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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
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>SDL_Palette</TITLE
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><H1
><A
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>SDL_Palette</A
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN2745"
></A
><H2
>Name</H2
>SDL_Palette&nbsp;--&nbsp;Color palette for 8-bit pixel formats</DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2748"
></A
><H2
>Structure Definition</H2
><PRE
CLASS="PROGRAMLISTING"
>typedef struct{
  int ncolors;
  SDL_Color *colors;
} SDL_Palette;</PRE
></DIV
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>Structure Data</H2
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><TT
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><I
>ncolors</I
></TT
></TD
><TD
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>Number of colors used in this palette</TD
></TR
><TR
><TD
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><TT
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><I
>colors</I
></TT
></TD
><TD
ALIGN="LEFT"
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>Pointer to <A
HREF="sdlcolor.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Color</SPAN
></A
> structures that make up the palette.</TD
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><H2
>Description</H2
><P
>Each pixel in an 8-bit surface is an index into the <TT
CLASS="STRUCTFIELD"
><I
>colors</I
></TT
> field of the <SPAN
CLASS="STRUCTNAME"
>SDL_Palette</SPAN
> structure store in <A
HREF="sdlpixelformat.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_PixelFormat</SPAN
></A
>. A <SPAN
CLASS="STRUCTNAME"
>SDL_Palette</SPAN
> should never need to be created manually. It is automatically created when SDL allocates a <SPAN
CLASS="STRUCTNAME"
>SDL_PixelFormat</SPAN
> for a surface. The colors values of a <A
HREF="sdlsurface.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
></A
>s palette can be set with the <A
HREF="sdlsetcolors.html"
><TT
CLASS="FUNCTION"
>SDL_SetColors</TT
></A
>.</P
></DIV
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><H2
>See Also</H2
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>SDL_Color</SPAN
></A
>,
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><SPAN
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>SDL_Surface</SPAN
></A
>,
<A
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><TT
CLASS="FUNCTION"
>SDL_SetColors</TT
></A
>
<A
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><TT
CLASS="FUNCTION"
>SDL_SetPalette</TT
></A
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