Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_ConvertAudio.3 @ 914:bbf8dcc8aed6
Date: Wed, 23 Jun 2004 17:05:33 -0400
From: Chris Nelson
Subject: [SDL] [Patch] WiseGroup MP-8800 / MP-8866 (PS2 Joystick)
In the current cvs version, SDL doesn't handle these Playstation2
controller => USB adapters correctly, in linux.
It will always assume that the maximum number of joysticks (2 in the
case of the MP-8866, 4 in the case of the 8800) are plugged in. This is
bad not only because it allows SDL to exaggerate the number of logical
joysticks, but primarily because the joystick axes are mapped
incorrectly, all over the place, such that the devices are effectively
unusable unless you have the maximum number of joysticks plugged in.
My changes to src/joystick/linux/SDL_sysjoystick.c build on another's
previous work (which was a special case for this very joystick,
actually), and fix both of these problems, as well as making the current
code a little more general, to allow for others to more easily drop in
code for quirky joysticks such as these.
I've tested this code under 2.6.7 as well as 2.4.24... Both work as
advertised (provided you load the JOYDEV linux code as a module,
otherwise they won't work at all, new code or old, but that's another
issue entirely).
Though this sounds horribly formal, you have my permission to distribute
all of my work on this issue under the LGPL. So there.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 25 Jul 2004 18:31:50 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
| rev | line source |
|---|---|
|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
1 .TH "SDL_ConvertAudio" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" |
| 0 | 2 .SH "NAME" |
| 3 SDL_ConvertAudio\- Convert audio data to a desired audio format\&. | |
| 4 .SH "SYNOPSIS" | |
| 5 .PP | |
| 6 \fB#include "SDL\&.h" | |
| 7 .sp | |
| 8 \fBint \fBSDL_ConvertAudio\fP\fR(\fBSDL_AudioCVT *cvt\fR); | |
| 9 .SH "DESCRIPTION" | |
| 10 .PP | |
| 11 \fBSDL_ConvertAudio\fP takes one parameter, \fBcvt\fR, which was previously initilized\&. Initilizing a \fI\fBSDL_AudioCVT\fR\fR is a two step process\&. First of all, the structure must be passed to \fI\fBSDL_BuildAudioCVT\fP\fR along with source and destination format parameters\&. Secondly, the \fBcvt\fR->\fBbuf\fR and \fBcvt\fR->\fBlen\fR fields must be setup\&. \fBcvt\fR->\fBbuf\fR should point to the audio data and \fBcvt\fR->\fBlen\fR should be set to the length of the audio data in bytes\&. Remember, the length of the buffer pointed to by \fBbuf\fR show be \fBlen\fR*\fBlen_mult\fR bytes in length\&. | |
| 12 .PP | |
| 13 Once the \fBSDL_AudioCVT\fRstructure is initilized then we can pass it to \fBSDL_ConvertAudio\fP, which will convert the audio data pointer to by \fBcvt\fR->\fBbuf\fR\&. If \fBSDL_ConvertAudio\fP returned \fB0\fR then the conversion was completed successfully, otherwise \fB-1\fR is returned\&. | |
| 14 .PP | |
| 15 If the conversion completed successfully then the converted audio data can be read from \fBcvt\fR->\fBbuf\fR\&. The amount of valid, converted, audio data in the buffer is equal to \fBcvt\fR->\fBlen\fR*\fBcvt\fR->\fBlen_ratio\fR\&. | |
| 16 .SH "EXAMPLES" | |
| 17 .PP | |
| 18 .nf | |
| 19 \f(CW/* Converting some WAV data to hardware format */ | |
| 20 void my_audio_callback(void *userdata, Uint8 *stream, int len); | |
| 21 | |
| 22 SDL_AudioSpec *desired, *obtained; | |
| 23 SDL_AudioSpec wav_spec; | |
| 24 SDL_AudioCVT wav_cvt; | |
| 25 Uint32 wav_len; | |
| 26 Uint8 *wav_buf; | |
| 27 int ret; | |
| 28 | |
| 29 /* Allocated audio specs */ | |
| 30 desired=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec)); | |
| 31 obtained=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec)); | |
| 32 | |
| 33 /* Set desired format */ | |
| 34 desired->freq=22050; | |
| 35 desired->format=AUDIO_S16LSB; | |
| 36 desired->samples=8192; | |
| 37 desired->callback=my_audio_callback; | |
| 38 desired->userdata=NULL; | |
| 39 | |
| 40 /* Open the audio device */ | |
| 41 if ( SDL_OpenAudio(desired, obtained) < 0 ){ | |
| 42 fprintf(stderr, "Couldn\&'t open audio: %s | |
| 43 ", SDL_GetError()); | |
| 44 exit(-1); | |
| 45 } | |
| 46 | |
| 47 free(desired); | |
| 48 | |
| 49 /* Load the test\&.wav */ | |
| 50 if( SDL_LoadWAV("test\&.wav", &wav_spec, &wav_buf, &wav_len) == NULL ){ | |
| 51 fprintf(stderr, "Could not open test\&.wav: %s | |
| 52 ", SDL_GetError()); | |
| 53 SDL_CloseAudio(); | |
| 54 free(obtained); | |
| 55 exit(-1); | |
| 56 } | |
| 57 | |
| 58 /* Build AudioCVT */ | |
| 59 ret = SDL_BuildAudioCVT(&wav_cvt, | |
| 60 wav_spec\&.format, wav_spec\&.channels, wav_spec\&.freq, | |
| 61 obtained->format, obtained->channels, obtained->freq); | |
| 62 | |
| 63 /* Check that the convert was built */ | |
| 64 if(ret==-1){ | |
| 65 fprintf(stderr, "Couldn\&'t build converter! | |
| 66 "); | |
| 67 SDL_CloseAudio(); | |
| 68 free(obtained); | |
| 69 SDL_FreeWAV(wav_buf); | |
| 70 } | |
| 71 | |
| 72 /* Setup for conversion */ | |
| 73 wav_cvt\&.buf=(Uint8 *)malloc(wav_len*wav_cvt\&.len_mult); | |
| 74 wav_cvt\&.len=wav_len; | |
| 75 memcpy(wav_cvt\&.buf, wav_buf, wav_len); | |
| 76 | |
| 77 /* We can delete to original WAV data now */ | |
| 78 SDL_FreeWAV(wav_buf); | |
| 79 | |
| 80 /* And now we\&'re ready to convert */ | |
| 81 SDL_ConvertAudio(&wav_cvt); | |
| 82 | |
| 83 /* do whatever */ | |
| 84 \&. | |
| 85 \&. | |
| 86 \&. | |
| 87 \&. | |
| 88 | |
| 89 \fR | |
| 90 .fi | |
| 91 .PP | |
| 92 .SH "SEE ALSO" | |
| 93 .PP | |
| 94 \fI\fBSDL_BuildAudioCVT\fP\fR, \fI\fBSDL_AudioCVT\fP\fR | |
|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
95 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58 |