kolibrios-fun/contrib/sdk/sources/SDL-1.2.2/docs/html/guideaudioexamples.html

220 lines
3.6 KiB
HTML
Raw Normal View History

<HTML
><HEAD
><TITLE
>Audio Examples</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="Examples"
HREF="guideexamples.html"><LINK
REL="PREVIOUS"
TITLE="Event Examples"
HREF="guideeventexamples.html"><LINK
REL="NEXT"
TITLE="CDROM Examples"
HREF="guidecdromexamples.html"></HEAD
><BODY
CLASS="SECT1"
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="guideeventexamples.html"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
>Chapter 4. Examples</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="guidecdromexamples.html"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="GUIDEAUDIOEXAMPLES"
>Audio Examples</A
></H1
><P
></P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN382"
>Opening the audio device</A
></H2
><P
><PRE
CLASS="PROGRAMLISTING"
> SDL_AudioSpec wanted;
extern void fill_audio(void *udata, Uint8 *stream, int len);
/* Set the audio format */
wanted.freq = 22050;
wanted.format = AUDIO_S16;
wanted.channels = 2; /* 1 = mono, 2 = stereo */
wanted.samples = 1024; /* Good low-latency value for callback */
wanted.callback = fill_audio;
wanted.userdata = NULL;
/* Open the audio device, forcing the desired format */
if ( SDL_OpenAudio(&#38;wanted, NULL) &#60; 0 ) {
fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError());
return(-1);
}
return(0);</PRE
></P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN386"
>Playing audio</A
></H2
><P
><PRE
CLASS="PROGRAMLISTING"
> static Uint8 *audio_chunk;
static Uint32 audio_len;
static Uint8 *audio_pos;
/* The audio function callback takes the following parameters:
stream: A pointer to the audio buffer to be filled
len: The length (in bytes) of the audio buffer
*/
void fill_audio(void *udata, Uint8 *stream, int len)
{
/* Only play if we have data left */
if ( audio_len == 0 )
return;
/* Mix as much data as possible */
len = ( len &#62; audio_len ? audio_len : len );
SDL_MixAudio(stream, audio_pos, len, SDL_MIX_MAXVOLUME)
audio_pos += len;
audio_len -= len;
}
/* Load the audio data ... */
;;;;;
audio_pos = audio_chunk;
/* Let the callback function play the audio chunk */
SDL_PauseAudio(0);
/* Do some processing */
;;;;;
/* Wait for sound to complete */
while ( audio_len &#62; 0 ) {
SDL_Delay(100); /* Sleep 1/10 second */
}
SDL_CloseAudio();</PRE
></P
></DIV
></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="guideeventexamples.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="guidecdromexamples.html"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Event Examples</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="guideexamples.html"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>CDROM Examples</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>