Cheat Engine

dexter3 · Newbie cheater Reputation: 0 Joined: 19 Jul 2018 Posts: 10

I'm writing a Lua script that is based off of the main Settings form. I'm getting odd behavior that I can't seem to resolve - I haven't yet concluded if this is a bug or if I'm just doing something wrong. I'd appreciate any help!

Basically, what's happening is I have a form that should show when a checkbox is checked in the main Settings form. The form very briefly appears, but disappears almost immediately (it seems to disappear as soon as all the code is done executing). The form is not closing, nor is it hiding. It is getting destroyed or crashing altogether? I'm not sure.

You can replicate it with this:

TheyCallMeTim13 · Posted: Sun Jul 29, 2018 5:27 am Post subject:

Yeah, seems that the thread your form is running on gets killed when the settings form closes, so I think you will need to create a thread to allow your form to continue running.

https://wiki.cheatengine.org/index.php?title=Lua:Class:Thread

ParkourPenguin · Posted: Sun Jul 29, 2018 9:41 am Post subject:

I can't replicate it. The window is shown and stays until closed. There are other bugs:

The OnClose function of the form should return caHide so it doesn't free itself when it's closed. Alternatively, create a new form every time the settings form is closed. Just don't access freed memory.
It won't show the form if the checkbox was already checked before the settings form is opened.
Checking and unchecking the checkbox will still show the form.
If the settings form is created when opened and destroyed when closed, your cached references to the GUI elements won't be valid. (although, the checkbox wouldn't exist either, so this probably isn't a problem)

PS: This has absolutely nothing to do with threads.

dexter3 · Newbie cheater Reputation: 0 Joined: 19 Jul 2018 Posts: 10

Thank you guys. @ParkourPenguin, I am really disappointed that you can't replicate this. It persists even across a restart on my computer. Did you place the script into a file in the autorun directory or run it directly?

I am aware of the other bugs and have handled them in the main script.

@TheyCallMeTim13 I also am feeling that this is not really threads, I have tried threading it and calling or synchronizing a thread just does the same thing. I am not an expert on threads though.

I changed the last function to this

Dark Byte · Posted: Sun Jul 29, 2018 1:47 pm Post subject:

autoclosing only happens on things with popupmode set (or have it as a parent/owner)

dexter3 · Newbie cheater Reputation: 0 Joined: 19 Jul 2018 Posts: 10

Thanks DarkByte Smile

but I don't believe popupmode is set:

print(getSettingsForm().PopupMode) --> prints pmNone

PopupMode is not set on any of the other involved elements either, unless I'm understanding incorrectly.

ParkourPenguin · Posted: Sun Jul 29, 2018 3:32 pm Post subject:

dexter3 · Newbie cheater Reputation: 0 Joined: 19 Jul 2018 Posts: 10

Thank you so much for your effort. I have been reducing the problem as much as possible. Here is everything I've done:

1. Reinstalled Cheat Engine
2. Tried both 32 and 64 bit versions
3. Removed all other scripts from autorun directory
4. I removed the checkbox altogether, and just made the form show when the OK button is pressed
5. Tried changing return value of OnClose event
6. Tried putting a print statement in OnClose event - nothing ever prints
7. Created a timer and printed out all the properties of the form before and after it is shown. The only thing that changes is the width
8. Tried doing this in "Advanced Options" form - it worked fine
9. If I show and then hide the form right after I create it, it works (but this is a weird workaround, and doesn't solve other problems I'm having)
10. Tried your script
11. Tried creating a form every time the OK button is pressed -doesn't work
[EDIT:] 12. If I hide the Settings Form rather than using the built-in OnClose function, the form remains visible and can be closed, but then my CE bugs out and I cannot close CE without using the Task Manager. So maybe the Settings OnClose function has something to do with this.

And this is exactly what happens:
1. I click OK - the form shows up very briefly but disappears along with the Settings Form
2. The Main CE window get pushed behind any other windows behind it (like my browser)
3. I cannot open the form again without restarting CE - it just won't show
4. No OnClose function is called, so I would assume the form is destroyed, but it is also not destroyed because I can't even create another new form

I also found something very strange!
1. If I click the "Enable Process Watcher" checkbox (in the extra tab) when I first start CE (remember my checkbox doesn't even exist anymore), the form shows and stays! It doesn't matter if the box is already checked or not.
2. But once I close it I still cannot open it again (even with return caHide), regardless if I check the box again
3. this time I do get an OnClose event
4. With this the Main CE Form does not hide behind the other windows below it
5. This works exactly the same with any other checkbox

Maybe now you're convinced this problem is CE and not the code, lol

EDIT: Progress

Alrighty I got it to work by using this:

ParkourPenguin · Posted: Sun Jul 29, 2018 6:23 pm Post subject:

dexter3 · Newbie cheater Reputation: 0 Joined: 19 Jul 2018 Posts: 10

No, it still disappears immediately after unfortunately.

Could you explain what you mean by reentrant?

And even if that is the case, what would cause them to be reentrant for you, but not me?

Edit: Okay, I was wrong before. The reason why the code with only the button worked is because I had a print statement as well. I didn't think it was influencing the outcome.

ParkourPenguin · Posted: Sun Jul 29, 2018 7:22 pm Post subject:

"Reentrant" basically means a function can be interrupted and still do what it's suppose to do. In this case, the OnClick callback function is being interrupted by calling a function to show another form. The process of showing another form can have side effects on the application as a whole, which might cause undefined behaviour if the OnClick callback wasn't expecting those side effects to happen.

Undefined behaviour is what it sounds like: anything can happen. It can work exactly as expected for some people, fail miserably for other people, or even open a portal to another dimension occupied by entities that will enslave humanity. Regardless of what happens, it's never a good thing and should be avoided if at all possible.

I'm not saying reentrancy is without a doubt the problem- it could be an unrelated bug.

Another total shot in the dark, but try this:

dexter3 · Newbie cheater Reputation: 0 Joined: 19 Jul 2018 Posts: 10

Great explanation! You could be right... it does fit the premise of the problem so far. Would there be some way we could check if the functions are reentrant?

I tried processMessages() and it didn't change anything. frmExample.bringToFront() in every location in the function did nothing, but sfrm.bringToFront() stopped the main CE window from going behind my other windows after I clicked OK.

Yeah, those are pretty hacky solutions. I already have a hacky solution to this, but that's why I brought it up here - I wanted to know what's really happening.

But interestingly, your timer solution works. In fact, I could even set the interval to 1ms and it seems to be working? So strange. I'll use this for now, and perhaps I'll pm you if I have any questions about it. I'm super grateful for your input, thank you Smile

ParkourPenguin · Posted: Sun Jul 29, 2018 8:57 pm Post subject:

I can't think of any good way of checking it besides looking at documentation (I haven't found anything yet).

The main thread is responsible for running that timer's code. Since the main thread can't run that code immediately, it has to finish executing the callback and closing the modal form. This means your form will only be shown after the settings form has closed completely (and not while the settings form is in the process of closing).

Creating the timer in the callback probably doesn't cause any problems because timers aren't significantly related to the GUI. Although, again, that's just a hypothesis.