Fix mouse when controlling through RDP (#309)

TestFramework/Input/Mouse.cpp

@@ -31,6 +31,7 @@ Mouse::Reset()
 void Mouse::ResetMouse()
 {
 	memset(&mMouseState, 0, sizeof(mMouseState));
+	mMousePosInitialized = false;
 	memset(&mDOD, 0, sizeof(mDOD));
 	mDODLength = 0;
 	mTimeLeftButtonLastReleased = 0;
@@ -110,6 +111,9 @@ void Mouse::Poll()
 {
 	JPH_PROFILE_FUNCTION();
 
+	// Remember last position
+	POINT old_mouse_pos = mMousePos;
+
 	// Get mouse position using the standard window call
 	if (!GetCursorPos(&mMousePos))
 	{
@@ -117,6 +121,13 @@ void Mouse::Poll()
 		return;
 	}
 
+	// If we lost mouse before, we need to reset the old mouse pos to the current one
+	if (!mMousePosInitialized)
+	{
+		old_mouse_pos = mMousePos;
+		mMousePosInitialized = true;
+	}
+
 	// Convert to window space
 	if (!ScreenToClient(mRenderer->GetWindowHandle(), &mMousePos))
 	{
@@ -136,6 +147,16 @@ void Mouse::Poll()
 			return;
 		}
 	}
+
+	// If we're connected through remote desktop then GetDeviceState returns faulty data for lX and lY so we need to use a fallback
+	if (GetSystemMetrics(SM_REMOTESESSION))
+	{
+		// Just use the delta between the current and last mouse position.
+		// Note that this has the disadvantage that you can no longer rotate any further if you're at the edge of the screen,
+		// but unfortunately a RDP session doesn't allow capturing the mouse so there doesn't seem to be a workaround for this.
+		mMouseState.lX = mMousePos.x - old_mouse_pos.x;
+		mMouseState.lY = mMousePos.y - old_mouse_pos.y;
+	}
 	
 	// Get the state in a buffer for checking doubleclicks	
 	if (FAILED(mMouse->GetDeviceData(sizeof(DIDEVICEOBJECTDATA), mDOD, &mDODLength, 0)))

TestFramework/Input/Mouse.h

@@ -54,6 +54,7 @@ private:
 	ComPtr<IDirectInput8>			mDI;
 	ComPtr<IDirectInputDevice8>		mMouse;
 	DIMOUSESTATE					mMouseState;
+	bool							mMousePosInitialized = false;
 	POINT							mMousePos;
 	DIDEVICEOBJECTDATA				mDOD[BUFFERSIZE];
 	DWORD							mDODLength;