Game Window Cursor Clipping

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Revision as of 08:50, 7 January 2021 by LordOf Xen (talk | contribs) (Summary)
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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. Those games are only meant to be examples and might not do it in the way we'll do below.

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.
Note.png Note: If you prefer to move all of the existing panels and dialogs to Client, you won't need the clipping for VGUI panels. This focuses on projects willing to use the existing dialogs coming from GameUI.
Note.png Note: This is an incomplete sample. When the resolution gets changed, this will get broken. It will be updated as soon as possible.


  • 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 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, or -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.