diff --git a/code/explosions.cpp b/code/explosions.cpp
index 483c929..f748eff 100644
--- a/code/explosions.cpp
+++ b/code/explosions.cpp
@@ -58,6 +58,11 @@ void addEngine(object *craft)
 	addExplosion(x, y, E_TINY_EXPLOSION);
 }
 
+static bool isOnScreen(int x, int y, int w, int h)
+{
+	return (x + w > 0) && (x < 800) && (y + h > 0) && (y < 600);
+}
+
 /*
 Loops through active explosions and decrements their think time.
 If their thinktime is divisable by 5, then the frame is changed to
diff --git a/code/graphics.cpp b/code/graphics.cpp
index 38f7f18..450f977 100644
--- a/code/graphics.cpp
+++ b/code/graphics.cpp
@@ -737,11 +737,3 @@ void doStarfield()
 		SDL_UnlockSurface(screen);
 	}
 }
-
-int isOnScreen(int x, int y, int w, int h)
-{
-	if ((x + w > 0) && (x < 800) && (y + h > 0) && (y < 600))
-		return 1;
-		
-	return 0;
-}
diff --git a/code/graphics.h b/code/graphics.h
index 6473475..f3c20fa 100644
--- a/code/graphics.h
+++ b/code/graphics.h
@@ -79,4 +79,3 @@ extern void freeGraphics();
 
 extern SDL_Surface *loadImage(const char *filename);
 extern void doStarfield();
-extern int isOnScreen(int x, int y, int w, int h);