diff --git a/src/win32/fb_d3d9.cpp b/src/win32/fb_d3d9.cpp
index 9fd1854318..e232757344 100644
--- a/src/win32/fb_d3d9.cpp
+++ b/src/win32/fb_d3d9.cpp
@@ -1028,28 +1028,6 @@ bool D3DFB::IsFullscreen ()
 	return !Windowed;
 }
 
-//==========================================================================
-//
-// D3DFB :: ScaleCoordsFromWindow
-//
-// Given coordinates in window space, return coordinates in what the game
-// thinks screen space is.
-//
-//==========================================================================
-
-void D3DFB::ScaleCoordsFromWindow(SWORD &x, SWORD &y)
-{
-	RECT rect;
-
-	if (GetClientRect(Window, &rect))
-	{
-		x = SWORD(x * Width / (rect.right - rect.left));
-		y = SWORD(y * TrueHeight / (rect.bottom - rect.top));
-	}
-	// Subtract letterboxing borders
-	y -= (TrueHeight - Height) / 2;
-}
-
 //==========================================================================
 //
 // D3DFB :: Lock
diff --git a/src/win32/fb_ddraw.cpp b/src/win32/fb_ddraw.cpp
index ecf570ff88..2aa694f3b4 100644
--- a/src/win32/fb_ddraw.cpp
+++ b/src/win32/fb_ddraw.cpp
@@ -806,19 +806,6 @@ bool DDrawFB::Is8BitMode()
 	return vid_displaybits == 8;
 }
 
-void DDrawFB::ScaleCoordsFromWindow(SWORD &x, SWORD &y)
-{
-	RECT rect;
-
-	if (GetClientRect(Window, &rect))
-	{
-		x = SWORD(x * Width / (rect.right - rect.left));
-		y = SWORD(y * TrueHeight / (rect.bottom - rect.top));
-	}
-	// Subtract letterboxing borders
-	y -= (TrueHeight - Height) / 2;
-}
-
 bool DDrawFB::IsValid ()
 {
 	return PrimarySurf != NULL;
diff --git a/src/win32/win32iface.h b/src/win32/win32iface.h
index 9699157cd9..934931ea01 100644
--- a/src/win32/win32iface.h
+++ b/src/win32/win32iface.h
@@ -127,10 +127,12 @@ public:
 	virtual void Blank () = 0;
 	virtual bool PaintToWindow () = 0;
 	virtual HRESULT GetHR () = 0;
+	virtual void ScaleCoordsFromWindow(SWORD &x, SWORD &y);
 
 protected:
 	virtual bool CreateResources () = 0;
 	virtual void ReleaseResources () = 0;
+    virtual int GetTrueHeight() { return GetHeight(); }
 
 	bool Windowed;
 
@@ -165,7 +167,7 @@ public:
 	void NewRefreshRate();
 	HRESULT GetHR ();
 	bool Is8BitMode();
-	void ScaleCoordsFromWindow(SWORD &x, SWORD &y);
+    virtual int GetTrueHeight() { return TrueHeight; }
 
 	void Blank ();
 	bool PaintToWindow ();
@@ -270,7 +272,7 @@ public:
 	void WipeCleanup();
 	HRESULT GetHR ();
 	bool Is8BitMode() { return false; }
-	void ScaleCoordsFromWindow(SWORD &x, SWORD &y);
+    virtual int GetTrueHeight() { return TrueHeight; }
 
 private:
 	friend class D3DTex;
diff --git a/src/win32/win32video.cpp b/src/win32/win32video.cpp
index 3071ae8e72..8aa74bfb58 100644
--- a/src/win32/win32video.cpp
+++ b/src/win32/win32video.cpp
@@ -736,6 +736,29 @@ void Win32Video::SetWindowedScale (float scale)
 	// FIXME
 }
 
+//==========================================================================
+//
+// BaseWinFB :: ScaleCoordsFromWindow
+//
+// Given coordinates in window space, return coordinates in what the game
+// thinks screen space is.
+//
+//==========================================================================
+
+void BaseWinFB::ScaleCoordsFromWindow(SWORD &x, SWORD &y)
+{
+	RECT rect;
+
+	int TrueHeight = GetTrueHeight();
+	if (GetClientRect(Window, &rect))
+	{
+		x = SWORD(x * Width / (rect.right - rect.left));
+		y = SWORD(y * TrueHeight / (rect.bottom - rect.top));
+	}
+	// Subtract letterboxing borders
+	y -= (TrueHeight - Height) / 2;
+}
+
 //==========================================================================
 //
 // SetFPSLimit