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 * See CONTRIBUTORS.TXT for a full list of copyright holders.
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 * 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
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 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;

namespace libTerrain
{
    partial class Channel
    {
        /// <summary>
        /// Raises land around the selection
        /// </summary>
        /// <param name="rx">The center the X coordinate of where you wish to raise the land</param>
        /// <param name="ry">The center the Y coordinate of where you wish to raise the land</param>
        /// <param name="size">The radius of the dimple</param>
        /// <param name="amount">How much impact to add to the terrain (0..2 usually)</param>
        public void Raise(double rx, double ry, double size, double amount)
        {
            RaiseSphere(rx, ry, size, amount);
        }

        /// <summary>
        /// Raises land in a sphere around the selection
        /// </summary>
        /// <param name="rx">The center the X coordinate of where you wish to raise the land</param>
        /// <param name="ry">The center the Y coordinate of where you wish to raise the land</param>
        /// <param name="size">The radius of the sphere dimple</param>
        /// <param name="amount">How much impact to add to the terrain (0..2 usually)</param>
        public void RaiseSphere(double rx, double ry, double size, double amount)
        {
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    double z = size;
                    z *= z;
                    z -= ((x - rx)*(x - rx)) + ((y - ry)*(y - ry));

                    if (z > 0.0)
                        Set(x, y, map[x, y] + (z * amount));
                }
            }
        }

        /// <summary>
        /// Raises land in a cone around the selection
        /// </summary>
        /// <param name="rx">The center the X coordinate of where you wish to raise the land</param>
        /// <param name="ry">The center the Y coordinate of where you wish to raise the land</param>
        /// <param name="size">The radius of the cone</param>
        /// <param name="amount">How much impact to add to the terrain (0..2 usually)</param>
        public void RaiseCone(double rx, double ry, double size, double amount)
        {
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    double z = size;
                    z -= Math.Sqrt(((x - rx)*(x - rx)) + ((y - ry)*(y - ry)));

                    if (z > 0.0)
                        Set(x, y, map[x, y] + (z * amount));
                }
            }
        }

        /// <summary>
        /// Lowers land in a sphere around the selection
        /// </summary>
        /// <param name="rx">The center the X coordinate of where you wish to lower the land</param>
        /// <param name="ry">The center the Y coordinate of where you wish to lower the land</param>
        /// <param name="size">The radius of the sphere dimple</param>
        /// <param name="amount">How much impact to remove from the terrain (0..2 usually)</param>
        public void Lower(double rx, double ry, double size, double amount)
        {
            LowerSphere(rx, ry, size, amount);
        }

        /// <summary>
        /// Lowers land in a sphere around the selection
        /// </summary>
        /// <param name="rx">The center the X coordinate of where you wish to lower the land</param>
        /// <param name="ry">The center the Y coordinate of where you wish to lower the land</param>
        /// <param name="size">The radius of the sphere dimple</param>
        /// <param name="amount">How much impact to remove from the terrain (0..2 usually)</param>
        public void LowerSphere(double rx, double ry, double size, double amount)
        {
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    double z = size;
                    z *= z;
                    z -= ((x - rx)*(x - rx)) + ((y - ry)*(y - ry));

                    if (z > 0.0)
                        Set(x, y, map[x, y] - (z * amount));
                }
            }
        }

        public double SphericalFactor(double x, double y, double rx, double ry, double size)
        {
            double z = size * size - ((x - rx) * (x - rx) + (y - ry) * (y - ry));
            return z;
        }
        
        public void SmoothRegion(double rx, double ry, double size, double amount)
        {
            int x, y;
            double[,] tweak = new double[w, h];
            
            double n, l;
            double area = size;
            double step = size / 4.0;
            
            // compute delta map 
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    double z = SphericalFactor(x, y, rx, ry, size);
                    
                    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 += GetBilinearInterpolate(x + n, y + l);
                            }
                        }
                        tweak[x, y] = average / avgsteps;
                        //if (x == rx && y == ry)
                        //    Console.WriteLine("tweak[ " + x + " , " + y + " ] = " + tweak[x, y]);
                    }
                }
            }
            // blend in map 
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    double z = SphericalFactor(x, y, rx, ry, size);
                    
                    if (z > 0) // add in non-zero amount 
                    {
                        double da = z * amount;
                        double a = (map[x, y] - tweak[x, y]) * da;
                        double newz = map[x, y] - a;
                        //if (rx == x || ry == y)
                        //    Console.WriteLine("map[ " + x + " , " + y + " ] = " + map[x, y] + " tweak, a , da, z, size, amount = " + tweak[x, y] + " " + a + " " + da + " " + z + " " + size + " " + amount);
                        if (newz > 0.0)
                            Set(x, y, newz);
                    }
                }
            }
        }
    }
}
