raze-gles/polymer/eduke32/source/jaudiolib/dsl.c

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/*
Copyright (C) 2003-2004 Ryan C. Gordon. and James Bentler
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Originally written by Ryan C. Gordon. (icculus@clutteredmind.org)
Adapted to work with JonoF's port by James Bentler (bentler@cs.umn.edu)
*/
#include <stdlib.h>
#include <string.h>
#include "dsl.h"
#include "compat.h"
#include "SDL.h"
#include "SDL_mixer.h"
extern int MV_MixPage;
int DSL_ErrorCode = DSL_Ok;
static int mixer_initialized;
static void(*_CallBackFunc)(void);
static volatile char *_BufferStart;
static int _BufferSize;
static int _NumDivisions;
static int _SampleRate;
static int _remainder;
static Mix_Chunk *blank;
static unsigned char *blank_buf;
/*
possible todo ideas: cache sdl/sdl mixer error messages.
*/
char *DSL_ErrorString(int ErrorNumber)
{
char *ErrorString;
switch (ErrorNumber)
{
case DSL_Warning:
case DSL_Error:
ErrorString = DSL_ErrorString(DSL_ErrorCode);
break;
case DSL_Ok:
ErrorString = "SDL Driver ok.";
break;
case DSL_SDLInitFailure:
ErrorString = "SDL Audio initialization failed.";
break;
case DSL_MixerActive:
ErrorString = "SDL Mixer already initialized.";
break;
case DSL_MixerInitFailure:
ErrorString = "SDL Mixer initialization failed.";
break;
default:
ErrorString = "Unknown SDL Driver error.";
break;
}
return ErrorString;
}
static void DSL_SetErrorCode(int ErrorCode)
{
DSL_ErrorCode = ErrorCode;
}
int DSL_Init(void)
{
DSL_SetErrorCode(DSL_Ok);
if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0)
{
DSL_SetErrorCode(DSL_SDLInitFailure);
return DSL_Error;
}
return DSL_Ok;
}
void DSL_Shutdown(void)
{
DSL_StopPlayback();
}
static void mixer_callback(int chan, void *stream, int len, void *udata)
{
Uint8 *stptr;
Uint8 *fxptr;
int copysize;
UNREFERENCED_PARAMETER(chan);
UNREFERENCED_PARAMETER(udata);
/* len should equal _BufferSize, else this is screwed up */
stptr = (Uint8 *)stream;
if (_remainder > 0)
{
copysize = min(len, _remainder);
fxptr = (Uint8 *)(&_BufferStart[MV_MixPage *
_BufferSize]);
memcpy(stptr, fxptr+(_BufferSize-_remainder), copysize);
len -= copysize;
_remainder -= copysize;
stptr += copysize;
}
while (len > 0)
{
/* new buffer */
_CallBackFunc();
fxptr = (Uint8 *)(&_BufferStart[MV_MixPage *
_BufferSize]);
copysize = min(len, _BufferSize);
memcpy(stptr, fxptr, copysize);
len -= copysize;
stptr += copysize;
}
_remainder = len;
}
int DSL_BeginBufferedPlayback(char *BufferStart,
int BufferSize, int NumDivisions, unsigned SampleRate,
int MixMode, void(*CallBackFunc)(void))
{
Uint16 format;
int channels;
int chunksize;
if (mixer_initialized)
{
DSL_SetErrorCode(DSL_MixerActive);
return DSL_Error;
}
_CallBackFunc = CallBackFunc;
_BufferStart = BufferStart;
_BufferSize = (BufferSize / NumDivisions);
_NumDivisions = NumDivisions;
_SampleRate = SampleRate;
_remainder = 0;
format = (MixMode & SIXTEEN_BIT) ? AUDIO_S16SYS : AUDIO_U8;
channels = (MixMode & STEREO) ? 2 : 1;
/*
23ms is typically ideal (11025,22050,44100)
46ms isn't bad
*/
chunksize = 512;
if (SampleRate >= 16000) chunksize *= 2;
if (SampleRate >= 32000) chunksize *= 2;
/*
// SDL mixer does this already
if (MixMode & SIXTEEN_BIT) chunksize *= 2;
if (MixMode & STEREO) chunksize *= 2;
*/
if (Mix_OpenAudio(SampleRate, format, channels, chunksize) < 0)
{
DSL_SetErrorCode(DSL_MixerInitFailure);
return DSL_Error;
}
/*
Mix_SetPostMix(mixer_callback, NULL);
*/
/* have to use a channel because postmix will overwrite the music... */
Mix_RegisterEffect(0, mixer_callback, NULL, NULL);
/* create a dummy sample just to allocate that channel */
blank_buf = (Uint8 *)malloc(4096);
memset(blank_buf, 0, 4096);
blank = Mix_QuickLoad_RAW(blank_buf, 4096);
Mix_PlayChannel(0, blank, -1);
mixer_initialized = 1;
return DSL_Ok;
}
void DSL_StopPlayback(void)
{
if (mixer_initialized)
{
Mix_HaltChannel(0);
}
if (blank != NULL)
{
Mix_FreeChunk(blank);
}
blank = NULL;
if (blank_buf != NULL)
{
free(blank_buf);
}
blank_buf = NULL;
if (mixer_initialized)
{
Mix_CloseAudio();
}
mixer_initialized = 0;
}
unsigned DSL_GetPlaybackRate(void)
{
return _SampleRate;
}
int DisableInterrupts(void)
{
SDL_LockAudio();
return(0);
}
int RestoreInterrupts(int flags)
{
UNREFERENCED_PARAMETER(flags);
SDL_UnlockAudio();
return(0);
}