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                         // As of SDL 2.0 buffer needs to be fully initialized, so fill leftover part with silence
  73                         memset(&stream[PartialLength1 + PartialLength2], snd_renderbuffer->format.width == 1 ? 0x80 : 0, len - (PartialLength1 + PartialLength2));
  74                 }
  75                 else
  76                 {
  77                         memcpy(stream, &snd_renderbuffer->ring[StartOffset * factor], FrameCount * factor);
  78
  79                         // As of SDL 2.0 buffer needs to be fully initialized, so fill leftover part with silence
  80                         memset(&stream[FrameCount * factor], snd_renderbuffer->format.width == 1 ? 0x80 : 0, len - (FrameCount * factor));
  81                 }
  82
  83                 snd_renderbuffer->startframe += FrameCount;
  84
  85                 if (FrameCount < RequestedFrames && developer_insane.integer && vid_activewindow)
  86                         Con_DPrintf("SDL sound: %u sample frames missing\n", RequestedFrames - FrameCount);
  87
  88                 sdlaudiotime += RequestedFrames;
  89
  90                 SndSys_UnlockRenderBuffer();
  91         }
  92 }
  93
  94
  95 /*
  96 ====================
  97 SndSys_Init
  98
  99 Create "snd_renderbuffer" with the proper sound format if the call is successful
 100 May return a suggested format if the requested format isn't available
 101 ====================
 102 */
 103 qboolean SndSys_Init (const snd_format_t* requested, snd_format_t* suggested)
 104 {
 105         unsigned int buffersize;
 106         SDL_AudioSpec wantspec;
 107         SDL_AudioSpec obtainspec;
 108
 109         snd_threaded = false;
 110
 111         Con_DPrint ("SndSys_Init: using the SDL module\n");
 112
 113         // Init the SDL Audio subsystem
 114         if( SDL_InitSubSystem( SDL_INIT_AUDIO ) ) {
 115                 Con_Print( "Initializing the SDL Audio subsystem failed!\n" );
 116                 return false;
 117         }
 118
 119         buffersize = (unsigned int)ceil((double)requested->speed / 25.0); // 2048 bytes on 24kHz to 48kHz
 120
 121         // Init the SDL Audio subsystem
 122         wantspec.callback = Buffer_Callback;
 123         wantspec.userdata = NULL;
 124         wantspec.freq = requested->speed;
 125         wantspec.format = ((requested->width == 1) ? AUDIO_U8 : AUDIO_S16SYS);
 126         wantspec.channels = requested->channels;
 127         wantspec.samples = CeilPowerOf2(buffersize);  // needs to be a power of 2 on some platforms.
 128
 129         Con_Printf("Wanted audio Specification:\n"
 130                                 "\tChannels  : %i\n"
 131                                 "\tFormat    : 0x%X\n"
 132                                 "\tFrequency : %i\n"
 133                                 "\tSamples   : %i\n",
 134                                 wantspec.channels, wantspec.format, wantspec.freq, wantspec.samples);
 135
 136         if ((audio_device = SDL_OpenAudioDevice(NULL, 0, &wantspec, &obtainspec, 0)) == 0)
 137         {
 138                 Con_Printf( "Failed to open the audio device! (%s)\n", SDL_GetError() );
 139                 return false;
 140         }
 141
 142         Con_Printf("Obtained audio specification:\n"
 143                                 "\tChannels  : %i\n"
 144                                 "\tFormat    : 0x%X\n"
 145                                 "\tFrequency : %i\n"
 146                                 "\tSamples   : %i\n",
 147                                 obtainspec.channels, obtainspec.format, obtainspec.freq, obtainspec.samples);
 148
 149         // If we haven't obtained what we wanted
 150         if (wantspec.freq != obtainspec.freq ||
 151                 wantspec.format != obtainspec.format ||
 152                 wantspec.channels != obtainspec.channels)
 153         {
 154                 SDL_CloseAudioDevice(audio_device);
 155
 156                 // Pass the obtained format as a suggested format
 157                 if (suggested != NULL)
 158                 {
 159                         suggested->speed = obtainspec.freq;
 160                         // FIXME: check the format more carefully. There are plenty of unsupported cases
 161                         suggested->width = ((obtainspec.format == AUDIO_U8) ? 1 : 2);
 162                         suggested->channels = obtainspec.channels;
 163                 }
 164
 165                 return false;
 166         }
 167
 168         snd_threaded = true;
 169
 170         snd_renderbuffer = Snd_CreateRingBuffer(requested, 0, NULL);
 171         if (snd_channellayout.integer == SND_CHANNELLAYOUT_AUTO)
 172                 Cvar_SetValueQuick (&snd_channellayout, SND_CHANNELLAYOUT_STANDARD);
 173
 174         sdlaudiotime = 0;
 175         SDL_PauseAudioDevice(audio_device, 0);
 176
 177         return true;
 178 }
 179
 180
 181 /*
 182 ====================
 183 SndSys_Shutdown
 184
 185 Stop the sound card, delete "snd_renderbuffer" and free its other resources
 186 ====================
 187 */
 188 void SndSys_Shutdown(void)
 189 {
 190         if (audio_device > 0) {
 191                 SDL_CloseAudioDevice(audio_device);
 192                 audio_device = 0;
 193         }
 194         if (snd_renderbuffer != NULL)
 195         {
 196                 Mem_Free(snd_renderbuffer->ring);
 197                 Mem_Free(snd_renderbuffer);
 198                 snd_renderbuffer = NULL;
 199         }
 200 }
 201
 202
 203 /*
 204 ====================
 205 SndSys_Submit
 206
 207 Submit the contents of "snd_renderbuffer" to the sound card
 208 ====================
 209 */
 210 void SndSys_Submit (void)
 211 {
 212         // Nothing to do here (this sound module is callback-based)
 213 }
 214
 215
 216 /*
 217 ====================
 218 SndSys_GetSoundTime
 219
 220 Returns the number of sample frames consumed since the sound started
 221 ====================
 222 */
 223 unsigned int SndSys_GetSoundTime (void)
 224 {
 225         return sdlaudiotime;
 226 }
 227
 228
 229 /*
 230 ====================
 231 SndSys_LockRenderBuffer
 232
 233 Get the exclusive lock on "snd_renderbuffer"
 234 ====================
 235 */
 236 qboolean SndSys_LockRenderBuffer (void)
 237 {
 238         SDL_LockAudioDevice(audio_device);
 239         return true;
 240 }
 241
 242
 243 /*
 244 ====================
 245 SndSys_UnlockRenderBuffer
 246
 247 Release the exclusive lock on "snd_renderbuffer"
 248 ====================
 249 */
 250 void SndSys_UnlockRenderBuffer (void)
 251 {
 252         SDL_UnlockAudioDevice(audio_device);
 253 }
 254
 255 /*
 256 ====================
 257 SndSys_SendKeyEvents
 258
 259 Send keyboard events originating from the sound system (e.g. MIDI)
 260 ====================
 261 */
 262 void SndSys_SendKeyEvents(void)
 263 {
 264         // not supported
 265 }