Cheese's Mouse Fixes (05/05/2008)


BACKGROUND

The purpose of these fixes is to completely abolish any mouse acceleration imposed by *certain* application and games' utilization of the Windows cursor acceleration curve, regardless of whether "Enhance pointer precision" is disabled. It was previously believed that Windows itself forced the unwanted acceleration, but some newer games, not written with DirectInput (an API not prone to the problem in the first place), do not experience this problem; in games such as Call of Duty 4 and Challenge Q3 unchecking "Enhance pointer precision" results in *zero* forced acceleration. However, many popular games are still plagued by this problem and mouse fixes like these are still relevant today.

Windows' cursor acceleration curve dictates how much mouse scaling is applied to the output cursor movement based on how large, or fast, the inputs from the mouse are. This relationship, under ideal (and obtainable) circumstances would be 1-to-1--one count of the mouse (a mouse typically outputs anywhere from 400 to 2000 counts per inch, or DPI) sent to Windows is registered as the cursor moving one unit. A unit is represented on the Windows desktop by a pixel, but games represent a unit as an arbitrary number, defined by your sensitivity, that is added to a vector made up of large, high-precision, floating-point numbers, representing the direction your player is facing in-game.

The Windows acceleration curve is defined by five points on an X/Y graph rather than a continuous equation. The coordinates of these points are stored in two registry keys: SmoothMouseXCurve and SmoothMouseYCurve. The first point is always (0,0) and if any mouse movement goes beyond the finite definition of the curve, the curve is simply extrapolated using the last two points. The default curve roughly takes the shape of an exponential function, but if one were to change the curve to abolish mouse acceleration it would have to take the shape of a straight line. Also note that Windows scales the Y coordinates by the computer screen's refresh rate, typically 60Hz to 120Hz.

There have been two previous attempts by third-parties to fix this problem, both of which were succsessful but each had their own disadvantages. The first popular fix to come about was the "CPL mousefix", a .reg file that changed the acceleration curve to a mostly straight line. Aside from the *minute* imperfections in the acceleration curve, the Hz scaling effect, explained in the previous paragraph, causes the users sensitivity to scale in accordance with the screen's refresh rate. This means that cursor outputs using the CPL Mousfix are rarely, if ever, perfect 1-to-1 representations of the actual mouse's outputs. The imperfections in the line, in theory, cause inconsistant mouse movement, but they are so small they aren't noticable by anyone--thus the CPL mousefix does a perfectly decent job of eliminating all mouse acceleration.

The second fix is much more robust than the CPL Mousefix, or even my own. Anir's accelfix.exe works by removing mouse acceleration from the drivers that cause it in the first place. It's invasive, potentially unsafe in clumsy hands (absolute retards), and generally isn't allowed at non-BYOC LANs and Tournaments because of this. Otherwise, Anir's fix yeilds perfect 1-to-1 mouse movements under every circumstance.

My fix aims to fill the gap between the two. When used correctly, it will provide the 1-to-1 mouse movements of Anir's fix while operating on the widely accepted principles of the CPL mousefix. It works by having many different acceleration "curves" which, in this case, are *perfectly* straight lines that account for most screen refresh rates users game with and can be easily modified for the refresh rates I didn't include. I've included many other .reg files for other feels and testing purposes--read INSTRUCTIONS for explanations. Ideally, someone will come around, analyze my work, and code a program that can sit in the system tray and automatically change the acceleration graph when the screen's refresh rate changes on-the-fly. I see something like that as being a very strong fix that is acceptable by LANs and Tournaments.



INSTRUCTIONS

Double-click on the .reg file that applies to you, click "Yes", then "OK", then log off or reboot.


#.reg The 1-to-1, perfect line fixes, use whichever one is the refresh rate you game at.

cplModified.reg Use this if you are comfortable with the CPL mousefix. This corrects the small imperfections in the line which is now perfectly straight.

CPL.reg The original CPL mousefix.

windowsDefault.reg The default Windows acceleration curve.

flatLine.reg Use this to test if a game forces acceleration or not. Try this fix and turn Enhance pointer precision on--you'll see what I mean.



LINKS

Explanation of
Windows' pointer ballistics: Pointer Ballistics for Windows XP

Anir's fix: accelfix.exe

Email Cheese at cucook[at]gmail.com

1) Why should I use this?

Many gamers were having problems with unwanted mouse acceleration under Windows XP.
This was caused by a faulty API call ("SystemParametersInfo") which unintendedly enabled mouse acceleration even if it had been disabled previously.
There were some registry fixes aimed at disabling this acceleration, but they did not succeed.
This patcher does not try to solve the symptom like the registry fixes did, but disables mouse acceleration at its origin, the system driver ("win32k.sys").
If you have never noticed any unwanted mouse acceleration, you do not need to apply this patch.


2) Are there any risks or drawbacks involved?

Of course, mouse acceleration will be completely disabled, so not even the user (all accounts) will have optional mouse acceleration anymore.
Since this patcher is modifying an essential core component of Windows, there is a certain risk present, of course.
There is the (minimal) probability that this patcher corrupts "win32k.sys" and the whole operating system will crash.
If that happens you must restore the original file using the backup copy ("win32k.bak") generated by the patcher.


3) Will I still be able to restore previous settings?

Yes, simply run the patcher again and it will ask you for it.


4) What operating systems are supported?

The patcher is designed to be version-independent with anything from Windows 2000 and above.
It searches for a certain byte pattern and if found, modifies it - so it does not depend on static offsets.
It has been successfully tested on:
- Windows 2000
- Windows 2000 SP2
- Windows 2000 SP4
- Windows 2000 SP4 with Update Roll-Up 1
- Windows XP
- Windows XP SP1
- Windows XP SP2
- Windows Server 2003
- Windows Server 2003 SP1
(all languages, only i386 builds)

If you have Windows XP or Windows Server 2003 "x64 Edition",
you can download the patched "win32k.sys" here:
http://home.arcor.de/_aero/win32k_x64fix.zip (Version 5.2.3790.1830, English)


5) Will future versions of "win32k.sys" be compatible with this?

Yet I cannot predict the future, I think it is very likely this patcher will work with the majority of future versions.
It has been successfully tested with the most recent version of "win32k.sys" to date.
If you have an unsupported version of "win32k.sys", feel free to send me an e-mail (anir<AT>online.de).


6) Do I really need administrative privileges to perform this patch?

Yes, "win32k.sys" is a system file, so no restriced account will have the rights to modify it.
Once the patch has been applied, all user accounts will be affected.


7) Should I run this patcher in Safe Mode?

Windows File Protection (WFP) usually screens system files from being modified.
This patcher is designed to overcome WFP, so it should perfectly work in Normal Mode.
But if you want highest possible guaranty or encounter any WFP related problems, execute this patcher in Safe Mode.
There were some problem reports with "Windows Mouse Acceleration Fix" not working properly in Normal Mode.


8) Will my mouse driver <XYZ> be compatible with it?

If your driver works with the original version, then it will work with the modified one, too.
This patcher does not alter your mouse driver, so all data will remain the same.
It changes the way Windows translates your mouse (real) movement to cursor (virtual) movement disabling any capability of acceleration.


9) Will I still be able to adjust mouse sensitivity?

Yes, only the "Enhance Pointer Precision" will be rendered useless.


10) Should I still use or remove one of these registry fixes?

Once this patch is applied, the registry values will not have any influence anymore.
Consequently, it will not matter what registry fix you have or have not applied.


11) Out of a sudden, mouse acceleration is back again. What happened?

If you install system updates, "win32k.sys" may be replaced by newer versions.
Simply run the patcher again to get rid of the acceleration.


12) Will gaming league <XYZ> tolerate this patch?

I cannot speak for these leagues, but I do not think it will be regarded as cheating.
Ask the persons of contact about this subject.


13) I really like this patch and want to support you. Is there any way I can donate money or something?

I really appreciate your gratitude.
But if you want to donate money, please donate it to people who need it most: http://www.terredeshommes.org/



- anir (anir<AT>online.de)