Refactor IID logic into marshaller type

src/ComputeSharp.UI/ComputeSharp.UI.projitems

@@ -17,7 +17,7 @@
  <Compile Include="$(MSBuildThisFileDirectory)Extensions\IDXGIAdapterExtensions.cs" />
  <Compile Include="$(MSBuildThisFileDirectory)Extensions\SemaphoreSlimExtensions.cs" />
  <Compile Include="$(MSBuildThisFileDirectory)Helpers\DynamicResolutionManager.cs" />
- <Compile Include="$(MSBuildThisFileDirectory)Helpers\SwapChainManager.IID.cs" />
+ <Compile Include="$(MSBuildThisFileDirectory)Helpers\SwapChainPanelNativeMarshaller.cs" />
  <Compile Include="$(MSBuildThisFileDirectory)Helpers\SwapChainManager.cs" />
  <Compile Include="$(MSBuildThisFileDirectory)Helpers\SwapChainManager.Rendering.cs" />
  <Compile Include="$(MSBuildThisFileDirectory)IFrameRequestQueue.cs" />

src/ComputeSharp.UI/Helpers/SwapChainManager.cs

@@ -20,7 +20,6 @@
 using Windows.System;
 using Windows.UI.Xaml.Controls;
 #endif
-using WinRT;
 
 #if WINDOWS_UWP
 namespace ComputeSharp.Uwp.Helpers;
@@ -233,7 +232,7 @@ public SwapChainManager(TOwner owner, GraphicsDevice device)
  // IDXGISwapChain reference just created and set that as the swap chain panel to use.
  fixed (ISwapChainPanelNative** swapChainPanelNative = this.swapChainPanelNative)
  {
- ((IWinRTObject)owner).NativeObject.TryAs(*IID_ISwapChainPanelNative, out *(nint*)swapChainPanelNative).Assert();
+ SwapChainPanelNativeMarshaller.GetNativeObject(owner, swapChainPanelNative);
  }
 
  // Get the underlying ID3D12Device in use

src/ComputeSharp.UI/Helpers/SwapChainPanelNativeMarshaller.cs

@@ -0,0 +1,68 @@
+using System;
+using System.Runtime.CompilerServices;
+using ComputeSharp.Core.Extensions;
+using ComputeSharp.Win32;
+#if !WINDOWS_UWP
+using Microsoft.UI.Xaml.Controls;
+#endif
+using System.Runtime.InteropServices;
+#if WINDOWS_UWP
+using Windows.UI.Xaml.Controls;
+#endif
+using WinRT;
+
+#if WINDOWS_UWP
+namespace ComputeSharp.Uwp.Helpers;
+#else
+namespace ComputeSharp.WinUI.Helpers;
+#endif
+
+/// <summary>
+/// A helper type to handle marshalling <see cref="SwapChainPanel"/> objects for native interop.
+/// </summary>
+internal static unsafe class SwapChainPanelNativeMarshaller
+{
+ /// <summary>
+ /// Retrieves the underlying <see cref="ISwapChainPanelNative"/> object for an input <see cref="SwapChainPanel"/> instance.
+ /// </summary>
+ /// <param name="managedObject">The input <see cref="SwapChainPanel"/> instance to unwrap.</param>
+ /// <param name="nativeObject">A pointer to the resulting <see cref="ISwapChainPanelNative"/> object to retrieve.</param>
+ public static void GetNativeObject(SwapChainPanel managedObject, ISwapChainPanelNative** nativeObject)
+ {
+#if WINDOWS_UWP
+ ReadOnlySpan<byte> data =
+ [
+ 0xD2, 0x19, 0x2F, 0xF9,
+ 0xDE, 0x3A,
+ 0xA6, 0x45,
+ 0xA2,
+ 0x0C,
+ 0xF6,
+ 0xF1,
+ 0xEA,
+ 0x90,
+ 0x55,
+ 0x4B
+ ];
+#else
+ ReadOnlySpan<byte> data =
+ [
+ 0xB8, 0xD0, 0xAA, 0x63,
+ 0x24, 0x7C,
+ 0xFF, 0x40,
+ 0x85,
+ 0xA8,
+ 0x64,
+ 0x0D,
+ 0x94,
+ 0x4C,
+ 0xC3,
+ 0x25
+ ];
+#endif
+ // Unwrap and get the 'ISwapChainPanelNative' interface with the right IID depending on the UI framework
+ ((IWinRTObject)managedObject).NativeObject.TryAs(
+ iid: Unsafe.As<byte, Guid>(ref MemoryMarshal.GetReference(data)),
+ ppv: out *(nint*)nativeObject).Assert();
+ }
+}