varregion: add new TerrainData and TerrainCompressor routines. TerrainCompressor needed to replace the one in libopenmetaverse that doesn't know about the larger terrain packets.

1 files changed, 958 insertions, 0 deletions

diff --git a/OpenSim/Region/Framework/Scenes/TerrainCompressor.cs b/OpenSim/Region/Framework/Scenes/TerrainCompressor.cs
new file mode 100644
index 0000000..2e856bc
--- /dev/null
+++ b/OpenSim/Region/Framework/Scenes/TerrainCompressor.cs
@@ -0,0 +1,958 @@
+/*
+ * 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 OpenSimulator 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.
+ */
+
+/* Freely adapted from the Aurora version of the terrain compressor.
+ * Copyright (c) Contributors, http://aurora-sim.org/, http://opensimulator.org/
+ */
+
+using System;
+using System.Reflection;
+
+using log4net;
+
+using OpenSim.Framework;
+using OpenSim.Region.Framework;
+using OpenSim.Region.Framework.Scenes;
+
+using OpenMetaverse;
+using OpenMetaverse.Packets;
+
+namespace OpenSim.Region.ClientStack.LindenUDP
+{
+    public static class OpenSimTerrainCompressor
+    {
+        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+        private static string LogHeader = "[TERRAIN COMPRESSOR]";
+
+        public const int END_OF_PATCHES = 97;
+
+        private const float OO_SQRT2 = 0.7071067811865475244008443621049f;
+        private const int STRIDE = 264;
+
+        private const int ZERO_CODE = 0x0;
+        private const int ZERO_EOB = 0x2;
+        private const int POSITIVE_VALUE = 0x6;
+        private const int NEGATIVE_VALUE = 0x7;
+
+        private static readonly float[] DequantizeTable16 =
+            new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+        private static readonly float[] DequantizeTable32 =
+            new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+        private static readonly float[] CosineTable16 = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+        //private static readonly float[] CosineTable32 = new float[Constants.TerrainPatchSize * Constants.TerrainPatchSize];
+        private static readonly int[] CopyMatrix16 = new int[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+        private static readonly int[] CopyMatrix32 = new int[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+        private static readonly float[] QuantizeTable16 =
+            new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+        static OpenSimTerrainCompressor()
+        {
+            // Initialize the decompression tables
+            BuildDequantizeTable16();
+            SetupCosines16();
+            BuildCopyMatrix16();
+            BuildQuantizeTable16();
+        }
+
+        // Unused: left for historical reference.
+        public static LayerDataPacket CreateLayerDataPacket(TerrainPatch[] patches, byte type, int pRegionSizeX,
+                                                            int pRegionSizeY)
+        {
+            LayerDataPacket layer = new LayerDataPacket {LayerID = {Type = type}};
+
+            TerrainPatch.GroupHeader header = new TerrainPatch.GroupHeader
+                                                  {Stride = STRIDE, PatchSize = Constants.TerrainPatchSize};
+
+            // Should be enough to fit even the most poorly packed data
+            byte[] data = new byte[patches.Length*Constants.TerrainPatchSize*Constants.TerrainPatchSize*2];
+            BitPack bitpack = new BitPack(data, 0);
+            bitpack.PackBits(header.Stride, 16);
+            bitpack.PackBits(header.PatchSize, 8);
+            bitpack.PackBits(type, 8);
+
+            foreach (TerrainPatch t in patches)
+                CreatePatch(bitpack, t.Data, t.X, t.Y, pRegionSizeX, pRegionSizeY);
+
+            bitpack.PackBits(END_OF_PATCHES, 8);
+
+            layer.LayerData.Data = new byte[bitpack.BytePos + 1];
+            Buffer.BlockCopy(bitpack.Data, 0, layer.LayerData.Data, 0, bitpack.BytePos + 1);
+
+            return layer;
+        }
+
+        // Legacy land packet generation gluing old land representation (heights) to compressed representation.
+        // This is an intermediate step in converting terrain into a variable sized heightmap. Some of the
+        //     routines (like IClientAPI) only pass the float array of heights around. This entry
+        //     converts that legacy representation into the more compact represenation used in
+        //     TerrainChannel. Someday fix the plumbing between here and the scene.
+        public static LayerDataPacket CreateLandPacket(float[] heightmap, int patchX, int patchY, uint sizeX, uint sizeY)
+        {
+            int[] xPieces = new int[1];
+            int[] yPieces = new int[1];
+
+            short[] newmap = new short[heightmap.Length];
+            for (int ii = 0; ii < heightmap.Length; ii++)
+                newmap[ii] = TerrainChannel.ToCompressedHeight(heightmap[ii]);
+
+            xPieces[0] = patchX;  // patch X dimension
+            yPieces[0] = patchY;
+
+            m_log.DebugFormat("{0} CreateLandPacket. patchX={1}, patchY={2}, sizeX={3}, sizeY={4}",
+                                    LogHeader, patchX, patchY, sizeX, sizeY);
+
+            return CreateLandPacket(newmap, xPieces, yPieces, (int)TerrainPatch.LayerType.Land, sizeX, sizeY);
+        }
+
+        /// <summary>
+        ///     Creates a LayerData packet for compressed land data given a full
+        ///     simulator heightmap and an array of indices of patches to compress
+        /// </summary>
+        /// <param name="heightmap">
+        ///     A 256 * 256 array of floating point values
+        ///     specifying the height at each meter in the simulator
+        /// </param>
+        /// <param name="x">
+        ///     Array of indexes in the 16x16 grid of patches
+        ///     for this simulator. For example if 1 and 17 are specified, patches
+        ///     x=1,y=0 and x=1,y=1 are sent
+        /// </param>
+        /// <param name="y">
+        ///     Array of indexes in the 16x16 grid of patches
+        ///     for this simulator. For example if 1 and 17 are specified, patches
+        ///     x=1,y=0 and x=1,y=1 are sent
+        /// </param>
+        /// <param name="type"></param>
+        /// <param name="pRegionSizeX"></param>
+        /// <param name="pRegionSizeY"></param>
+        /// <returns></returns>
+        public static LayerDataPacket CreateLandPacket(short[] heightmap, int[] x, int[] y, byte type,
+                                        uint pRegionSizeX, uint pRegionSizeY)
+        {
+            LayerDataPacket layer = new LayerDataPacket {LayerID = {Type = type}};
+
+            TerrainPatch.GroupHeader header = new TerrainPatch.GroupHeader
+                                                  {Stride = STRIDE, PatchSize = Constants.TerrainPatchSize};
+
+            byte[] data = new byte[x.Length * Constants.TerrainPatchSize * Constants.TerrainPatchSize * 2];
+            BitPack bitpack = new BitPack(data, 0);
+            bitpack.PackBits(header.Stride, 16);
+            bitpack.PackBits(header.PatchSize, 8);
+            bitpack.PackBits(type, 8);
+
+            for (int i = 0; i < x.Length; i++)
+                CreatePatchFromHeightmap(bitpack, heightmap, x[i], y[i], pRegionSizeX, pRegionSizeY);
+
+            bitpack.PackBits(END_OF_PATCHES, 8);
+
+            layer.LayerData.Data = new byte[bitpack.BytePos + 1];
+            Buffer.BlockCopy(bitpack.Data, 0, layer.LayerData.Data, 0, bitpack.BytePos + 1);
+
+            return layer;
+        }
+
+        // Unused: left for historical reference.
+        public static void CreatePatch(BitPack output, float[] patchData, int x, int y, int pRegionSizeX, int pRegionSizeY)
+        {
+            TerrainPatch.Header header = PrescanPatch(patchData);
+            header.QuantWBits = 136;
+            if (pRegionSizeX > Constants.RegionSize || pRegionSizeY > Constants.RegionSize)
+            {
+                header.PatchIDs = (y & 0xFFFF);
+                header.PatchIDs += (x << 16);
+            }
+            else
+            {
+                header.PatchIDs = (y & 0x1F);
+                header.PatchIDs += (x << 5);
+            }
+
+            // NOTE: No idea what prequant and postquant should be or what they do
+
+            int wbits;
+            int[] patch = CompressPatch(patchData, header, 10, out wbits);
+            wbits = EncodePatchHeader(output, header, patch, Constants.RegionSize, Constants.RegionSize, wbits);
+            EncodePatch(output, patch, 0, wbits);
+        }
+
+        /// <summary>
+        ///     Add a patch of terrain to a BitPacker
+        /// </summary>
+        /// <param name="output">BitPacker to write the patch to</param>
+        /// <param name="heightmap">
+        ///     Heightmap of the simulator. Presumed to be an sizeX*sizeY array.
+        /// </param>
+        /// <param name="patchX">
+        ///     X offset of the patch to create.
+        /// </param>
+        /// <param name="patchY">
+        ///     Y offset of the patch to create.
+        /// </param>
+        /// <param name="pRegionSizeX"></param>
+        /// <param name="pRegionSizeY"></param>
+        public static void CreatePatchFromHeightmap(BitPack output, short[] heightmap, int patchX, int patchY,
+                                        uint pRegionSizeX, uint pRegionSizeY)
+        {
+            TerrainPatch.Header header = PrescanPatch(heightmap, patchX, patchY, pRegionSizeX, pRegionSizeY);
+            header.QuantWBits = 136;
+
+            // If larger than legacy region size, pack patch X and Y info differently.
+            if (pRegionSizeX > Constants.RegionSize || pRegionSizeY > Constants.RegionSize)
+            {
+                header.PatchIDs = (patchY & 0xFFFF);
+                header.PatchIDs += (patchX << 16);
+            }
+            else
+            {
+                header.PatchIDs = (patchY & 0x1F);
+                header.PatchIDs += (patchX << 5);
+            }
+
+            // NOTE: No idea what prequant and postquant should be or what they do
+            int wbits;
+            int[] patch = CompressPatch(heightmap, patchX, patchY, header, 10, pRegionSizeX, pRegionSizeY, out wbits);
+            wbits = EncodePatchHeader(output, header, patch, pRegionSizeX, pRegionSizeY, wbits);
+            EncodePatch(output, patch, 0, wbits);
+        }
+
+        private static TerrainPatch.Header PrescanPatch(float[] patch)
+        {
+            TerrainPatch.Header header = new TerrainPatch.Header();
+            float zmax = -99999999.0f;
+            float zmin = 99999999.0f;
+
+            for (int i = 0; i < Constants.TerrainPatchSize*Constants.TerrainPatchSize; i++)
+            {
+                float val = patch[i];
+                if (val > zmax) zmax = val;
+                if (val < zmin) zmin = val;
+            }
+
+            header.DCOffset = zmin;
+            header.Range = (int) ((zmax - zmin) + 1.0f);
+
+            return header;
+        }
+
+        // Scan the height info we're returning and return a patch packet header for this patch.
+        // TODO. Why are patches ordered Y,X rather than X,Y?
+        private static TerrainPatch.Header PrescanPatch(short[] heightmap, int patchX, int patchY,
+                                uint pRegionSizeX, uint pRegionSizeY)
+        {
+            TerrainPatch.Header header = new TerrainPatch.Header();
+            short zmax = -32767;
+            short zmin = 32767;
+
+            for (int j = patchY*16; j < (patchY + 1)*16; j++)
+            {
+                for (int i = patchX*16; i < (patchX + 1)*16; i++)
+                {
+                    short val = heightmap[j*pRegionSizeX + i];
+                    if (val > zmax) zmax = val;
+                    if (val < zmin) zmin = val;
+                }
+            }
+
+            // Since the the min and max values are the shorts, rescale to be real values.
+            // TODO: all this logic should go into the class wrapping the short values.
+            header.DCOffset = TerrainChannel.FromCompressedHeight(zmin);
+            header.Range = (int)(TerrainChannel.FromCompressedHeight(zmax) - TerrainChannel.FromCompressedHeight(zmin) + 1.0f);
+
+            return header;
+        }
+
+        public static TerrainPatch.Header DecodePatchHeader(BitPack bitpack)
+        {
+            TerrainPatch.Header header = new TerrainPatch.Header {QuantWBits = bitpack.UnpackBits(8)};
+
+            // Quantized word bits
+            if (header.QuantWBits == END_OF_PATCHES)
+                return header;
+
+            // DC offset
+            header.DCOffset = bitpack.UnpackFloat();
+
+            // Range
+            header.Range = bitpack.UnpackBits(16);
+
+            // Patch IDs (10 bits)
+            header.PatchIDs = bitpack.UnpackBits(10);
+
+            // Word bits
+            header.WordBits = (uint) ((header.QuantWBits & 0x0f) + 2);
+
+            return header;
+        }
+
+        private static int EncodePatchHeader(BitPack output, TerrainPatch.Header header, int[] patch, uint pRegionSizeX,
+                                             uint pRegionSizeY, int wbits)
+        {
+            /*
+                    int temp;
+                    int wbits = (header.QuantWBits & 0x0f) + 2;
+                    uint maxWbits = (uint)wbits + 5;
+                    uint minWbits = ((uint)wbits >> 1);
+                    int wbitsMaxValue;
+        */
+            // goal is to determ minimum number of bits to use so all data fits
+            /*
+                    wbits = (int)minWbits;
+                    wbitsMaxValue = (1 << wbits);
+
+                    for (int i = 0; i < patch.Length; i++)
+                    {
+                        temp = patch[i];
+                        if (temp != 0)
+                        {
+                            // Get the absolute value
+                            if (temp < 0) temp *= -1;
+
+         no coments..
+
+                            for (int j = (int)maxWbits; j > (int)minWbits; j--)
+                            {
+                                if ((temp & (1 << j)) != 0)
+                                {
+                                    if (j > wbits) wbits = j;
+                                    break;
+                                }
+                            }
+ 
+                            while (temp > wbitsMaxValue)
+                                {
+                                wbits++;
+                                if (wbits == maxWbits)
+                                    goto Done;
+                                wbitsMaxValue = 1 << wbits;
+                                }
+                        }
+                    }
+
+                Done:
+
+                    //            wbits += 1;
+         */
+            // better check
+            if (wbits > 17)
+                wbits = 16;
+            else if (wbits < 3)
+                wbits = 3;
+
+            header.QuantWBits &= 0xf0;
+
+            header.QuantWBits |= (wbits - 2);
+
+            output.PackBits(header.QuantWBits, 8);
+            output.PackFloat(header.DCOffset);
+            output.PackBits(header.Range, 16);
+            if (pRegionSizeX > Constants.RegionSize || pRegionSizeY > Constants.RegionSize)
+                output.PackBits(header.PatchIDs, 32);
+            else
+                output.PackBits(header.PatchIDs, 10);
+
+            return wbits;
+        }
+
+        private static void IDCTColumn16(float[] linein, float[] lineout, int column)
+        {
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                float total = OO_SQRT2*linein[column];
+
+                for (int u = 1; u < Constants.TerrainPatchSize; u++)
+                {
+                    int usize = u*Constants.TerrainPatchSize;
+                    total += linein[usize + column]*CosineTable16[usize + n];
+                }
+
+                lineout[Constants.TerrainPatchSize*n + column] = total;
+            }
+        }
+
+        private static void IDCTLine16(float[] linein, float[] lineout, int line)
+        {
+            const float oosob = 2.0f/Constants.TerrainPatchSize;
+            int lineSize = line*Constants.TerrainPatchSize;
+
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                float total = OO_SQRT2*linein[lineSize];
+
+                for (int u = 1; u < Constants.TerrainPatchSize; u++)
+                {
+                    total += linein[lineSize + u]*CosineTable16[u*Constants.TerrainPatchSize + n];
+                }
+
+                lineout[lineSize + n] = total*oosob;
+            }
+        }
+
+/*
+        private static void DCTLine16(float[] linein, float[] lineout, int line)
+        {
+            float total = 0.0f;
+            int lineSize = line * Constants.TerrainPatchSize;
+
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                total += linein[lineSize + n];
+            }
+
+            lineout[lineSize] = OO_SQRT2 * total;
+
+            int uptr = 0;
+            for (int u = 1; u < Constants.TerrainPatchSize; u++)
+            {
+                total = 0.0f;
+                uptr += Constants.TerrainPatchSize;
+
+                for (int n = 0; n < Constants.TerrainPatchSize; n++)
+                {
+                    total += linein[lineSize + n] * CosineTable16[uptr + n];
+                }
+
+                lineout[lineSize + u] = total;
+            }
+        }
+*/
+
+        private static void DCTLine16(float[] linein, float[] lineout, int line)
+        {
+            // outputs transpose data (lines exchanged with coluns )
+            // so to save a bit of cpu when doing coluns
+            float total = 0.0f;
+            int lineSize = line*Constants.TerrainPatchSize;
+
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                total += linein[lineSize + n];
+            }
+
+            lineout[line] = OO_SQRT2*total;
+
+            for (int u = Constants.TerrainPatchSize;
+                 u < Constants.TerrainPatchSize*Constants.TerrainPatchSize;
+                 u += Constants.TerrainPatchSize)
+            {
+                total = 0.0f;
+                for (int ptrn = lineSize, ptru = u; ptrn < lineSize + Constants.TerrainPatchSize; ptrn++,ptru++)
+                {
+                    total += linein[ptrn]*CosineTable16[ptru];
+                }
+
+                lineout[line + u] = total;
+            }
+        }
+
+
+        /*
+                private static void DCTColumn16(float[] linein, int[] lineout, int column)
+                {
+                    float total = 0.0f;
+        //            const float oosob = 2.0f / Constants.TerrainPatchSize;
+
+                    for (int n = 0; n < Constants.TerrainPatchSize; n++)
+                    {
+                        total += linein[Constants.TerrainPatchSize * n + column];
+                    }
+
+        //            lineout[CopyMatrix16[column]] = (int)(OO_SQRT2 * total * oosob * QuantizeTable16[column]);
+                    lineout[CopyMatrix16[column]] = (int)(OO_SQRT2 * total * QuantizeTable16[column]);
+
+                    for (int uptr = Constants.TerrainPatchSize; uptr < Constants.TerrainPatchSize * Constants.TerrainPatchSize; uptr += Constants.TerrainPatchSize)
+                    {
+                        total = 0.0f;
+
+                        for (int n = 0; n < Constants.TerrainPatchSize; n++)
+                        {
+                            total += linein[Constants.TerrainPatchSize * n + column] * CosineTable16[uptr + n];
+                        }
+
+        //                lineout[CopyMatrix16[Constants.TerrainPatchSize * u + column]] = (int)(total * oosob * QuantizeTable16[Constants.TerrainPatchSize * u + column]);
+                        lineout[CopyMatrix16[uptr + column]] = (int)(total * QuantizeTable16[uptr + column]);
+                        }
+                }
+        */
+
+        private static void DCTColumn16(float[] linein, int[] lineout, int column)
+        {
+            // input columns are in fact stored in lines now
+
+            float total = 0.0f;
+//            const float oosob = 2.0f / Constants.TerrainPatchSize;
+            int inlinesptr = Constants.TerrainPatchSize*column;
+
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                total += linein[inlinesptr + n];
+            }
+
+            //            lineout[CopyMatrix16[column]] = (int)(OO_SQRT2 * total * oosob * QuantizeTable16[column]);
+            lineout[CopyMatrix16[column]] = (int) (OO_SQRT2*total*QuantizeTable16[column]);
+
+            for (int uptr = Constants.TerrainPatchSize;
+                 uptr < Constants.TerrainPatchSize*Constants.TerrainPatchSize;
+                 uptr += Constants.TerrainPatchSize)
+            {
+                total = 0.0f;
+
+                for (int n = inlinesptr, ptru = uptr; n < inlinesptr + Constants.TerrainPatchSize; n++, ptru++)
+                {
+                    total += linein[n]*CosineTable16[ptru];
+                }
+
+//                lineout[CopyMatrix16[Constants.TerrainPatchSize * u + column]] = (int)(total * oosob * QuantizeTable16[Constants.TerrainPatchSize * u + column]);
+                lineout[CopyMatrix16[uptr + column]] = (int) (total*QuantizeTable16[uptr + column]);
+            }
+        }
+
+        private static int DCTColumn16Wbits(float[] linein, int[] lineout, int column, int wbits, int maxwbits)
+        {
+            // input columns are in fact stored in lines now
+
+            bool dowbits = wbits != maxwbits;
+            int wbitsMaxValue = 1 << wbits;
+
+            float total = 0.0f;
+            //            const float oosob = 2.0f / Constants.TerrainPatchSize;
+            int inlinesptr = Constants.TerrainPatchSize*column;
+
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                total += linein[inlinesptr + n];
+            }
+
+            //            lineout[CopyMatrix16[column]] = (int)(OO_SQRT2 * total * oosob * QuantizeTable16[column]);
+            int tmp = (int) (OO_SQRT2*total*QuantizeTable16[column]);
+            lineout[CopyMatrix16[column]] = tmp;
+
+            if (dowbits)
+            {
+                if (tmp < 0) tmp *= -1;
+                while (tmp > wbitsMaxValue)
+                {
+                    wbits++;
+                    wbitsMaxValue = 1 << wbits;
+                    if (wbits == maxwbits)
+                    {
+                        dowbits = false;
+                        break;
+                    }
+                }
+            }
+
+            for (int uptr = Constants.TerrainPatchSize;
+                 uptr < Constants.TerrainPatchSize*Constants.TerrainPatchSize;
+                 uptr += Constants.TerrainPatchSize)
+            {
+                total = 0.0f;
+
+                for (int n = inlinesptr, ptru = uptr; n < inlinesptr + Constants.TerrainPatchSize; n++, ptru++)
+                {
+                    total += linein[n]*CosineTable16[ptru];
+                }
+
+                tmp = (int) (total*QuantizeTable16[uptr + column]);
+                lineout[CopyMatrix16[uptr + column]] = tmp;
+
+                if (dowbits)
+                {
+                    if (tmp < 0) tmp *= -1;
+                    while (tmp > wbitsMaxValue)
+                    {
+                        wbits++;
+                        wbitsMaxValue = 1 << wbits;
+                        if (wbits == maxwbits)
+                        {
+                            dowbits = false;
+                            break;
+                        }
+                    }
+                }
+            }
+            return wbits;
+        }
+
+        public static void DecodePatch(int[] patches, BitPack bitpack, TerrainPatch.Header header, int size)
+        {
+            for (int n = 0; n < size*size; n++)
+            {
+                // ?
+                int temp = bitpack.UnpackBits(1);
+                if (temp != 0)
+                {
+                    // Value or EOB
+                    temp = bitpack.UnpackBits(1);
+                    if (temp != 0)
+                    {
+                        // Value
+                        temp = bitpack.UnpackBits(1);
+                        if (temp != 0)
+                        {
+                            // Negative
+                            temp = bitpack.UnpackBits((int) header.WordBits);
+                            patches[n] = temp*-1;
+                        }
+                        else
+                        {
+                            // Positive
+                            temp = bitpack.UnpackBits((int) header.WordBits);
+                            patches[n] = temp;
+                        }
+                    }
+                    else
+                    {
+                        // Set the rest to zero
+                        // TODO: This might not be necessary
+                        for (int o = n; o < size*size; o++)
+                        {
+                            patches[o] = 0;
+                        }
+                        break;
+                    }
+                }
+                else
+                {
+                    patches[n] = 0;
+                }
+            }
+        }
+
+        private static void EncodePatch(BitPack output, int[] patch, int postquant, int wbits)
+        {
+            int maxwbitssize = (1 << wbits) - 1;
+
+            if (postquant > Constants.TerrainPatchSize*Constants.TerrainPatchSize || postquant < 0)
+            {
+                Logger.Log("Postquant is outside the range of allowed values in EncodePatch()", Helpers.LogLevel.Error);
+                return;
+            }
+
+            if (postquant != 0) patch[Constants.TerrainPatchSize*Constants.TerrainPatchSize - postquant] = 0;
+
+            for (int i = 0; i < Constants.TerrainPatchSize*Constants.TerrainPatchSize; i++)
+            {
+                int temp = patch[i];
+
+                if (temp == 0)
+                {
+                    bool eob = true;
+
+                    for (int j = i; j < Constants.TerrainPatchSize*Constants.TerrainPatchSize - postquant; j++)
+                    {
+                        if (patch[j] != 0)
+                        {
+                            eob = false;
+                            break;
+                        }
+                    }
+
+                    if (eob)
+                    {
+                        output.PackBits(ZERO_EOB, 2);
+                        return;
+                    }
+                    output.PackBits(ZERO_CODE, 1);
+                }
+                else
+                {
+                    if (temp < 0)
+                    {
+                        temp *= -1;
+
+                        if (temp > maxwbitssize) temp = maxwbitssize;
+
+                        output.PackBits(NEGATIVE_VALUE, 3);
+                        output.PackBits(temp, wbits);
+                    }
+                    else
+                    {
+                        if (temp > maxwbitssize) temp = maxwbitssize;
+
+                        output.PackBits(POSITIVE_VALUE, 3);
+                        output.PackBits(temp, wbits);
+                    }
+                }
+            }
+        }
+
+        public static float[] DecompressPatch(int[] patches, TerrainPatch.Header header, TerrainPatch.GroupHeader group)
+        {
+            float[] block = new float[group.PatchSize*group.PatchSize];
+            float[] output = new float[group.PatchSize*group.PatchSize];
+            int prequant = (header.QuantWBits >> 4) + 2;
+            int quantize = 1 << prequant;
+            float ooq = 1.0f/quantize;
+            float mult = ooq*header.Range;
+            float addval = mult*(1 << (prequant - 1)) + header.DCOffset;
+
+            if (group.PatchSize == Constants.TerrainPatchSize)
+            {
+                for (int n = 0; n < Constants.TerrainPatchSize*Constants.TerrainPatchSize; n++)
+                {
+                    block[n] = patches[CopyMatrix16[n]]*DequantizeTable16[n];
+                }
+
+                float[] ftemp = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+                for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                    IDCTColumn16(block, ftemp, o);
+                for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                    IDCTLine16(ftemp, block, o);
+            }
+            else
+            {
+                for (int n = 0; n < Constants.TerrainPatchSize*2*Constants.TerrainPatchSize*2; n++)
+                {
+                    block[n] = patches[CopyMatrix32[n]]*DequantizeTable32[n];
+                }
+
+                Logger.Log("Implement IDCTPatchLarge", Helpers.LogLevel.Error);
+            }
+
+            for (int j = 0; j < block.Length; j++)
+            {
+                output[j] = block[j]*mult + addval;
+            }
+
+            return output;
+        }
+
+        private static int[] CompressPatch(float[] patchData, TerrainPatch.Header header, int prequant, out int wbits)
+        {
+            float[] block = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            int wordsize = (prequant - 2) & 0x0f;
+            float oozrange = 1.0f/header.Range;
+            float range = (1 << prequant);
+            float premult = oozrange*range;
+            float sub = (1 << (prequant - 1)) + header.DCOffset*premult;
+
+            header.QuantWBits = wordsize;
+            header.QuantWBits |= wordsize << 4;
+
+            int k = 0;
+            for (int j = 0; j < Constants.TerrainPatchSize; j++)
+            {
+                for (int i = 0; i < Constants.TerrainPatchSize; i++)
+                    block[k++] = patchData[j*Constants.TerrainPatchSize + i]*premult - sub;
+            }
+
+            float[] ftemp = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            int[] itemp = new int[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+
+            int maxWbits = prequant + 5;
+            wbits = (prequant >> 1);
+
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                DCTLine16(block, ftemp, o);
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                wbits = DCTColumn16Wbits(ftemp, itemp, o, wbits, maxWbits);
+
+            return itemp;
+        }
+
+        private static int[] CompressPatch(float[,] patchData, TerrainPatch.Header header, int prequant, out int wbits)
+        {
+            float[] block = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            float oozrange = 1.0f/header.Range;
+            float range = (1 << prequant);
+            float premult = oozrange*range;
+            float sub = (1 << (prequant - 1)) + header.DCOffset*premult;
+            int wordsize = (prequant - 2) & 0x0f;
+
+            header.QuantWBits = wordsize;
+            header.QuantWBits |= wordsize << 4;
+
+            int k = 0;
+            for (int j = 0; j < Constants.TerrainPatchSize; j++)
+            {
+                for (int i = 0; i < Constants.TerrainPatchSize; i++)
+                    block[k++] = patchData[j, i]*premult - sub;
+            }
+
+            float[] ftemp = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            int[] itemp = new int[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+            int maxWbits = prequant + 5;
+            wbits = (prequant >> 1);
+
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                DCTLine16(block, ftemp, o);
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                wbits = DCTColumn16Wbits(ftemp, itemp, o, wbits, maxWbits);
+
+            return itemp;
+        }
+
+        private static int[] CompressPatch(short[] heightmap, int patchX, int patchY, TerrainPatch.Header header,
+                                           int prequant, uint pRegionSizeX, uint pRegionSizeY, out int wbits)
+        {
+            float[] block = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            int wordsize = prequant;
+            float oozrange = 1.0f/header.Range;
+            float range = (1 << prequant);
+            float premult = oozrange*range;
+            float sub = (1 << (prequant - 1)) + header.DCOffset*premult;
+
+            header.QuantWBits = wordsize - 2;
+            header.QuantWBits |= (prequant - 2) << 4;
+
+            int k = 0;
+
+            premult /= Constants.TerrainCompression; // put here short to float factor
+
+            int jPatchLimit = patchY;
+            if (patchY >= (pRegionSizeY / Constants.TerrainPatchSize))
+            {
+                jPatchLimit = (int)(pRegionSizeY - Constants.TerrainPatchSize) / Constants.TerrainPatchSize;
+            }
+            jPatchLimit = (jPatchLimit + 1) * Constants.TerrainPatchSize;
+
+            int iPatchLimit = patchX;
+            if (patchX >= (pRegionSizeX / Constants.TerrainPatchSize))
+            {
+                iPatchLimit = (int)(pRegionSizeX - Constants.TerrainPatchSize) / Constants.TerrainPatchSize;
+            }
+            iPatchLimit = (iPatchLimit + 1) * Constants.TerrainPatchSize;
+
+            for (int j = patchY * Constants.TerrainPatchSize; j < jPatchLimit; j++)
+            {
+                for (int i = patchX * Constants.TerrainPatchSize; i < iPatchLimit; i++)
+                {
+                    block[k++] = (heightmap[j*pRegionSizeX + i])*premult - sub;
+                }
+            }
+
+            float[] ftemp = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            int[] itemp = new int[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+            int maxWbits = prequant + 5;
+            wbits = (prequant >> 1);
+
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                DCTLine16(block, ftemp, o);
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                wbits = DCTColumn16Wbits(ftemp, itemp, o, wbits, maxWbits);
+
+            return itemp;
+        }
+
+        #region Initialization
+
+        private static void BuildDequantizeTable16()
+        {
+            for (int j = 0; j < Constants.TerrainPatchSize; j++)
+            {
+                for (int i = 0; i < Constants.TerrainPatchSize; i++)
+                {
+                    DequantizeTable16[j*Constants.TerrainPatchSize + i] = 1.0f + 2.0f*(i + j);
+                }
+            }
+        }
+
+        private static void BuildQuantizeTable16()
+        {
+            const float oosob = 2.0f/Constants.TerrainPatchSize;
+            for (int j = 0; j < Constants.TerrainPatchSize; j++)
+            {
+                for (int i = 0; i < Constants.TerrainPatchSize; i++)
+                {
+//                    QuantizeTable16[j * Constants.TerrainPatchSize + i] = 1.0f / (1.0f + 2.0f * ((float)i + (float)j));
+                    QuantizeTable16[j*Constants.TerrainPatchSize + i] = oosob/(1.0f + 2.0f*(i + (float) j));
+                }
+            }
+        }
+
+        private static void SetupCosines16()
+        {
+            const float hposz = (float) Math.PI*0.5f/Constants.TerrainPatchSize;
+
+            for (int u = 0; u < Constants.TerrainPatchSize; u++)
+            {
+                for (int n = 0; n < Constants.TerrainPatchSize; n++)
+                {
+                    CosineTable16[u*Constants.TerrainPatchSize + n] = (float) Math.Cos((2.0f*n + 1.0f)*u*hposz);
+                }
+            }
+        }
+
+        private static void BuildCopyMatrix16()
+        {
+            bool diag = false;
+            bool right = true;
+            int i = 0;
+            int j = 0;
+            int count = 0;
+
+            while (i < Constants.TerrainPatchSize && j < Constants.TerrainPatchSize)
+            {
+                CopyMatrix16[j*Constants.TerrainPatchSize + i] = count++;
+
+                if (!diag)
+                {
+                    if (right)
+                    {
+                        if (i < Constants.TerrainPatchSize - 1) i++;
+                        else j++;
+
+                        right = false;
+                        diag = true;
+                    }
+                    else
+                    {
+                        if (j < Constants.TerrainPatchSize - 1) j++;
+                        else i++;
+
+                        right = true;
+                        diag = true;
+                    }
+                }
+                else
+                {
+                    if (right)
+                    {
+                        i++;
+                        j--;
+                        if (i == Constants.TerrainPatchSize - 1 || j == 0) diag = false;
+                    }
+                    else
+                    {
+                        i--;
+                        j++;
+                        if (j == Constants.TerrainPatchSize - 1 || i == 0) diag = false;
+                    }
+                }
+            }
+        }
+
+        #endregion Initialization
+    }
+}
\ No newline at end of file