snd_sdl.c

   1 /*
   2 Copyright (C) 2004 Andreas Kirsch
   3
   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.
   8
   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.
  12
  13 See the GNU General Public License for more details.
  14
  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.
  18 */
  19 #include <math.h>
  20 #include <SDL.h>
  21
  22 #include "quakedef.h"
  23
  24 #include "snd_main.h"
  25
  26
  27 static unsigned int sdlaudiotime = 0;
  28 static int audio_device = 0;
  29
  30
  31 // Note: SDL calls SDL_LockAudio() right before this function, so no need to lock the audio data here
  32 static void Buffer_Callback (void *userdata, Uint8 *stream, int len)
  33 {
  34         unsigned int factor, RequestedFrames, MaxFrames, FrameCount;
  35         unsigned int StartOffset, EndOffset;
  36
  37         factor = snd_renderbuffer->format.channels * snd_renderbuffer->format.width;
  38         if ((unsigned int)len % factor != 0)
  39                 Sys_Error("SDL sound: invalid buffer length passed to Buffer_Callback (%d bytes)\n", len);
  40
  41         RequestedFrames = (unsigned int)len / factor;
  42
  43         if (SndSys_LockRenderBuffer())
  44         {
  45                 if (snd_usethreadedmixing)
  46                 {
  47                         S_MixToBuffer(stream, RequestedFrames);
  48                         if (snd_blocked)
  49                                 memset(stream, snd_renderbuffer->format.width == 1 ? 0x80 : 0, len);
  50                         SndSys_UnlockRenderBuffer();
  51                         return;
  52                 }
  53
  54                 // Transfert up to a chunk of samples from snd_renderbuffer to stream
  55                 MaxFrames = snd_renderbuffer->endframe - snd_renderbuffer->startframe;
  56                 if (MaxFrames > RequestedFrames)
  57                         FrameCount = RequestedFrames;
  58                 else
  59                         FrameCount = MaxFrames;
  60                 StartOffset = snd_renderbuffer->startframe % snd_renderbuffer->maxframes;
  61                 EndOffset = (snd_renderbuffer->startframe + FrameCount) % snd_renderbuffer->maxframes;
  62                 if (StartOffset > EndOffset)  // if the buffer wraps
  63                 {
  64                         unsigned int PartialLength1, PartialLength2;
  65
  66                         PartialLength1 = (snd_renderbuffer->maxframes - StartOffset) * factor;
  67                         memcpy(stream, &snd_renderbuffer->ring[StartOffset * factor], PartialLength1);
  68
  69                         PartialLength2 = FrameCount * factor - PartialLength1;
  70                         memcpy(&stream[PartialLength1], &snd_renderbuffer->ring[0], PartialLength2);
  71                 }
  72                 else
  73                         memcpy(stream, &snd_renderbuffer->ring[StartOffset * factor], FrameCount * factor);
  74
  75                 snd_renderbuffer->startframe += FrameCount;
  76
  77                 if (FrameCount < RequestedFrames && developer_insane.integer && vid_activewindow)
  78                         Con_DPrintf("SDL sound: %u sample frames missing\n", RequestedFrames - FrameCount);
  79
  80                 sdlaudiotime += RequestedFrames;
  81
  82                 SndSys_UnlockRenderBuffer();
  83         }
  84 }
  85
  86
  87 /*
  88 ====================
  89 SndSys_Init
  90
  91 Create "snd_renderbuffer" with the proper sound format if the call is successful
  92 May return a suggested format if the requested format isn't available
  93 ====================
  94 */
  95 qboolean SndSys_Init (const snd_format_t* requested, snd_format_t* suggested)
  96 {
  97         unsigned int buffersize;
  98         SDL_AudioSpec wantspec;
  99         SDL_AudioSpec obtainspec;
 100
 101         snd_threaded = false;
 102
 103         Con_DPrint ("SndSys_Init: using the SDL module\n");
 104
 105         // Init the SDL Audio subsystem
 106         if( SDL_InitSubSystem( SDL_INIT_AUDIO ) ) {
 107                 Con_Print( "Initializing the SDL Audio subsystem failed!\n" );
 108                 return false;
 109         }
 110
 111         buffersize = (unsigned int)ceil((double)requested->speed / 25.0); // 2048 bytes on 24kHz to 48kHz
 112
 113         // Init the SDL Audio subsystem
 114         wantspec.callback = Buffer_Callback;
 115         wantspec.userdata = NULL;
 116         wantspec.freq = requested->speed;
 117         wantspec.format = ((requested->width == 1) ? AUDIO_U8 : AUDIO_S16SYS);
 118         wantspec.channels = requested->channels;
 119         wantspec.samples = CeilPowerOf2(buffersize);  // needs to be a power of 2 on some platforms.
 120
 121         Con_Printf("Wanted audio Specification:\n"
 122                                 "\tChannels  : %i\n"
 123                                 "\tFormat    : 0x%X\n"
 124                                 "\tFrequency : %i\n"
 125                                 "\tSamples   : %i\n",
 126                                 wantspec.channels, wantspec.format, wantspec.freq, wantspec.samples);
 127
 128         if ((audio_device = SDL_OpenAudioDevice(NULL, 0, &wantspec, &obtainspec, 0)) == 0)
 129         {
 130                 Con_Printf( "Failed to open the audio device! (%s)\n", SDL_GetError() );
 131                 return false;
 132         }
 133
 134         Con_Printf("Obtained audio specification:\n"
 135                                 "\tChannels  : %i\n"
 136                                 "\tFormat    : 0x%X\n"
 137                                 "\tFrequency : %i\n"
 138                                 "\tSamples   : %i\n",
 139                                 obtainspec.channels, obtainspec.format, obtainspec.freq, obtainspec.samples);
 140
 141         // If we haven't obtained what we wanted
 142         if (wantspec.freq != obtainspec.freq ||
 143                 wantspec.format != obtainspec.format ||
 144                 wantspec.channels != obtainspec.channels)
 145         {
 146                 SDL_CloseAudioDevice(audio_device);
 147
 148                 // Pass the obtained format as a suggested format
 149                 if (suggested != NULL)
 150                 {
 151                         suggested->speed = obtainspec.freq;
 152                         // FIXME: check the format more carefully. There are plenty of unsupported cases
 153                         suggested->width = ((obtainspec.format == AUDIO_U8) ? 1 : 2);
 154                         suggested->channels = obtainspec.channels;
 155                 }
 156
 157                 return false;
 158         }
 159
 160         snd_threaded = true;
 161
 162         snd_renderbuffer = Snd_CreateRingBuffer(requested, 0, NULL);
 163         if (snd_channellayout.integer == SND_CHANNELLAYOUT_AUTO)
 164                 Cvar_SetValueQuick (&snd_channellayout, SND_CHANNELLAYOUT_STANDARD);
 165
 166         sdlaudiotime = 0;
 167         SDL_PauseAudioDevice(audio_device, 0);
 168
 169         return true;
 170 }
 171
 172
 173 /*
 174 ====================
 175 SndSys_Shutdown
 176
 177 Stop the sound card, delete "snd_renderbuffer" and free its other resources
 178 ====================
 179 */
 180 void SndSys_Shutdown(void)
 181 {
 182         if (audio_device > 0) {
 183                 SDL_CloseAudioDevice(audio_device);
 184                 audio_device = 0;
 185         }
 186         if (snd_renderbuffer != NULL)
 187         {
 188                 Mem_Free(snd_renderbuffer->ring);
 189                 Mem_Free(snd_renderbuffer);
 190                 snd_renderbuffer = NULL;
 191         }
 192 }
 193
 194
 195 /*
 196 ====================
 197 SndSys_Submit
 198
 199 Submit the contents of "snd_renderbuffer" to the sound card
 200 ====================
 201 */
 202 void SndSys_Submit (void)
 203 {
 204         // Nothing to do here (this sound module is callback-based)
 205 }
 206
 207
 208 /*
 209 ====================
 210 SndSys_GetSoundTime
 211
 212 Returns the number of sample frames consumed since the sound started
 213 ====================
 214 */
 215 unsigned int SndSys_GetSoundTime (void)
 216 {
 217         return sdlaudiotime;
 218 }
 219
 220
 221 /*
 222 ====================
 223 SndSys_LockRenderBuffer
 224
 225 Get the exclusive lock on "snd_renderbuffer"
 226 ====================
 227 */
 228 qboolean SndSys_LockRenderBuffer (void)
 229 {
 230         SDL_LockAudioDevice(audio_device);
 231         return true;
 232 }
 233
 234
 235 /*
 236 ====================
 237 SndSys_UnlockRenderBuffer
 238
 239 Release the exclusive lock on "snd_renderbuffer"
 240 ====================
 241 */
 242 void SndSys_UnlockRenderBuffer (void)
 243 {
 244         SDL_UnlockAudioDevice(audio_device);
 245 }
 246
 247 /*
 248 ====================
 249 SndSys_SendKeyEvents
 250
 251 Send keyboard events originating from the sound system (e.g. MIDI)
 252 ====================
 253 */
 254 void SndSys_SendKeyEvents(void)
 255 {
 256         // not supported
 257 }