shut up a gcc warning
[divverent/darkplaces.git] / 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 "quakedef.h"
20
21 #include <math.h>
22 #include <SDL.h>
23
24 #include "snd_main.h"
25
26
27 static unsigned int sdlaudiotime = 0;
28
29
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)
32 {
33         unsigned int factor, RequestedFrames, MaxFrames, FrameCount;
34         unsigned int StartOffset, EndOffset;
35
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);
39
40         RequestedFrames = (unsigned int)len / factor;
41
42         if (SndSys_LockRenderBuffer())
43         {
44                 if (snd_usethreadedmixing)
45                 {
46                         S_MixToBuffer(stream, RequestedFrames);
47                         if (snd_blocked)
48                                 memset(stream, snd_renderbuffer->format.width == 1 ? 0x80 : 0, len);
49                         SndSys_UnlockRenderBuffer();
50                         return;
51                 }
52
53                 // Transfert up to a chunk of samples from snd_renderbuffer to stream
54                 MaxFrames = snd_renderbuffer->endframe - snd_renderbuffer->startframe;
55                 if (MaxFrames > RequestedFrames)
56                         FrameCount = RequestedFrames;
57                 else
58                         FrameCount = MaxFrames;
59                 StartOffset = snd_renderbuffer->startframe % snd_renderbuffer->maxframes;
60                 EndOffset = (snd_renderbuffer->startframe + FrameCount) % snd_renderbuffer->maxframes;
61                 if (StartOffset > EndOffset)  // if the buffer wraps
62                 {
63                         unsigned int PartialLength1, PartialLength2;
64
65                         PartialLength1 = (snd_renderbuffer->maxframes - StartOffset) * factor;
66                         memcpy(stream, &snd_renderbuffer->ring[StartOffset * factor], PartialLength1);
67
68                         PartialLength2 = FrameCount * factor - PartialLength1;
69                         memcpy(&stream[PartialLength1], &snd_renderbuffer->ring[0], PartialLength2);
70                 }
71                 else
72                         memcpy(stream, &snd_renderbuffer->ring[StartOffset * factor], FrameCount * factor);
73
74                 snd_renderbuffer->startframe += FrameCount;
75
76                 if (FrameCount < RequestedFrames && developer_insane.integer && vid_activewindow)
77                         Con_DPrintf("SDL sound: %u sample frames missing\n", RequestedFrames - FrameCount);
78
79                 sdlaudiotime += RequestedFrames;
80
81                 SndSys_UnlockRenderBuffer();
82         }
83 }
84
85
86 /*
87 ====================
88 SndSys_Init
89
90 Create "snd_renderbuffer" with the proper sound format if the call is successful
91 May return a suggested format if the requested format isn't available
92 ====================
93 */
94 qboolean SndSys_Init (const snd_format_t* requested, snd_format_t* suggested)
95 {
96         unsigned int buffersize;
97         SDL_AudioSpec wantspec;
98         SDL_AudioSpec obtainspec;
99
100         snd_threaded = false;
101
102         Con_DPrint ("SndSys_Init: using the SDL module\n");
103
104         // Init the SDL Audio subsystem
105         if( SDL_InitSubSystem( SDL_INIT_AUDIO ) ) {
106                 Con_Print( "Initializing the SDL Audio subsystem failed!\n" );
107                 return false;
108         }
109
110         buffersize = (unsigned int)ceil((double)requested->speed / 25.0); // 2048 bytes on 24kHz to 48kHz
111
112         // Init the SDL Audio subsystem
113         wantspec.callback = Buffer_Callback;
114         wantspec.userdata = NULL;
115         wantspec.freq = requested->speed;
116         wantspec.format = ((requested->width == 1) ? AUDIO_U8 : AUDIO_S16SYS);
117         wantspec.channels = requested->channels;
118         wantspec.samples = CeilPowerOf2(buffersize);  // needs to be a power of 2 on some platforms.
119
120         Con_Printf("Wanted audio Specification:\n"
121                                 "\tChannels  : %i\n"
122                                 "\tFormat    : 0x%X\n"
123                                 "\tFrequency : %i\n"
124                                 "\tSamples   : %i\n",
125                                 wantspec.channels, wantspec.format, wantspec.freq, wantspec.samples);
126
127         if( SDL_OpenAudio( &wantspec, &obtainspec ) )
128         {
129                 Con_Printf( "Failed to open the audio device! (%s)\n", SDL_GetError() );
130                 return false;
131         }
132
133         Con_Printf("Obtained audio specification:\n"
134                                 "\tChannels  : %i\n"
135                                 "\tFormat    : 0x%X\n"
136                                 "\tFrequency : %i\n"
137                                 "\tSamples   : %i\n",
138                                 obtainspec.channels, obtainspec.format, obtainspec.freq, obtainspec.samples);
139
140         // If we haven't obtained what we wanted
141         if (wantspec.freq != obtainspec.freq ||
142                 wantspec.format != obtainspec.format ||
143                 wantspec.channels != obtainspec.channels)
144         {
145                 SDL_CloseAudio();
146
147                 // Pass the obtained format as a suggested format
148                 if (suggested != NULL)
149                 {
150                         suggested->speed = obtainspec.freq;
151                         // FIXME: check the format more carefully. There are plenty of unsupported cases
152                         suggested->width = ((obtainspec.format == AUDIO_U8) ? 1 : 2);
153                         suggested->channels = obtainspec.channels;
154                 }
155
156                 return false;
157         }
158
159         snd_threaded = true;
160
161         snd_renderbuffer = Snd_CreateRingBuffer(requested, 0, NULL);
162         if (snd_channellayout.integer == SND_CHANNELLAYOUT_AUTO)
163                 Cvar_SetValueQuick (&snd_channellayout, SND_CHANNELLAYOUT_STANDARD);
164
165         sdlaudiotime = 0;
166         SDL_PauseAudio( false );
167
168         return true;
169 }
170
171
172 /*
173 ====================
174 SndSys_Shutdown
175
176 Stop the sound card, delete "snd_renderbuffer" and free its other resources
177 ====================
178 */
179 void SndSys_Shutdown(void)
180 {
181         SDL_CloseAudio();
182
183         if (snd_renderbuffer != NULL)
184         {
185                 Mem_Free(snd_renderbuffer->ring);
186                 Mem_Free(snd_renderbuffer);
187                 snd_renderbuffer = NULL;
188         }
189 }
190
191
192 /*
193 ====================
194 SndSys_Submit
195
196 Submit the contents of "snd_renderbuffer" to the sound card
197 ====================
198 */
199 void SndSys_Submit (void)
200 {
201         // Nothing to do here (this sound module is callback-based)
202 }
203
204
205 /*
206 ====================
207 SndSys_GetSoundTime
208
209 Returns the number of sample frames consumed since the sound started
210 ====================
211 */
212 unsigned int SndSys_GetSoundTime (void)
213 {
214         return sdlaudiotime;
215 }
216
217
218 /*
219 ====================
220 SndSys_LockRenderBuffer
221
222 Get the exclusive lock on "snd_renderbuffer"
223 ====================
224 */
225 qboolean SndSys_LockRenderBuffer (void)
226 {
227         SDL_LockAudio();
228         return true;
229 }
230
231
232 /*
233 ====================
234 SndSys_UnlockRenderBuffer
235
236 Release the exclusive lock on "snd_renderbuffer"
237 ====================
238 */
239 void SndSys_UnlockRenderBuffer (void)
240 {
241         SDL_UnlockAudio();
242 }
243
244 /*
245 ====================
246 SndSys_SendKeyEvents
247
248 Send keyboard events originating from the sound system (e.g. MIDI)
249 ====================
250 */
251 void SndSys_SendKeyEvents(void)
252 {
253         // not supported
254 }