From ce4df857e9e64ebba8cae69a0a37f3b934e2a543 Mon Sep 17 00:00:00 2001
From: Alan Liu <alanliu90@gmail.com>
Date: Wed, 10 Aug 2022 16:26:42 +0800
Subject: [PATCH] Fixed an issue that deserialized guids in SpriteAtlas and
 Sprite don't match the value in Unity

---
 AssetStudio/Classes/Sprite.cs      |  2 +-
 AssetStudio/Classes/SpriteAtlas.cs |  2 +-
 AssetStudio/UnityGuidHelper.cs     | 28 ++++++++++++++++++++++++++++
 3 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 AssetStudio/UnityGuidHelper.cs

diff --git a/AssetStudio/Classes/Sprite.cs b/AssetStudio/Classes/Sprite.cs
index 752794f5..653ee08f 100644
--- a/AssetStudio/Classes/Sprite.cs
+++ b/AssetStudio/Classes/Sprite.cs
@@ -233,7 +233,7 @@ public Sprite(ObjectReader reader) : base(reader)
 
             if (version[0] >= 2017) //2017 and up
             {
-                var first = new Guid(reader.ReadBytes(16));
+                var first = UnityGuidHelper.UnityGuidToGuid(reader.ReadBytes(16));
                 var second = reader.ReadInt64();
                 m_RenderDataKey = new KeyValuePair<Guid, long>(first, second);
 
diff --git a/AssetStudio/Classes/SpriteAtlas.cs b/AssetStudio/Classes/SpriteAtlas.cs
index c1a97c5c..d1c0a329 100644
--- a/AssetStudio/Classes/SpriteAtlas.cs
+++ b/AssetStudio/Classes/SpriteAtlas.cs
@@ -63,7 +63,7 @@ public SpriteAtlas(ObjectReader reader) : base(reader)
             m_RenderDataMap = new Dictionary<KeyValuePair<Guid, long>, SpriteAtlasData>(m_RenderDataMapSize);
             for (int i = 0; i < m_RenderDataMapSize; i++)
             {
-                var first = new Guid(reader.ReadBytes(16));
+                var first = UnityGuidHelper.UnityGuidToGuid(reader.ReadBytes(16));
                 var second = reader.ReadInt64();
                 var value = new SpriteAtlasData(reader);
                 m_RenderDataMap.Add(new KeyValuePair<Guid, long>(first, second), value);
diff --git a/AssetStudio/UnityGuidHelper.cs b/AssetStudio/UnityGuidHelper.cs
new file mode 100644
index 00000000..f067a9b4
--- /dev/null
+++ b/AssetStudio/UnityGuidHelper.cs
@@ -0,0 +1,28 @@
+using System;
+using System.Buffers.Binary;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AssetStudio
+{
+    class UnityGuidHelper
+    {
+        public static Guid UnityGuidToGuid(byte[] data, int offset = 0)
+        {
+            for (int i = 0; i < 16; ++i)
+            {
+                data[i + offset] = (byte)(((data[i + offset] & 0xF0) >> 4) | ((data[i + offset] & 0x0F) << 4));
+            }
+
+            int d1 = BinaryPrimitives.ReadInt32BigEndian(new ReadOnlySpan<byte>(data, offset, 4));
+            short d2 = BinaryPrimitives.ReadInt16BigEndian(new ReadOnlySpan<byte>(data, offset + 4, 2));
+            short d3 = BinaryPrimitives.ReadInt16BigEndian(new ReadOnlySpan<byte>(data, offset + 6, 2));
+
+            return new Guid(d1, d2, d3,
+                data[offset + 8], data[offset + 9], data[offset + 10], data[offset + 11],
+                data[offset + 12], data[offset + 13], data[offset + 14], data[offset + 15]);
+        }
+    }
+}