/*******************************************************************************
 * Copyright (c) 2013, Daniel Murphy
 * All rights reserved.
 * 
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 * are permitted provided that the following conditions are met:
 * 	* Redistributions of source code must retain the above copyright notice,
 * 	  this list of conditions and the following disclaimer.
 * 	* Redistributions in binary form must reproduce the above copyright notice,
 * 	  this list of conditions and the following disclaimer in the documentation
 * 	  and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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using SharpBox2D.Common;

namespace SharpBox2D.TestBed.Tests.Math
{
    public class SinCosTable
    {

        public static float TWOPI = (float)(System.Math.PI * 2);

        public static bool LERP_LOOKUP = true;

        public float precision;
        public int tableLength;

        public float[] sinLUT;
        //public  float[] cosLUT;

        public SinCosTable(float argPrecision)
        {
            precision = argPrecision;
            tableLength = (int) System.Math.Ceiling(TWOPI/precision);

            sinLUT = new float[tableLength];
            //cosLUT = new float[tableLength];

            for (int i = 0; i < tableLength; i++)
            {
                sinLUT[i] = (float)System.Math.Sin(i * precision);
                //cosLUT[i] = (float) System.Math.Cos( i * precision);
            }
        }

        public float sin(float x)
        {
            x %= TWOPI;

            if (LERP_LOOKUP)
            {

                x /= precision;

                int index = (int) x;

                if (index != 0)
                {
                    x %= index;
                }

                // the next index is 0
                if (index == tableLength - 1)
                {
                    return ((1 - x)*sinLUT[index] + x*sinLUT[0]);
                }
                else
                {
                    return ((1 - x)*sinLUT[index] + x*sinLUT[index + 1]);
                }

            }
            else
            {
                return sinLUT[MathUtils.round(x/precision)%tableLength];
            }
        }
    }
}
