diff --git a/Engine.cc b/Engine.cc
index 6d4a6ab..90f931b 100644
--- a/Engine.cc
+++ b/Engine.cc
@@ -31,6 +31,8 @@ Engine::Engine(const string & path)
     m_up[2] = 1;
     m_drawing = false;
     m_autoPhysics = true;
+    m_autoStartFrame = true;
+    m_autoEndFrame = true;
 
     size_t pos = path.find_last_of("\\/");
     m_engine_path = (pos != string::npos) ? string(path, 0, pos) : ".";
@@ -165,7 +167,7 @@ Engine::Object * Engine::getObject(int id)
     return m_objects.find(id) != m_objects.end() ? m_objects[id] : NULL;
 }
 
-int Engine::startFrame(lua_State * L)
+void Engine::startFrame()
 {
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     glMatrixMode(GL_MODELVIEW);
@@ -173,13 +175,11 @@ int Engine::startFrame(lua_State * L)
     gluLookAt(m_eye[0], m_eye[1], m_eye[2],
               m_center[0], m_center[1], m_center[2],
               m_up[0], m_up[1], m_up[2]);
-    return 0;
 }
 
-int Engine::endFrame(lua_State * L)
+void Engine::endFrame()
 {
     SDL_GL_SwapBuffers();
-    return 0;
 }
 
 int Engine::setCamera(lua_State * L)
@@ -272,6 +272,8 @@ void Engine::update()
     m_drawing = true;
     if (m_autoPhysics)
         doPhysics();
+    if (m_autoStartFrame)
+        startFrame();
     lua_getfield(m_luaState, LUA_GLOBALSINDEX, "update");
     if (lua_type(m_luaState, -1) == LUA_TFUNCTION)
     {
@@ -283,6 +285,8 @@ void Engine::update()
     {
         lua_pop(m_luaState, 1);
     }
+    if (m_autoEndFrame)
+        endFrame();
     m_drawing = false;
 }
 
diff --git a/Engine.h b/Engine.h
index 43b460f..34e9862 100644
--- a/Engine.h
+++ b/Engine.h
@@ -62,10 +62,14 @@ class Engine
         void drawObjects();
         void setAutoPhysics(bool autoPhysics) { m_autoPhysics = autoPhysics; }
         bool getAutoPhysics() { return m_autoPhysics; }
+        void setAutoStartFrame(bool asf) { m_autoStartFrame = asf; }
+        bool getAutoStartFrame() { return m_autoStartFrame; }
+        void setAutoEndFrame(bool asf) { m_autoEndFrame = asf; }
+        bool getAutoEndFrame() { return m_autoEndFrame; }
+        void startFrame();
+        void endFrame();
 
         /* lua services */
-        int startFrame(lua_State * L);
-        int endFrame(lua_State * L);
         int setCamera(lua_State * L);
 
     protected:
@@ -93,6 +97,8 @@ class Engine
         GLdouble    m_up[3];
         bool        m_drawing;
         bool        m_autoPhysics;
+        bool        m_autoStartFrame;
+        bool        m_autoEndFrame;
 };
 
 extern Engine * g_engine;
diff --git a/ag.cc b/ag.cc
index ab5db3b..b205e26 100644
--- a/ag.cc
+++ b/ag.cc
@@ -33,6 +33,8 @@ namespace ag
             { "doPhysics", doPhysics },
             { "drawObjects", drawObjects },
             { "setAutoPhysics", setAutoPhysics },
+            { "setAutoStartFrame", setAutoStartFrame },
+            { "setAutoEndFrame", setAutoEndFrame },
             { NULL, NULL }
         };
         luaL_register(L, "ag", functions);
@@ -201,12 +203,14 @@ namespace ag
 
     int startFrame(lua_State * L)
     {
-        return g_engine->startFrame(L);
+        g_engine->startFrame();
+        return 0;
     }
 
     int endFrame(lua_State * L)
     {
-        return g_engine->endFrame(L);
+        g_engine->endFrame();
+        return 0;
     }
 
     int setCamera(lua_State * L)
@@ -235,15 +239,24 @@ namespace ag
     int setAutoPhysics(lua_State * L)
     {
         int argc = lua_gettop(L);
+        if (argc == 1 && lua_isboolean(L, 1))
+            g_engine->setAutoPhysics(lua_toboolean(L, 1));
+        return 0;
+    }
 
-        if (argc == 1)
-        {
-            if (lua_isboolean(L, 1))
-            {
-                g_engine->setAutoPhysics(lua_toboolean(L, 1));
-            }
-        }
+    int setAutoStartFrame(lua_State * L)
+    {
+        int argc = lua_gettop(L);
+        if (argc == 1 && lua_isboolean(L, 1))
+            g_engine->setAutoStartFrame(lua_toboolean(L, 1));
+        return 0;
+    }
 
+    int setAutoEndFrame(lua_State * L)
+    {
+        int argc = lua_gettop(L);
+        if (argc == 1 && lua_isboolean(L, 1))
+            g_engine->setAutoEndFrame(lua_toboolean(L, 1));
         return 0;
     }
 
diff --git a/ag.h b/ag.h
index df4abe1..333aae2 100644
--- a/ag.h
+++ b/ag.h
@@ -19,6 +19,8 @@ namespace ag
     int doPhysics(lua_State * L);
     int drawObjects(lua_State * L);
     int setAutoPhysics(lua_State * L);
+    int setAutoStartFrame(lua_State * L);
+    int setAutoEndFrame(lua_State * L);
 
     namespace object
     {
diff --git a/tests/ballstairs.lua b/tests/ballstairs.lua
index f7a181c..3919938 100755
--- a/tests/ballstairs.lua
+++ b/tests/ballstairs.lua
@@ -2,9 +2,7 @@
 function update()
     ballx, bally, ballz = ball:getPosition()
     ag.setCamera(7, -6, 15, ballx, bally, ballz, 0, 0, 1)
-    ag.startFrame()
     ag.drawObjects()
-    ag.endFrame()
 end
 
 --ag.setCamera(8, -8, 15, -8, 8, 4, 0, 0, 1)