Add patch to fix UnityXRHelper exception when using FPFC

Auros · Nov 15, 2024 · f08a03c · f08a03c
1 parent 541b50c
commit f08a03c
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Showing 2 changed files with 61 additions and 4 deletions.
diff --git a/SiraUtil/SiraUtil.csproj b/SiraUtil/SiraUtil.csproj
@@ -151,10 +151,14 @@
             <HintPath>$(BeatSaberDir)\Beat Saber_Data\Managed\UnityEngine.ParticleSystemModule.dll</HintPath>
             <Private>False</Private>
         </Reference>
-        <Reference Include="UnityEngine.SpatialTracking">
-            <HintPath>$(BeatSaberDir)\Beat Saber_Data\Managed\UnityEngine.SpatialTracking.dll</HintPath>
-            <Private>False</Private>
-        </Reference>
+		<Reference Include="UnityEngine.SpatialTracking">
+			<HintPath>$(BeatSaberDir)\Beat Saber_Data\Managed\UnityEngine.SpatialTracking.dll</HintPath>
+			<Private>False</Private>
+		</Reference>
+		<Reference Include="UnityEngine.SubsystemsModule">
+			<HintPath>$(BeatSaberDir)\Beat Saber_Data\Managed\UnityEngine.SubsystemsModule.dll</HintPath>
+			<Private>False</Private>
+		</Reference>
         <Reference Include="UnityEngine.UI">
             <HintPath>$(BeatSaberDir)\Beat Saber_Data\Managed\UnityEngine.UI.dll</HintPath>
             <Private>False</Private>
@@ -186,6 +190,7 @@
         </Reference>
         <Reference Include="HMLib">
             <HintPath>$(BeatSaberDir)\Beat Saber_Data\Managed\HMLib.dll</HintPath>
+			<Publicize>True</Publicize>
             <Private>False</Private>
         </Reference>
         <Reference Include="HMUI">

diff --git a/SiraUtil/Tweaks/UnityXRHelperExceptionFixer.cs b/SiraUtil/Tweaks/UnityXRHelperExceptionFixer.cs
@@ -0,0 +1,52 @@
+using HarmonyLib;
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Reflection.Emit;
+using UnityEngine;
+using UnityEngine.XR;
+
+namespace SiraUtil.Tweaks
+{
+    [HarmonyPatch(typeof(UnityXRHelper), nameof(UnityXRHelper.Start))]
+    internal static class UnityXRHelperExceptionFixer
+    {
+        private static readonly MethodInfo XRInputSubsystemListIndexer = AccessTools.DeclaredMethod(typeof(List<XRInputSubsystem>), "get_Item");
+        private static readonly MethodInfo XRInputSubsystemListCountGetter = AccessTools.DeclaredPropertyGetter(typeof(List<XRInputSubsystem>), nameof(List<XRInputSubsystem>.Count));
+        private static readonly MethodInfo AddTrackingOriginUpdatedMethod = typeof(XRInputSubsystem).GetEvent(nameof(XRInputSubsystem.trackingOriginUpdated)).GetAddMethod();
+        private static readonly MethodInfo SubsystemManagerGetInstancesMethod = AccessTools.DeclaredMethod(typeof(SubsystemManager), nameof(SubsystemManager.GetInstances), generics: new Type[] { typeof(XRInputSubsystem) });
+
+        private static IEnumerable<CodeInstruction> Transpiler(IEnumerable<CodeInstruction> instructions, ILGenerator ilGenerator)
+        {
+            // Create a new local so we can store the XRInputSubsystem
+            LocalBuilder localBuilder = ilGenerator.DeclareLocal(typeof(XRInputSubsystem));
+
+            return new CodeMatcher(instructions, ilGenerator)
+                // Create a label after `xrInputSubsystem.trackingOriginUpdated += OnTrackingOriginUpdated;` (last use of xrInputSubsystem)
+                .MatchForward(
+                    true,
+                    new CodeMatch(i => i.Calls(AddTrackingOriginUpdatedMethod)))
+                .ThrowIfInvalid("`trackingOriginUpdated +=` not found")
+                .CreateLabelWithOffsets(1, out Label doneUsingInputSystemLabel)
+                // Backtrack to right after `new List<XRInputSubsystem>()`
+                .MatchBack(
+                    false,
+                    new CodeMatch(OpCodes.Dup),
+                    new CodeMatch(i => i.Calls(SubsystemManagerGetInstancesMethod)))
+                .ThrowIfInvalid("`SubsystemManager.GetInstances` not found")
+                // Replace `dup` with storing to & loading from our local variable
+                .SetAndAdvance(OpCodes.Stloc, localBuilder)
+                .InsertAndAdvance(new CodeInstruction(OpCodes.Ldloc, localBuilder))
+                // Move to after `SubsystemManager.GetInstances` call, right before `XRInputSubsystem xrInputSubsystem = list[0]`
+                .Advance(1)
+                // Insert the branching logic `if (list.Count > 0) { ... }`
+                .InsertAndAdvance(
+                    new CodeInstruction(OpCodes.Ldloc, localBuilder),
+                    new CodeInstruction(OpCodes.Callvirt, XRInputSubsystemListCountGetter),
+                    new CodeInstruction(OpCodes.Ldc_I4_0),
+                    new CodeInstruction(OpCodes.Ble, doneUsingInputSystemLabel),
+                    new CodeInstruction(OpCodes.Ldloc, localBuilder)) // This last ldloc be used by `XRInputSubsystem xrInputSubsystem = list[0]`
+                .InstructionEnumeration();
+        }
+    }
+}