/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, 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.
 *     * Neither the name of the OpenSim Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``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 CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using OpenSim.Region.Environment.Interfaces;

namespace OpenSim.Region.Environment.Modules.Terrain.PaintBrushes
{
    public class SmoothSphere : ITerrainPaintableEffect
    {
        #region ITerrainPaintableEffect Members

        public void PaintEffect(ITerrainChannel map, double rx, double ry, double strength, double duration)
        {
            strength = TerrainUtil.MetersToSphericalStrength(strength);

            int x, y;
            double[,] tweak = new double[map.Width, map.Height];
            
            double n, l;
            double area = strength;
            double step = strength / 4.0;
            
            // compute delta map 
            for (x = 0; x < map.Width; x++)
            {
                for (y = 0; y < map.Height; y++)
                {
                    double z = TerrainUtil.SphericalFactor(x, y, rx, ry, strength);
                    
                    if (z > 0) // add in non-zero amount 
                    {
                        double average = 0.0;
                        int avgsteps = 0;
                        
                        for (n = 0.0 - area; n < area; n += step)
                        {
                            for (l = 0.0 - area; l < area; l += step)
                            {
                                avgsteps++;
                                average += TerrainUtil.GetBilinearInterpolate(x + n, y + l, map);
                            }
                        }
                        tweak[x, y] = average / avgsteps;
                    }
                }
            }
            // blend in map 
            for (x = 0; x < map.Width; x++)
            {
                for (y = 0; y < map.Height; y++)
                {
                    double z = TerrainUtil.SphericalFactor(x, y, rx, ry, strength);
                    
                    if (z > 0) // add in non-zero amount 
                    {
                        double da = z;
                        double a = (map[x, y] - tweak[x, y]) * da;
                        double newz = map[x, y] - (a * duration);

                        if (newz > 0.0)
                            map[x, y] = newz;
                    }
                }
            }
        }

        #endregion
    }
}
