Fix the mouse grabbing

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# 5. Fix the mouse grabbing

Fix the mouse hide problem.

The quake code, as it is, does not hide the mouse when you use it. The pointer would remain visible and jitter around a fixed point in the middle of the screen - very annoying. I found the following simple fix in a mail archive about glx development at: http://lists.openprojects.net/pipermail/glx-dev/1999-October/000994.html

See the patch listing and the link to download it below, or you can make the changes yourself.

    	cd q1src/QW/client
    	edit the file: gl_vidlinuxglx.c

At the top of the function called install_grabs(void) (Line 234), add the following code:

    	static void install_grabs(void)
    	{
    		/* vars to make blank cursor */
    		Pixmap blank;
    		XColor dummy;
    		char data[1] = {0};
    		Cursor cursor;

    		/* make a blank cursor */
    		blank = XCreateBitmapFromData (dpy, win, data, 1, 1);
    		if(blank == None) fprintf(stderr, "error: out of memory.\n");
    		cursor = XCreatePixmapCursor(dpy, blank, blank, &dummy, &dummy, 0, 0);
    		XFreePixmap (dpy, blank);
    		Con_Printf("Cursor blanked.\n");

The 8th parameter to XGrabPointer should be changed from "None" to "cursor" to use the blank cursor:

    	XGrabPointer(dpy, win,
    			 True,
    			 0,
    			 GrabModeAsync, GrabModeAsync,
    			 win,
    			 cursor,
    			 CurrentTime);

(see: man XGrabPointer)

This fix might work for the other client builds if you make similar changes in the appropriate *vid*.c file. As it is, this creates a memory leak as it allocates another Cursor object everytime through and doesn't call XFreeCursor() but this is probably not a problem since I don't think a 1x1 cursor is using much memory. If you want, you can apply the following patch against `q1src/QW/client/gl_vidlinuxglx.c` (patch gl_vidlinuxglx.c patchfile). Just cut and paste the contents between the begin/end patchfile lines into a file called gl_vidlinuxglx.c.patch (or whatever you want to call it). Save patchfile in the `q1src/QW/client` directory where gl_vidlinuxglx.c is. Then run the command:

    	patch gl_vidlinuxglx.c gl_vidlinuxglx.c.patch

This patch file will make gl_vidlinuxglx.c such that it doesn't have any memory leak. You can download this patch file at: http://www.comptechnews.com/~reaster/mini-HOWTO/LinuxGL-QuakeWorld-mini-HOWTO/gl_vidlinuxglx.c.patch.

    *************************** begin patchfile ************************************
    *** q1src-p/QW/client/gl_vidlinuxglx.c	Tue Dec 21 18:45:54 1999
    --- gl_vidlinuxglx.c	Sat Aug 19 20:47:42 2000
    ***************
    *** 1,22 ****
    ! /*
    ! Copyright (C) 1996-1997 Id Software, Inc.
    !
    ! This program is free software; you can redistribute it and/or
    ! modify it under the terms of the GNU General Public License
    ! as published by the Free Software Foundation; either version 2
    ! of the License, or (at your option) any later version.
    !
    ! This program is distributed in the hope that it will be useful,
    ! but WITHOUT ANY WARRANTY; without even the implied warranty of
    ! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    !
    ! See the GNU General Public License for more details.
    !
    ! You should have received a copy of the GNU General Public License
    ! along with this program; if not, write to the Free Software
    ! Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
    !
    ! */
      #include <termios.h>
      #include <sys/ioctl.h>
      #include <sys/stat.h>
    --- 1,22 ----
    ! /*
    ! Copyright (C) 1996-1997 Id Software, Inc.
    !
    ! This program is free software; you can redistribute it and/or
    ! modify it under the terms of the GNU General Public License
    ! as published by the Free Software Foundation; either version 2
    ! of the License, or (at your option) any later version.
    !
    ! This program is distributed in the hope that it will be useful,
    ! but WITHOUT ANY WARRANTY; without even the implied warranty of
    ! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    !
    ! See the GNU General Public License for more details.
    !
    ! You should have received a copy of the GNU General Public License
    ! along with this program; if not, write to the Free Software
    ! Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
    !
    ! */
      #include <termios.h>
      #include <sys/ioctl.h>
      #include <sys/stat.h>
    ***************
    *** 66,71 ****
    --- 66,74 ----

      static int scr_width, scr_height;

    + /* blank cursor - gets initialized in VID_Init, freed in VID_Shutdown */
    + Cursor cursor;
    +
      /*-----------------------------------------------------------------------*/

      //int		texture_mode = GL_NEAREST;
    ***************
    *** 236,243 ****
      				 0,
      				 GrabModeAsync, GrabModeAsync,
      				 win,
    ! 				 None,
      				 CurrentTime);

      #ifdef USE_DGA
      	XF86DGADirectVideo(dpy, DefaultScreen(dpy), XF86DGADirectMouse);
    --- 239,247 ----
      				 0,
      				 GrabModeAsync, GrabModeAsync,
      				 win,
    ! 				 cursor,
      				 CurrentTime);
    + 	Con_Printf("Cursor blanked.\n");

      #ifdef USE_DGA
      	XF86DGADirectVideo(dpy, DefaultScreen(dpy), XF86DGADirectMouse);
    ***************
    *** 350,355 ****
    --- 354,360 ----
      	if (!ctx)
      		return;

    + 	XFreeCursor(dpy, cursor);
      	glXDestroyContext(dpy, ctx);
      }

    ***************
    *** 602,608 ****
      	unsigned long mask;
      	Window root;
      	XVisualInfo *visinfo;
    !
      	S_Init();

      	Cvar_RegisterVariable (&vid_mode);
    --- 607,617 ----
      	unsigned long mask;
      	Window root;
      	XVisualInfo *visinfo;
    ! 	/* vars to make blank cursor */
    ! 	Pixmap blank;
    ! 	XColor dummy;
    ! 	char data[1] = {0};
    !
      	S_Init();

      	Cvar_RegisterVariable (&vid_mode);
    ***************
    *** 701,706 ****
    --- 710,720 ----
      	Con_SafePrintf ("Video mode %dx%d initialized.\n", width, height);

      	vid.recalc_refdef = 1;				// force a surface cache flush
    +
    + 	blank = XCreateBitmapFromData(dpy, win, data, 1, 1);
    + 	if(blank == None) fprintf(stderr, "error: out of memory.\n");
    + 	cursor = XCreatePixmapCursor(dpy, blank, blank, &dummy, &dummy, 0, 0);
    + 	XFreePixmap(dpy, blank);
      }

      void Sys_SendKeyEvents(void)

    *************************** end patchfile   ************************************

It is handy to bind some keys at the quake console to toggle mouse grabbing:

    	bind q "_windowed_mouse 0"
    	bind w "_windowed_mouse 1"

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