version 2.3.0

com.htc.upm.vive.openxr/Runtime/Common/ViveInterceptors.cs

@@ -0,0 +1,83 @@
+// Copyright HTC Corporation All Rights Reserved.
+using System.Runtime.InteropServices;
+using System;
+using UnityEngine;
+using AOT;
+
+namespace VIVE.OpenXR
+{
+	/// <summary>
+	/// This class is made for all features that need to intercept OpenXR API calls.
+	/// Some APIs will be called by Unity internally, and we need to intercept them in c# to get some information.
+	/// Append more interceptable functions for this class by adding a new partial class.
+	/// The partial class can help the delegate name be nice to read and search.
+	/// Please create per function in one partial class.
+	/// 
+	/// For all features want to use this class, please call <see cref="HookGetInstanceProcAddr" /> in your feature class.
+	/// For example:
+	///     protected override IntPtr HookGetInstanceProcAddr(IntPtr func)
+	///     {
+	///         return HtcInterceptors.Instance.HookGetInstanceProcAddr(func);
+	///     }
+	/// </summary>
+	partial class ViveInterceptors
+	{
+		public const string TAG = "Interceptors";
+
+		public static ViveInterceptors instance = null;
+		public static ViveInterceptors Instance
+		{
+			get
+			{
+				if (instance == null)
+					instance = new ViveInterceptors();
+				return instance;
+			}
+		}
+
+		public ViveInterceptors()
+		{
+			Debug.Log("HtcInterceptors");
+		}
+
+		bool isInited = false;
+
+		public delegate XrResult DelegateXrGetInstanceProcAddr(XrInstance instance, string name, out IntPtr function);
+		private static readonly DelegateXrGetInstanceProcAddr hookXrGetInstanceProcAddrHandle = new DelegateXrGetInstanceProcAddr(XrGetInstanceProcAddrInterceptor);
+		private static readonly IntPtr hookGetInstanceProcAddrHandlePtr = Marshal.GetFunctionPointerForDelegate(hookXrGetInstanceProcAddrHandle);
+		static DelegateXrGetInstanceProcAddr XrGetInstanceProcAddrOriginal = null;
+
+		[MonoPInvokeCallback(typeof(DelegateXrGetInstanceProcAddr))]
+		private static XrResult XrGetInstanceProcAddrInterceptor(XrInstance instance, string name, out IntPtr function)
+		{
+			// Custom interceptors
+			if (name == "xrWaitFrame")
+			{
+				Debug.Log($"{TAG}: XrGetInstanceProcAddrInterceptor() {name} is intercepted.");
+				var ret = XrGetInstanceProcAddrOriginal(instance, name, out function);
+				if (ret == XrResult.XR_SUCCESS)
+				{
+					XrWaitFrameOriginal = Marshal.GetDelegateForFunctionPointer<DelegateXrWaitFrame>(function);
+					function = xrWaitFrameInterceptorPtr;
+				}
+				return ret;
+			}
+			return XrGetInstanceProcAddrOriginal(instance, name, out function);
+		}
+
+		public IntPtr HookGetInstanceProcAddr(IntPtr func)
+		{
+			Debug.Log($"{TAG}: registering our own xrGetInstanceProcAddr");
+			if (XrGetInstanceProcAddrOriginal == null)
+			{
+				XrGetInstanceProcAddrOriginal = Marshal.GetDelegateForFunctionPointer<DelegateXrGetInstanceProcAddr>(func);
+				isInited = true;
+				return hookGetInstanceProcAddrHandlePtr;
+			}
+			else
+			{
+				return func;
+			}
+		}
+	}
+}