/*
 * 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;
 * 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.Drawing;
using System.Drawing.Imaging;
using System.Globalization;
using System.IO;
using System.Threading;
using libTerrain;
using OpenJPEGNet;
using OpenSim.Framework;

namespace OpenSim.Region.Terrain
{
    public class TerrainCommand
    {
        public virtual bool run(string[] cmdargs, ref string output)
        {
            return false;
        }

        public string args;
        public string help;
    }

    public class TerrainEngine
    {
        public static Mutex fileIOLock = new Mutex();

        /// <summary>
        /// Plugin library for scripts
        /// </summary>
        public FilterHost customFilters = new FilterHost();

        /// <summary>
        /// A [normally] 256x256 heightmap
        /// </summary>
        public Channel heightmap;

        /// <summary>
        /// A copy of heightmap at the last save point (for reverting)
        /// </summary>
        public Channel revertmap;

        /// <summary>
        /// Water heightmap (needs clientside mods to work)
        /// </summary>
        public Channel watermap;

        /// <summary>
        /// Max amount the terrain can be raised from the revert parameters
        /// </summary>
        public double maxRaise = 500.0;

        /// <summary>
        /// Min amount the terrain can be lowered from the revert parameters
        /// </summary>
        public double minLower = 500.0;

        /// <summary>
        /// The last time the terrain was edited
        /// </summary>
        public DateTime lastEdit = DateTime.Now;


        private int counter = 0;

        /// <summary>
        /// Whether or not the terrain has been modified since it was last saved and sent to the Physics engine.
        /// Counts the number of modifications since the last save. (0 = Untainted)
        /// </summary>
        public int tainted;

        private int w, h;

        /// <summary>
        /// Used to determine what offset to use when loading singular heightmaps across multiple sims
        /// </summary>
        private int offsetX;

        private int offsetY;


        /// <summary>
        /// Generate a new TerrainEngine instance and creates a new heightmap
        /// </summary>
        public TerrainEngine(int X, int Y)
        {
            w = 256;
            h = 256;
            heightmap = new Channel(w, h);
            revertmap = new Channel(w, h);
            watermap = new Channel(w, h);
            watermap.Fill(20);

            offsetX = X;
            offsetY = Y;

            tainted++;
        }

        public bool IsTainted()
        {
            return (tainted != 0);
        }

        public bool IsUserStillEditing()
        {
            TimeSpan gap = DateTime.Now - lastEdit;

            if (gap.TotalSeconds <= 4.0)
                return true;

            return false;
        }

        public bool IsTainted(int x, int y)
        {
            return (heightmap.diff[x/16, y/16] != 0);
        }

        public void ResetTaint()
        {
            tainted = 0;
            heightmap.diff = new int[w/16,h/16];
        }

        //Testing to see if moving the TerraForming packet handling code into here works well
        /// <summary>
        /// Modifies terrain using the specified information
        /// </summary>
        /// <param name="height">The height at which the user started modifying the terrain</param>
        /// <param name="seconds">The number of seconds the modify button was pressed</param>
        /// <param name="brushsize">The size of the brush used</param>
        /// <param name="action">The action to be performed</param>
        /// <param name="north">Distance from the north border where the cursor is located</param>
        /// <param name="west">Distance from the west border where the cursor is located</param>
        public void ModifyTerrain(float height, float seconds, byte brushsize, byte action, float north, float west,
                                  float south, float east,
                                  IClientAPI remoteUser)
        {
            // Shiny.
            double size = (double) (1 << brushsize);
            //System.Console.WriteLine("SIZE:" + size.ToString() + " Seconds:" + seconds.ToString());
            if (seconds == 1)
            {
                seconds = 0.0315f;
            }
            /*  Okay, so here's the deal
             * This has to handle both when a user draws on the terrain *and* when a user selects 
             * a selection of AABB on terrain and applies whatever routine the client requests
             * There's something currently wrong with the brushsize --> size conversion..   however
             * it's workable..  just unpredictable.
             * 
             * North is always higher and East is always higher
             * in the AABB representation
             * 
             * Therefore what we're doing is looping from south to north and west to east
             * and applying the associated algorithm with the brush.
             * 
             * This works good on the fast ones, but things like smooth take 12 seconds a single click..  
             * for now, smooth won't be 'selectionated'
             * 
             * If the user draws instead of selects, north will = south, and east will = west.
             * if the user selects, then the selection is inclusive
             * it'll always affect at least one point on the heightmap.
             * 
             *  that means we use the <= operator
             * 
             * Again, libTerrain is yx instead of xy..  so, it's reflected in the function calls
             * 
             */


            switch (action)
            {
                case 0:
                    // flatten terrain
                    for (float x = south; x <= north; x++)
                    {
                        for (float y = west; y <= east; y++)
                        {
                            FlattenTerrain(y, x, size, (double) seconds/5.0);
                            lastEdit = DateTime.Now;
                            //remoteUser.SendLayerData((int)(x / 16), (int)(x / 16), GetHeights1D());

                        }
                    }
                    break;
                case 1:
                    // raise terrain
                    for (float x = south; x <= north; x++)
                    {
                        for (float y = west; y <= east; y++)
                        {
                            RaiseTerrain(y, x, size, (double) seconds/5.0);
                            lastEdit = DateTime.Now;
                            //remoteUser.SendLayerData((int)(x / 16), (int)(x / 16), GetHeights1D());
                        }
                    }
                    break;
                case 2:
                    //lower terrain
                    for (float x = south; x <= north; x++)
                    {
                        for (float y = west; y <= east; y++)
                        {
                            LowerTerrain(y, x, size, (double) seconds/5.0);
                            lastEdit = DateTime.Now;
                            //remoteUser.SendLayerData((int)(x / 16), (int)(x / 16), GetHeights1D());
                        }
                    }
                    break;
                case 3:
                    // smooth terrain
                    // 
                    // We're leaving this out of the parcel calculations for now
                    // because just a single one of these will stall your sim for 
                    // 12 seconds.   Looping over the parcel on this one is just stupid
                    //
                    //for (float x = south; x <= north; x++)
                    //{
                    //for (float y = west; y <= east; y++)
                    //{
                    //SmoothTerrain(y, x , size, (double)seconds / 5.0);
                    //}
                    //}
                    SmoothTerrain(west, north, size, (double) seconds/5.0);

                    break;
                case 4:
                    // noise
                    for (float x = south; x <= north; x++)
                    {
                        for (float y = west; y <= east; y++)
                        {
                            NoiseTerrain(y, x, size, (double) seconds/5.0);
                            lastEdit = DateTime.Now;
                        }
                    }
                    break;
                case 5:
                    // revert
                    for (float x = south; x <= north; x++)
                    {
                        for (float y = west; y <= east; y++)
                        {
                            RevertTerrain(y, x, size, (double) seconds/5.0);
                            lastEdit = DateTime.Now;
                        }
                    }
                    break;

                    // CLIENT EXTENSIONS GO HERE
                case 128:
                    // erode-thermal
                    break;
                case 129:
                    // erode-aerobic
                    break;
                case 130:
                    // erode-hydraulic
                    break;
            }

            counter++;
            if(counter==2)
            {
                counter=0;
                for (int x = 0; x < 16; x++)
                {
                    for (int y = 0; y < 16; y++)
                    {
                        if (IsTainted(x * 16, y * 16))
                        {
                            bool usingTerrainModule = true;

                            if (!usingTerrainModule)
                            {
                                remoteUser.SendLayerData(x, y, GetHeights1D());
                            }
                        }
                    }
                }
            }

            lastEdit = DateTime.Now;

            return;
        }

// TODO: unused
//         /// <summary>
//         /// Checks to make sure the terrain is within baked values +/- maxRaise/minLower
//         /// </summary>
//         private void SetTerrainWithinBounds()
//         {
//             int x, y;
//             for (x = 0; x < w; x++)
//             {
//                 for (y = 0; y < h; y++)
//                 {
//                     if ((heightmap.Get(x, y) > revertmap.Get(x, y) + maxRaise))
//                     {
//                         heightmap.map[x, y] = revertmap.Get(x, y) + maxRaise;
//                     }
//                     if ((heightmap.Get(x, y) > revertmap.Get(x, y) - minLower))
//                     {
//                         heightmap.map[x, y] = revertmap.Get(x, y) - minLower;
//                     }
//                 }
//             }
//         }

        /// <summary>
        /// Converts the heightmap to a 65536 value 1D floating point array
        /// </summary>
        /// <returns>A float[65536] array containing the heightmap</returns>
        public float[] GetHeights1D()
        {
            float[] heights = new float[w*h];
            int i;

            for (i = 0; i < w*h; i++)
            {
                heights[i] = (float) heightmap.map[i%w, i/w];
            }

            return heights;
        }

        /// <summary>
        /// Converts the heightmap to a 256x256 value 2D floating point array.
        /// </summary>
        /// <returns>An array of 256,256 values containing the heightmap</returns>
        public float[,] GetHeights2D()
        {
            float[,] heights = new float[w,h];
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    heights[x, y] = (float) heightmap.map[x, y];
                }
            }
            return heights;
        }

        /// <summary>
        /// Converts the heightmap to a 256x256 value 2D floating point array. Double precision version.
        /// </summary>
        /// <returns>An array of 256,256 values containing the heightmap</returns>
        public double[,] GetHeights2DD()
        {
            return heightmap.map;
        }

        /// <summary>
        /// Imports a 1D floating point array into the 2D heightmap array
        /// </summary>
        /// <param name="heights">The array to import (must have 65536 members)</param>
        public void GetHeights1D(float[] heights)
        {
            int i;
            for (i = 0; i < w*h; i++)
            {
                heightmap.map[i%w, i/w] = heights[i];
            }

            tainted++;
        }

        /// <summary>
        /// Loads a 2D array of values into the heightmap
        /// </summary>
        /// <param name="heights">An array of 256,256 float values</param>
        public void SetHeights2D(float[,] heights)
        {
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    heightmap.Set(x, y, (double) heights[x, y]);
                }
            }
            SaveRevertMap();
            tainted++;
        }

        /// <summary>
        /// Loads a 2D array of values into the heightmap (Double Precision Version)
        /// </summary>
        /// <param name="heights">An array of 256,256 float values</param>
        public void SetHeights2D(double[,] heights)
        {
            int x, y;
            for (x = 0; x < w; x++)
            {
                for (y = 0; y < h; y++)
                {
                    heightmap.Set(x, y, heights[x, y]);
                }
            }
            SaveRevertMap();
            ResetTaint();
        }

        /// <summary>
        /// Swaps the two heightmap buffers (the 'revert map' and the heightmap)
        /// </summary>
        public void SwapRevertMaps()
        {
            Channel backup = heightmap.Copy();
            heightmap = revertmap;
            revertmap = backup;
        }

        /// <summary>
        /// Saves the current heightmap into the revertmap
        /// </summary>
        public void SaveRevertMap()
        {
            revertmap = heightmap.Copy();
        }

        /// <summary>
        /// Processes a terrain-specific command
        /// </summary>
        /// <param name="args">Commandline arguments (space seperated)</param>
        /// <param name="resultText">Reference that returns error or help text if returning false</param>
        /// <returns>If the operation was successful (if not, the error is placed into resultText)</returns>
        public bool RunTerrainCmd(string[] args, ref string resultText, string simName)
        {
            string command;
            if (args.Length > 0)
            {
                command = args[0];
            }
            else
            {
                command = "help";
            }

            try
            {
                switch (command)
                {
                    case "help":
                        resultText += "terrain regenerate - rebuilds the sims terrain using a default algorithm\n";
                        resultText +=
                            "terrain hills <type> <number of hills> <min height> <max height> <island t/f> <additive t/f> <noisy t/f>\n";
                        resultText += "   type should be spheres, blocks, cones, or squared\n";
                        resultText +=
                            "terrain voronoi <points> <blocksize> - generates a worley fractal with X points per block";
                        resultText += "terrain seed <seed> - sets the random seed value to <seed>\n";
                        resultText +=
                            "terrain load <type> <filename> - loads a terrain from disk, type can be 'F32', 'F64', 'RAW' or 'IMG'\n";
                        resultText +=
                            "terrain save <type> <filename> - saves a terrain to disk, type can be 'F32', 'F64', 'PNG', 'RAW' or 'HIRAW'\n";
                        resultText +=
                            "terrain save grdmap <filename> <gradient map> - creates a PNG snapshot of the region using a named gradient map\n";
                        resultText +=
                            "terrain rescale <min> <max> - rescales a terrain to be between <min> and <max> meters high\n";
                        resultText += "terrain fill <val> - fills a terrain at the specified height\n";
                        resultText +=
                            "terrain erode aerobic <windspeed> <pickupmin> <dropmin> <carry> <rounds> <lowest t/f> <fluid dynamics t/f>\n";
                        resultText += "terrain erode thermal <talus> <rounds> <carry>\n";
                        resultText += "terrain erode hydraulic <rain> <evaporation> <solubility> <frequency> <rounds>\n";
                        resultText += "terrain multiply <val> - multiplies a terrain by <val>\n";
                        resultText += "terrain elevate <val> - elevates a terrain by <val>\n";
                        resultText += "terrain revert - reverts the terrain to the stored original\n";
                        resultText += "terrain bake - saves the current terrain into the revert map\n";
                        resultText +=
                            "terrain csfilter <filename.cs> - loads a new filter from the specified .cs file\n";
                        resultText +=
                            "terrain jsfilter <filename.js> - loads a new filter from the specified .js file\n";
                        foreach (KeyValuePair<string, ITerrainFilter> filter in customFilters.filters)
                        {
                            resultText += filter.Value.Help();
                        }

                        return false;

                    case "revert":
                        SwapRevertMaps();
                        SaveRevertMap();
                        break;

                    case "bake":
                        SaveRevertMap();
                        break;

                    case "seed":
                        SetSeed(Convert.ToInt32(args[1]));
                        break;

                    case "erode":
                        return ConsoleErosion(args, ref resultText);

                    case "voronoi":
                        double[] c = new double[2];
                        c[0] = -1;
                        c[1] = 1;
                        heightmap.VoronoiDiagram(Convert.ToInt32(args[1]), Convert.ToInt32(args[2]), c);
                        break;

                    case "hills":
                        return ConsoleHills(args, ref resultText);

                    case "regenerate":
                        SetDefaultTerrain();
                        break;

                    case "rescale":
                        SetRange(Convert.ToSingle(args[1]), Convert.ToSingle(args[2]));
                        break;

                    case "elevate":
                        Elevate(Convert.ToSingle(args[1]));
                        break;

                    case "fill":
                        heightmap.Fill(Convert.ToDouble(args[1]));
                        tainted++;
                        break;

                    case "clip":
                        heightmap.Clip(Convert.ToDouble(args[1]), Convert.ToDouble(args[2]));
                        tainted++;
                        break;

                    case "smooth":
                        heightmap.Smooth(Convert.ToDouble(args[1]));
                        tainted++;
                        break;

                    case "add":
                        heightmap += Convert.ToDouble(args[1]);
                        tainted++;
                        break;

                    case "multiply":
                        heightmap *= Convert.ToDouble(args[1]);
                        tainted++;
                        break;

                    case "load":
                        string filenameL = args[2].Replace("%name%", simName);
                        filenameL = filenameL.Replace("%x%", offsetX.ToString());
                        filenameL = filenameL.Replace("%y%", offsetY.ToString());

                        switch (args[1].ToLower())
                        {
                            case "f32":
                                LoadFromFileF32(filenameL);
                                break;

                            case "f64":
                                LoadFromFileF64(filenameL);
                                break;

                            case "raw":
                                LoadFromFileSLRAW(filenameL);
                                break;

                            case "img":
                                heightmap = heightmap.LoadImage(filenameL);
                                tainted++;
                                break;

                            default:
                                resultText = "Unknown image or data format";
                                return false;
                        }
                        break;

                    case "load-tile":
                        switch (args[1].ToLower())
                        {
                            case "f32":
                                LoadFromFileF32(args[2], Convert.ToInt32(args[3]), Convert.ToInt32(args[4]),
                                                Convert.ToInt32(args[5]), Convert.ToInt32(args[6]));
                                break;
                            case "raw":
                                LoadFromFileSLRAW(args[2], Convert.ToInt32(args[3]), Convert.ToInt32(args[4]),
                                                Convert.ToInt32(args[5]), Convert.ToInt32(args[6]));
                                break;
                            case "img":
                                LoadFromFileIMG(args[2], Convert.ToInt32(args[3]), Convert.ToInt32(args[4]),
                                                Convert.ToInt32(args[5]), Convert.ToInt32(args[6]));
                                break;
                            default:
                                resultText = "Unknown or unsupported image or data format";
                                return false;
                        }
                        break;

                    case "save":
                        string filename = args[2].Replace("%name%", simName);
                        filename = filename.Replace("%x%", offsetX.ToString());
                        filename = filename.Replace("%y%", offsetY.ToString());

                        switch (args[1].ToLower())
                        {
                            case "f32":
                                WriteToFileF32(filename);
                                break;

                            case "f64":
                                WriteToFileF64(filename);
                                break;

                            case "grdmap":
                                if (args.Length >= 4)
                                    WriteImage(filename, args[3]);
                                else
                                    WriteImage(filename, "defaultstripe.png");
                                break;

                            case "png":
                                heightmap.SaveImage(filename);
                                break;

                            case "raw":
                                WriteToFileRAW(filename);
                                break;

                            case "hiraw":
                                WriteToFileHiRAW(filename);
                                break;

                            default:
                                resultText = "Unknown image or data format";
                                return false;
                        }
                        break;

                    case "csfilter":
                        customFilters.LoadFilterCSharp(args[1]);
                        break;
                    case "jsfilter":
                        customFilters.LoadFilterJScript(args[1]);
                        break;

                    default:
                        // Run any custom registered filters
                        if (customFilters.filters.ContainsKey(command))
                        {
                            customFilters.filters[command].Filter(heightmap, args);
                            break;
                        }
                        else
                        {
                            resultText = "Unknown terrain command";
                            return false;
                        }
                }
                return true;
            }
            catch (Exception e) // SEMI-LEGIT: Catching problems caused by user input or scripts
            {
                resultText = "Error running terrain command: " + e.ToString();
                return false;
            }
        }

        private bool ConsoleErosion(string[] args, ref string resultText)
        {
            double min = heightmap.FindMin();
            double max = heightmap.FindMax();

            switch (args[1].ToLower())
            {
                case "aerobic":
                    // WindSpeed, PickupMinimum,DropMinimum,Carry,Rounds,Lowest
                    heightmap.AerobicErosion(Convert.ToDouble(args[2]), Convert.ToDouble(args[3]),
                                             Convert.ToDouble(args[4]), Convert.ToDouble(args[5]),
                                             Convert.ToInt32(args[6]), Convert.ToBoolean(args[7]),
                                             Convert.ToBoolean(args[8]));
                    break;
                case "thermal":
                    heightmap.ThermalWeathering(Convert.ToDouble(args[2]), Convert.ToInt32(args[3]),
                                                Convert.ToDouble(args[4]));
                    break;
                case "hydraulic":
                    Channel rainMap = new Channel(w, h);
                    rainMap.Fill(Convert.ToDouble(args[2]));
                    heightmap.HydraulicErosion(rainMap, Convert.ToDouble(args[3]), Convert.ToDouble(args[4]),
                                               Convert.ToInt32(args[5]), Convert.ToInt32(args[6]));
                    break;
                default:
                    resultText = "Unknown erosion type";
                    return false;
            }

            heightmap.Normalise(min, max);

            tainted++;
            return true;
        }

        private bool ConsoleHills(string[] args, ref string resultText)
        {
            Random RandomClass = new Random();
            SetSeed(RandomClass.Next());
            int count;
            double sizeMin;
            double sizeRange;
            bool island;
            bool additive;
            bool noisy;

            if (args.GetLength(0) > 2)
            {
                int.TryParse(args[2].ToString(), out count);
                double.TryParse(args[3].ToString(), NumberStyles.AllowDecimalPoint, Culture.NumberFormatInfo,
                                out sizeMin);
                double.TryParse(args[4].ToString(), NumberStyles.AllowDecimalPoint, Culture.NumberFormatInfo,
                                out sizeRange);
                bool.TryParse(args[5].ToString(), out island);
                bool.TryParse(args[6].ToString(), out additive);
                bool.TryParse(args[7].ToString(), out noisy);
            }
            else
            {
                count = 200;
                sizeMin = 20;
                sizeRange = 40;
                island = true;
                additive = true;
                noisy = false;
            }

            switch (args[1].ToLower())
            {
                case "blocks":
                    heightmap.HillsBlocks(count, sizeMin, sizeRange, island, additive, noisy);
                    break;
                case "cones":
                    heightmap.HillsCones(count, sizeMin, sizeRange, island, additive, noisy);
                    break;
                case "spheres":
                    heightmap.HillsSpheres(count, sizeMin, sizeRange, island, additive, noisy);
                    break;
                case "squared":
                    heightmap.HillsSquared(count, sizeMin, sizeRange, island, additive, noisy);
                    break;
                default:
                    resultText = "Unknown hills type";
                    return false;
            }
            tainted++;
            return true;
        }

        /// <summary>
        /// Renormalises the array between min and max
        /// </summary>
        /// <param name="min">Minimum value of the new array</param>
        /// <param name="max">Maximum value of the new array</param>
        public void SetRange(float min, float max)
        {
            heightmap.Normalise((double) min, (double) max);
            tainted++;
        }

        /// <summary>
        /// Adds meters (positive or negative) to terrain height
        /// </summary>
        /// <param name="meters">Positive or negative value to add to new array</param>
        public void Elevate(float meters)
        {
            heightmap.Elevate((double)meters);
            tainted++;
        }

        /// <summary>
        /// Loads a file consisting of 256x256 doubles and imports it as an array into the map.
        /// </summary>
        /// <remarks>TODO: Move this to libTerrain itself</remarks>
        /// <param name="filename">The filename of the double array to import</param>
        public void LoadFromFileF64(string filename)
        {
            FileInfo file = new FileInfo(filename);
            FileStream s = file.Open(FileMode.Open, FileAccess.Read);
            BinaryReader bs = new BinaryReader(s);
            int x, y;
            for (y = 0; y < h; y++)
            {
                for (x = 0; x < h; x++)
                {
                    heightmap.Set(x, y, (double) bs.ReadSingle());
                }
            }

            bs.Close();
            s.Close();

            tainted++;
        }

        /// <summary>
        /// Loads a file consisting of 256x256 floats and imports it as an array into the map.
        /// </summary>
        /// <remarks>TODO: Move this to libTerrain itself</remarks>
        /// <param name="filename">The filename of the float array to import</param>
        public void LoadFromFileF32(string filename)
        {
            FileInfo file = new FileInfo(filename);
            FileStream s = file.Open(FileMode.Open, FileAccess.Read);
            BinaryReader bs = new BinaryReader(s);
            int x, y;
            for (y = 0; y < h; y++)
            {
                for (x = 0; x < w; x++)
                {
                    heightmap.Set(x, y, (double) bs.ReadSingle());
                }
            }

            bs.Close();
            s.Close();

            tainted++;
        }

        /// <summary>
        /// Loads a section of a larger heightmap (F32)
        /// </summary>
        /// <param name="filename">File to load</param>
        /// <param name="dimensionX">Size of the file</param>
        /// <param name="dimensionY">Size of the file</param>
        /// <param name="lowerboundX">Where do the region coords start for this terrain?</param>
        /// <param name="lowerboundY">Where do the region coords start for this terrain?</param>
        public void LoadFromFileF32(string filename, int dimensionX, int dimensionY, int lowerboundX, int lowerboundY)
        {
            fileIOLock.WaitOne();
            try
            {
                int sectionToLoadX = ((offsetX - lowerboundX)*w);
                int sectionToLoadY = ((offsetY - lowerboundY)*h);

                double[,] tempMap = new double[dimensionX,dimensionY];

                FileInfo file = new FileInfo(filename);
                FileStream s = file.Open(FileMode.Open, FileAccess.Read);
                BinaryReader bs = new BinaryReader(s);

                int x, y;
                for (x = 0; x < dimensionX; x++)
                {
                    for (y = 0; y < dimensionY; y++)
                    {
                        tempMap[x, y] = (double) bs.ReadSingle();
                    }
                }

                for (y = 0; y < h; y++)
                {
                    for (x = 0; x < w; x++)
                    {
                        heightmap.Set(x, y, tempMap[x + sectionToLoadX, y + sectionToLoadY]);
                    }
                }

                bs.Close();
                s.Close();

                tainted++;
            }
            finally
            {
                fileIOLock.ReleaseMutex();
            }
        }

        /// <summary>
        /// Loads a larger tiled image across a terrain
        /// </summary>
        /// <param name="filename">Filename to load from (any generic image format should work)</param>
        /// <param name="dimensionX">The dimensions of the image</param>
        /// <param name="dimensionY">The dimensions of the image</param>
        /// <param name="lowerboundX">Where sim coords begin for this patch</param>
        /// <param name="lowerboundY">Where sim coords begin for this patch</param>
        public void LoadFromFileIMG(string filename, int dimensionX, int dimensionY, int lowerboundX, int lowerboundY)
        {
            int sectionToLoadX = ((offsetX - lowerboundX)*w);
            int sectionToLoadY = ((offsetY - lowerboundY)*h);

            double[,] tempMap = new double[dimensionX,dimensionY];

            Bitmap lgrBmp = new Bitmap(filename);

            int x, y;
            for (x = 0; x < dimensionX; x++)
            {
                for (y = 0; y < dimensionY; y++)
                {
                    tempMap[x, y] = (float) lgrBmp.GetPixel(x, y).GetBrightness();
                }
            }

            for (y = 0; y < h; y++)
            {
                for (x = 0; x < w; x++)
                {
                    heightmap.Set(x, y, tempMap[x + sectionToLoadX, y + sectionToLoadY]);
                }
            }

            tainted++;
        }

        /// <summary>
        /// Loads a file formatted in the SL .RAW Format used on the main grid
        /// </summary>
        /// <remarks>This file format stinks and is best avoided.</remarks>
        /// <param name="filename">A path to the .RAW format</param>
        public void LoadFromFileSLRAW(string filename)
        {
            FileInfo file = new FileInfo(filename);
            FileStream s = file.Open(FileMode.Open, FileAccess.Read);
            BinaryReader bs = new BinaryReader(s);
            int x, y;
            for (y = 0; y < h; y++)
            {
                for (x = 0; x < w; x++)
                {
                    heightmap.Set(x, y, (double) bs.ReadByte()*((double) bs.ReadByte()/127.0));
                    bs.ReadBytes(11); // Advance the stream to next bytes.
                }
            }

            bs.Close();
            s.Close();

            tainted++;
        }

        /// <summary>
        /// Loads a section of a larger heightmap (RAW)
        /// </summary>
        /// <param name="filename">File to load</param>
        /// <param name="dimensionX">Size of the file</param>
        /// <param name="dimensionY">Size of the file</param>
        /// <param name="lowerboundX">Where do the region coords start for this terrain?</param>
        /// <param name="lowerboundY">Where do the region coords start for this terrain?</param>
        public void LoadFromFileSLRAW(string filename, int dimensionX, int dimensionY, int lowerboundX, int lowerboundY)
        {
            // TODO: Mutex fails to release readlock on folder! --> only one file can be loaded into sim
            //fileIOLock.WaitOne();
            //try
            //{
                int sectionToLoadX = ((offsetX - lowerboundX)*w);
                int sectionToLoadY = ((offsetY - lowerboundY)*h);

                double[,] tempMap = new double[dimensionX,dimensionY];

                FileInfo file = new FileInfo(filename);
                FileStream s = file.Open(FileMode.Open, FileAccess.Read);
                BinaryReader bs = new BinaryReader(s);

                int x, y;
                for (x = 0; x < dimensionX; x++)
                {
                    for (y = 0; y < dimensionY; y++)
                    {
                        tempMap[x, y] = (double) bs.ReadByte()*((double) bs.ReadByte()/127.0);
                        bs.ReadBytes(11); // Advance the stream to next bytes.
                    }
                }

                for (y = 0; y < h; y++)
                {
                    for (x = 0; x < w; x++)
                    {
                        heightmap.Set(x, y, tempMap[x + sectionToLoadX, y + sectionToLoadY]);
                    }
                }

                bs.Close();
                s.Close();

                tainted++;
            //}
            //finally
            //{
            //    fileIOLock.ReleaseMutex();
            //}
        }

        /// <summary>
        /// Writes the current terrain heightmap to disk, in the format of a 65536 entry double[] array.
        /// </summary>
        /// <param name="filename">The desired output filename</param>
        public void WriteToFileF64(string filename)
        {
            FileInfo file = new FileInfo(filename);
            FileStream s = file.Open(FileMode.CreateNew, FileAccess.Write);
            BinaryWriter bs = new BinaryWriter(s);

            int x, y;
            for (y = 0; y < h; y++)
            {
                for (x = 0; x < w; x++)
                {
                    bs.Write(heightmap.Get(x, y));
                }
            }

            bs.Close();
            s.Close();
        }

        /// <summary>
        /// Writes the current terrain heightmap to disk, in the format of a 65536 entry float[] array
        /// </summary>
        /// <param name="filename">The desired output filename</param>
        public void WriteToFileF32(string filename)
        {
            FileInfo file = new FileInfo(filename);
            FileStream s = file.Open(FileMode.CreateNew, FileAccess.Write);
            BinaryWriter bs = new BinaryWriter(s);

            int x, y;
            for (y = 0; y < h; y++)
            {
                for (x = 0; x < w; x++)
                {
                    bs.Write((float) heightmap.Get(x, y));
                }
            }

            bs.Close();
            s.Close();
        }

        /// <summary>
        /// A very fast LL-RAW file output mechanism - lower precision mechanism but wont take 5 minutes to run either.
        /// (is also editable in an image application)
        /// </summary>
        /// <param name="filename">Filename to write to</param>
        public void WriteToFileRAW(string filename)
        {
            FileInfo file = new FileInfo(filename);
            FileStream s = file.Open(FileMode.CreateNew, FileAccess.Write);
            BinaryWriter binStream = new BinaryWriter(s);

            int x, y;

            // Used for the 'green' channel.
            byte avgMultiplier = (byte) heightmap.Avg();
            byte backupMultiplier = (byte) revertmap.Avg();

            // Limit the multiplier so it can represent points >64m.
            if (avgMultiplier > 196)
                avgMultiplier = 196;
            if (backupMultiplier > 196)
                backupMultiplier = 196;
            // Make sure it's at least one to prevent a div by zero
            if (avgMultiplier < 1)
                avgMultiplier = 1;
            if (backupMultiplier < 1)
                backupMultiplier = 1;

            for (y = 0; y < h; y++)
            {
                for (x = 0; x < h; x++)
                {
                    byte red = (byte) (heightmap.Get(x, y)/((double) avgMultiplier/128.0));
                    byte green = avgMultiplier;
                    byte blue = (byte) watermap.Get(x, y);
                    byte alpha1 = 0; // Land Parcels
                    byte alpha2 = 0; // For Sale Land
                    byte alpha3 = 0; // Public Edit Object
                    byte alpha4 = 0; // Public Edit Land
                    byte alpha5 = 255; // Safe Land
                    byte alpha6 = 255; // Flying Allowed
                    byte alpha7 = 255; // Create Landmark
                    byte alpha8 = 255; // Outside Scripts
                    byte alpha9 = (byte) (revertmap.Get(x, y)/((double) backupMultiplier/128.0));
                    byte alpha10 = backupMultiplier;

                    binStream.Write(red);
                    binStream.Write(green);
                    binStream.Write(blue);
                    binStream.Write(alpha1);
                    binStream.Write(alpha2);
                    binStream.Write(alpha3);
                    binStream.Write(alpha4);
                    binStream.Write(alpha5);
                    binStream.Write(alpha6);
                    binStream.Write(alpha7);
                    binStream.Write(alpha8);
                    binStream.Write(alpha9);
                    binStream.Write(alpha10);
                }
            }
            binStream.Close();
            s.Close();
        }

        /// <summary> 
        /// Outputs to a LL compatible RAW in the most efficient manner possible
        /// </summary>
        /// <remarks>Does not calculate the revert map</remarks>
        /// <param name="filename">The filename to output to</param>
        public void WriteToFileHiRAW(string filename)
        {
            FileInfo file = new FileInfo(filename);
            FileStream s = file.Open(FileMode.CreateNew, FileAccess.Write);
            BinaryWriter binStream = new BinaryWriter(s);

            // Generate a smegging big lookup table to speed the operation up (it needs it)
            double[] lookupHeightTable = new double[65536];
            int i, j, x, y;
            for (i = 0; i < 256; i++)
            {
                for (j = 0; j < 256; j++)
                {
                    lookupHeightTable[i + (j*256)] = ((double) i*((double) j/127.0));
                }
            }

            // Output the calculated raw
            for (y = 0; y < h; y++)
            {
                for (x = 0; x < w; x++)
                {
                    double t = heightmap.Get(x, y);
                    double min = double.MaxValue;
                    int index = 0;

                    for (i = 0; i < 65536; i++)
                    {
                        if (Math.Abs(t - lookupHeightTable[i]) < min)
                        {
                            min = Math.Abs(t - lookupHeightTable[i]);
                            index = i;
                        }
                    }

                    byte red = (byte) (index & 0xFF);
                    byte green = (byte) ((index >> 8) & 0xFF);
                    byte blue = (byte) watermap.Get(x, y);
                    byte alpha1 = 0; // Land Parcels
                    byte alpha2 = 0; // For Sale Land
                    byte alpha3 = 0; // Public Edit Object
                    byte alpha4 = 0; // Public Edit Land
                    byte alpha5 = 255; // Safe Land
                    byte alpha6 = 255; // Flying Allowed
                    byte alpha7 = 255; // Create Landmark
                    byte alpha8 = 255; // Outside Scripts
                    byte alpha9 = red;
                    byte alpha10 = green;

                    binStream.Write(red);
                    binStream.Write(green);
                    binStream.Write(blue);
                    binStream.Write(alpha1);
                    binStream.Write(alpha2);
                    binStream.Write(alpha3);
                    binStream.Write(alpha4);
                    binStream.Write(alpha5);
                    binStream.Write(alpha6);
                    binStream.Write(alpha7);
                    binStream.Write(alpha8);
                    binStream.Write(alpha9);
                    binStream.Write(alpha10);
                }
            }

            binStream.Close();
            s.Close();
        }

        /// <summary>
        /// Sets the random seed to be used by procedural functions which involve random numbers.
        /// </summary>
        /// <param name="val">The desired seed</param>
        public void SetSeed(int val)
        {
            heightmap.seed = val;
        }

        /// <summary>
        /// Sets a particular heightmap point to a specified value
        /// </summary>
        /// <param name="x">X Coordinate</param>
        /// <param name="y">Y Coordinate</param>
        /// <param name="val">Value</param>
        public void Set(int x, int y, double val)
        {
            lock (heightmap)
            {
                heightmap.Set(x, y, val);
            }
            tainted++;
        }

        /// <summary>
        /// Raises land in a sphere around the specified coordinates
        /// </summary>
        /// <param name="rx">Center of the sphere on the X axis</param>
        /// <param name="ry">Center of the sphere on the Y axis</param>
        /// <param name="size">The radius of the sphere</param>
        /// <param name="amount">Scale the height of the sphere by this amount (recommended 0..2)</param>
        public void RaiseTerrain(double rx, double ry, double size, double amount)
        {
            lock (heightmap)
            {
                heightmap.Raise(rx, ry, size, amount);
            }

            tainted++;
        }

        /// <summary>
        /// Lowers the land in a sphere around the specified coordinates
        /// </summary>
        /// <param name="rx">The center of the sphere at the X axis</param>
        /// <param name="ry">The center of the sphere at the Y axis</param>
        /// <param name="size">The radius of the sphere in meters</param>
        /// <param name="amount">Scale the height of the sphere by this amount (recommended 0..2)</param>
        public void LowerTerrain(double rx, double ry, double size, double amount)
        {
            lock (heightmap)
            {
                heightmap.Lower(rx, ry, size, amount);
            }

            tainted++;
        }

        /// <summary>
        /// Flattens the land under the brush of specified coordinates (spherical mask)
        /// </summary>
        /// <param name="rx">Center of sphere</param>
        /// <param name="ry">Center of sphere</param>
        /// <param name="size">Radius of the sphere</param>
        /// <param name="amount">Thickness of the mask (0..2 recommended)</param>
        public void FlattenTerrain(double rx, double ry, double size, double amount)
        {
            lock (heightmap)
            {
                heightmap.Flatten(rx, ry, size, amount);
            }

            tainted++;
        }

        /// <summary>
        /// Creates noise within the specified bounds
        /// </summary>
        /// <param name="rx">Center of the bounding sphere</param>
        /// <param name="ry">Center of the bounding sphere</param>
        /// <param name="size">The radius of the sphere</param>
        /// <param name="amount">Strength of the mask (0..2) recommended</param>
        public void NoiseTerrain(double rx, double ry, double size, double amount)
        {
            lock (heightmap)
            {
                Channel smoothed = new Channel();
                smoothed.Noise();

                Channel mask = new Channel();
                mask.Raise(rx, ry, size, amount);

                heightmap.Blend(smoothed, mask);
            }

            tainted++;
        }

        /// <summary>
        /// Reverts land within the specified bounds
        /// </summary>
        /// <param name="rx">Center of the bounding sphere</param>
        /// <param name="ry">Center of the bounding sphere</param>
        /// <param name="size">The radius of the sphere</param>
        /// <param name="amount">Strength of the mask (0..2) recommended</param>
        public void RevertTerrain(double rx, double ry, double size, double amount)
        {
            lock (heightmap)
            {
                Channel mask = new Channel();
                mask.Raise(rx, ry, size, amount);

                heightmap.Blend(revertmap, mask);
            }

            tainted++;
        }

        /// <summary>
        /// Smooths land under the brush of specified coordinates (spherical mask)
        /// </summary>
        /// <param name="rx">Center of the sphere</param>
        /// <param name="ry">Center of the sphere</param>
        /// <param name="size">Radius of the sphere</param>
        /// <param name="amount">Thickness of the mask (0..2 recommended)</param>
        public void SmoothTerrain(double rx, double ry, double size, double amount)
        {
            lock (heightmap)
            {
                // perform essential computation as a channel method    
                heightmap.SmoothRegion(rx, ry, size, amount);
            }   

            tainted++;
        }

        /// <summary>
        /// Generates a simple set of hills in the shape of an island
        /// </summary>
        public void SetDefaultTerrain()
        {
            lock (heightmap)
            {
                heightmap.HillsSpheres(200, 20, 40, true, true, false);
                heightmap.Normalise();
                heightmap *= 60.0; // Raise to 60m
                heightmap.Clip(0.0, 25.0);
                heightmap.Pertubation(2.5);
                heightmap.Smooth(35.0);
                heightmap.Normalise(0.0, 21.0);
            }

            tainted++;
        }

        /// <summary>
        /// Wrapper to heightmap.get()
        /// </summary>
        /// <param name="x">X coord</param>
        /// <param name="y">Y coord</param>
        /// <returns>Height at specified coordinates</returns>
        public double GetHeight(int x, int y)
        {
            return heightmap.Get(x, y);
        }

        /// <summary>
        /// Multiplies the heightfield by val
        /// </summary>
        /// <param name="meep">The heightfield</param>
        /// <param name="val">The multiplier</param>
        /// <returns></returns>
        public static TerrainEngine operator *(TerrainEngine terrain, Double val)
        {
            terrain.heightmap *= val;
            terrain.tainted++;
            return terrain;
        }

        /// <summary>
        /// Exports the current heightmap to a PNG file
        /// </summary>
        /// <param name="filename">The destination filename for the image</param>
        /// <param name="gradientmap">A 1x*height* image which contains the colour gradient to export with. Must be at least 1x2 pixels, 1x256 or more is ideal.</param>
        public void WriteImage(string filename, string gradientmap)
        {
            try
            {
                Bitmap bmp = TerrainToBitmap(gradientmap);

                bmp.Save(filename, ImageFormat.Png);
            }
            catch (Exception e) // LEGIT: Catching problems caused by OpenJPEG p/invoke
            {
                Console.WriteLine("Failed generating terrain map: " + e.ToString());
            }
        }

        /// <summary>
        /// Exports the current heightmap in Jpeg2000 format to a byte[]
        /// </summary>
        /// <param name="gradientmap">A 1x*height* image which contains the colour gradient to export with. Must be at least 1x2 pixels, 1x256 or more is ideal.</param>
        public byte[] WriteJpegImage(string gradientmap)
        {
            byte[] imageData = null;
            try
            {
                Bitmap bmp = TerrainToBitmap(gradientmap);

                imageData = OpenJPEG.EncodeFromImage(bmp, true);
            }
            catch (Exception e) // LEGIT: Catching problems caused by OpenJPEG p/invoke
            {
                Console.WriteLine("Failed generating terrain map: " + e.ToString());
            }

            return imageData;
        }

        private Bitmap TerrainToBitmap(string gradientmap)
        {
            Bitmap gradientmapLd = new Bitmap(gradientmap);

            int pallete = gradientmapLd.Height;

            Bitmap bmp = new Bitmap(heightmap.w, heightmap.h);
            Color[] colours = new Color[pallete];

            for (int i = 0; i < pallete; i++)
            {
                colours[i] = gradientmapLd.GetPixel(0, i);
            }

            Channel copy = heightmap.Copy();
            for (int y = 0; y < copy.h; y++)
            {
                for (int x = 0; x < copy.w; x++)
                {
                    // 512 is the largest possible height before colours clamp
                    int colorindex = (int) (Math.Max(Math.Min(1.0, copy.Get(x, y)/512.0), 0.0)*(pallete - 1));
                    bmp.SetPixel(x, copy.h - y - 1, colours[colorindex]);
                }
            }
            return bmp;
        }
    }
}
