fix bug #2 that causes crash after returning from UAC.

Plugins/uDesktopDuplication/uDesktopDuplication/Monitor.cpp

@@ -113,10 +113,11 @@ void Monitor::Render(UINT timeout)
 {
     if (!deskDupl_) return;
 
+    HRESULT hr;
     ComPtr<IDXGIResource> resource;
     DXGI_OUTDUPL_FRAME_INFO frameInfo;
 
-    const auto hr = deskDupl_->AcquireNextFrame(timeout, &frameInfo, &resource);
+    hr = deskDupl_->AcquireNextFrame(timeout, &frameInfo, &resource);
     if (FAILED(hr))
     {
         switch (hr)
@@ -191,9 +192,30 @@ void Monitor::Render(UINT timeout)
     UpdateMetadata(frameInfo);
     UpdateCursor(frameInfo);
 
-    if (FAILED(deskDupl_->ReleaseFrame()))
+    hr = deskDupl_->ReleaseFrame();
+    if (FAILED(hr))
     {
-        Debug::Error("Monitor::Render() => ReleaseFrame() failed.");
+        switch (hr)
+        {
+            case DXGI_ERROR_ACCESS_LOST:
+            {
+                Debug::Log("Monitor::Render() => DXGI_ERROR_ACCESS_LOST.");
+                state_ = State::AccessLost;
+                break;
+            }
+            case DXGI_ERROR_INVALID_CALL:
+            {
+                Debug::Error("Monitor::Render() => DXGI_ERROR_INVALID_CALL.");
+                break;
+            }
+            default:
+            {
+                state_ = State::Unknown;
+                Debug::Error("Monitor::Render() => Unknown Error.");
+                break;
+            }
+        }
+        return;
     }
 }