public static Guid GenerateGuids(IEnumerable <ZipArchiveEntry> entries)
{
var stream = new MemoryStream();
foreach (var entry in entries.OrderBy(x => x.Name, StringComparer.Ordinal))
{
stream.Write(BitConverter.GetBytes(entry.CompressedLength), 0, 8);
stream.Write(BitConverter.GetBytes(entry.Length), 0, 8);
stream.Write(BitConverter.GetBytes(GetChecksum(entry)), 0, 4);
}
stream.Position = 0;
return(new Guid(HashBuilder.ComputeHash(stream)));
}
private void UpdateTriangulationHash()
{
using (var md5 = HashBuilder.CreateHashAlgorithm())
{
foreach (var mesh in Meshes)
{
var indices = mesh.GetTriangleIndices();
var block = new byte[indices.Length * sizeof(int)];
Buffer.BlockCopy(indices, 0, block, 0, block.Length);
md5.TransformBlock(block, 0, block.Length, block, 0);
}
md5.TransformFinalBlock(new byte[0], 0, 0);
Metadata.TriangulationHash = new Guid(md5.Hash);
}
}