/*
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 libTerrain 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 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
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 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;
using System.Collections.Generic;
using System.Text;

namespace libTerrain
{
    partial class Channel
    {
        /// <summary>
        /// Flattens the area underneath rx,ry by moving it to the average of the area. Uses a spherical mask provided by the raise() function.
        /// </summary>
        /// <param name="rx">The X coordinate of the terrain mask</param>
        /// <param name="ry">The Y coordinate of the terrain mask</param>
        /// <param name="size">The size of the terrain mask</param>
        /// <param name="amount">The scale of the terrain mask</param>
        public void flatten(double rx, double ry, double size, double amount)
        {
            // Generate the mask
            Channel temp = new Channel(w, h);
            temp.fill(0);
            temp.raise(rx, ry, size, amount);
            temp.normalise();
            double total_mod = temp.sum();

            // Establish the average height under the area
            Channel newmap = new Channel(w, h);
            newmap.map = (double[,])map.Clone();

            newmap *= temp;

            double total_terrain = newmap.sum();
            double avg_height = total_terrain / total_mod;

            // Create a flat terrain using the average height
            Channel flat = new Channel(w, h);
            flat.fill(avg_height);

            // Blend the current terrain with the average height terrain
            // using the "raised" empty terrain as a mask
            blend(flat, temp);

        }

        public void flatten(Channel mask, double amount)
        {
            // Generate the mask
            Channel temp = mask * amount;
            temp.clip(0, 1); // Cut off out-of-bounds values

            double total_mod = temp.sum();

            // Establish the average height under the area
            Channel map = new Channel(w, h);
            map.map = (double[,])this.map.Clone();

            map *= temp;

            double total_terrain = map.sum();
            double avg_height = total_terrain / total_mod;

            // Create a flat terrain using the average height
            Channel flat = new Channel(w, h);
            flat.fill(avg_height);

            // Blend the current terrain with the average height terrain
            // using the "raised" empty terrain as a mask
            blend(flat, temp);
        }
    }
}