diff --git a/src/Draw.cpp b/src/Draw.cpp
index bea72ee7..9ae8dfd4 100644
--- a/src/Draw.cpp
+++ b/src/Draw.cpp
@@ -635,7 +635,7 @@ void PutBitmap4(const RECT *rcView, int x, int y, const RECT *rect, SurfaceID su
 	backbuffer->Blt(&rcSet, surf[surf_no], &rcWork, DDBLT_WAIT, NULL);
 }
 
-void Surface2Surface(int x, int y, const RECT *rect, int to, int from)
+void Surface2Surface(int x, int y, const RECT *rect, SurfaceID to, SurfaceID from)
 {
 	static RECT rcWork;
 	static RECT rcSet;
diff --git a/src/Draw.h b/src/Draw.h
index 80538220..61234437 100644
--- a/src/Draw.h
+++ b/src/Draw.h
@@ -54,7 +54,7 @@ BOOL MakeSurface_Generic(int bxsize, int bysize, SurfaceID surf_no, BOOL bSystem
 void BackupSurface(SurfaceID surf_no, const RECT *rect);
 void PutBitmap3(const RECT *rcView, int x, int y, const RECT *rect, SurfaceID surf_no);
 void PutBitmap4(const RECT *rcView, int x, int y, const RECT *rect, SurfaceID surf_no);
-void Surface2Surface(int x, int y, const RECT *rect, int to, int from);
+void Surface2Surface(int x, int y, const RECT *rect, SurfaceID to, SurfaceID from);
 unsigned long GetCortBoxColor(COLORREF col);
 void CortBox(const RECT *rect, unsigned long col);
 void CortBox2(const RECT *rect, unsigned long col, SurfaceID surf_no);