view docs/man3/SDL_JoystickOpen.3 @ 1544:ab1e4c41ab71

Fixed bug #33 Mike Frysinger wrote: > with libsdl-1.2.9, some games (like bomberclone) started > segfaulting in Gentoo [...snip...] > the last change in the last hunk: [...snip...] > if i change the statement to read: > (table[which].blit_features & GetBlitFeatures()) == GetBlitFeatures() > bomberclone no longer segfaults on my box Alex Volkov wrote: > The test "(table[which].blit_features & GetBlitFeatures()) == > table[which].blit_features)" is correct, and the previous > "(table[which].cpu_mmx == SDL_HasMMX())" was actually broken. I think there is potentially a slightly different cause of the above problem. During the introduction of the Altivec code, the blit_table struct field 'alpha' got changed from a straightforward enum to a bitmask, which makes perfect sense by itself. However, now the table driven blitter selection code in SDL_CalculateBlitN() can choose the wrong blitters when searching for a NO_ALPHA blitter because of the following code: int a_need = 0; ... (a_need & table[which].alpha) == a_need && When searching through the normal_blit_2[] table, a SET_ALPHA blitter (like Blit_RGB565_ARGB8888) can now be selected instead of a NO_ALPHA one, causing alpha channel bits to appear in a non-alpha destination surface. I suppose this could theoretically be an indirect cause of the segfault mentioned above. I *think* this can be fixed by changing to int a_need = NO_ALPHA;
author Sam Lantinga <slouken@libsdl.org>
date Wed, 15 Mar 2006 15:47:49 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_JoystickOpen" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_JoystickOpen\- Opens a joystick for use\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBSDL_Joystick *\fBSDL_JoystickOpen\fP\fR(\fBint index\fR);
.SH "DESCRIPTION"
.PP
Opens a joystick for use within SDL\&. The \fBindex\fR refers to the N\&'th joystick in the system\&. A joystick must be opened before it game be used\&.
.SH "RETURN VALUE"
.PP
Returns a \fBSDL_Joystick\fR structure on success\&. \fBNULL\fR on failure\&.
.SH "EXAMPLES"
.PP
.PP
.nf
\f(CWSDL_Joystick *joy;
// Check for joystick
if(SDL_NumJoysticks()>0){
  // Open joystick
  joy=SDL_JoystickOpen(0);
  
  if(joy)
  {
    printf("Opened Joystick 0
");
    printf("Name: %s
", SDL_JoystickName(0));
    printf("Number of Axes: %d
", SDL_JoystickNumAxes(joy));
    printf("Number of Buttons: %d
", SDL_JoystickNumButtons(joy));
    printf("Number of Balls: %d
", SDL_JoystickNumBalls(joy));
  }
  else
    printf("Couldn\&'t open Joystick 0
");
  
  // Close if opened
  if(SDL_JoystickOpened(0))
    SDL_JoystickClose(joy);
}\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_JoystickClose\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00