Some old voxel lighting code

If you look at some of the previous posts you will see this code or a variant of it in use. It may be useful to some. It is very much a hack and i hope to revisit it perhaps in c++ or java.

 public static void SpreadChunkLight(Chunk chunk)
    {

        int x, y, z; byte l;


        using (new Timer("Spread Light"))
        {
            while (chunk.lightSources.Count > 0)
            {
                LightUnit lu = chunk.lightSources.Dequeue();
                x = lu.pos.X; y = lu.pos.Y; z = lu.pos.Z;
                l = lu.val;
                if (IsolatedSunlight(lu.pos.X, lu.pos.Y, lu.pos.Z)) { continue; }

                Spread(x - 1, y, z, l, chunk);
                Spread(x + 1, y, z, l, chunk);
                Spread(x, y + 1, z, l, chunk);
                Spread(x, y - 1, z, l, chunk);
                Spread(x, y, z + 1, l, chunk);
                Spread(x, y, z - 1, l, chunk);
            }
        }


        chunk.State = ChunkState.SpreadLight; chunk.working = false;
        chunk.StateCheck();

    }

    static void Spread(int x, int y, int z, byte l, Chunk pchunk)
    {

        if (l <2) { return; }
        if (World.IsOpaque(x, y, z)) { return; }

        Chunk chunk = World.GetChunkFromHit(x, y, z);
       
        if (chunk == null) { return; }
        byte blocklight = GetBlockLightIndex(x, y, z);
        if (blocklight > (byte)(l - 2)) { return; }


        if (World.loadedChunks >= World.totalChunks)
        {
          
            if (chunk.X != pchunk.X || chunk.Y != pchunk.Y || chunk.Z != pchunk.Z)
            {
             //   Debug.Log("light into chunk");

              //  if (!Pool.toCheckState.Contains(chunk) && chunk.State == ChunkState.Render) { chunk.working = false; chunk.State = ChunkState.SpreadLight; Pool.toCheckState.Enqueue(chunk); }
            }
        }

        lightspreadcount++;
        l = (byte)(l - 1);

        CoreLighting.SetBlockLight(x, y, z, l);

        Spread(x - 1, y, z, l, pchunk);
        Spread(x + 1, y, z, l, pchunk);
        Spread(x, y + 1, z, l, pchunk);
        Spread(x, y - 1, z, l, pchunk);
        Spread(x, y, z + 1, l, pchunk);
        Spread(x, y, z - 1, l, pchunk);

    }

Compressing Voxel Data

My first attempt at saving and loading voxel data seems to work reasonably well. It manages to save approx 4 million voxel points in about 64kb which seems reasonable. The compression ratio would decrease as the usefulness of RLE (Run Length Encoding) wanes due to excessive fragmentation. What remains to be done is to only save those blocks that have changed along with the seed. I’m not building never ending minecraft type worlds so i’m dealing with known quantities here. Currently it just saves and loads everything, surprising quickly.

public static void SaveWorld()
    {
        string saveFile = Directory.GetCurrentDirectory() + @"SavesSave000.txt";
        byte[] wb = new byte[World.blocks.Length];       
        int i = 0;
        for (int x = 0; x < World.maxX - 1; x++)
        {
            for (int y = 0; y < World.maxY - 1; y++)
            {
                for (int z = 0; z < World.maxZ - 1; z++)
                {
                    wb[i] = (byte)World.blocks[x, y, z].blocktype;
                    i++;
                }
            }
        }

        wb = CLZF2.Compress(wb);
        using (BinaryWriter writer = new BinaryWriter(File.Open(saveFile, FileMode.Create)))
        {
            writer.Write(wb);
        }
    }
/*
 * Improved version to C# LibLZF Port:
 * Copyright (c) 2010 Roman Atachiants 
 *
 * Original CLZF Port:
 * Copyright (c) 2005 Oren J. Maurice 
 *
 * Original LibLZF Library  Algorithm:
 * Copyright (c) 2000-2008 Marc Alexander Lehmann 
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 *
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *
 *   2.  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.
 *
 *   3.  The name of the author may not be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, 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 OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License version 2 (the "GPL"), in which case the
 * provisions of the GPL are applicable instead of the above. If you wish to
 * allow the use of your version of this file only under the terms of the
 * GPL and not to allow others to use your version of this file under the
 * BSD license, indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by the GPL. If
 * you do not delete the provisions above, a recipient may use your version
 * of this file under either the BSD or the GPL.
 */
using System;

/* Benchmark with Alice29 Canterbury Corpus
        ---------------------------------------
        (Compression) Original CLZF C#
        Raw = 152089, Compressed = 101092
         8292,4743 ms.
        ---------------------------------------
        (Compression) My LZF C#
        Raw = 152089, Compressed = 101092
         33,0019 ms.
        ---------------------------------------
        (Compression) Zlib using SharpZipLib
        Raw = 152089, Compressed = 54388
         8389,4799 ms.
        ---------------------------------------
        (Compression) QuickLZ C#
        Raw = 152089, Compressed = 83494
         80,0046 ms.
        ---------------------------------------
        (Decompression) Original CLZF C#
        Decompressed = 152089
         16,0009 ms.
        ---------------------------------------
        (Decompression) My LZF C#
        Decompressed = 152089
         15,0009 ms.
        ---------------------------------------
        (Decompression) Zlib using SharpZipLib
        Decompressed = 152089
         3577,2046 ms.
        ---------------------------------------
        (Decompression) QuickLZ C#
        Decompressed = 152089
         21,0012 ms.
    */


/// 
/// Improved C# LZF Compressor, a very small data compression library. The compression algorithm is extremely fast.
public static class CLZF2
{
	private static readonly uint HLOG = 14;
	private static readonly uint HSIZE = (1 << 14);
	private static readonly uint MAX_LIT = (1 << 5);
	private static readonly uint MAX_OFF = (1 << 13);
	private static readonly uint MAX_REF = ((1 << 8) + (1 << 3));
	
	/// 
	/// Hashtable, that can be allocated only once
	/// 
	private static readonly long[] HashTable = new long[HSIZE];
	
	// Compresses inputBytes
	public static byte[] Compress(byte[] inputBytes)
	{
		// Starting guess, increase it later if needed
		int outputByteCountGuess = inputBytes.Length * 2;
		byte[] tempBuffer = new byte[outputByteCountGuess];
		int byteCount = lzf_compress (inputBytes, ref tempBuffer);
		
		// If byteCount is 0, then increase buffer and try again
		while (byteCount == 0)
		{
			outputByteCountGuess *=2;
			tempBuffer = new byte[outputByteCountGuess];
			byteCount = lzf_compress (inputBytes, ref tempBuffer);
		}
		
		byte[] outputBytes = new byte[byteCount];
		Buffer.BlockCopy(tempBuffer, 0, outputBytes, 0, byteCount);
		return outputBytes;
	}
	
	// Decompress outputBytes
	public static byte[] Decompress(byte[] inputBytes)
	{
		// Starting guess, increase it later if needed
		int outputByteCountGuess = inputBytes.Length * 2;
		byte[] tempBuffer = new byte[outputByteCountGuess];
		int byteCount = lzf_decompress (inputBytes, ref tempBuffer);
		
		// If byteCount is 0, then increase buffer and try again
		while (byteCount == 0)
		{
			outputByteCountGuess *=2;
			tempBuffer = new byte[outputByteCountGuess];
			byteCount = lzf_decompress (inputBytes, ref tempBuffer);
		}
		
		byte[] outputBytes = new byte[byteCount];
		Buffer.BlockCopy(tempBuffer, 0, outputBytes, 0, byteCount);
		return outputBytes;
	}
	
	/// 
	/// Compresses the data using LibLZF algorithm
	/// 
	/// Reference to the data to compress
	/// Reference to a buffer which will contain the compressed data
	/// The size of the compressed archive in the output buffer
	public static int lzf_compress(byte[] input, ref byte[] output)
	{
		int inputLength = input.Length;
		int outputLength = output.Length;
		
		Array.Clear(HashTable, 0, (int)HSIZE);
		
		long hslot;
		uint iidx = 0;
		uint oidx = 0;
		long reference;
		
		uint hval = (uint)(((input[iidx]) << 8) | input[iidx + 1]); // FRST(in_data, iidx);
		long off;
		int lit = 0;
		
		for (; 😉
		{
			if (iidx < inputLength - 2)
			{
				hval = (hval << 8) | input[iidx + 2];
				hslot = ((hval ^ (hval <> (int)(((3 * 8 - HLOG)) - hval * 5) & (HSIZE - 1));
				reference = HashTable[hslot];
				HashTable[hslot] = (long)iidx;
				
				
				if ((off = iidx - reference - 1) < MAX_OFF
				    && iidx + 4  0
				    && input[reference + 0] == input[iidx + 0]
				    && input[reference + 1] == input[iidx + 1]
				    && input[reference + 2] == input[iidx + 2]
				    )
				{
					/* match found at *reference++ */
					uint len = 2;
					uint maxlen = (uint)inputLength - iidx - len;
					maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
					
					if (oidx + lit + 1 + 3 >= outputLength)
						return 0;
					
					do
						len++;
					while (len < maxlen && input[reference + len] == input[iidx + len]);
					
					if (lit != 0)
					{
						output[oidx++] = (byte)(lit - 1);
						lit = -lit;
						do
							output[oidx++] = input[iidx + lit];
						while ((++lit) != 0);
					}
					
					len -= 2;
					iidx++;
					
					if (len > 8) + (len <> 8) + (7 << 5));
						output[oidx++] = (byte)(len - 7);
					}
					
					output[oidx++] = (byte)off;
					
					iidx += len - 1;
					hval = (uint)(((input[iidx]) << 8) | input[iidx + 1]);
					
					hval = (hval << 8) | input[iidx + 2];
					HashTable[((hval ^ (hval <> (int)(((3 * 8 - HLOG)) - hval * 5) & (HSIZE - 1))] = iidx;
					iidx++;
					
					hval = (hval << 8) | input[iidx + 2];
					HashTable[((hval ^ (hval <> (int)(((3 * 8 - HLOG)) - hval * 5) & (HSIZE - 1))] = iidx;
					iidx++;
					continue;
				}
			}
			else if (iidx == inputLength)
				break;
			
			/* one more literal byte we must copy */
			lit++;
			iidx++;
			
			if (lit == MAX_LIT)
			{
				if (oidx + 1 + MAX_LIT >= outputLength)
					return 0;
				
				output[oidx++] = (byte)(MAX_LIT - 1);
				lit = -lit;
				do
					output[oidx++] = input[iidx + lit];
				while ((++lit) != 0);
			}
		}
		
		if (lit != 0)
		{
			if (oidx + lit + 1 >= outputLength)
				return 0;
			
			output[oidx++] = (byte)(lit - 1);
			lit = -lit;
			do
				output[oidx++] = input[iidx + lit];
			while ((++lit) != 0);
		}
		
		return (int)oidx;
	}
	
	
	/// 
	/// Decompresses the data using LibLZF algorithm
	/// 
	/// Reference to the data to decompress
	/// Reference to a buffer which will contain the decompressed data
	/// Returns decompressed size
	public static int lzf_decompress(byte[] input, ref byte[] output)
	{
		int inputLength = input.Length;
		int outputLength = output.Length;
		
		uint iidx = 0;
		uint oidx = 0;
		
		do
		{
			uint ctrl = input[iidx++];
			
			if (ctrl < (1 < outputLength)
				{
					//SET_ERRNO (E2BIG);
					return 0;
				}
				
				do
					output[oidx++] = input[iidx++];
				while ((--ctrl) != 0);
			}
			else /* back reference */
			{
				uint len = ctrl >> 5;
				
				int reference = (int)(oidx - ((ctrl & 0x1f) < outputLength)
				{
					//SET_ERRNO (E2BIG);
					return 0;
				}
				
				if (reference < 0)
				{
					//SET_ERRNO (EINVAL);
					return 0;
				}
				
				output[oidx++] = output[reference++];
				output[oidx++] = output[reference++];
				
				do
					output[oidx++] = output[reference++];
				while ((--len) != 0);
			}
		}
		while (iidx < inputLength);
		
		return (int)oidx;
	}
	
}