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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 55f1f1b3e27d
children 355632dca928
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<HTML
><HEAD
><TITLE
>Joystick</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.64
"><LINK
REL="HOME"
TITLE="SDL Library Documentation"
HREF="index.html"><LINK
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TITLE="SDL Reference"
HREF="reference.html"><LINK
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TITLE="SDL_JoystickEventState"
HREF="sdljoystickeventstate.html"><LINK
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TITLE="SDL_NumJoysticks"
HREF="sdlnumjoysticks.html"><META
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CONTENT="joystick"><META
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CONTENT="function"></HEAD
><BODY
CLASS="CHAPTER"
BGCOLOR="#FFF8DC"
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><DIV
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BORDER="0"
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><TH
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ALIGN="center"
>SDL Library Documentation</TH
></TR
><TR
><TD
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><A
HREF="sdljoystickeventstate.html"
>Prev</A
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><HR
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WIDTH="100%"></DIV
><DIV
CLASS="CHAPTER"
><H1
><A
NAME="JOYSTICK"
>Chapter 9. Joystick</A
></H1
><DIV
CLASS="TOC"
><DL
><DT
><B
>Table of Contents</B
></DT
><DT
><A
HREF="sdlnumjoysticks.html"
>SDL_NumJoysticks</A
> &#8212; Count available joysticks.</DT
><DT
><A
HREF="sdljoystickname.html"
>SDL_JoystickName</A
> &#8212; Get joystick name.</DT
><DT
><A
HREF="sdljoystickopen.html"
>SDL_JoystickOpen</A
> &#8212; Opens a joystick for use.</DT
><DT
><A
HREF="sdljoystickopened.html"
>SDL_JoystickOpened</A
> &#8212; Determine if a joystick has been opened</DT
><DT
><A
HREF="sdljoystickindex.html"
>SDL_JoystickIndex</A
> &#8212; Get the index of an SDL_Joystick.</DT
><DT
><A
HREF="sdljoysticknumaxes.html"
>SDL_JoystickNumAxes</A
> &#8212; Get the number of joystick axes</DT
><DT
><A
HREF="sdljoysticknumballs.html"
>SDL_JoystickNumBalls</A
> &#8212; Get the number of joystick trackballs</DT
><DT
><A
HREF="sdljoysticknumhats.html"
>SDL_JoystickNumHats</A
> &#8212; Get the number of joystick hats</DT
><DT
><A
HREF="sdljoysticknumbuttons.html"
>SDL_JoystickNumButtons</A
> &#8212; Get the number of joysitck buttons</DT
><DT
><A
HREF="sdljoystickupdate.html"
>SDL_JoystickUpdate</A
> &#8212; Updates the state of all joysticks</DT
><DT
><A
HREF="sdljoystickgetaxis.html"
>SDL_JoystickGetAxis</A
> &#8212; Get the current state of an axis</DT
><DT
><A
HREF="sdljoystickgethat.html"
>SDL_JoystickGetHat</A
> &#8212; Get the current state of a joystick hat</DT
><DT
><A
HREF="sdljoystickgetbutton.html"
>SDL_JoystickGetButton</A
> &#8212; Get the current state of a given button on a given joystick</DT
><DT
><A
HREF="sdljoystickgetball.html"
>SDL_JoystickGetBall</A
> &#8212; Get relative trackball motion</DT
><DT
><A
HREF="sdljoystickclose.html"
>SDL_JoystickClose</A
> &#8212; Closes a previously opened joystick</DT
></DL
></DIV
><P
>Joysticks, and other similar input devices, have a very strong role in game playing and SDL provides comprehensive support for them. Axes, Buttons, POV Hats and trackballs are all supported.</P
><P
>Joystick support is initialized by passed the <TT
CLASS="LITERAL"
>SDL_INIT_JOYSTICK</TT
> flag to <A
HREF="sdlinit.html"
><TT
CLASS="FUNCTION"
>SDL_Init</TT
></A
>. Once initilized joysticks must be opened using <A
HREF="sdljoystickopen.html"
><TT
CLASS="FUNCTION"
>SDL_JoystickOpen</TT
></A
>.</P
><P
>While using the functions describe in this secton may seem like the best way to access and read from joysticks, in most cases they aren't. Ideally joysticks should be read using the <A
HREF="event.html"
>event</A
> system. To enable this, you must set the joystick event processing state with <A
HREF="sdljoystickeventstate.html"
><TT
CLASS="FUNCTION"
>SDL_JoystickEventState</TT
></A
>. Joysticks must be <A
HREF="sdljoystickopen.html"
>opened</A
> before they can be used of course.</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>If you are <I
CLASS="EMPHASIS"
>not</I
> handling the joystick via the event queue then you must explicitly request a joystick update by calling <A
HREF="sdljoystickupdate.html"
><TT
CLASS="FUNCTION"
>SDL_JoystickUpdate</TT
></A
>.</P
></BLOCKQUOTE
></DIV
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>Force Feedback is not yet support. Sam (slouken@libsdl.org) is soliciting suggestions from people with force-feedback experience on the best wat to desgin the API.</P
></BLOCKQUOTE
></DIV
></DIV
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