Update README.md

README.md

@@ -21,6 +21,26 @@ Create a file named doomgeneric_yourplatform.c and just implement these function
 |DG_GetKey            |Provide keyboard events.
 |DG_SetWindowTitle    |Not required. This is for setting the window title as Doom sets this from WAD file.
 
+### main loop
+At start, call doomgeneric_Create().
+
+In a loop, call doomgeneric_Tick().
+
+In simplest form:
+```
+int main(int argc, char **argv)
+{
+    doomgeneric_Create(argc, argv);
+
+    while (1)
+    {
+        doomgeneric_Tick();
+    }
+    
+    return 0;
+}
+```
+
 # sound
 Sound is much harder to implement! If you need sound, take a look at SDL port. It fully supports sound and music! Where to start? Define FEATURE_SOUND, assign DG_sound_module and DG_music_module.