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Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
parents
children 55f1f1b3e27d
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+++ b/docs/html/guideaudioexamples.html	Thu Apr 26 16:45:43 2001 +0000
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+<HTML
+><HEAD
+><TITLE
+>Audio Examples</TITLE
+><META
+NAME="GENERATOR"
+CONTENT="Modular DocBook HTML Stylesheet Version 1.61
+"><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="AEN343"
+>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="AEN347"
+>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
+>
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