saner frameskip logic

Author: warmist

docs/dev/Lua API.rst

@@ -6566,7 +6566,7 @@ Functions
 * ``setAnimationInfo(workshop_type, frames, frame_skip)``
 
   Animate workshop by replacing displayed tiles (or graphical tiles). There are two ways this works:
-  if ``frame_skip>=0`` then it shows each frame for ``frame_skip`` of frames or if ``frame_skip<0``
+  if ``frame_skip>0`` then it shows each frame for ``frame_skip`` of frames or if ``frame_skip<=0``
   Frames are synchronized with the machines this building is connected to.
 
   :workshop_type:   custom workshop string id, e.g. ``SOAPMAKER`` or numeric id

plugins/building-hacks.cpp

@@ -539,9 +539,7 @@ static int setAnimationInfo(lua_State* L)
     //animation
     loadFrames(L, def, 2);
     def.frame_skip = luaL_optinteger(L, 3, -1);
-    if (def.frame_skip == 0)
-        def.frame_skip = 1;
-    if (def.frame_skip < 0)
+    if (def.frame_skip <= 0)
         def.machine_timing = true;
     else
         def.machine_timing = false;