Add mousewheel support

UWP/App.cpp

@@ -136,10 +136,8 @@ void App::OnPointerCaptureLost(Windows::UI::Core::CoreWindow^ sender, Windows::U
 
 void App::OnPointerWheelChanged(Windows::UI::Core::CoreWindow^ sender, Windows::UI::Core::PointerEventArgs^ args) {
 	int pointerId = args->CurrentPoint->PointerId;
-	float X = args->CurrentPoint->Position.X;
-	float Y = args->CurrentPoint->Position.Y;
-	int64_t timestamp = args->CurrentPoint->Timestamp;
-	m_main->OnTouchEvent(TOUCH_WHEEL, pointerId, X, Y, timestamp);
+	float delta = args->CurrentPoint->GetCurrentPoint(args->CurrentPoint->PointerId)->Properties->MouseWheelDelta;
+	m_main->OnMouseWheel(delta);
 }
 
 // Initializes scene resources, or loads a previously saved app state.

UWP/PPSSPP_UWPMain.cpp

@@ -212,6 +212,21 @@ void PPSSPP_UWPMain::OnKeyUp(int scanCode, Windows::System::VirtualKey virtualKe
 	}
 }
 
+void PPSSPP_UWPMain::OnMouseWheel(float delta) {
+	int key = NKCODE_EXT_MOUSEWHEEL_UP;
+	if (delta < 0) {
+		key = NKCODE_EXT_MOUSEWHEEL_DOWN;
+	} else if (delta == 0) {
+		return;
+	}
+
+	KeyInput keyInput{};
+	keyInput.keyCode = key;
+	keyInput.deviceId = DEVICE_ID_MOUSE;
+	keyInput.flags = KEY_DOWN | KEY_UP;
+	NativeKey(keyInput);
+}
+
 void PPSSPP_UWPMain::OnTouchEvent(int touchEvent, int touchId, float x, float y, double timestamp) {
 	// It appears that Windows' touchIds start from 1. Let's fix that.
 	touchId--;

UWP/PPSSPP_UWPMain.h

@@ -49,6 +49,8 @@ public:
 
 	void OnTouchEvent(int touchEvent, int touchId, float x, float y, double timestamp);
 
+	void OnMouseWheel(float delta);
+
 	// Save state fast if we can!
 	void OnSuspend();
 	void Close();