From d861518d2ed34aa13757791a690741f3d43f38ed Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Mon, 27 Jun 2022 23:33:51 +0200
Subject: [PATCH] Add origin updating for LargeWorlds

---
 Source/Engine/Level/Level.cpp     |  3 +++
 Source/Engine/Tests/TestLevel.cpp | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+)
 create mode 100644 Source/Engine/Tests/TestLevel.cpp

diff --git a/Source/Engine/Level/Level.cpp b/Source/Engine/Level/Level.cpp
index 0e35e9dac..983b814e1 100644
--- a/Source/Engine/Level/Level.cpp
+++ b/Source/Engine/Level/Level.cpp
@@ -50,6 +50,9 @@ void LargeWorlds::UpdateOrigin(Vector3& origin, const Vector3& position)
 {
     if (Enable)
     {
+        constexpr Real chunkSizeInv = 1.0 / ChunkSize;
+        constexpr Real chunkSizeHalf = ChunkSize * 0.5;
+        origin = Vector3(Int3((position - chunkSizeHalf) * chunkSizeInv)) * ChunkSize;
     }
 }
 
diff --git a/Source/Engine/Tests/TestLevel.cpp b/Source/Engine/Tests/TestLevel.cpp
new file mode 100644
index 000000000..830868a1d
--- /dev/null
+++ b/Source/Engine/Tests/TestLevel.cpp
@@ -0,0 +1,18 @@
+// Copyright (c) 2012-2022 Wojciech Figat. All rights reserved.
+
+#include "Engine/Core/Math/Vector3.h"
+#include "Engine/Level/LargeWorlds.h"
+#include <ThirdParty/catch2/catch.hpp>
+
+TEST_CASE("LargeWorlds")
+{
+    SECTION("UpdateOrigin")
+    {
+        LargeWorlds::Enable = true;
+        Vector3 origin = Vector3::Zero;
+        LargeWorlds::UpdateOrigin(origin, Vector3::Zero);
+        CHECK(origin == Vector3::Zero);
+        LargeWorlds::UpdateOrigin(origin, Vector3(LargeWorlds::ChunkSize * 0.5, LargeWorlds::ChunkSize * 1.0001, LargeWorlds::ChunkSize * 1.5));
+        CHECK(origin == Vector3(0, 0, LargeWorlds::ChunkSize * 1));
+    }
+}