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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 | e5bc29de3f0a |
children | 355632dca928 |
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<HTML ><HEAD ><TITLE >SDL_CreateRGBSurfaceFrom</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="Video" HREF="video.html"><LINK REL="PREVIOUS" TITLE="SDL_CreateRGBSurface" HREF="sdlcreatergbsurface.html"><LINK REL="NEXT" TITLE="SDL_FreeSurface" HREF="sdlfreesurface.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="sdlcreatergbsurface.html" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlfreesurface.html" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCREATERGBSURFACEFROM" >SDL_CreateRGBSurfaceFrom</A ></H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN1472" ></A ><H2 >Name</H2 >SDL_CreateRGBSurfaceFrom -- Create an SDL_Surface from pixel data</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN1475" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN1476" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >SDL_Surface *<B CLASS="FSFUNC" >SDL_CreateRGBSurfaceFrom</B ></CODE >(void *pixels, int width, int height, int depth, int pitch, Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1482" ></A ><H2 >Description</H2 ><P >Creates an SDL_Surface from the provided pixel data.</P ><P >The data stored in <TT CLASS="PARAMETER" ><I >pixels</I ></TT > is assumed to be of the <TT CLASS="PARAMETER" ><I >depth</I ></TT > specified in the parameter list. The pixel data is not copied into the <SPAN CLASS="STRUCTNAME" >SDL_Surface</SPAN > structure so it should not be freed until the surface has been freed with a called to <A HREF="sdlfreesurface.html" >SDL_FreeSurface</A >. <TT CLASS="PARAMETER" ><I >pitch</I ></TT > is the length of each scanline in bytes. </P ><P >See <A HREF="sdlcreatergbsurface.html" ><TT CLASS="FUNCTION" >SDL_CreateRGBSurface</TT ></A > for a more detailed description of the other parameters.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1494" ></A ><H2 >Return Value</H2 ><P >Returns the created surface, or <SPAN CLASS="RETURNVALUE" >NULL</SPAN > upon error.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1498" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlcreatergbsurface.html" ><TT CLASS="FUNCTION" >SDL_CreateRGBSurface</TT ></A >, <A HREF="sdlfreesurface.html" ><TT CLASS="FUNCTION" >SDL_FreeSurface</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="sdlcreatergbsurface.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="sdlfreesurface.html" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_CreateRGBSurface</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="video.html" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_FreeSurface</TD ></TR ></TABLE ></DIV ></BODY ></HTML >