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.
27 static unsigned int sdlaudiotime = 0;
28 static int audio_device = 0;
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)
34 unsigned int factor, RequestedFrames, MaxFrames, FrameCount;
35 unsigned int StartOffset, EndOffset;
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);
41 RequestedFrames = (unsigned int)len / factor;
43 if (SndSys_LockRenderBuffer())
45 if (snd_usethreadedmixing)
47 S_MixToBuffer(stream, RequestedFrames);
49 memset(stream, snd_renderbuffer->format.width == 1 ? 0x80 : 0, len);
50 SndSys_UnlockRenderBuffer();
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;
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
64 unsigned int PartialLength1, PartialLength2;
66 PartialLength1 = (snd_renderbuffer->maxframes - StartOffset) * factor;
67 memcpy(stream, &snd_renderbuffer->ring[StartOffset * factor], PartialLength1);
69 PartialLength2 = FrameCount * factor - PartialLength1;
70 memcpy(&stream[PartialLength1], &snd_renderbuffer->ring[0], PartialLength2);
72 // As of SDL 2.0 buffer needs to be fully initialized, so fill leftover part with silence
73 // FIXME this is another place that assumes 8bit is always unsigned and others always signed
74 memset(&stream[PartialLength1 + PartialLength2], snd_renderbuffer->format.width == 1 ? 0x80 : 0, len - (PartialLength1 + PartialLength2));
78 memcpy(stream, &snd_renderbuffer->ring[StartOffset * factor], FrameCount * factor);
80 // As of SDL 2.0 buffer needs to be fully initialized, so fill leftover part with silence
81 // FIXME this is another place that assumes 8bit is always unsigned and others always signed
82 memset(&stream[FrameCount * factor], snd_renderbuffer->format.width == 1 ? 0x80 : 0, len - (FrameCount * factor));
85 snd_renderbuffer->startframe += FrameCount;
87 if (FrameCount < RequestedFrames && developer_insane.integer && vid_activewindow)
88 Con_DPrintf("SDL sound: %u sample frames missing\n", RequestedFrames - FrameCount);
90 sdlaudiotime += RequestedFrames;
92 SndSys_UnlockRenderBuffer();
101 Create "snd_renderbuffer" with the proper sound format if the call is successful
102 May return a suggested format if the requested format isn't available
105 qboolean SndSys_Init (snd_format_t* fmt)
107 unsigned int buffersize;
108 SDL_AudioSpec wantspec;
109 SDL_AudioSpec obtainspec;
111 snd_threaded = false;
113 Con_DPrint ("SndSys_Init: using the SDL module\n");
115 // Init the SDL Audio subsystem
116 if( SDL_InitSubSystem( SDL_INIT_AUDIO ) ) {
117 Con_Print( "Initializing the SDL Audio subsystem failed!\n" );
121 buffersize = (unsigned int)ceil((double)fmt->speed / 25.0); // 2048 bytes on 24kHz to 48kHz
123 // Init the SDL Audio subsystem
124 memset(&wantspec, 0, sizeof(wantspec));
125 wantspec.callback = Buffer_Callback;
126 wantspec.userdata = NULL;
127 wantspec.freq = fmt->speed;
128 wantspec.format = fmt->width == 1 ? AUDIO_U8 : (fmt->width == 2 ? AUDIO_S16SYS : AUDIO_F32);
129 wantspec.channels = fmt->channels;
130 wantspec.samples = CeilPowerOf2(buffersize); // needs to be a power of 2 on some platforms.
132 Con_Printf("Wanted audio Specification:\n"
137 wantspec.channels, wantspec.format, wantspec.freq, wantspec.samples);
139 if ((audio_device = SDL_OpenAudioDevice(NULL, 0, &wantspec, &obtainspec, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE | SDL_AUDIO_ALLOW_CHANNELS_CHANGE)) == 0)
141 Con_Printf( "Failed to open the audio device! (%s)\n", SDL_GetError() );
145 Con_Printf("Obtained audio specification:\n"
150 obtainspec.channels, obtainspec.format, obtainspec.freq, obtainspec.samples);
152 fmt->speed = obtainspec.freq;
153 fmt->channels = obtainspec.channels;
157 snd_renderbuffer = Snd_CreateRingBuffer(fmt, 0, NULL);
158 if (snd_channellayout.integer == SND_CHANNELLAYOUT_AUTO)
159 Cvar_SetValueQuick (&snd_channellayout, SND_CHANNELLAYOUT_STANDARD);
162 SDL_PauseAudioDevice(audio_device, 0);
172 Stop the sound card, delete "snd_renderbuffer" and free its other resources
175 void SndSys_Shutdown(void)
177 if (audio_device > 0) {
178 SDL_CloseAudioDevice(audio_device);
181 if (snd_renderbuffer != NULL)
183 Mem_Free(snd_renderbuffer->ring);
184 Mem_Free(snd_renderbuffer);
185 snd_renderbuffer = NULL;
194 Submit the contents of "snd_renderbuffer" to the sound card
197 void SndSys_Submit (void)
199 // Nothing to do here (this sound module is callback-based)
207 Returns the number of sample frames consumed since the sound started
210 unsigned int SndSys_GetSoundTime (void)
218 SndSys_LockRenderBuffer
220 Get the exclusive lock on "snd_renderbuffer"
223 qboolean SndSys_LockRenderBuffer (void)
225 SDL_LockAudioDevice(audio_device);
232 SndSys_UnlockRenderBuffer
234 Release the exclusive lock on "snd_renderbuffer"
237 void SndSys_UnlockRenderBuffer (void)
239 SDL_UnlockAudioDevice(audio_device);
246 Send keyboard events originating from the sound system (e.g. MIDI)
249 void SndSys_SendKeyEvents(void)