view docs/man3/SDL_JoyBallEvent.3 @ 1748:5e86e34453d4

------- Comment #1 From Max Horn 2006-04-17 03:08 [reply] ------- Created an attachment (id=106) [edit] Patch for src/joystick/win32/SDL_mmjoystick.c I am not even a Windows user, so take the following with a grain of salt: SDL_mmjoystick.c has a function GetJoystickName which obtains the joystick name by looking at the registry. The way it does that seems very fishy to me. Namely, it uses the parameter "index" to construct a registry value name (BTW, those variables used in the code are really badly named). The value of "index" in turn equals the current value of "numdevs", as called from SDL_SYS_JoystickInit. I read through the MSDN docs at <http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/dnarinput/html/msdn_extdirect.asp>, and I believe the simple fix is to replace line 183 of said file SYS_JoystickName[numdevs] = GetJoystickName(numdevs, joycaps.szRegKey); by the following: SYS_JoystickName[numdevs] = GetJoystickName(SYS_JoystickID[i], joycaps.szRegKey); However, that is only *hiding* the real issue. Problem is, the list of joysticks as returned by windows may contains "gaps", and the code deals incorrectly with that. Namely those gaps occur if joysticks are removed/(re)added, as the reporter observed. The attached patch fixes this and another (off-by-one) issue in the code. But since I have no Windows machine, I can't even test-compile it, so use with caution.
author Sam Lantinga <slouken@libsdl.org>
date Sat, 29 Apr 2006 20:22:31 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_JoyBallEvent" "3" "Tue 11 Sep 2001, 22:59" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_JoyBallEvent\- Joystick trackball motion event structure
.SH "STRUCTURE DEFINITION"
.PP
.nf
\f(CWtypedef struct{
  Uint8 type;
  Uint8 which;
  Uint8 ball;
  Sint16 xrel, yrel;
} SDL_JoyBallEvent;\fR
.fi
.PP
.SH "STRUCTURE DATA"
.TP 20
\fBtype\fR
\fBSDL_JOYBALLMOTION\fP
.TP 20
\fBwhich\fR
Joystick device index
.TP 20
\fBball\fR
Joystick trackball index
.TP 20
\fBxrel\fR, \fByrel\fR
The relative motion in the X/Y direction
.SH "DESCRIPTION"
.PP
\fBSDL_JoyBallEvent\fR is a member of the \fI\fBSDL_Event\fR\fR union and is used when an event of type \fBSDL_JOYBALLMOTION\fP is reported\&.
.PP
A \fBSDL_JOYBALLMOTION\fP event occurs when a user moves a trackball on the joystick\&. The field \fBwhich\fR is the index of the joystick that reported the event and \fBball\fR is the index of the trackball (for a more detailed explaination see the \fIJoystick section\fR)\&. 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 \fBxrel\fR and \fByrel\fR\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_Event\fR\fR, \fIJoystick Functions\fR, \fI\fBSDL_JoystickEventState\fP\fR, \fI\fBSDL_JoystickGetBall\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:59