ref: 3e82d3d2f14bf12f077beb9603caba84d54b445d
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, };