view docs/html/sdljoystickgetaxis.html @ 765:4c2ba6161939

Editors Note: The original patch was modified to use SDL_Delay() instead of nanosleep because nanosleep may not be portable to all systems using SDL with the ALSA backend. This may be a moot point with the switch to blocking writes anyway... Date: Sat, 27 Dec 2003 21:47:36 +0100 From: Michel Daenzer To: Debian Bug Tracking System Subject: [SDL] Bug#225252: [PATCH] ALSA fixes Package: libsdl1.2debian-all Version: 1.2.6-2 Severity: normal Tags: patch For SDL 1.2.6, the ALSA backend was changed to call snd_pcm_open() with SND_PCM_NONBLOCK. That's a good idea per se, however, it causes high CPU usage, interrupted sound and stuttering in some games here. Taking a nanosleep whenever snd_pcm_writei() returns -EAGAIN fixes this, but I think it's more efficient to use blocking mode for the actual sound playback. Feedback from the SDL and ALSA lists appreciated. The patch also fixes the default ALSA device to be used.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 04 Jan 2004 15:40:50 +0000
parents e5bc29de3f0a
children 355632dca928
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><H1
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>SDL_JoystickGetAxis</A
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><DIV
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><H2
>Name</H2
>SDL_JoystickGetAxis&nbsp;--&nbsp;Get the current state of an axis</DIV
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>Synopsis</H2
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><P
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><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>Sint16 <B
CLASS="FSFUNC"
>SDL_JoystickGetAxis</B
></CODE
>(SDL_Joystick *joystick, int axis);</CODE
></P
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CLASS="REFSECT1"
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NAME="AEN5942"
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><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_JoystickGetAxis</TT
> returns the current state of the given <TT
CLASS="PARAMETER"
><I
>axis</I
></TT
> on the given <TT
CLASS="PARAMETER"
><I
>joystick</I
></TT
>.</P
><P
>On most modern joysticks the X axis is usually represented by <TT
CLASS="PARAMETER"
><I
>axis</I
></TT
> 0 and the Y axis by <TT
CLASS="PARAMETER"
><I
>axis</I
></TT
> 1. The value returned by <TT
CLASS="FUNCTION"
>SDL_JoystickGetAxis</TT
> is a signed integer (-32768 to 32768) representing the current position of the <TT
CLASS="PARAMETER"
><I
>axis</I
></TT
>, it maybe necessary to impose certain tolerances on these values to account for jitter. It is worth noting that some joysticks use axes 2 and 3 for extra buttons.</P
></DIV
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><A
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></A
><H2
>Return Value</H2
><P
>Returns a 16-bit signed integer representing the current position of the <TT
CLASS="PARAMETER"
><I
>axis</I
></TT
>.</P
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><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>Sint16 x_move, y_move;
SDL_Joystick *joy1;
.
.
x_move=SDL_JoystickGetAxis(joy1, 0);
y_move=SDL_JoystickGetAxis(joy1, 1);</PRE
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><H2
>See Also</H2
><P
><A
HREF="sdljoysticknumaxes.html"
><TT
CLASS="FUNCTION"
>SDL_JoystickNumAxes</TT
></A
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