Mercurial > sdl-ios-xcode
view docs/man3/SDL_JoyHatEvent.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 |
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.TH "SDL_JoyHatEvent" "3" "Tue 11 Sep 2001, 22:59" "SDL" "SDL API Reference" .SH "NAME" SDL_JoyHatEvent\- Joystick hat position change event structure .SH "STRUCTURE DEFINITION" .PP .nf \f(CWtypedef struct{ Uint8 type; Uint8 which; Uint8 hat; Uint8 value; } SDL_JoyHatEvent;\fR .fi .PP .SH "STRUCTURE DATA" .TP 20 \fBtype\fR \fBSDL_JOY\fP .TP 20 \fBwhich\fR Joystick device index .TP 20 \fBhat\fR Joystick hat index .TP 20 \fBvalue\fR Hat position .SH "DESCRIPTION" .PP \fBSDL_JoyHatEvent\fR is a member of the \fI\fBSDL_Event\fR\fR union and is used when an event of type \fBSDL_JOYHATMOTION\fP is reported\&. .PP A \fBSDL_JOYHATMOTION\fP event occurs when ever a user moves a hat on the joystick\&. The field \fBwhich\fR is the index of the joystick that reported the event and \fBhat\fR is the index of the hat (for a more detailed exlaination see the \fIJoystick section\fR)\&. \fBvalue\fR is the current position of the hat\&. It is a logically OR\&'d combination of the following values (whose meanings should be pretty obvious:) : .IP "" 10 \fBSDL_HAT_CENTERED\fP .IP "" 10 \fBSDL_HAT_UP\fP .IP "" 10 \fBSDL_HAT_RIGHT\fP .IP "" 10 \fBSDL_HAT_DOWN\fP .IP "" 10 \fBSDL_HAT_LEFT\fP .PP The following defines are also provided: .IP "" 10 \fBSDL_HAT_RIGHTUP\fP .IP "" 10 \fBSDL_HAT_RIGHTDOWN\fP .IP "" 10 \fBSDL_HAT_LEFTUP\fP .IP "" 10 \fBSDL_HAT_LEFTDOWN\fP .SH "SEE ALSO" .PP \fI\fBSDL_Event\fR\fR, \fIJoystick Functions\fR, \fI\fBSDL_JoystickEventState\fP\fR, \fI\fBSDL_JoystickGetHat\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:59