Manually changing the mouse sensitivity with windows hooks

William Hemsworth 1 2K Views

Heres a code that allows you to manually change the sensitivity of the mouse by using windows hooks.

/*
 *  Make sure project type is windows application
 */

#define _WIN32_WINNT 0x0500
#include<windows.h>
#include<cmath>

float sensitivity = 0.1f;


LRESULT CALLBACK mouseHookProc(int nCode, WPARAM wParam, LPARAM lParam) {

   // Let windows handle mouse clicks
   if (wParam != WM_MOUSEMOVE) {
      return CallNextHookEx(NULL, nCode, wParam, lParam);
   }

   // Get event information
   PMSLLHOOKSTRUCT p = reinterpret_cast<PMSLLHOOKSTRUCT>( lParam );

   // Old mouse location
   static float ox = static_cast<float>( p->pt.x );
   static float oy = static_cast<float>( p->pt.y );

   // Mouse location without sensitivity changed
   float x = static_cast<float>( p->pt.x );
   float y = static_cast<float>( p->pt.y );
   
   // New mouse location
   float nx = ox + (x - ox) * sensitivity;
   float ny = oy + (y - oy) * sensitivity;

   // Set cursor position
   SetCursorPos(
      static_cast<int>( nx ),
      static_cast<int>( ny )
   );

   // Set old location ready for next time
   ox = nx;
   oy = ny;

   return 1;
}

int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine,
                   int nShowCmd) {

   // Set mouse hook
   HHOOK mouseHook = SetWindowsHookEx(
                  WH_MOUSE_LL,      /* Type of hook */
                  mouseHookProc,    /* Hook process */
                  hInstance,        /* Instance */
                  NULL);

   // Wait for user to exit
   MessageBox(NULL, "Press OK to close.", "", MB_OK);
   return 0;
}
Member Avatar for William Hemsworth
William Hemsworth 1,339 Posting Virtuoso

Small bug when using a higher sensitivity, to fix it, add this function at the beginning. (line 10)

int round(float a) {
   return int(a + 0.5f);
}

and on line 36 & 37, change them to this.

round( nx ),
round( ny )

Now the mouse doesn't jump about unexpectedly.

Member Avatar for mksafi
mksafi 0 Newbie Poster

This doesn't even compile in Visual C++ Express.

1>c:\path\visual studio 2008\projects\two\two\two.cpp(63) : error C2664: 'MessageBoxW' : cannot convert parameter 2 from 'const char [19]' to 'LPCWSTR'

Member Avatar for William Hemsworth
William Hemsworth 1,339 Posting Virtuoso

That's because you've not set up your compiler properly, don't blame the code. Turn off UNICODE then try compiling again.

Member Avatar for CppBuilder2006
CppBuilder2006 -5 Junior Poster

Thanks. I needed such a program!
but it has an error in my Borland compiler. to fix the error instead of:

HHOOK mouseHook = SetWindowsHookEx(
                  WH_MOUSE_LL,      /* Type of hook */
                 mouseHookProc,    /* Hook process */
                  hInstance,        /* Instance */
				  NULL);

write:

HHOOK mouseHook = SetWindowsHookEx(
                  WH_MOUSE_LL,      /* Type of hook */
                  (HOOKPROC)mouseHookProc,    /* Hook process */
                  hInstance,        /* Instance */
				  NULL);

And do you have a program for hooking keyboard? or the shell?

Member Avatar for Freaky_Chris
Freaky_Chris 299 Master Poster

@CppBuilder

I'd recommend getting an upto date compiler. You might find that they work properly then ;)

Member Avatar for CppBuilder2006
CppBuilder2006 -5 Junior Poster

I'd recommend getting an upto date compiler

I have a 2006 version! ;)

Member Avatar for William Hemsworth
William Hemsworth 1,339 Posting Virtuoso

And do you have a program for hooking keyboard? or the shell?

Look at my other snippets, indeed I do ;]

I dont mind any changes people make to the code if it makes it compatiable with a wider range of compilers.

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