Cheat Engine

Attack · Posted: Fri Feb 06, 2015 9:24 pm Post subject: if x do aobscan?

I don't know if this is possible. I need to do an aobscan, but only if I have set a flag.

Reason is, the character structure is not created until the level is loaded. So I set a flag for when the code is executed that creates the pointer, so that I know not to alter the value until then.
Does the aobscan always execute or only if I put it behind a cmp je?

I'm asking because at the moment it doesn't work and I am thinking it may be because of the aobscan.

Otherwise I am facing a different challenge. If the table is activated too late, i.e. level is already loaded, then the code I am attaching to won't set the flag... so I need another thing where I can do an aobscan and if it fails, set a flag, but AFAIK, if the aobscan fails, the script doesn't work?

Is it time to use LUA?

Geri · Moderator Reputation: 111 Joined: 05 Feb 2010 Posts: 5636

aobscan is executed when you try to enable the script. And if aobscan will find nothing, the script will not be enabled at all.

Attack · Posted: Fri Feb 06, 2015 9:35 pm Post subject:

++METHOS · Posted: Fri Feb 06, 2015 9:54 pm Post subject:

Why can't the flags be used after the level is loaded? What are you checking against?

Attack · Posted: Fri Feb 06, 2015 10:11 pm Post subject:

SteveAndrew · Posted: Fri Feb 06, 2015 10:17 pm Post subject:

Yeah, and why not just test if the pointer is null before trying to use it? That usually works for most games.

ex.

Attack · Posted: Fri Feb 06, 2015 10:30 pm Post subject:

I didn't know about that. Would've saved me some hours. Oh well, I learnt how to do some things the hard way.

Can I get some more insight on your code? What I want is a code that keeps trying until it can enable itself. As far as I can tell, you just have to keep trying to enable what you wrote until it works?
I don't want to create an infinite loop, just a script that waits to run until it can.

Though I may have just made a realization while typing this. I can edit the code, and people will become invincible after the first hit. Then I don't need to worry about anything else. Not as nice as I would like it, but it'll do.

EDIT: As for your edits. I was really just looking at a piece of code that runs every level that changes the value of the pointer. I never bothered to find the actual pointer as it wasn't necessary anymore at that point.
The only problem that can arise now is that the pointer, once set initially, will remain until the new level loads. An issue for another time.

Script 1 cannot be enabled because it checks a flag. Or more accurately, if enabled and flag is 0, it does nothing. Runs the same code on enable and disable. Script 0 runs all the real clean up.

++METHOS · Posted: Fri Feb 06, 2015 10:43 pm Post subject:

I'm having a hard time following. First, what you're describing regarding the invincibility is indicative of using 'what writes' as opposed to 'what accesses' when using the debugger to check addresses.

Second, are you checking a pointer by manually adding it to the script, or from the register, or from a pointer tree inside a data structure?

You should be able to do as SteveAndrew suggests, and just check that pointer to see if it's any good, and if it is, allow your custom code to run. Better yet, don't use any pointers, and just use multiple scripts.

SteveAndrew · Posted: Fri Feb 06, 2015 10:57 pm Post subject:

Yeah it's not an infinite loop, it's more like everytime your hooked code runs it determines whether the pointer you captured is able to be written to. If your first script has gotten the pointer it will use it, if not you execute the game's original code and jump back (jmp returnhere).

It's never a good idea to trap one of the game's running threads and hold it in an infinite loop. (except rare circumstances which I can't even think of one right now)

So say the game's code is: (for your second script / script 1)

Attack · Posted: Sat Feb 07, 2015 12:19 am Post subject:

Steve, you just gave me a different idea, basically adding what you suggested into my script 0. As that only runs on level load, I will do all my stuff regarding altering the value there. Why I didn't do this before is beyond me. I feel like a retard. It's such a simple solution. I am already hooking into something that runs after level load, creates the pointer, and thus executing my value change afterwards will be fine. Duh.
Now I just need to figure out what my pointer is, because originally I was going to use an aobscan.