Game Window Cursor Clipping

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This implementation allows you to clip the cursor to the game window such as in DOOM and DOOM Eternal (id Tech 6 - 7), also brings some fixes to various bugs on VGUI.

Note.png Note: This works only when the window is active, otherwise, the cursor will be unlocked automatically just as in the games specified above.


  • Knowledge of C++
  • Knowledge of Source Engine
  • Source SDK Base 2013 - Currently tested on Source SDK Base 2013 Multiplayer

Getting the Implementation/Code

First of all, you'll need the following files from the following GitHub repository:

Which you will copy to src/game/client/. You can also create a subfolder if you wish to, and copy these files there.


Now head over to cdll_client_int.cpp' and include

#include "CCursorClipManagement.h"

Anywhere before

// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"
Note.png Note: Note that if you copy the header to a subfolder, you gotta specify that in your #include

In the same cpp, find CHLClient::PostInit() and add this to the end:


Now find ind void OnRenderEnd() in the same cpp and add this to the end:


Once you're done with the steps above, head over to baseviewport.cpp and add the following:

#include "../CCursorClipManagement.h"


// our definition
#include "baseviewport.h"
#include <filesystem.h>
#include <convar.h>
#include "ienginevgui.h"
#include "iclientmode.h"


#include "tier0/etwprof.h"

Lastly, find CBaseViewport::OnScreenSizeChanged(int iOldWide, int iOldTall) and add this to the end:

Note.png Note: This must be updated accordingly to your changes on how CCursorClipManagement::Think() is being used.


You're all set! Compile your client project and check if it works.


  • If you start the game with -tools, -dev, -developer, and -nocursorclipping the cursor clipping will be disabled and won't work by default.
  • If you're compiling into a different platform, else than WIN32, the cursor clipping will be disabled and won't work by default.
  • You can also add a ConVar to enable or disable this dynamically in-game, all you'll need to do is adding one more check on CCursorClipManagement::Think().
  • If you do not want to check whether the window is active or not every time OnRenderEnd() gets called, you can also do this by hooking into window events/messages. Check SetWindowsHookExA.