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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_CreateCursor</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_WarpMouse" HREF="sdlwarpmouse.html"><LINK REL="NEXT" TITLE="SDL_FreeCursor" HREF="sdlfreecursor.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="sdlwarpmouse.html" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlfreecursor.html" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCREATECURSOR" >SDL_CreateCursor</A ></H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN2103" ></A ><H2 >Name</H2 >SDL_CreateCursor -- Creates a new mouse cursor.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN2106" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN2107" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >SDL_Cursor *<B CLASS="FSFUNC" >SDL_CreateCursor</B ></CODE >(Uint8 *data, Uint8 *mask, int w, int h, int hot_x, int hot_y);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2113" ></A ><H2 >Description</H2 ><P >Create a cursor using the specified <TT CLASS="PARAMETER" ><I >data</I ></TT > and <TT CLASS="PARAMETER" ><I >mask</I ></TT > (in MSB format). The cursor width must be a multiple of 8 bits.</P ><P >The cursor is created in black and white according to the following: <DIV CLASS="INFORMALTABLE" ><A NAME="AEN2119" ></A ><P ></P ><TABLE BORDER="1" CLASS="CALSTABLE" ><THEAD ><TR ><TH ALIGN="LEFT" VALIGN="TOP" >Data / Mask</TH ><TH ALIGN="LEFT" VALIGN="TOP" >Resulting pixel on screen</TH ></TR ></THEAD ><TBODY ><TR ><TD ALIGN="LEFT" VALIGN="TOP" >0 / 1</TD ><TD ALIGN="LEFT" VALIGN="TOP" >White</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" >1 / 1</TD ><TD ALIGN="LEFT" VALIGN="TOP" >Black</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" >0 / 0</TD ><TD ALIGN="LEFT" VALIGN="TOP" >Transparent</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" >1 / 0</TD ><TD ALIGN="LEFT" VALIGN="TOP" >Inverted color if possible, black if not.</TD ></TR ></TBODY ></TABLE ><P ></P ></DIV ></P ><P >Cursors created with this function must be freed with <A HREF="sdlfreecursor.html" >SDL_FreeCursor</A >.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2140" ></A ><H2 >Example</H2 ><PRE CLASS="PROGRAMLISTING" >/* Stolen from the mailing list */ /* Creates a new mouse cursor from an XPM */ /* XPM */ static const char *arrow[] = { /* width height num_colors chars_per_pixel */ " 32 32 3 1", /* colors */ "X c #000000", ". c #ffffff", " c None", /* pixels */ "X ", "XX ", "X.X ", "X..X ", "X...X ", "X....X ", "X.....X ", "X......X ", "X.......X ", "X........X ", "X.....XXXXX ", "X..X..X ", "X.X X..X ", "XX X..X ", "X X..X ", " X..X ", " X..X ", " X..X ", " XX ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", "0,0" }; static SDL_Cursor *init_system_cursor(const char *image[]) { int i, row, col; Uint8 data[4*32]; Uint8 mask[4*32]; int hot_x, hot_y; i = -1; for ( row=0; row<32; ++row ) { for ( col=0; col<32; ++col ) { if ( col % 8 ) { data[i] <<= 1; mask[i] <<= 1; } else { ++i; data[i] = mask[i] = 0; } switch (image[4+row][col]) { case 'X': data[i] |= 0x01; k[i] |= 0x01; break; case '.': mask[i] |= 0x01; break; case ' ': break; } } } sscanf(image[4+row], "%d,%d", &hot_x, &hot_y); return SDL_CreateCursor(data, mask, 32, 32, hot_x, hot_y); }</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2143" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlfreecursor.html" ><TT CLASS="FUNCTION" >SDL_FreeCursor</TT ></A >, <A HREF="sdlsetcursor.html" ><TT CLASS="FUNCTION" >SDL_SetCursor</TT ></A >, <A HREF="sdlshowcursor.html" ><TT CLASS="FUNCTION" >SDL_ShowCursor</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="sdlwarpmouse.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="sdlfreecursor.html" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_WarpMouse</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="video.html" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_FreeCursor</TD ></TR ></TABLE ></DIV ></BODY ></HTML >