ref: 75292c1548ba30ddfb906f878eedf7828097dcd1
dir: /src/i_sdlsound.c/
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005 Simon Howard
//
// 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.
//
// DESCRIPTION:
// System interface for sound.
//
//-----------------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include "SDL.h"
#include "SDL_mixer.h"
#include "deh_main.h"
#include "s_sound.h"
#include "m_argv.h"
#include "w_wad.h"
#include "z_zone.h"
#include "doomdef.h"
#define NUM_CHANNELS 16
static boolean sound_initialised = false;
static Mix_Chunk sound_chunks[NUMSFX];
static int channels_playing[NUM_CHANNELS];
static int mixer_freq;
static Uint16 mixer_format;
static int mixer_channels;
// When a sound stops, check if it is still playing. If it is not,
// we can mark the sound data as CACHE to be freed back for other
// means.
static void ReleaseSoundOnChannel(int channel)
{
int i;
int id = channels_playing[channel];
if (!id)
{
return;
}
channels_playing[channel] = sfx_None;
for (i=0; i<NUM_CHANNELS; ++i)
{
// Playing on this channel? if so, don't release.
if (channels_playing[i] == id)
return;
}
// Not used on any channel, and can be safely released
Z_ChangeTag(sound_chunks[id].abuf, PU_CACHE);
}
static boolean ConvertibleRatio(int freq1, int freq2)
{
int ratio;
if (freq1 > freq2)
{
return ConvertibleRatio(freq2, freq1);
}
else if ((freq2 % freq1) != 0)
{
// Not in a direct ratio
return false;
}
else
{
// Check the ratio is a power of 2
ratio = freq2 / freq1;
while ((ratio & 1) == 0)
{
ratio = ratio >> 1;
}
return ratio == 1;
}
}
// Generic sound expansion function for any sample rate
static void ExpandSoundData(byte *data,
int samplerate,
int length,
Mix_Chunk *destination)
{
SDL_AudioCVT convertor;
if (samplerate <= mixer_freq
&& ConvertibleRatio(samplerate, mixer_freq)
&& SDL_BuildAudioCVT(&convertor,
AUDIO_U8, 1, samplerate,
mixer_format, mixer_channels, mixer_freq))
{
convertor.buf = destination->abuf;
convertor.len = length;
memcpy(convertor.buf, data, length);
SDL_ConvertAudio(&convertor);
}
else
{
Sint16 *expanded = (Sint16 *) destination->abuf;
int expanded_length;
int expand_ratio;
int i;
// Generic expansion if conversion does not work:
//
// SDL's audio conversion only works for rate conversions that are
// powers of 2; if the two formats are not in a direct power of 2
// ratio, do this naive conversion instead.
// number of samples in the converted sound
expanded_length = (length * mixer_freq) / samplerate;
expand_ratio = (length << 8) / expanded_length;
for (i=0; i<expanded_length; ++i)
{
Sint16 sample;
int src;
src = (i * expand_ratio) >> 8;
sample = data[src] | (data[src] << 8);
sample -= 32768;
// expand 8->16 bits, mono->stereo
expanded[i * 2] = expanded[i * 2 + 1] = sample;
}
}
}
// Load and convert a sound effect
// Returns true if successful
static boolean CacheSFX(int sound)
{
int lumpnum;
unsigned int lumplen;
int samplerate;
unsigned int length;
unsigned int expanded_length;
byte *data;
// need to load the sound
lumpnum = S_sfx[sound].lumpnum;
data = W_CacheLumpNum(lumpnum, PU_STATIC);
lumplen = W_LumpLength(lumpnum);
// Check the header, and ensure this is a valid sound
if (lumplen < 8
|| data[0] != 0x03 || data[1] != 0x00)
{
// Invalid sound
return false;
}
// 16 bit sample rate field, 32 bit length field
samplerate = (data[3] << 8) | data[2];
length = (data[7] << 24) | (data[6] << 16) | (data[5] << 8) | data[4];
// If the header specifies that the length of the sound is greater than
// the length of the lump itself, this is an invalid sound lump
if (length - 8 > lumplen)
{
return false;
}
expanded_length = (uint32_t) ((((uint64_t) length) * 4 * mixer_freq) / samplerate);
sound_chunks[sound].allocated = 1;
sound_chunks[sound].alen = expanded_length;
sound_chunks[sound].abuf
= Z_Malloc(expanded_length, PU_STATIC, &sound_chunks[sound].abuf);
sound_chunks[sound].volume = MIX_MAX_VOLUME;
ExpandSoundData(data + 8,
samplerate,
length - 8,
&sound_chunks[sound]);
// don't need the original lump any more
Z_ChangeTag(data, PU_CACHE);
return true;
}
static Mix_Chunk *GetSFXChunk(int sound_id)
{
if (sound_chunks[sound_id].abuf == NULL)
{
if (!CacheSFX(sound_id))
return NULL;
}
else
{
// don't free the sound while it is playing!
Z_ChangeTag(sound_chunks[sound_id].abuf, PU_STATIC);
}
return &sound_chunks[sound_id];
}
//
// Retrieve the raw data lump index
// for a given SFX name.
//
static int I_SDL_GetSfxLumpNum(sfxinfo_t* sfx)
{
char namebuf[9];
sprintf(namebuf, "ds%s", DEH_String(sfx->name));
return W_GetNumForName(namebuf);
}
static void I_SDL_UpdateSoundParams(int handle, int vol, int sep)
{
int left, right;
if (!sound_initialised)
{
return;
}
left = ((254 - sep) * vol) / 127;
right = ((sep) * vol) / 127;
Mix_SetPanning(handle, left, right);
}
//
// Starting a sound means adding it
// to the current list of active sounds
// in the internal channels.
// As the SFX info struct contains
// e.g. a pointer to the raw data,
// it is ignored.
// As our sound handling does not handle
// priority, it is ignored.
// Pitching (that is, increased speed of playback)
// is set, but currently not used by mixing.
//
static int I_SDL_StartSound(int id, int channel, int vol, int sep)
{
Mix_Chunk *chunk;
if (!sound_initialised)
{
return -1;
}
// Release a sound effect if there is already one playing
// on this channel
ReleaseSoundOnChannel(channel);
// Get the sound data
chunk = GetSFXChunk(id);
if (chunk == NULL)
{
return -1;
}
// play sound
Mix_PlayChannelTimed(channel, chunk, 0, -1);
channels_playing[channel] = id;
// set separation, etc.
I_SDL_UpdateSoundParams(channel, vol, sep);
return channel;
}
static void I_SDL_StopSound (int handle)
{
if (!sound_initialised)
{
return;
}
Mix_HaltChannel(handle);
// Sound data is no longer needed; release the
// sound data being used for this channel
ReleaseSoundOnChannel(handle);
}
static boolean I_SDL_SoundIsPlaying(int handle)
{
if (handle < 0)
{
return false;
}
return Mix_Playing(handle);
}
//
// Periodically called to update the sound system
//
static void I_SDL_UpdateSound(void)
{
int i;
// Check all channels to see if a sound has finished
for (i=0; i<NUM_CHANNELS; ++i)
{
if (channels_playing[i] && !I_SDL_SoundIsPlaying(i))
{
// Sound has finished playing on this channel,
// but sound data has not been released to cache
ReleaseSoundOnChannel(i);
}
}
}
static void I_SDL_ShutdownSound(void)
{
if (!sound_initialised)
{
return;
}
Mix_CloseAudio();
SDL_QuitSubSystem(SDL_INIT_AUDIO);
sound_initialised = false;
}
static boolean I_SDL_InitSound()
{
int i;
// No sounds yet
for (i=0; i<NUMSFX; ++i)
{
sound_chunks[i].abuf = NULL;
}
for (i=0; i<NUM_CHANNELS; ++i)
{
channels_playing[i] = sfx_None;
}
if (SDL_Init(SDL_INIT_AUDIO) < 0)
{
fprintf(stderr, "Unable to set up sound.\n");
return false;
}
if (Mix_OpenAudio(snd_samplerate, AUDIO_S16SYS, 2, 1024) < 0)
{
fprintf(stderr, "Error initialising SDL_mixer: %s\n", Mix_GetError());
return false;
}
Mix_QuerySpec(&mixer_freq, &mixer_format, &mixer_channels);
Mix_AllocateChannels(NUM_CHANNELS);
SDL_PauseAudio(0);
sound_initialised = true;
return true;
}
static snddevice_t sound_sdl_devices[] =
{
SNDDEVICE_SB,
SNDDEVICE_PAS,
SNDDEVICE_GUS,
SNDDEVICE_WAVEBLASTER,
SNDDEVICE_SOUNDCANVAS,
SNDDEVICE_AWE32,
};
sound_module_t sound_sdl_module =
{
sound_sdl_devices,
arrlen(sound_sdl_devices),
I_SDL_InitSound,
I_SDL_ShutdownSound,
I_SDL_GetSfxLumpNum,
I_SDL_UpdateSound,
I_SDL_UpdateSoundParams,
I_SDL_StartSound,
I_SDL_StopSound,
I_SDL_SoundIsPlaying,
};