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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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<HTML ><HEAD ><TITLE >SDL_JoystickGetAxis</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.64 "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Joystick" HREF="joystick.html"><LINK REL="PREVIOUS" TITLE="SDL_JoystickUpdate" HREF="sdljoystickupdate.html"><LINK REL="NEXT" TITLE="SDL_JoystickGetHat" HREF="sdljoystickgethat.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdljoystickupdate.html" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdljoystickgethat.html" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLJOYSTICKGETAXIS" >SDL_JoystickGetAxis</A ></H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN5932" ></A ><H2 >Name</H2 >SDL_JoystickGetAxis -- Get the current state of an axis</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN5935" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN5936" ></A ><P ></P ><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 ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN5942" ></A ><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 ><DIV CLASS="REFSECT1" ><A NAME="AEN5953" ></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 ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN5957" ></A ><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 ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN5961" ></A ><H2 >See Also</H2 ><P ><A HREF="sdljoysticknumaxes.html" ><TT CLASS="FUNCTION" >SDL_JoystickNumAxes</TT ></A ></P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdljoystickupdate.html" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdljoystickgethat.html" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_JoystickUpdate</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="joystick.html" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_JoystickGetHat</TD ></TR ></TABLE ></DIV ></BODY ></HTML >