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Date: Sat, 8 Sep 2001 04:42:23 +0200 From: Max Horn <max@quendi.de> Subject: SDL/OSX: Joystick; Better key handling I just finished implementing improved keyhandling for OS X (in fact the code should be easily ported to the "normal" MacOS part of SDL, I just had no chance yet). Works like this: First init the mapping table statically like before. Them, it queries the OS for the "official" key table, then iterates over all 127 scancode and gets the associates ascii code. It ignores everythng below 32 (has to, as it would lead to many problems if we did not... e.g. both ESC and NUM LOCk produce an ascii code 27 on my keyboard), and all stuff above 127 is mapped to SDLK_WORLD_* simply in the order it is encountered. In addition, caps lock is now working, too. The code work flawless for me, but since I only have one keyboard, I may have not encountered some serious problem... but I am pretty confident that it is better than the old code in most cases. The joystick driver works fine for me, too. I think it can be added to CVS already. It would simply be helpful if more people would test it. Hm, I wonder if Maelstrom or GLTron has Joystick support? That would be a wonderful test application :) I also took the liberty of modifying some text files like BUGS, README.CVS, README.MacOSX (which now contains the OS X docs I long promised)
author Sam Lantinga <slouken@libsdl.org>
date Tue, 11 Sep 2001 19:00:18 +0000
parents 55f1f1b3e27d
children e5bc29de3f0a
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<HTML
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>SDL_ConvertAudio</TITLE
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><H1
><A
NAME="SDLCONVERTAUDIO"
>SDL_ConvertAudio</A
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN6501"
></A
><H2
>Name</H2
>SDL_ConvertAudio&nbsp;--&nbsp;Convert audio data to a desired audio format.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN6504"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN6505"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_ConvertAudio</B
></CODE
>(SDL_AudioCVT *cvt);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN6511"
></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_ConvertAudio</TT
> takes one parameter, <TT
CLASS="PARAMETER"
><I
>cvt</I
></TT
>, which was previously initilized. Initilizing a <A
HREF="sdlaudiocvt.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_AudioCVT</SPAN
></A
> is a two step process. First of all, the structure must be passed to <A
HREF="sdlbuildaudiocvt.html"
><TT
CLASS="FUNCTION"
>SDL_BuildAudioCVT</TT
></A
> along with source and destination format parameters. Secondly, the <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>buf</I
></TT
> and <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>len</I
></TT
> fields must be setup. <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>buf</I
></TT
> should point to the audio data and <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>len</I
></TT
> should be set to the length of the audio data in bytes. Remember, the length of the buffer pointed to by <TT
CLASS="STRUCTFIELD"
><I
>buf</I
></TT
> show be <TT
CLASS="STRUCTFIELD"
><I
>len</I
></TT
>*<TT
CLASS="STRUCTFIELD"
><I
>len_mult</I
></TT
> bytes in length.</P
><P
>Once the <SPAN
CLASS="STRUCTNAME"
>SDL_AudioCVT</SPAN
>structure is initilized then we can pass it to <TT
CLASS="FUNCTION"
>SDL_ConvertAudio</TT
>, which will convert the audio data pointer to by <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>buf</I
></TT
>. If <TT
CLASS="FUNCTION"
>SDL_ConvertAudio</TT
> returned <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> then the conversion was completed successfully, otherwise <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> is returned.</P
><P
>If the conversion completed successfully then the converted audio data can be read from <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>buf</I
></TT
>. The amount of valid, converted, audio data in the buffer is equal to <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>len</I
></TT
>*<TT
CLASS="STRUCTFIELD"
><I
>cvt</I
></TT
>-&#62;<SPAN
CLASS="STRUCTNAME"
>len_ratio</SPAN
>.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN6546"
></A
><H2
>Examples</H2
><PRE
CLASS="PROGRAMLISTING"
>/* Converting some WAV data to hardware format */
void my_audio_callback(void *userdata, Uint8 *stream, int len);

SDL_AudioSpec *desired, *obtained;
SDL_AudioSpec wav_spec;
SDL_AudioCVT  wav_cvt;
Uint32 wav_len;
Uint8 *wav_buf;
int ret;

/* Allocated audio specs */
desired=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec));
obtained=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec));

/* Set desired format */
desired-&#62;freq=22050;
desired-&#62;format=AUDIO_S16LSB;
desired-&#62;samples=8192;
desired-&#62;callback=my_audio_callback;
desired-&#62;userdata=NULL;

/* Open the audio device */
if ( SDL_OpenAudio(desired, obtained) &#60; 0 ){
  fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError());
  exit(-1);
}
        
free(desired);

/* Load the test.wav */
if( SDL_LoadWAV("test.wav", &#38;wav_spec, &#38;wav_buf, &#38;wav_len) == NULL ){
  fprintf(stderr, "Could not open test.wav: %s\n", SDL_GetError());
  SDL_CloseAudio();
  free(obtained);
  exit(-1);
}
                                            
/* Build AudioCVT */
ret = SDL_BuildAudioCVT(&#38;wav_cvt,
                        wav_spec.format, wav_spec.channels, wav_spec.freq,
                        obtained-&#62;format, obtained-&#62;channels, obtained-&#62;freq);

/* Check that the convert was built */
if(ret==-1){
  fprintf(stderr, "Couldn't build converter!\n");
  SDL_CloseAudio();
  free(obtained);
  SDL_FreeWAV(wav_buf);
}

/* Setup for conversion */
wav_cvt.buf=(Uint8 *)malloc(wav_len*wav_cvt.len_mult);
wav_cvt.len=wav_len;
memcpy(wav_cvt.buf, wav_buf, wav_len);

/* We can delete to original WAV data now */
SDL_FreeWAV(wav_buf);

/* And now we're ready to convert */
SDL_ConvertAudio(&#38;wav_cvt);

/* do whatever */
.
.
.
.
&#13;</PRE
></DIV
><DIV
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><A
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></A
><H2
>See Also</H2
><P
><A
HREF="sdlbuildaudiocvt.html"
><TT
CLASS="FUNCTION"
>SDL_BuildAudioCVT</TT
></A
>,
<A
HREF="sdlaudiocvt.html"
><TT
CLASS="FUNCTION"
>SDL_AudioCVT</TT
></A
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