Fix SteamVR not behaving properly when recentering is allowed

SiraUtil/SiraUtil.csproj

@@ -50,6 +50,7 @@
     <ItemGroup>
         <Reference Include="0Harmony">
             <HintPath>$(BeatSaberDir)\Libs\0Harmony.dll</HintPath>
+			<Private>False</Private>
         </Reference>
         <Reference Include="BeatSaber.Init">
             <HintPath>$(BeatSaberDir)\Beat Saber_Data\Managed\BeatSaber.Init.dll</HintPath>
@@ -131,6 +132,10 @@
             <HintPath>$(BeatSaberDir)\Beat Saber_Data\Managed\Unity.XR.Management.dll</HintPath>
             <Private>False</Private>
         </Reference>
+        <Reference Include="Unity.XR.OpenXR">
+            <HintPath>$(BeatSaberDir)\Beat Saber_Data\Managed\Unity.XR.OpenXR.dll</HintPath>
+			<Private>False</Private>
+        </Reference>
         <Reference Include="UnityEngine">
             <HintPath>$(BeatSaberDir)\Beat Saber_Data\Managed\UnityEngine.dll</HintPath>
             <Private>False</Private>

SiraUtil/Tweaks/DisableOpenXRRecentering.cs

@@ -0,0 +1,26 @@
+using HarmonyLib;
+using UnityEngine.XR.OpenXR;
+
+namespace SiraUtil.Tweaks
+{
+    /// <summary>
+    /// This patch fixes an issue with SteamVR where Unity will decide to not use SteamVR's room center
+    /// and instead try to invent its own origin, often resulting in the headset being under the floor.
+    /// This tends to happen when using FPFCToggle.
+    /// </summary>
+    /// <remarks>
+    /// This post explains the various possible OpenXR tracking spaces: <see href="https://discussions.unity.com/t/how-to-recenter-in-openxr/935209/9"/>
+    /// </remarks>
+    [HarmonyPatch(typeof(OpenXRLoaderBase), nameof(OpenXRLoaderBase.Initialize))]
+    internal static class DisableOpenXRRecentering
+    {
+        private static void Postfix(ref bool __result)
+        {
+            if (__result && OpenXRRuntime.name == "SteamVR/OpenXR")
+            {
+                Plugin.Log.Info("Disabling recentering");
+                OpenXRSettings.SetAllowRecentering(false, 0);
+            }
+        }
+    }
+}