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Glossary:Mouse acceleration

From PCGamingWiki, the wiki about fixing PC games

Mouse acceleration is often confused with mouse smoothing although these two are very different things:

Mouse acceleration is a setting where the cursor distances increases if the mouse is moved quickly.
Mouse smoothing is the interpolation of raw input data from the mouse in order to prevent jerky movement in low resolution mice.

Unfortunately developers are using these terms very loosely so in one game smoothing can mean acceleration, in another some completely different system for enhancing mouse movement.

Mouse smoothing

Mouse smoothing is the interpolation of raw input data from the mouse in order to prevent jerky movement in low resolution mice. The technique was originally created for opto-mechanical mice (more commonly know as ball mice) as these mice did not have a very high resolution (usually up to 400 DPI) so cursor movement appeared jerky - the cursor jumped few pixels each time. To prevent the jerky cursor movement mouse smoothing was introduced which allowed the system to interpolate raw data from the mouse and creating additional data points so the final mouse movement on the screen would be smoothed out.

This feature should not exist today as every mouse on the market has at least 800 DPI resolution, however it is still used in some games and some mouse manufacturers are using it to further increase the perceived DPI. Unfortunately is not easily detectable apart from mouse movement feeling weird.

Mouse acceleration

Mouse acceleration is a different system to enhance mouse movement. Distance of the cursor on the screen is highly dependent on the speed which mouse is moved. For example, a user moves their mouse 5 cm in 5 seconds and the cursor travels 200 pixels across the screen. With acceleration, if the mouse is moved by the same 5 cm but in 1 second, the cursor travels 1000 pixels - five times the distance of the slower movement.

This behaviour can be beneficial in desktop environment where you'd need low speeds for precision task (image editing) and simultaneously fast speeds for quickly moving cursor to the different parts of the screen. However it is highly undesirable in any game, where you are often in control of a camera. Every game will have different acceleration setting and it is impossible to achieve any consistent behaviour.

How to detect mouse acceleration in game

It is very easy to spot mouse acceleration in-game, as usually very fast mouse movement will result in several 360° rotations of the player's character. Follow the guide below to find out whether a game uses acceleration:

Mouse acceleration detection in FPS/TPS games[1]
  1. Launch the game and find a quiet area.
  2. Move the crosshair to a specific spot - edge of a building, distant window etc. This will be the starting point.
  3. Put a hand on the mousepad on one side of the mouse to create a barrier.
  4. Move the mouse slowly from the hand and create 90° or 180° rotation in-game. This movement should take more than 2 seconds.
  5. Now move the mouse back to the default position marked by the hand as fast as possible.
  6. If the crosshair ended up roughly on the same spot, the game does not feature acceleration. Usually when games use acceleration, the crosshair will end up on a vastly different location.

Types of mouse acceleration

There are two basic types of mouse acceleration: positive acceleration and negative acceleration.

Positive mouse acceleration

Positive mouse acceleration means that faster you are moving your mouse, farther cursor will travel on the screen. This is the most common implementation and you can find it in Windows (under Enhance pointer precision) and in many games. Some games let you even tweak strength of acceleration.

Negative mouse acceleration

Exactly opposite behavior - faster your mouse is moving, less distance cursor will travel. This is undesirable behavior and could indicate some sort of input or performance problem as game is dropping mouse input data, but more commonly mouse control implementation is botched and not tested properly. Examples are Dunia engine based games like Far Cry 3 or Far Cry 3 Blood Dragon where you need to increase polling rate within game data files.

Combination of positive and negative mouse acceleration

Rarely you can also encounter a combination of these two (example Remember Me, Watch_Dogs), where the game practically ignores low speed mouse movements and camera just staying still. Positive acceleration is applied to medium speed movements and there is also strong negative acceleration to high speed mouse movements.

Recommendations

While the setting is a personal choice, it is recommend that you disable mouse acceleration to provide a more consistent aim in more competitive titles. While playing without mouse acceleration may initially be difficult for players used to playing with it, after playing without it for some time most players become used to it, and often may see an improvement in the precision of their aim.

There are also ways to customize the acceleration levels of the mouse.[2]

If you want to be able to move the mouse around the screen with fewer swipes without enabling mouse acceleration, it is recommend that you pickup a gaming mouse with a high DPI sensor. This allows for the ability to move the cursor farther while keeping the cursor movement consistent.

Also it is almost impossible to achieve the same acceleration setting between different games as games rarely let users tweak acceleration strength.

The best option is to always use raw mouse input although not many game supports this feature. Raw input means the game is taking unchanged data directly from mouse drivers before it goes through operating system enhancements.

Issues fixed

Mouse lag in Windows 8.1

With Windows 8.1 Microsoft introduced new DPI scaling enhancements.[3] which is causing mouse lag and strange mouse behavior in games.[4][5][6]
Download Windows 8.1 update (KB2908279)
  1. Microsoft has fixed this issue in update (KB2908279)
Disable DPI scalling[4][6]
  1. Navigate to the game executable, right click on it and select properties.
  2. Navigate to the compatibility tab.
  3. Check Run this program in compatibility mode for and select Windows 8.
  4. Check Disable scaling on high DPI settings.
  5. Click OK to close the window.
Registry fix[citation needed]
  1. Download The MarkC Windows 8.1 + 8 + 7 Mouse Acceleration Fix.
  2. Set up your display DPI.
  3. Extract downloaded archive.
  4. Find corresponding .REG file for your system and DPI setting and run it.
  5. Reboot or log off to apply the fix.

Note: This will completely disable mouse acceleration for your system even in desktop environment.

Windows smooth mouse even if you disable pointer precision

Completely disable mouse smoothing[7]

1. Open regedit
2. Go to HKEY_CURRENT_USER\Control Panel\Mouse
3. Edit SmoothMouseXCurve hex value like below and save

00,00,00,00,00,00,00,00
00,a0,00,00,00,00,00,00
00,40,01,00,00,00,00,00
00,80,02,00,00,00,00,00
00,00,05,00,00,00,00,00

4. Edit SmoothMouseYCurve hex value like below and save

00,00,00,00,00,00,00,00
66,a6,02,00,00,00,00,00
cd,4c,05,00,00,00,00,00
a0,99,0a,00,00,00,00,00
38,33,15,00,00,00,00,00 

See also

Glossary:Mouse


References