Cheat Engine

[tuxlu]

Hi!

I'm trying to improve my skills in CheatEngine scripting, and I'd like to know about some of the "best practices" for scripting, or if I'm not reinventing the wheel.

TLDR: is creating an LUA script that manages autoassembly ones a good idea?

Right now, as I couldn't get pointer scanning to work with my game, I created an autoassembly script to retreive the pointer when it passes on the instruction I found with "Find out what writes at this address"

However thinking about doing a "clean" script, I wondered: "once I find the pointer, I don't need my autoassembly patch, I can disable it!"
But if I disable the autoassembly script, ideally I should deallocate my memory and unregister the symbols... So what do?

My solution was creating an LUA script, that will enable/disable the Autoassembly script when needed. workflow:

* - LUA script is enabled
* - registerSymbol of my variable (say "posX")
- enable the autoassembly script
I do it via `getAddressList().getMemoryRecordByDescription("scriptName").Active`
I know I could do it inside the LUA script via `autoassemble`, but I find it cleaner to read this way.
- on autoassembly Script:
- register a temporary symbol (say "xTemp")
- patch my instruction to read the register, and store it to "xTemp" symbol
of course, I also add offsets, and checks in case of shared instructions
- back on the LUA:
- I set a timer every 10th a second to check if "xTemp" is available and not null
- if available, I copy it's value to my LUA registered symbol "posX"
- Then I disable the autoassembly script and the timer.
- The disabling of the autoassembly script unregisters "xTemp" and repatches the game instructions.
- When I disable the LUA script, I clean all and unregister "posX" / disable the autoassembly script if still running.

The advantages for me are:
- It's more performant, as my autoassembly patch is automatically disabled when not needed anymore.
- It's surely a bit stealthier (not that I aimed specially for it)
- In my LUA script I can know when the pointer is available, and do more stuff/ enable additional LUA scripts accordingly (ex: hotkeys to teleport)


I don't know if my explanation is clear, I can provide a small code example if needed (I didn't included the code because I was afraid it would make it *less* clear ^^')
So, is it an "elegant" solution, is there a better one that was found?

Also small detail, I fail to see the difference between autoassembly scripts in LUA and the "Cheat Table LUA Script".
They work the same way, except that the "Cheat Table LUA Script" is autorunned at load and is the good place to put trainer specific code, am I right, or missing something?

Thanks again for the support, last time I asked a question here i got super fast insightful answers!
Also, I did a talk about game hacking, with a focus on CheatEngine, on a pretty big hacking conference in France! But Youtube replays won't be available until a few months :/

[ParkourPenguin]

That seems overly complicated to me. One alternative is to set a breakpoint on the instruction that will copy the address and remove itself when triggered, but I don't think you should be doing that in the first place. Keeping the code injection active is the best and "most elegant" solution IMO. I'm ignoring any games that try to protect themselves against external software since that's outside the scope of these forums.

[tuxlu]

thank you again so much for the fast and insightful answer!

Indeed, I may have overcomplicated my script and I overlooked the fact that the address coiuld change when reloading the level.

and indeed stealth was never the point of this approach, just wanted to justify myself on the advantages of doing it my way ^^'

I misunderstood a bit of your advice, I tought for a moment you implied the idea that you could sandwich some LUA code inside an ASM patch, like this:

[Dark Byte]

replace {$lua} with {$luacode}

[ParkourPenguin]

If you want the game to run some Lua code in CE synchronously within a code injection, use {$luacode}
https://forum.cheatengine.org/viewtopic.php?t=618134

A {$lua} block is basically a preprocessor macro for AA scripts. They run some Lua code and substitute any returned string into the location where the {$lua} block was located. Returning nothing is also fine.
Again, use a search engine to search the forums. There's plenty of examples.

[tuxlu]

damn, that's impressive, I had no idea you could do that.
I promise I'll read more of the wiki and check on the forum before asking any more questions.
Thanks again!