From ef948cf7fb6bb7c913692810e037812fdc4d4f54 Mon Sep 17 00:00:00 2001
From: cosmonaut <evan@moonside.games>
Date: Tue, 8 Dec 2020 17:20:10 -0800
Subject: [PATCH] add quaternion utility function

---
 Kav.Framework.csproj     |  2 +-
 Utils/QuaternionUtils.cs | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 Utils/QuaternionUtils.cs

diff --git a/Kav.Framework.csproj b/Kav.Framework.csproj
index 494053c..90aacaa 100644
--- a/Kav.Framework.csproj
+++ b/Kav.Framework.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
diff --git a/Utils/QuaternionUtils.cs b/Utils/QuaternionUtils.cs
new file mode 100644
index 0000000..2d12391
--- /dev/null
+++ b/Utils/QuaternionUtils.cs
@@ -0,0 +1,18 @@
+using Microsoft.Xna.Framework;
+
+namespace Kav.Utils
+{
+    public static class QuaternionUtils
+    {
+        // assumes that the input vectors are normalized and orthogonal
+        public static Quaternion LookAt(in Vector3 forward, in Vector3 up)
+        {
+            Matrix orientation = Matrix.Identity;
+            orientation.Forward = forward;
+            orientation.Right = Vector3.Normalize(Vector3.Cross(forward, up));
+            orientation.Up = Vector3.Cross(orientation.Right, forward);
+
+            return Quaternion.CreateFromRotationMatrix(orientation);
+        }
+    }
+}