
import static org.jwildfire.base.mathlib.MathLib.sin;
import static org.jwildfire.base.mathlib.MathLib.cos;
import static org.jwildfire.base.mathlib.MathLib.floor;

import org.jwildfire.base.Tools;

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

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

  private static final String PARAM_N = "n";
  private static final String PARAM_ROTATION = "rotation";
  private static final String PARAM_REVERSE = "reverse";

  private static final String[] paramNames = { PARAM_N, PARAM_ROTATION, PARAM_REVERSE };

  private int n = 4;
  private double rotation = 45;
  private double rot_rad = M_PI_4;
  private int reverse = 0;
  
  private double pi_n, cospi_n;
  
  private void circlize(XYZPoint pAffineTP, XYZPoint pVarTP, double pAmount) {
	  double theta = pAffineTP.getPrecalcAtanYX();
	  double r = pAffineTP.getPrecalcSqrt();
	  double factor = cospi_n / cos((theta - rot_rad) - pi_n * (2 * floor((n * (theta - rot_rad)) / M_2PI) + 1));
	  
	  pVarTP.x = lerp(r, r / factor, pAmount) * cos(theta);
	  pVarTP.y = lerp(r, r / factor, pAmount) * sin(theta);	  
  }

  private void uncirclize(XYZPoint pAffineTP, XYZPoint pVarTP, double pAmount) {
	  double theta = pAffineTP.getPrecalcAtanYX();
	  double r = pAffineTP.getPrecalcSqrt();
	  double factor = cospi_n / cos((theta - rot_rad) - pi_n * (2 * floor((n * (theta - rot_rad)) / M_2PI) + 1));
	  
	  pVarTP.x = lerp(r, r * factor, pAmount) * cos(theta);
	  pVarTP.y = lerp(r, r * factor, pAmount) * sin(theta);	  
  }

  @Override
  public void init(FlameTransformationContext pContext, Layer pLayer, XForm pXForm, double pAmount) {
	  pi_n = M_PI / n;
	  cospi_n = cos(pi_n);
  }
 
  @Override
  public void transform(FlameTransformationContext pContext, XForm pXForm, XYZPoint pAffineTP, XYZPoint pVarTP, double pAmount) {
	  if (reverse == 0) {
		  uncirclize(pVarTP, pVarTP, pAmount);
	  }
	  else {
		  circlize(pVarTP, pVarTP, pAmount);
	  }
  }

  @Override
  public void invtransform(FlameTransformationContext pContext, XForm pXForm, XYZPoint pAffineTP, XYZPoint pVarTP, double pAmount) {
	  if (reverse == 0) {
		  circlize(pAffineTP, pAffineTP, pAmount);
	  }
	  else {
		  uncirclize(pAffineTP, pAffineTP, pAmount);
	  }
  }
  
  @Override
  public String[] getParameterNames() {
    return paramNames;
  }

  @Override
  public Object[] getParameterValues() {
    return new Object[] { n, rotation, reverse };
  }

  @Override
  public void setParameter(String pName, double pValue) {
    if (PARAM_N.equalsIgnoreCase(pName))
      n = limitIntVal(Tools.FTOI(pValue), 3, 50);
    else if (PARAM_ROTATION.equalsIgnoreCase(pName)) {
      rotation = pValue;
      rot_rad = rotation * M_PI / 180;
    }
    else if (PARAM_REVERSE.equalsIgnoreCase(pName))
      reverse = limitIntVal(Tools.FTOI(pValue), 0, 1);
    else
      throw new IllegalArgumentException(pName);
  }

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

  @Override
  public int getPriority() {
    return 2;
  }
  
  private double lerp(double v0, double v1, double t) {
	  return (1-t) * v0 + t * v1;
  }

}