2 Copyright (C) 2004 Andreas Kirsch
4 This program is free software; you can redistribute it and/or
5 modify it under the terms of the GNU General Public License
6 as published by the Free Software Foundation; either version 2
7 of the License, or (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
13 See the GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
25 One SDL sample consists of x channel samples
26 The mixer supposes that the driver has one channel entry/sample though it has x channels/sample
30 #define AUDIO_SDL_SAMPLES 4096
31 #define AUDIO_LOCALFACTOR 4
33 typedef struct AudioState_s
42 extern mempool_t *snd_mempool;
45 static void Buffer_Callback(void *userdata, Uint8 *stream, int len);
52 void S_BlockSound( void )
56 if( snd_blocked == 1 )
57 SDL_PauseAudio( true );
66 void S_UnblockSound( void )
69 if( snd_blocked == 0 )
70 SDL_PauseAudio( false );
78 Try to find a sound device to mix for.
79 Returns false if nothing is found.
83 qboolean SNDDMA_Init(void)
88 // Init the SDL Audio subsystem
89 if( SDL_InitSubSystem( SDL_INIT_AUDIO ) ) {
90 Con_Print( "Initializing the SDL Audio subsystem failed!\n" );
94 // Init the shm structure
95 memset( (void*) shm, 0, sizeof(*shm) );
97 shm->format.channels = 2; //stereo
98 shm->format.width = 2;
100 // COMMANDLINEOPTION: SDL Sound: -sndspeed <hz> chooses 44100 hz, 22100 hz, or 11025 hz sound output rate
101 i = COM_CheckParm( "-sndspeed" );
102 if( i && i != ( com_argc - 1 ) )
103 shm->format.speed = atoi( com_argv[ i+1 ] );
105 shm->format.speed = 44100;
108 shm->samples = AUDIO_SDL_SAMPLES * AUDIO_LOCALFACTOR;
109 shm->bufferlength = shm->samples * shm->format.width;
110 shm->buffer = Mem_Alloc( snd_mempool, shm->bufferlength );
112 // Init the as structure
113 as.buffer = shm->buffer;
114 as.width = shm->format.width;
116 as.size = shm->bufferlength;
118 // Init the SDL Audio subsystem
119 spec.callback = Buffer_Callback;
120 spec.channels = shm->format.channels;
121 spec.format = AUDIO_S16SYS;
122 spec.freq = shm->format.speed;
123 spec.userdata = NULL;
124 spec.samples = AUDIO_SDL_SAMPLES;
126 if( SDL_OpenAudio( &spec, NULL ) ) {
127 Con_Print( "Failed to open the audio device!\n" );
129 "Audio Specification:\n"
133 "\tBuffersize: %i Bytes(%i Samples)\n",
134 spec.channels, spec.format, spec.freq, shm->bufferlength , spec.samples );
135 Mem_Free( shm->buffer );
139 SDL_PauseAudio( false );
148 return the current sample position (in mono samples read)
149 inside the recirculating dma buffer, so the mixing code will know
150 how many sample are required to fill it up.
153 int SNDDMA_GetDMAPos(void)
155 shm->samplepos = (as.pos / as.width) % shm->samples;
156 return shm->samplepos;
163 Send sound to device if buffer isn't really the dma buffer
166 void SNDDMA_Submit(void)
175 Reset the sound device for exiting
178 void SNDDMA_Shutdown(void)
181 Mem_Free( as.buffer );
184 void *S_LockBuffer(void)
190 void S_UnlockBuffer(void)
195 static void Buffer_Callback(void *userdata, Uint8 *stream, int len)
199 if( len > as.size - as.pos ) {
200 memcpy( stream, (Uint8*) as.buffer + as.pos, as.size - as.pos );
201 len -= as.size - as.pos;
204 memcpy( stream, (Uint8*) as.buffer + as.pos, len );
205 as.pos = (as.pos + len) % as.size;