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Fixed bug #611 From Tim Angus 2008-08-12 11:18:06 I'm one of the maintainers of ioquake3.org, an updated version of the Quake 3 engine. Relatively recently, we moved ioq3 to use SDL as a replacement for 95% of the platform specific code that was there. On the whole it's doing a great job but unfortunately since the move we've been getting complaints about the quality of the mouse input on the Windows platform to the point where for many the game is unplayable. Put in other terms, the current stable SDL 1.2 is basically not fit for purpose if you need high quality mouse input as you do in a first person shooter. Over the weekend I decided to pull my finger out and actually figure out what's going on. There are basically two major problems. Firstly, when using the "windib" driver, mouse input is gathered via the WM_MOUSEMOVE message. Googling for this indicates that often this is known to result in "spurious" and/or "missing" mouse movement events; this is the primary cause of the poor mouse input. The second problem is that the "directx" driver does not work at all in combination with OpenGL meaning that you can't use DirectInput if your application also uses OpenGL. In other words you're locked into using the "windib" driver and its poor mouse input. In order to address these problems I've done the following: * Remove WM_MOUSEMOVE based motion event generation and replace with calls to GetCursorPos which seems much more reliable. In order to achieve this I've moved mouse motion out into a separate function that is called once per DIB_PumpEvents. * Remove the restriction on the "directx" driver being inoperable in combination with OpenGL. There is a bug for this issues that I've hijacked to a certain extent (http://bugzilla.libsdl.org/show_bug.cgi?id=265). I'm the first to admit I don't really understand why this restriction is there in the first place. The commit message for the bug fix that introduced this restriction (r581) isn't very elaborate and I couldn't see any other bug tracking the issue. If anyone has more information on the bug that was avoided by r581 it would be helpful as I/someone could then look into addressing the problem without disabling the "directx" driver. * I've also removed the restriction on not being allowed to use DirectInput in windowed mode. I couldn't see any reason for this, at least not from our perspective. I have my suspicions that it'll be something like matching up the cursor with the mouse coordinates... * I bumped up the DirectInput API used to version 7 in order to get access to mouse buttons 4-7. I've had to inject a little bit of the DX7 headers into SDL there as the MinGW ones aren't up to date in this respect.
author Sam Lantinga <slouken@libsdl.org>
date Thu, 02 Apr 2009 04:43:36 +0000
parents 355632dca928
children
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>SDL_JoyBallEvent</TITLE
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><H1
><A
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>SDL_JoyBallEvent</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4396"
></A
><H2
>Name</H2
>SDL_JoyBallEvent&nbsp;--&nbsp;Joystick trackball motion event structure</DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4399"
></A
><H2
>Structure Definition</H2
><PRE
CLASS="PROGRAMLISTING"
>typedef struct{
  Uint8 type;
  Uint8 which;
  Uint8 ball;
  Sint16 xrel, yrel;
} SDL_JoyBallEvent;</PRE
></DIV
><DIV
CLASS="REFSECT1"
><A
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></A
><H2
>Structure Data</H2
><DIV
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></A
><P
></P
><TABLE
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><TBODY
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><TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
></TD
><TD
ALIGN="LEFT"
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><TT
CLASS="LITERAL"
>SDL_JOYBALLMOTION</TT
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>which</I
></TT
></TD
><TD
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>Joystick device index</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>ball</I
></TT
></TD
><TD
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VALIGN="TOP"
>Joystick trackball index</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>xrel</I
></TT
>, <TT
CLASS="STRUCTFIELD"
><I
>yrel</I
></TT
></TD
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ALIGN="LEFT"
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>The relative motion in the X/Y direction</TD
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><A
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></A
><H2
>Description</H2
><P
><SPAN
CLASS="STRUCTNAME"
>SDL_JoyBallEvent</SPAN
> is a member of the <A
HREF="sdlevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
></A
> union and is used when an event of type <TT
CLASS="LITERAL"
>SDL_JOYBALLMOTION</TT
> is reported.</P
><P
>A <TT
CLASS="LITERAL"
>SDL_JOYBALLMOTION</TT
> event occurs when a user moves a trackball on the joystick. The field <TT
CLASS="STRUCTFIELD"
><I
>which</I
></TT
> is the index of the joystick that reported the event and <TT
CLASS="STRUCTFIELD"
><I
>ball</I
></TT
> is the index of the trackball (for a more detailed explaination see the <A
HREF="joystick.html"
>Joystick section</A
>). Trackballs only return relative motion, this is the change in position on the ball since it was last polled (last cycle of the event loop) and it is stored in <TT
CLASS="STRUCTFIELD"
><I
>xrel</I
></TT
> and <TT
CLASS="STRUCTFIELD"
><I
>yrel</I
></TT
>.</P
></DIV
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></A
><H2
>See Also</H2
><P
><A
HREF="sdlevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
></A
>,
<A
HREF="joystick.html"
>Joystick Functions</A
>,
<A
HREF="sdljoystickeventstate.html"
><TT
CLASS="FUNCTION"
>SDL_JoystickEventState</TT
></A
>,
<A
HREF="sdljoystickgetball.html"
><TT
CLASS="FUNCTION"
>SDL_JoystickGetBall</TT
></A
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