public void CompressVoxelData( ushort[] data, out byte[] result, out int bytes_used )
{
BitStream stream = new BitStream();
int len = data.Length;
int n;
List<ushort> types = new List<ushort>();
for( n = 0; n < len; n++ )
{
if( !types.Contains( data[n] ) )
types.Add( data[n] );
}
int bits = BitStream.GetMinBitsNeededForValue( types.Count - 1 ); // 4 is 0,1,2,3; needs only 2 bits...
//bits = (bits + 7 ) & 0xf8;
stream.Seek( 16 ); // seek bit count
stream.Write( (byte)bits, 8 );
stream.Write( (uint)types.Count-1, bits );
foreach( ushort type in types )
stream.Write( type, 16 );
ushort prior_cube = 0xFFFF, cube;
uint index = 0;
int count = 0;
for( n = 0; n < len; n++ )
{
cube = data[n];
if( prior_cube != cube )
{
if( count > 0 )
WriteCubes( stream, bits, (uint)count, index );
index = (uint)types.IndexOf( cube );
prior_cube = cube;
count = 1;
}
else
count++;
}
WriteCubes( stream, bits, (uint)count, index );
stream.GetBytes( out result, out bytes_used );
result[0] = (byte)(( bytes_used ) & 0xFF);
result[1] = (byte)( ( bytes_used ) >> 8);
if( bytes_used < 20 )
return;
MemoryStream final_stream = new MemoryStream();
final_stream.Seek( 2, SeekOrigin.Begin );
//DeflateStream gz_stream = new DeflateStream( final_stream, CompressionMode.Compress );
//GZipStream gz_stream = new GZipStream( final_stream, CompressionMode.Compress );
GZipStream gz_stream = new GZipStream( final_stream, CompressionLevel.Fastest );
//for( n = 2; n < bytes_used; n++ )
// gz_stream.WriteByte( result[n] );
gz_stream.Write( result, 2, bytes_used - 2 );
gz_stream.Close();
result = final_stream.ToArray();//.GetBuffer();
Log.log( "Compressed another {0}%", (float)( 100.0f * (float)( bytes_used - result.Length ) / ( bytes_used - 2 ) ) );
// store old length so we know how much to request decompressing.
result[0] = (byte)( ( bytes_used ) & 0xFF );
result[1] = (byte)( ( bytes_used ) >> 8 );
bytes_used = result.Length;// (int)final_stream.Length;
gz_stream.Dispose();
}
