Square.Tiled Class

/*
Squared.Tiled
Copyright (C) 2009 Kevin Gadd

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.

  Kevin Gadd kevin.gadd@gmail.com http://luminance.org/
*/
/*
 * Updates by Stephen Belanger - July, 13 2009
 * 
 * -added ProhibitDtd = false, so you don't need to remove the doctype line after each time you edit the map.
 * -changed everything to use SortedLists for easier referencing
 * -added objectgroups
 * -added movable and resizable objects
 * -added object images
 * -added meta property support to maps, layers, object groups and objects
 * -added non-binary encoded layer data
 * -added layer and object group transparency
 * 
 * TODO: I might add support for .tsx Tileset definitions. Note sure yet how beneficial that would be...
*/
/*
 * Modifications by Zach Musgrave - August 2012.
 * 
 * - Fixed errors in TileExample.cs
 * - Added support for rotated and flipped tiles (press Z, X, or Y in Tiled to rotate or flip tiles)
 * - Fixed exception when loading an object without a height or width attribute
 * - Fixed property loading bugs (properties now loaded for Layers, Maps, Objects)
 * - Added support for margin and spacing in tile sets
 * - CF-compatible System.IO.Compression library available via GitHub release. See releases at https://github.com/zachmu/tiled-xna
 * 
 * Zach Musgrave zach.musgrave@gmail.com http://gamedev.sleptlate.org
 */

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Schema;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework;
using System.IO;
using System.IO.Compression;
using System.Globalization;

namespace Squared.Tiled {
    public class Tileset {
        public class TilePropertyList : Dictionary<string, string> {
        }

        public string Name;
        public int FirstTileID;
        public int TileWidth;
        public int TileHeight;
        public int Spacing;
        public int Margin;
        public Dictionary<int, TilePropertyList> TileProperties = new Dictionary<int, TilePropertyList>();
        public string Image;
        protected Texture2D _Texture;
        protected int _TexWidth, _TexHeight;

        internal static Tileset Load (XmlReader reader) {
            var result = new Tileset();

            result.Name = reader.GetAttribute("name");
            result.FirstTileID = int.Parse(reader.GetAttribute("firstgid"));
            result.TileWidth = int.Parse(reader.GetAttribute("tilewidth"));
            result.TileHeight = int.Parse(reader.GetAttribute("tileheight"));
            int.TryParse(reader.GetAttribute("margin"), out result.Margin);
            int.TryParse(reader.GetAttribute("spacing"), out result.Spacing);

            int currentTileId = -1;

            while (reader.Read()) {
                var name = reader.Name;

                switch (reader.NodeType) {
                    case XmlNodeType.Element:
                        switch (name) {
                            case "image":
                                result.Image = reader.GetAttribute("source");
                            break;
                            case "tile":
                                currentTileId = int.Parse(reader.GetAttribute("id"));
                            break;
                            case "property": {
                                TilePropertyList props;
                                if (!result.TileProperties.TryGetValue(currentTileId, out props)) {
                                    props = new TilePropertyList();
                                    result.TileProperties[currentTileId] = props;
                                }

                                props[reader.GetAttribute("name")] = reader.GetAttribute("value");
                            } break;
                        }

                        break;
                    case XmlNodeType.EndElement:
                        break;
                }
            }

            return result;
        }

        public TilePropertyList GetTileProperties (int index) {
            index -= FirstTileID;

            if (index < 0)
                return null;

            TilePropertyList result = null;
            TileProperties.TryGetValue(index, out result);

            return result;
        }

        public Texture2D Texture {
            get {
                return _Texture;
            }
            set {
                _Texture = value;
                _TexWidth = value.Width;
                _TexHeight = value.Height;
            }
        }

        internal bool MapTileToRect (int index, ref Rectangle rect) {
            index -= FirstTileID;

            if (index < 0)
                return false;

            int rowSize = _TexWidth / (TileWidth + Spacing);
            int row = index / rowSize;
            int numRows = _TexHeight / (TileHeight + Spacing);
            if (row >= numRows)
                return false;

            int col = index % rowSize;

            rect.X = col * TileWidth + col * Spacing + Margin;
            rect.Y = row * TileHeight + row * Spacing + Margin;
            rect.Width = TileWidth;
            rect.Height = TileHeight;
            return true;
        }
    }

    public class Layer
    {
        /*
         * High-order bits in the tile data indicate tile flipping
         */
        private const uint FlippedHorizontallyFlag = 0x80000000;
        private const uint FlippedVerticallyFlag = 0x40000000;
        private const uint FlippedDiagonallyFlag = 0x20000000;

        internal const byte HorizontalFlipDrawFlag = 1;
        internal const byte VerticalFlipDrawFlag = 2;
        internal const byte DiagonallyFlipDrawFlag = 4;

        public SortedList<string, string> Properties = new SortedList<string, string>();
        public struct TileInfo
        {
            public Texture2D Texture;
            public Rectangle Rectangle;
        }

        public string Name;
        public int Width, Height;
        public float Opacity = 1;
        public int[] Tiles;
        public byte[] FlipAndRotate;
        private TileInfo[] _TileInfoCache = null;

        internal static Layer Load(XmlReader reader)
        {
            CultureInfo ci = (CultureInfo)CultureInfo.CurrentCulture.Clone();
            ci.NumberFormat.CurrencyDecimalSeparator = ".";
            var result = new Layer();

            if (reader.GetAttribute("name") != null)
            {
                result.Name = reader.GetAttribute("name");
            }
            if (reader.GetAttribute("width") != null)
            {
                result.Width = int.Parse(reader.GetAttribute("width"));
            }
            if (reader.GetAttribute("height") != null)
            {
                result.Height = int.Parse(reader.GetAttribute("height"));
            }    
            if (reader.GetAttribute("opacity") != null)
            {                
                result.Opacity = float.Parse(reader.GetAttribute("opacity"), NumberStyles.Any, ci);
            }
            result.Tiles = new int[result.Width * result.Height];
            result.FlipAndRotate = new byte[result.Width * result.Height];

            while (!reader.EOF)
            {
                var name = reader.Name;

                switch (reader.NodeType)
                {
                    case XmlNodeType.Element:
                        switch (name)
                        {
                            case "data":
                                {
                                    if (reader.GetAttribute("encoding") != null)
                                    {
                                        var encoding = reader.GetAttribute("encoding");
                                        var compressor = reader.GetAttribute("compression");
                                        switch (encoding)
                                        {
                                            case "base64":
                                                {
                                                    int dataSize = (result.Width * result.Height * 4) + 1024;
                                                    var buffer = new byte[dataSize];
                                                    reader.ReadElementContentAsBase64(buffer, 0, dataSize);

                                                    Stream stream = new MemoryStream(buffer, false);
                                                    if (compressor == "gzip")
                                                        stream = new GZipStream(stream, CompressionMode.Decompress, false);

                                                    using (stream)
                                                    using (var br = new BinaryReader(stream))
                                                    {
                                                        for ( int i = 0; i < result.Tiles.Length; i++ ) {
                                                            uint tileData = br.ReadUInt32();

                                                            // The data contain flip information as well as the tileset index
                                                            byte flipAndRotateFlags = 0;
                                                            if ( (tileData & FlippedHorizontallyFlag) != 0 ) {
                                                                flipAndRotateFlags |= HorizontalFlipDrawFlag;
                                                            }
                                                            if ( (tileData & FlippedVerticallyFlag) != 0 ) {
                                                                flipAndRotateFlags |= VerticalFlipDrawFlag;
                                                            }
                                                            if ( (tileData & FlippedDiagonallyFlag) != 0 ) {
                                                                flipAndRotateFlags |= DiagonallyFlipDrawFlag;
                                                            }
                                                            result.FlipAndRotate[i] = flipAndRotateFlags;

                                                            // Clear the flip bits before storing the tile data
                                                            tileData &= ~(FlippedHorizontallyFlag |
                                                                          FlippedVerticallyFlag |
                                                                          FlippedDiagonallyFlag);
                                                            result.Tiles[i] = (int) tileData;
                                                        }
                                                    }

                                                    continue;
                                                };

                                            default:
                                                throw new Exception("Unrecognized encoding.");
                                        }
                                    }
                                    else
                                    {
                                        using (var st = reader.ReadSubtree())
                                        {
                                            int i = 0;
                                            while (!st.EOF)
                                            {
                                                switch (st.NodeType)
                                                {
                                                    case XmlNodeType.Element:
                                                        if (st.Name == "tile")
                                                        {
                                                            if(i < result.Tiles.Length)
                                                            {
                                                                result.Tiles[i] = int.Parse(st.GetAttribute("gid"));
                                                                i++;
                                                            }
                                                        }

                                                        break;
                                                    case XmlNodeType.EndElement:
                                                        break;
                                                }

                                                st.Read();
                                            }
                                        }
                                    }
                    Console.WriteLine("It made it!");
                                } break;
                            case "properties":
                                {
                                    using (var st = reader.ReadSubtree())
                                    {
                                        while (!st.EOF)
                                        {
                                            switch (st.NodeType)
                                            {
                                                case XmlNodeType.Element:
                                                    if (st.Name == "property")
                                                    {
                                                        if (st.GetAttribute("name") != null)
                                                        {
                                                            result.Properties.Add(st.GetAttribute("name"), st.GetAttribute("value"));
                                                        }
                                                    }

                                                    break;
                                                case XmlNodeType.EndElement:
                                                    break;
                                            }

                                            st.Read();
                                        }
                                    }
                                } break;
                        }

                        break;
                    case XmlNodeType.EndElement:
                        break;
                }

                reader.Read();
            }

            return result;
        }

        public int GetTile(int x, int y)
        {
            if ((x < 0) || (y < 0) || (x >= Width) || (y >= Height))
                throw new InvalidOperationException();

            int index = (y * Width) + x;
            return Tiles[index];
        }

        public Texture2D GetTileTexture(int tileNo, Tileset tileset, Texture2D tile)
        {
            Texture2D tilesheet = tileset.Texture;
            Color[] TileTextureData = new Color[tilesheet.Width * tilesheet.Height];

            int row= (tileNo - 1) % tileset.TileWidth;
            int col = (tileNo - 1) / tileset.TileWidth;
            int tileWidth = tile.Width;
            int tileHeight = tile.Height;
            
            Rectangle tilehit = new Rectangle(row * tileWidth, col * tileHeight, tileWidth, tileHeight);
            
            tilesheet.GetData(TileTextureData);

            Color[] test = new Color[tileWidth* tileHeight];

            int count = 0;
            for (int c = tilehit.Top; c < tilehit.Bottom; c++)
            {
                for (int r = tilehit.Left; r < tilehit.Right; r++)
                {
                    Color colorA = TileTextureData[r + (c * tilesheet.Width)];
                    test[count] = colorA;
                    count++;
                }
            }

            tile.SetData(test);

            return tile;
        }

        public Color[] GetTextureData(Texture2D tile)
        {
            Color[] data = new Color[tile.Width*tile.Height];
            tile.GetData(data);
            return data;
        }

        protected void BuildTileInfoCache(IList<Tileset> tilesets)
        {
            Rectangle rect = new Rectangle();
            var cache = new List<TileInfo>();
            int i = 1;

        next:
            for (int t = 0; t < tilesets.Count; t++)
            {
                if (tilesets[t].MapTileToRect(i, ref rect))
                {
                    cache.Add(new TileInfo
                    {
                        Texture = tilesets[t].Texture,
                        Rectangle = rect
                    });
                    i += 1;
                    goto next;
                }
            }

            _TileInfoCache = new TileInfo[cache.Count];
            _TileInfoCache = cache.ToArray();
        }

        public void Draw(SpriteBatch batch, IList<Tileset> tilesets, Rectangle rectangle, Vector2 viewportPosition, int tileWidth, int tileHeight)
        {
            int i = 0;
            Vector2 destPos = new Vector2(rectangle.Left, rectangle.Top);
            Vector2 viewPos = viewportPosition;

            int minX = (int)Math.Floor(viewportPosition.X / tileWidth);
            int minY = (int)Math.Floor(viewportPosition.Y / tileHeight);
            int maxX = (int)Math.Ceiling((rectangle.Width + viewportPosition.X) / tileWidth);
            int maxY = (int)Math.Ceiling((rectangle.Height + viewportPosition.Y) / tileHeight);

            if (minX < 0)
                minX = 0;
            if (minY < 0)
                minY = 0;
            if (maxX >= Width)
                maxX = Width - 1;
            if (maxY >= Height)
                maxY = Height - 1;

            if (viewPos.X > 0)
            {
                viewPos.X = ((int)Math.Floor(viewPos.X)) % tileWidth;
            }
            else
            {
                viewPos.X = (float)Math.Floor(viewPos.X);
            }

            if (viewPos.Y > 0)
            {
                viewPos.Y = ((int)Math.Floor(viewPos.Y)) % tileHeight;
            }
            else
            {
                viewPos.Y = (float)Math.Floor(viewPos.Y);
            }

            TileInfo info = new TileInfo();
            if (_TileInfoCache == null)
                BuildTileInfoCache(tilesets);

            // We're drawing at the center of the tile, so adjust our y offset
            destPos.Y += tileHeight / 2f;

            for (int y = minY; y <= maxY; y++)
            {
                // We're drawing at the center of the tile, so adjust the x offset
                destPos.X = rectangle.Left + tileWidth / 2f;

                for (int x = minX; x <= maxX; x++)
                {
                    i = (y * Width) + x;

                    byte flipAndRotate = FlipAndRotate[i];
                    SpriteEffects flipEffect = SpriteEffects.None;
                    float rotation = 0f;

                    if ( (flipAndRotate & Layer.HorizontalFlipDrawFlag) != 0 ) {
                        flipEffect |= SpriteEffects.FlipHorizontally;
                    }
                    if ( (flipAndRotate & Layer.VerticalFlipDrawFlag) != 0 ) {
                        flipEffect |= SpriteEffects.FlipVertically;
                    }
                    if ( (flipAndRotate & Layer.DiagonallyFlipDrawFlag) != 0 ) {
                        if ( (flipAndRotate & Layer.HorizontalFlipDrawFlag) != 0 &&
                             (flipAndRotate & Layer.VerticalFlipDrawFlag) != 0 ) {
                            rotation = (float) (Math.PI / 2);
                            flipEffect ^= SpriteEffects.FlipVertically;
                        } else if ( (flipAndRotate & Layer.HorizontalFlipDrawFlag) != 0 ) {
                            rotation = (float) -(Math.PI / 2);
                            flipEffect ^= SpriteEffects.FlipVertically;
                        } else if ( (flipAndRotate & Layer.VerticalFlipDrawFlag) != 0 ) {
                            rotation = (float) (Math.PI / 2);
                            flipEffect ^= SpriteEffects.FlipHorizontally;
                        } else {
                            rotation = -(float) (Math.PI / 2);
                            flipEffect ^= SpriteEffects.FlipHorizontally;
                        }
                    }

                    int index = Tiles[i] - 1;
                    if ((index >= 0) && (index < _TileInfoCache.Length))
                    {
                        info = _TileInfoCache[index];
                        batch.Draw(info.Texture, destPos - viewPos, info.Rectangle,
                                   Color.White * this.Opacity, rotation, new Vector2(tileWidth / 2f, tileHeight / 2f), 
                                   1f, flipEffect, 0);
                    }

                    destPos.X += tileWidth;
                }

                destPos.Y += tileHeight;
            }
        }
    }

    public class ObjectGroup
    {
        public SortedList<string, Object> Objects = new SortedList<string, Object>();
        public SortedList<string, string> Properties = new SortedList<string, string>();

        public string Name;
        public int Width, Height, X, Y;
        float Opacity = 1;

        internal static ObjectGroup Load(XmlReader reader)
        {
            var result = new ObjectGroup();
            CultureInfo ci = (CultureInfo)CultureInfo.CurrentCulture.Clone();
            ci.NumberFormat.CurrencyDecimalSeparator = ".";

            if (reader.GetAttribute("name") != null)
                result.Name = reader.GetAttribute("name");
            if (reader.GetAttribute("width") != null)
                result.Width = int.Parse(reader.GetAttribute("width"));
            if (reader.GetAttribute("height") != null)
                result.Height = int.Parse(reader.GetAttribute("height"));
            if (reader.GetAttribute("x") != null)
                result.X = int.Parse(reader.GetAttribute("x"));
            if (reader.GetAttribute("y") != null)
                result.Y = int.Parse(reader.GetAttribute("y"));
            if(reader.GetAttribute("opacity") != null)
                result.Opacity = float.Parse(reader.GetAttribute("opacity"), NumberStyles.Any, ci);

            while (!reader.EOF)
            {
                var name = reader.Name;

                switch (reader.NodeType)
                {
                    case XmlNodeType.Element:
                        switch (name)
                        {
                            case "object":
                                {
                                    using (var st = reader.ReadSubtree())
                                    {
                                        st.Read();
                                        var objects = Object.Load(st);
                                        if (!result.Objects.ContainsKey(objects.Name))
                                        {
                                            result.Objects.Add(objects.Name, objects);
                                        }
                                        else {
                                            int count = result.Objects.Keys.Count((item) => item.Equals(objects.Name));
                                            result.Objects.Add(string.Format("{0}{1}", objects.Name, count), objects);
                                        }
                                    }
                                } break;
                            case "properties":
                                {
                                    using (var st = reader.ReadSubtree())
                                    {
                                        while (!st.EOF)
                                        {
                                            switch (st.NodeType)
                                            {
                                                case XmlNodeType.Element:
                                                    if (st.Name == "property")
                                                    {
                                                        if (st.GetAttribute("name") != null)
                                                        {
                                                            result.Properties.Add(st.GetAttribute("name"), st.GetAttribute("value"));
                                                        }
                                                    }

                                                    break;
                                                case XmlNodeType.EndElement:
                                                    break;
                                            }

                                            st.Read();
                                        }
                                    }
                                } break;
                            }

                        break;
                    case XmlNodeType.EndElement:
                        break;
                }

                reader.Read();
            }

            return result;
        }

        public void Draw(Map result, SpriteBatch batch, Rectangle rectangle, Vector2 viewportPosition)
        {
            foreach (var objects in Objects.Values)
            {
                if (objects.Texture != null)
                {
                    objects.Draw(batch, rectangle, new Vector2(this.X * result.TileWidth, this.Y * result.TileHeight), viewportPosition, this.Opacity);
                }
            }
        }
    }

    public class Object
    {
        public SortedList<string, string> Properties = new SortedList<string, string>();

        public string Name, Image;
        public int Width, Height, X, Y;

        protected Texture2D _Texture;
        protected int _TexWidth, _TexHeight;

        public Texture2D Texture
        {
            get
            {
                return _Texture;
            }
            set
            {
                _Texture = value;
                _TexWidth = value.Width;
                _TexHeight = value.Height;
            }
        }

        internal static Object Load(XmlReader reader)
        {
            var result = new Object();

            result.Name = reader.GetAttribute("name");
            result.X = int.Parse(reader.GetAttribute("x"));
            result.Y = int.Parse(reader.GetAttribute("y"));

            /*
             * Height and width are optional on objects
             */
            int width;
            if ( int.TryParse(reader.GetAttribute("width"), out width) ) 
            {
                result.Width = width;
            }

            int height;
            if ( int.TryParse(reader.GetAttribute("height"), out height) ) 
            {
                result.Height = height;
            }

            while (!reader.EOF)
            {
                switch (reader.NodeType)
                {
                    case XmlNodeType.Element:
                        if (reader.Name == "properties")
                        {
                            using (var st = reader.ReadSubtree())
                            {
                                while (!st.EOF)
                                {
                                    switch (st.NodeType)
                                    {
                                        case XmlNodeType.Element:
                                            if (st.Name == "property")
                                            {
                                                if (st.GetAttribute("name") != null)
                                                {
                                                    result.Properties.Add(st.GetAttribute("name"), st.GetAttribute("value"));
                                                }
                                            }

                                            break;
                                        case XmlNodeType.EndElement:
                                            break;
                                    }

                                    st.Read();
                                }
                            }
                        }
                        if (reader.Name == "image")
                        {
                            result.Image = reader.GetAttribute("source");
                        }

                        break;
                    case XmlNodeType.EndElement:
                        break;
                }

                reader.Read();
            }

            return result;
        }

        public void Draw(SpriteBatch batch, Rectangle rectangle, Vector2 offset, Vector2 viewportPosition, float opacity)
        {
            Vector2 viewPos = viewportPosition;

            int minX = (int)Math.Floor(viewportPosition.X);
            int minY = (int)Math.Floor(viewportPosition.Y);
            int maxX = (int)Math.Ceiling((rectangle.Width + viewportPosition.X));
            int maxY = (int)Math.Ceiling((rectangle.Height + viewportPosition.Y));

            if (this.X + offset.X + this.Width > minX && this.X + offset.X < maxX)
                if (this.Y + offset.Y + this.Height > minY && this.Y + offset.Y < maxY)
                {
                    int x = (int)(this.X + offset.X - viewportPosition.X);
                    int y = (int)(this.Y + offset.Y - viewportPosition.Y);
                    batch.Draw(_Texture, new Rectangle(x, y, this.Width, this.Height), new Rectangle(0, 0, _Texture.Width, _Texture.Height), Color.White * opacity);
                }
        }
    }

    public class Map
    {
        public SortedList<string, Tileset> Tilesets = new SortedList<string, Tileset>();
        public SortedList<string, Layer> Layers = new SortedList<string, Layer>();
        public SortedList<string, ObjectGroup> ObjectGroups = new SortedList<string, ObjectGroup>();
        public SortedList<string, string> Properties = new SortedList<string, string>();
        //added the combined list to store a list of all objectgroups and layers
        //this is so that they can be drawn all in the correct order within the layers.
        public SortedList<string, bool> Combined;
        public int Width, Height;
        public int TileWidth, TileHeight;

        public static Map Load (string filename, ContentManager content) {
            var result = new Map();
                XmlReaderSettings settings = new XmlReaderSettings();
                settings.ProhibitDtd = false;

                using (var stream = System.IO.File.OpenText(filename))
                using (var reader = XmlReader.Create(stream, settings))
                    while (reader.Read())
                    {
                        var name = reader.Name;

                        switch (reader.NodeType)
                        {
                            case XmlNodeType.DocumentType:
                                if (name != "map")
                                    throw new Exception("Invalid map format");
                                break;
                            case XmlNodeType.Element:
                                switch (name)
                                {
                                    case "map":
                                        {
                                            result.Width = int.Parse(reader.GetAttribute("width"));
                                            result.Height = int.Parse(reader.GetAttribute("height"));
                                            result.TileWidth = int.Parse(reader.GetAttribute("tilewidth"));
                                            result.TileHeight = int.Parse(reader.GetAttribute("tileheight"));
                                        } break;
                                    case "tileset":
                                        {
                                            using (var st = reader.ReadSubtree())
                                            {
                                                st.Read();
                                                var tileset = Tileset.Load(st);
                                                result.Tilesets.Add(tileset.Name, tileset);
                                            }
                                        } break;
                                    case "layer":
                                        {
                                            using (var st = reader.ReadSubtree())
                                            {
                                                st.Read();
                                                var layer = Layer.Load(st);
                                                if (null != layer)
                                                {
                                                    result.Layers.Add(layer.Name, layer);
                                                }
                                            }
                                        } break;
                                    case "objectgroup":
                                        {
                                            using (var st = reader.ReadSubtree())
                                            {
                                                st.Read();
                                                var objectgroup = ObjectGroup.Load(st);
                                                result.ObjectGroups.Add(objectgroup.Name, objectgroup);
                                            }
                                        } break;
                                    case "properties":
                                        {
                                            using (var st = reader.ReadSubtree())
                                            {
                                                while (!st.EOF)
                                                {
                                                    switch (st.NodeType)
                                                    {
                                                        case XmlNodeType.Element:
                                                            if (st.Name == "property")
                                                            {
                                                                if (st.GetAttribute("name") != null)
                                                                {
                                                                    result.Properties.Add(st.GetAttribute("name"), st.GetAttribute("value"));
                                                                }
                                                            }

                                                            break;
                                                        case XmlNodeType.EndElement:
                                                            break;
                                                    }

                                                    st.Read();
                                                }
                                            }
                                        } break;
                                }
                                break;
                            case XmlNodeType.EndElement:
                                break;
                            case XmlNodeType.Whitespace:
                                break;
                        }
                    }


            foreach (var tileset in result.Tilesets.Values)
            {
                tileset.Texture = content.Load<Texture2D>(
                    Path.Combine(Path.GetDirectoryName(tileset.Image), Path.GetFileNameWithoutExtension(tileset.Image))
                );
            }


            foreach (var objects in result.ObjectGroups.Values)
            {
                foreach (var item in objects.Objects.Values)
                {
                    if (item.Image != null)
                    {
                        item.Texture = content.Load<Texture2D>
                        (
                            Path.Combine
                            (
                                Path.GetDirectoryName(item.Image),
                                Path.GetFileNameWithoutExtension(item.Image)
                            )
                        );
                    }
                }
            }

            return result;
        }

        //new method to generate the list of all layers and objectgroups to draw
        private SortedList<string,bool> CombinedList()
        {
            SortedList<string, bool> temp = new SortedList<string, bool>();

            //bool of true denotes a layer
            foreach (Layer layers in Layers.Values)
            {
               temp.Add(layers.Name,true);
            }

            //bool of false denotes an object group
            foreach (var objectgroups in ObjectGroups.Values)
            {
                temp.Add(objectgroups.Name, false);
            }
            Console.WriteLine("Combined List Created");
            return temp;
        }

        public void Draw (SpriteBatch batch, Rectangle rectangle, Vector2 viewportPosition) {

            //check if combined list is created if not create it.
            if (Combined == null)
                Combined = CombinedList();

            //cycle through each item in combined list
            //if the value is true its a layer, false its an object group
            //the key should be the name of the layer or object group
            foreach (var layer in Combined)
            {
                if (layer.Value == true)
                    Layers[layer.Key].Draw(batch, Tilesets.Values, rectangle, viewportPosition, TileWidth, TileHeight);
                else
                    ObjectGroups[layer.Key].Draw(this, batch, rectangle, viewportPosition);
                }
            }
        }
    }