diff --git a/ag.cc b/ag.cc
index 6e7e1fc..2728ed2 100644
--- a/ag.cc
+++ b/ag.cc
@@ -24,8 +24,10 @@ namespace ag
             { "println", println },
             { "loadModel", loadModel },
             { "loadStaticModel", loadStaticModel },
+#if 0
             { "videoStart", videoStart },
             { "videoStop", videoStop },
+#endif
             { "sleep", sleep },
             { "startFrame", startFrame },
             { "endFrame", endFrame },
@@ -161,6 +163,7 @@ namespace ag
         loadModelSpecify(L, true);
     }
 
+#if 0
     int videoStart(lua_State * L)
     {
         g_engine->getVideo()->start();
@@ -172,6 +175,7 @@ namespace ag
         g_engine->getVideo()->stop();
         return 0;
     }
+#endif
 
     int sleep(lua_State * L)
     {
diff --git a/anaglym.cc b/anaglym.cc
index 639762b..6a7aeac 100644
--- a/anaglym.cc
+++ b/anaglym.cc
@@ -17,6 +17,8 @@ static void usage();
 
 Engine * g_engine;
 
+SDL_Event Engine::userEvent;
+
 static void usage()
 {
     cerr << "Usage: anaglym [options] program.lua[c]" << endl;
@@ -52,8 +54,8 @@ int main(int argc, char * argv[])
     }
 
     g_engine = new Engine();
-    g_engine->load(program);
-    g_engine->run();
+    if (g_engine->load(program))
+        g_engine->run();
     delete g_engine;
 
     return 0;
@@ -72,10 +74,18 @@ Engine::Engine()
     m_up[0] = 0;
     m_up[1] = 0;
     m_up[2] = 1;
+    m_drawing = false;
+
+    /* setup redraw SDL event structure */
+    userEvent.type = SDL_USEREVENT;
+    userEvent.user.code = 0;
+    m_video->start();
 }
 
 Engine::~Engine()
 {
+    m_video->stop();
+    lua_close(m_luaState);
     for (std::map<int, Object *>::iterator it = m_objects.begin();
          it != m_objects.end();
          it++)
@@ -99,7 +109,7 @@ bool Engine::load(const char * program)
 
     int s = luaL_loadfile(m_luaState, program);
 
-    if ( s == 0 )
+    if (s == 0)
     {
         // execute Lua program
         s = lua_pcall(m_luaState, 0, LUA_MULTRET, 0);
@@ -107,11 +117,16 @@ bool Engine::load(const char * program)
     else
     {
         cerr << "Warning: problem loading '" << program << "'" << endl;
-        return 1;
+        return false;
     }
 
-    reportErrors(s);
-    lua_close(m_luaState);
+    if (s != 0)
+    {
+        reportErrors(s);
+        return false;
+    }
+
+    return true;
 }
 
 void Engine::reportErrors(int status)
@@ -231,8 +246,68 @@ int Engine::setCamera(lua_State * L)
     return 0;
 }
 
+/* called by SDL when the update timer expires */
+Uint32 Engine::updateCallback(Uint32 interval, void * param)
+{
+    Engine * engine = (Engine *) param;
+    return engine->updateCallback(interval);
+}
+
+/* member update function to be called by our registered
+ * SDL callback non-member function */
+Uint32 Engine::updateCallback(Uint32 interval)
+{
+    if (!m_drawing)
+    {
+        SDL_PushEvent(&userEvent);
+    }
+    return interval;
+}
+
 void Engine::run()
 {
+    /* register a screen redrawing SDL event */
+    SDL_AddTimer(20, &updateCallback, this);
+
+    SDL_Event event;
+    while (SDL_WaitEvent(&event))
+    {
+        switch (event.type)
+        {
+            case SDL_KEYDOWN:
+                switch (event.key.keysym.sym)
+                {
+                    case SDLK_ESCAPE:
+                        goto RET;
+                        break;
+                }
+                break;
+            case SDL_QUIT:
+                goto RET;
+                break;
+            case SDL_USEREVENT:
+                if (event.user.code == 0)
+                {
+                    update();
+                }
+                break;
+        }
+    }
+RET:
+    ;
+}
+
+void Engine::update()
+{
+    m_drawing = true;
+    lua_getfield(m_luaState, LUA_GLOBALSINDEX, "update");
+    if (lua_type(m_luaState, -1) == LUA_TFUNCTION)
+    {
+        int s = lua_pcall(m_luaState, 0, 0, 0);
+        reportErrors(s);
+    }
+    lua_pop(m_luaState, 1);
+    m_drawing = false;
 }
 
 void Engine::Object::loadPhy(const std::string & path, bool static_data)
diff --git a/anaglym.h b/anaglym.h
index be603b3..fcd5ed3 100644
--- a/anaglym.h
+++ b/anaglym.h
@@ -48,8 +48,13 @@ class Engine
         int setCamera(lua_State * L);
 
     protected:
+        static Uint32 updateCallback(Uint32 interval, void * param);
+        static SDL_Event userEvent;
+
+        Uint32 updateCallback(Uint32 interval);
         void registerLibraries();
         bool fileExists(const std::string & path);
+        void update();
 
         lua_State * m_luaState;
         Video *     m_video;
@@ -60,6 +65,7 @@ class Engine
         GLdouble    m_eye[3];
         GLdouble    m_center[3];
         GLdouble    m_up[3];
+        bool        m_drawing;
 };
 
 extern Engine * g_engine;