public static int GetHashBucket(PartialRow row, HashBucketSchema hashSchema, int maxSize)
{
Span <byte> buffer = stackalloc byte[maxSize];
EncodeColumns(row, hashSchema.ColumnIds, buffer, out int bytesWritten);
var slice = buffer.Slice(0, bytesWritten);
var hash = Murmur2.Hash64(slice, hashSchema.Seed);
var bucket = hash % (uint)hashSchema.NumBuckets;
return((int)bucket);
}
/// <summary>
/// Calculate a hash for all primitives in a group
/// </summary>
/// <param name="group"></param>
/// <returns></returns>
public ulong GetGroupHash(SceneObjectGroup group)
{
ulong hash = 5381;
var parts = group.GetParts().OrderBy(p => p.LinkNum);
foreach (var part in parts)
{
hash = Murmur2.Hash(GetPrimHash(part.Shape), hash);
}
return(hash);
}
private ulong GetGroupHash(GroupDisplayData group)
{
ulong groupHash = 5381;
foreach (var prim in group.Prims)
{
groupHash = Murmur2.Hash(prim.ShapeHash, groupHash);
groupHash = Murmur2.Hash(prim.MaterialHash, groupHash);
}
return(groupHash);
}
public ulong GetMaterialFaceHash(ulong hash, Primitive.TextureEntryFace teFace)
{
hash = Murmur2.Hash((ushort)teFace.Bump, hash);
hash = Murmur2.Hash((byte)(teFace.Fullbright ? 1 : 0), hash);
hash = Murmur2.Hash(BitConverter.GetBytes(teFace.Glow), hash);
hash = Murmur2.Hash((byte)(teFace.MediaFlags ? 1 : 0), hash);
hash = Murmur2.Hash(BitConverter.GetBytes(teFace.OffsetU), hash);
hash = Murmur2.Hash(BitConverter.GetBytes(teFace.OffsetV), hash);
hash = Murmur2.Hash(BitConverter.GetBytes(teFace.RepeatU), hash);
hash = Murmur2.Hash(BitConverter.GetBytes(teFace.RepeatV), hash);
hash = Murmur2.Hash(BitConverter.GetBytes(teFace.Rotation), hash);
hash = Murmur2.Hash(teFace.RGBA.GetBytes(), hash);
hash = Murmur2.Hash((byte)teFace.Shiny, hash);
hash = Murmur2.Hash((byte)teFace.TexMapType, hash);
hash = Murmur2.Hash(teFace.TextureID.GetBytes(), hash);
return(hash);
}
/// <summary>
/// Calculate a hash value over fields that can affect the underlying physics shape.
/// Things like RenderMaterials and TextureEntry data are not included.
/// </summary>
/// <param name="shape"></param>
/// <param name="lod"></param>
/// <returns>ulong - a calculated hash value</returns>
public ulong GetMeshShapeHash(PrimitiveBaseShape shape)
{
const DetailLevel lod = DetailLevel.Highest;
ulong hash = 5381;
hash = Murmur2.Hash(shape.PathCurve, hash);
hash = Murmur2.Hash((byte)((byte)shape.HollowShape | (byte)shape.ProfileShape), hash);
hash = Murmur2.Hash(shape.PathBegin, hash);
hash = Murmur2.Hash(shape.PathEnd, hash);
hash = Murmur2.Hash(shape.PathScaleX, hash);
hash = Murmur2.Hash(shape.PathScaleY, hash);
hash = Murmur2.Hash(shape.PathShearX, hash);
hash = Murmur2.Hash(shape.PathShearY, hash);
hash = Murmur2.Hash((byte)shape.PathTwist, hash);
hash = Murmur2.Hash((byte)shape.PathTwistBegin, hash);
hash = Murmur2.Hash((byte)shape.PathRadiusOffset, hash);
hash = Murmur2.Hash((byte)shape.PathTaperX, hash);
hash = Murmur2.Hash((byte)shape.PathTaperY, hash);
hash = Murmur2.Hash(shape.PathRevolutions, hash);
hash = Murmur2.Hash((byte)shape.PathSkew, hash);
hash = Murmur2.Hash(shape.ProfileBegin, hash);
hash = Murmur2.Hash(shape.ProfileEnd, hash);
hash = Murmur2.Hash(shape.ProfileHollow, hash);
// Include LOD in hash, accounting for endianness
byte[] lodBytes = new byte[4];
Buffer.BlockCopy(BitConverter.GetBytes((int)lod), 0, lodBytes, 0, 4);
if (!BitConverter.IsLittleEndian)
{
Array.Reverse(lodBytes, 0, 4);
}
hash = Murmur2.Hash(shape.ProfileHollow, hash);
// include sculpt UUID
if (shape.SculptEntry)
{
var sculptUuidBytes = shape.SculptTexture.GetBytes();
hash = Murmur2.Hash(sculptUuidBytes, hash);
hash = Murmur2.Hash(shape.SculptType, hash);
}
return(hash);
}
/// <summary>
/// Calculate a hash that takes both the prim shape and materials into account
/// </summary>
public ulong GetPrimHash(ulong hash, PrimitiveBaseShape shape, DetailLevel lod, FacetedMesh mesh, Primitive prim)
{
hash = Murmur2.Hash(GetMeshShapeHash(shape, lod), hash);
return(Murmur2.Hash(GetMeshMaterialHash(mesh, prim), hash));
}
/// <summary>
/// Calculate a hash that takes both the prim shape and materials into account
/// </summary>
public ulong GetPrimHash(ulong materialHash, ulong shapeHash)
{
return(Murmur2.Hash(materialHash, shapeHash));
}
public void TestMurmur2Hash64(string data, ulong seed, ulong expectedHash)
{
ulong hash = Murmur2.Hash64(data.ToUtf8ByteArray(), seed);
Assert.Equal(expectedHash, hash);
}
