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
44 static void Buffer_Callback(void *userdata, Uint8 *stream, int len);
51 void S_BlockSound( void )
55 if( snd_blocked == 1 )
56 SDL_PauseAudio( true );
65 void S_UnblockSound( void )
68 if( snd_blocked == 0 )
69 SDL_PauseAudio( false );
77 Try to find a sound device to mix for.
78 Returns false if nothing is found.
82 qboolean SNDDMA_Init(void)
87 // Init the SDL Audio subsystem
88 if( SDL_InitSubSystem( SDL_INIT_AUDIO ) ) {
89 Con_Print( "Initializing the SDL Audio subsystem failed!\n" );
93 // Init the shm structure
94 memset( (void*) shm, 0, sizeof(*shm) );
96 shm->format.channels = 2; //stereo
97 shm->format.width = 2;
99 // COMMANDLINEOPTION: SDL Sound: -sndspeed <hz> chooses 44100 hz, 22100 hz, or 11025 hz sound output rate
100 i = COM_CheckParm( "-sndspeed" );
101 if( i && i != ( com_argc - 1 ) )
102 shm->format.speed = atoi( com_argv[ i+1 ] );
104 shm->format.speed = 44100;
107 shm->samples = AUDIO_SDL_SAMPLES * AUDIO_LOCALFACTOR;
108 shm->bufferlength = shm->samples * shm->format.width;
109 shm->buffer = (unsigned char *)Mem_Alloc( snd_mempool, shm->bufferlength );
111 // Init the as structure
112 as.buffer = shm->buffer;
113 as.width = shm->format.width;
115 as.size = shm->bufferlength;
117 // Init the SDL Audio subsystem
118 spec.callback = Buffer_Callback;
119 spec.channels = shm->format.channels;
120 spec.format = AUDIO_S16SYS;
121 spec.freq = shm->format.speed;
122 spec.userdata = NULL;
123 spec.samples = AUDIO_SDL_SAMPLES;
125 if( SDL_OpenAudio( &spec, NULL ) ) {
126 Con_Print( "Failed to open the audio device!\n" );
128 "Audio Specification:\n"
132 "\tBuffersize: %i Bytes(%i Samples)\n",
133 spec.channels, spec.format, spec.freq, shm->bufferlength , spec.samples );
134 Mem_Free( shm->buffer );
138 SDL_PauseAudio( false );
147 return the current sample position (in mono samples read)
148 inside the recirculating dma buffer, so the mixing code will know
149 how many sample are required to fill it up.
152 int SNDDMA_GetDMAPos(void)
154 shm->samplepos = (as.pos / as.width) % shm->samples;
155 return shm->samplepos;
162 Send sound to device if buffer isn't really the dma buffer
165 void SNDDMA_Submit(void)
174 Reset the sound device for exiting
177 void SNDDMA_Shutdown(void)
180 Mem_Free( as.buffer );
183 void *S_LockBuffer(void)
189 void S_UnlockBuffer(void)
194 static void Buffer_Callback(void *userdata, Uint8 *stream, int len)
198 if( len > as.size - as.pos ) {
199 memcpy( stream, (Uint8*) as.buffer + as.pos, as.size - as.pos );
200 len -= as.size - as.pos;
203 memcpy( stream, (Uint8*) as.buffer + as.pos, len );
204 as.pos = (as.pos + len) % as.size;