Mercurial > sdl-ios-xcode
view docs/html/sdlcdstatus.html @ 968:4675910b0b7b
Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
From: Hannu Savolainen
Subject: Re: SDL uses obsolete OSS features
I did some work on getting OSS to work better with SDL. There have been
some problems with select which should be fixed now.
I'm having some problems in understanding what is the purpose of the
DSP_WaitAudio() routine. I added a return to the very beginning of this
routine and commendted out the define for USE_BLOCKING_WRITES. At least
lbreakout2 seems to work as well as earlier. The latencies are the same.
An ordinary blocking write does exactly the same thing than DSP_WaitAudio
does. So I would recommend using the USE_BLOCKING_WRITES approach and
removing everything from the DSP_WaitAudio routine. Also enabling
USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because
you don't need to handle the partial writes (the do-while loop).
Attached is a patch against SDL-1.2.7. After these changes SDL will use
OSS as it's designed to be used (make it as simple as possible). This code
should work with all OSS implementations because it uses only the very
fundamental features that have been there since the jurassic times.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Fri, 12 Nov 2004 21:39:04 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_CDStatus</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="CD-ROM" HREF="cdrom.html"><LINK REL="PREVIOUS" TITLE="SDL_CDOpen" HREF="sdlcdopen.html"><LINK REL="NEXT" TITLE="SDL_CDPlay" HREF="sdlcdplay.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation 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="sdlcdopen.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlcdplay.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCDSTATUS" ></A >SDL_CDStatus</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN7308" ></A ><H2 >Name</H2 >SDL_CDStatus -- Returns the current status of the given drive.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN7311" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN7312" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >CDstatus <B CLASS="FSFUNC" >SDL_CDStatus</B ></CODE >(SDL_CD *cdrom);</CODE ></P ><PRE CLASS="FUNCSYNOPSISINFO" >/* Given a status, returns true if there's a disk in the drive */ #define CD_INDRIVE(status) ((int)status > 0)</PRE ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7319" ></A ><H2 >Description</H2 ><P >This function returns the current status of the given drive. Status is described like so: <PRE CLASS="PROGRAMLISTING" >typedef enum { CD_TRAYEMPTY, CD_STOPPED, CD_PLAYING, CD_PAUSED, CD_ERROR = -1 } CDstatus;</PRE ></P ><P >If the drive has a CD in it, the table of contents of the CD and current play position of the CD will be stored in the SDL_CD structure.</P ><P >The macro <TT CLASS="LITERAL" >CD_INDRIVE</TT > is provided for convenience, and given a status returns true if there's a disk in the drive.</P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B ><TT CLASS="FUNCTION" >SDL_CDStatus</TT > also updates the <A HREF="sdlcd.html" ><SPAN CLASS="STRUCTNAME" >SDL_CD</SPAN ></A > structure passed to it.</P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7331" ></A ><H2 >Example</H2 ><PRE CLASS="PROGRAMLISTING" >int playTrack(int track) { int playing = 0; if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) { /* clamp to the actual number of tracks on the CD */ if (track >= cdrom->numtracks) { track = cdrom->numtracks-1; } if ( SDL_CDPlayTracks(cdrom, track, 0, 1, 0) == 0 ) { playing = 1; } } return playing; }</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7334" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlcd.html" ><TT CLASS="FUNCTION" >SDL_CD</TT ></A ></P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdlcdopen.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlcdplay.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_CDOpen</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="cdrom.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_CDPlay</TD ></TR ></TABLE ></DIV ></BODY ></HTML >