diff --git a/Engine.cc b/Engine.cc
index 22bf17c..c61550b 100644
--- a/Engine.cc
+++ b/Engine.cc
@@ -61,13 +61,6 @@ Engine * g_engine;
 
 /* static helper functions */
 
-static void cross_product(dVector3 result, dVector3 first, dVector3 second)
-{
-    result[0] = first[1] * second[2] - first[2] * second[1];
-    result[1] = first[2] * second[0] - first[0] * second[2];
-    result[2] = first[0] * second[1] - first[1] * second[0];
-}
-
 static void debug_hook(lua_State * L, lua_Debug * debug)
 {
     g_engine->debug_hook(debug);
@@ -714,7 +707,7 @@ refptr< vector<Engine::PickedObjectRef> > Engine::pickObjects(int x, int y)
     forward[0] = m_center[0] - m_eye[0];
     forward[1] = m_center[1] - m_eye[1];
     forward[2] = m_center[2] - m_eye[2];
-    cross_product(right, forward, up);
+    dCROSS(right, =, forward, up);
     dRFrom2Axes(r, right[0], right[1], right[2],
             forward[0], forward[1], forward[2]);
     initial_direction[0] = x - m_av.getWidth() / 2;
@@ -749,7 +742,7 @@ Engine::PickedObjectRef Engine::pickOne(int x, int y, Engine::Object *obj)
     forward[0] = m_center[0] - m_eye[0];
     forward[1] = m_center[1] - m_eye[1];
     forward[2] = m_center[2] - m_eye[2];
-    cross_product(right, forward, up);
+    dCROSS(right, =, forward, up);
     dRFrom2Axes(r, right[0], right[1], right[2],
             forward[0], forward[1], forward[2]);
     initial_direction[0] = x - m_av.getWidth() / 2;
diff --git a/Engine_Object.cc b/Engine_Object.cc
index b9d9c88..68c8312 100644
--- a/Engine_Object.cc
+++ b/Engine_Object.cc
@@ -25,15 +25,6 @@ static void checkGLErrorLine(const char * function, int line)
 
 #define FP_EQ(a,b) (fabsf(a - b) < 0.0001)
 
-/* static helper functions */
-
-static void cross_product(dVector3 result, dVector3 first, dVector3 second)
-{
-    result[0] = first[1] * second[2] - first[2] * second[1];
-    result[1] = first[2] * second[0] - first[0] * second[2];
-    result[2] = first[0] * second[1] - first[1] * second[0];
-}
-
 /* used for objects loaded directly from model files */
 Engine::Object::Object(bool is_static, bool is_reference, bool enable_blending,
         OdeWorld & world, WFObj * obj, float scale)
@@ -374,8 +365,8 @@ void Engine::Object::render()
                 dVector3 cross_vec;
                 for (int i = 0; i < 3; i++)
                     cross_vec[i] = (i == min_component) ? 1 : 0;
-                cross_product(rotated_x, normal, cross_vec);
-                cross_product(rotated_y, normal, rotated_x);
+                dCROSS(rotated_x, =, normal, cross_vec);
+                dCROSS(rotated_y, =, normal, rotated_x);
                 x_o = normal[0] * d;
                 y_o = normal[1] * d;
                 z_o = normal[2] * d;