Cheat Engine

Zander3709 · How do I cheat? Reputation: 0 Joined: 06 Aug 2019 Posts: 6

So I have been trying to make a game compatible with other aspect ratios besides 16:9 [1.78]. I have sucessfully managed to remove letterboxing and make the game show more on the sides of the screen. The side effect of this though is that the UI will be zoomed in. I already know how to decrease the UI size again, but wanted to apply this change automatically instead of using a fixed value like 21:9 [2.38]. The problem i am having is that if i insert a calculated value into the xmm register which is used to scale the UI, it doesn't work. But if i manually insert the exact same value, even in hex to avoid any decimal point difference, it works perfectly.

This is what i have by now:

ParkourPenguin · Posted: Thu Dec 19, 2019 12:33 pm Post subject:

What does the original code look like, as well as the code around the injection point?

May you post the full script instead of just a snippet?

Zander3709 · How do I cheat? Reputation: 0 Joined: 06 Aug 2019 Posts: 6

ParkourPenguin · Posted: Thu Dec 19, 2019 2:39 pm Post subject:

The aspectratio alloc isn't guaranteed to be located near the ui_newmem alloc. Directly addressing aspectratio might fail. You might get lucky and it'll be fine, but you should use the same third parameter for all the allocs all the same.

Also dealloc only takes a symbol (CE remembers how much it allocated).

Alternatively, remove that alloc entirely and use some of the memory in ui_newmem:

Zander3709 · How do I cheat? Reputation: 0 Joined: 06 Aug 2019 Posts: 6

Csimbi · Posted: Thu Dec 19, 2019 3:37 pm Post subject:

So, what do you need in that XMM register for this to work?
- int,
- float,
- or double?
The instructions you use are mixed while we don't actually see what's at the memory location when it works.

Zander3709 · How do I cheat? Reputation: 0 Joined: 06 Aug 2019 Posts: 6

ParkourPenguin · Posted: Thu Dec 19, 2019 4:05 pm Post subject:

Based on what you said did work in your first post, the only thing I can think of is that xmm3 doesn't hold the value you think it does. Or maybe you had another script active at the same time that messed things up. I can't tell what the problem is without debugging it.

This shouldn't fix the problem, but instead of xmm6, I'd use xmm8. xmm8 is immediately clobbered afterwards by movaps which means nothing is using it at the code injection. I can't see where xmm6 is used either, but that doesn't mean it isn't used.
If you insist on using xmm6, pxor isn't a good solution to restore it unless you can see that it's set to 0 on all code paths to the injection point. Back up the old value to some memory location and use that to restore it (e.g. sub rsp,10 / movups [rsp],xmm6 / movups xmm6,[rsp] / add rsp,10).

Edit: they're all floats; I don't know what Csimbi is referring to.

Zander3709 · How do I cheat? Reputation: 0 Joined: 06 Aug 2019 Posts: 6

ParkourPenguin · Posted: Thu Dec 19, 2019 5:05 pm Post subject:

Something different was happening when you had a breakpoint set. There are too many possibilities as to the reason why for any one to have notable significance... maybe it had something to do with which window was in focus, or an operation took a few microseconds longer with a breakpoint set.

The act of observing a program can change what the program does even if you yourself don't change anything.

Zander3709 · How do I cheat? Reputation: 0 Joined: 06 Aug 2019 Posts: 6