fixing performance in BTD3
The classic Bloons Tower Defense 3 is known to lag badly, despite being a rather simple game. Here's how to fix it just in time for a Flash-discontinuation-nostalgia playthrough.cause
Strangely, Ninja Kiwi decided to add anENTER_FRAME handler to every single Bloon, unnecessarily causing thousands of event listeners to run concurrently each frame.
solution
Performance can be dramatically improved by using a singlefor loop instead.
prerequisites
- JPEXS Free Flash Decompiler
- Direct link to the BTD3 SWF on Ninja Kiwi's server
- Flash Player debug downloads, from which a standalone Flash Player and
playerglobal.swccan be acquired
decryption
Open the SWF in FFDec and find themochicrypt.Preloader script.
Add
import flash.net.FileReference; near the top.
Add
new FileReference().save(data); at the end of the finish() function.
Running the game should now prompt you to save a decrypted SWF.
BloonsTD patches
Open the decrypted SWF, navigate to theBloonsTD class, find the EnterFrame() function, and insert the following code at the start:
for(var i=0;this.bloonholder.numChildren>i;i++)
{
this.bloonholder.getChildAt(i).Update(null);
}
However, FFDec's direct AS3 editor will corrupt this script upon saving. Writing P-code (Flash assembly language) is difficult. The easiest solution is to make the change in AS3, copy the equivalent P-code (everything from
pushbyte 0 to the first ifgt), reload the SWF, and then re-insert the P-code.
Rename the
ofsXXXX labels in the pasted P-code, or they might collide with existing ones.
Bloon patches
FindBloon's constructor and click the addEventListener() call. Once again, editing the AS3 will cause corruption, so delete the call via P-code.
It's also necessary to make
Update() public so BloonsTD can call it. Change PackageInternalNs to PackageNamespace in the function's P-code's first line.