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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);
        }
    }
}