1 /*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /** \file SDL.c SDL platform implementation */
18
19 #include "sles_allinclusive.h"
20
21
22 /** \brief Called by SDL to fill the next audio output buffer */
23
SDL_callback(void * context,Uint8 * stream,int len)24 static void SDLCALL SDL_callback(void *context, Uint8 *stream, int len)
25 {
26 assert(len > 0);
27 IEngine *thisEngine = (IEngine *) context;
28 // A peek lock would be risky if output mixes are dynamic, so we use SDL_PauseAudio to
29 // temporarily disable callbacks during any change to the current output mix, and use a
30 // shared lock here
31 interface_lock_shared(thisEngine);
32 COutputMix *outputMix = thisEngine->mOutputMix;
33 interface_unlock_shared(thisEngine);
34 if (NULL != outputMix) {
35 SLOutputMixExtItf OutputMixExt = &outputMix->mOutputMixExt.mItf;
36 IOutputMixExt_FillBuffer(OutputMixExt, stream, (SLuint32) len);
37 } else {
38 memset(stream, 0, (size_t) len);
39 }
40 }
41
42
43 /** \brief Called during slCreateEngine to initialize SDL */
44
SDL_open(IEngine * thisEngine)45 void SDL_open(IEngine *thisEngine)
46 {
47 SDL_AudioSpec fmt;
48 fmt.freq = 44100;
49 fmt.format = AUDIO_S16;
50 fmt.channels = STEREO_CHANNELS;
51 #ifdef _WIN32 // FIXME Either a bug or a serious misunderstanding
52 fmt.samples = SndFile_BUFSIZE;
53 #else
54 fmt.samples = SndFile_BUFSIZE / sizeof(short);
55 #endif
56 fmt.callback = SDL_callback;
57 fmt.userdata = (void *) thisEngine;
58
59 if (SDL_OpenAudio(&fmt, NULL) < 0) {
60 SL_LOGE("Unable to open audio: %s", SDL_GetError());
61 exit(EXIT_FAILURE);
62 }
63 }
64
65
66 /** \brief Called during Object::Destroy for engine to shutdown SDL */
67
SDL_close(void)68 void SDL_close(void)
69 {
70 SDL_CloseAudio();
71 }
72