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
29
30 // Note: SDL calls SDL_LockAudio() right before this function, so no need to lock the audio data here
Buffer_Callback(void * userdata,Uint8 * stream,int len)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 */
SndSys_Init(const snd_format_t * requested,snd_format_t * suggested)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 */
SndSys_Shutdown(void)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 */
SndSys_Submit(void)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 */
SndSys_GetSoundTime(void)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 */
SndSys_LockRenderBuffer(void)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 */
SndSys_UnlockRenderBuffer(void)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 */
SndSys_SendKeyEvents(void)251 void SndSys_SendKeyEvents(void)
252 {
253 // not supported
254 }
255