Add wgc demo

demo/direct3d11.interop.h

@@ -0,0 +1,41 @@
+#pragma once
+#include <winrt/windows.graphics.directx.direct3d11.h>
+
+extern "C" {
+HRESULT __stdcall CreateDirect3D11DeviceFromDXGIDevice(
+    ::IDXGIDevice *dxgiDevice, ::IInspectable **graphicsDevice);
+
+HRESULT __stdcall CreateDirect3D11SurfaceFromDXGISurface(
+    ::IDXGISurface *dgxiSurface, ::IInspectable **graphicsSurface);
+}
+
+struct __declspec(uuid("A9B3D012-3DF2-4EE3-B8D1-8695F457D3C1"))
+    IDirect3DDxgiInterfaceAccess : ::IUnknown {
+  virtual HRESULT __stdcall GetInterface(GUID const &id, void **object) = 0;
+};
+
+inline auto CreateDirect3DDevice(IDXGIDevice *dxgi_device) {
+  winrt::com_ptr<::IInspectable> d3d_device;
+  winrt::check_hresult(
+      CreateDirect3D11DeviceFromDXGIDevice(dxgi_device, d3d_device.put()));
+  return d3d_device
+      .as<winrt::Windows::Graphics::DirectX::Direct3D11::IDirect3DDevice>();
+}
+
+inline auto CreateDirect3DSurface(IDXGISurface *dxgi_surface) {
+  winrt::com_ptr<::IInspectable> d3d_surface;
+  winrt::check_hresult(
+      CreateDirect3D11SurfaceFromDXGISurface(dxgi_surface, d3d_surface.put()));
+  return d3d_surface
+      .as<winrt::Windows::Graphics::DirectX::Direct3D11::IDirect3DSurface>();
+}
+
+template <typename T>
+auto GetDXGIInterfaceFromObject(
+    winrt::Windows::Foundation::IInspectable const &object) {
+  auto access = object.as<IDirect3DDxgiInterfaceAccess>();
+  winrt::com_ptr<T> result;
+  winrt::check_hresult(
+      access->GetInterface(winrt::guid_of<T>(), result.put_void()));
+  return result;
+}