WoW:Using OnUpdate correctly: Difference between revisions

WoW:Using OnUpdate correctly (source)

Revision as of 23:33, 30 August 2005

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-first of all you have to have a main frame where you define the onUpdate function that will be called on every update. it is important, that this frame has the tags stated below ... hidden="false" toplevel="true", otherwise your function will not be called
+= How often is it called =
+The game engine will call your OnUpdate function approximately every 0.1 seconds (as defined by the UPDATE_DELAY [[WoW Constants]]).  This is usually more often then necessary, and executing your code so often will cause lag!  What you need to do is limit how often your OnUpdate code runs, strategies are outlined bellow.
--------------------------
+= When is it called =
-this is in your XML file.
+OnUpdate is not called on any hidden frames, only while they are shown on-screen.  OnUpdate will also never be called on a virtual frame, but will be called on any frames that inherit from one.
--------------------------
+= Proper Use Example =
+; your_xml_file.xml
+  <Ui ...>
    <Frame name="MyAddon_MainFrame" parent="UIParent" hidden="false" toplevel="true">
-     <Frames>
+     ...
-    </Frames>
      <Scripts>
-       <OnUpdate>
+       <OnUpdate> MyAddon_OnUpdate(elapsed); </OnUpdate>
-        MyAddon_OnUpdate(arg1);
-      </OnUpdate>
      </Scripts>
    </Frame>
+  </Ui>
--------------------------
+; your_lua_file.lua
-this is in your LUA file
--------------------------
-   MyAddon_LastUpdate = 0;
+   -- Globals Section
-   MyAddon_Update_Interval = 1; --the update interval in seconds
+   MyAddon_updateInterval = 1; -- how often my OnUpdate code will run
+  -- Functions Section
    function MyAddon_OnUpdate(elapsed)
-     MyAddon_LastUpdate = MyAddon_LastUpdate + elapsed;
+     this.timeSinceLastUpdate = this.timeSinceLastUpdate + elapsed;
-     if (MyAddon_LastUpdate > MyAddon_Update_Interval) then
+     if (this.timeSinceLastUpdate > MyAddon_updateInterval) then
-       MyAddon_LastUpdate = 0;
+       --
-       --do Stuff here
+       -- Insert your OnUpdate code here
+      --
+      this.timeSinceLastUpdate = 0;
      end
    end
-for '--do stuff here' you should insert your own sourcecode that should be run every 'MyAddon_Update_Interval' seconds. of course you should replace all function / variable names ( MyAddon_ ) with a unique string representing your addon.
+Insert your code at the '-- Insert your OnUpdate code here', and substitute the 'MyAddon_' with your addon's name.  You might also want to tweak your 'MyAddon_updateInterval' global variable to reflect how often your addon needs the code run, the less the better.  This solution also happens to be thread-safe, which is another issue when your code is being run every 0.1 seconds, finished or not.
+[[Category:HOWTOs]]