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;
30 // Note: SDL calls SDL_LockAudio() right before this function, so no need to lock the audio data here
31 static void Buffer_Callback (void *userdata, Uint8 *stream, int len)
33 unsigned int factor, RequestedFrames, MaxFrames, FrameCount;
34 unsigned int StartOffset, EndOffset;
36 factor = snd_renderbuffer->format.channels * snd_renderbuffer->format.width;
37 if ((unsigned int)len % factor != 0)
38 Sys_Error("SDL sound: invalid buffer length passed to Buffer_Callback (%d bytes)\n", len);
40 RequestedFrames = (unsigned int)len / factor;
42 // Transfert up to a chunk of samples from snd_renderbuffer to stream
43 MaxFrames = snd_renderbuffer->endframe - snd_renderbuffer->startframe;
44 if (MaxFrames > RequestedFrames)
45 FrameCount = RequestedFrames;
47 FrameCount = MaxFrames;
48 StartOffset = snd_renderbuffer->startframe % snd_renderbuffer->maxframes;
49 EndOffset = (snd_renderbuffer->startframe + FrameCount) % snd_renderbuffer->maxframes;
50 if (StartOffset > EndOffset) // if the buffer wraps
52 unsigned int PartialLength1, PartialLength2;
54 PartialLength1 = (snd_renderbuffer->maxframes - StartOffset) * factor;
55 memcpy(stream, &snd_renderbuffer->ring[StartOffset * factor], PartialLength1);
57 PartialLength2 = FrameCount * factor - PartialLength1;
58 memcpy(&stream[PartialLength1], &snd_renderbuffer->ring[0], PartialLength2);
61 memcpy(stream, &snd_renderbuffer->ring[StartOffset * factor], FrameCount * factor);
63 snd_renderbuffer->startframe += FrameCount;
65 if (FrameCount < RequestedFrames && developer.integer >= 100)
66 Con_DPrintf("SDL sound: %u sample frames missing\n", RequestedFrames - FrameCount);
68 sdlaudiotime += RequestedFrames;
76 Create "snd_renderbuffer" with the proper sound format if the call is successful
77 May return a suggested format if the requested format isn't available
80 qboolean SndSys_Init (const snd_format_t* requested, snd_format_t* suggested)
82 unsigned int buffersize;
83 SDL_AudioSpec wantspec;
84 SDL_AudioSpec obtainspec;
86 Con_Print ("SndSys_Init: using the SDL module\n");
88 // Init the SDL Audio subsystem
89 if( SDL_InitSubSystem( SDL_INIT_AUDIO ) ) {
90 Con_Print( "Initializing the SDL Audio subsystem failed!\n" );
94 buffersize = (unsigned int)ceil((double)requested->speed / 20.0);
96 // Init the SDL Audio subsystem
97 wantspec.callback = Buffer_Callback;
98 wantspec.userdata = NULL;
99 wantspec.freq = requested->speed;
100 wantspec.format = ((requested->width == 1) ? AUDIO_U8 : AUDIO_S16SYS);
101 wantspec.channels = requested->channels;
102 wantspec.samples = CeilPowerOf2(buffersize); // needs to be a power of 2 on some platforms.
104 Con_DPrintf("Wanted audio Specification:\n"
109 wantspec.channels, wantspec.format, wantspec.freq, wantspec.samples);
111 if( SDL_OpenAudio( &wantspec, &obtainspec ) )
113 Con_Printf( "Failed to open the audio device! (%s)\n", SDL_GetError() );
117 Con_DPrintf("Obtained audio specification:\n"
122 obtainspec.channels, obtainspec.format, obtainspec.freq, obtainspec.samples);
124 // If we haven't obtained what we wanted
125 if (wantspec.freq != obtainspec.freq ||
126 wantspec.format != obtainspec.format ||
127 wantspec.channels != obtainspec.channels)
131 // Pass the obtained format as a suggested format
132 if (suggested != NULL)
134 suggested->speed = obtainspec.freq;
135 // FIXME: check the format more carefully. There are plenty of unsupported cases
136 suggested->width = ((obtainspec.format == AUDIO_U8) ? 1 : 2);
137 suggested->channels = obtainspec.channels;
143 snd_renderbuffer = Snd_CreateRingBuffer(requested, 0, NULL);
144 if (snd_channellayout.integer == SND_CHANNELLAYOUT_AUTO)
149 newlayout = SND_CHANNELLAYOUT_ALSA;
151 newlayout = SND_CHANNELLAYOUT_STANDARD;
153 Cvar_SetValueQuick (&snd_channellayout, newlayout);
157 SDL_PauseAudio( false );
167 Stop the sound card, delete "snd_renderbuffer" and free its other resources
170 void SndSys_Shutdown(void)
174 if (snd_renderbuffer != NULL)
176 Mem_Free(snd_renderbuffer->ring);
177 Mem_Free(snd_renderbuffer);
178 snd_renderbuffer = NULL;
187 Submit the contents of "snd_renderbuffer" to the sound card
190 void SndSys_Submit (void)
192 // Nothing to do here (this sound module is callback-based)
200 Returns the number of sample frames consumed since the sound started
203 unsigned int SndSys_GetSoundTime (void)
211 SndSys_LockRenderBuffer
213 Get the exclusive lock on "snd_renderbuffer"
216 qboolean SndSys_LockRenderBuffer (void)
225 SndSys_UnlockRenderBuffer
227 Release the exclusive lock on "snd_renderbuffer"
230 void SndSys_UnlockRenderBuffer (void)