1 /*************************************************************************/
2 /* audio_driver_alsa.cpp */
3 /*************************************************************************/
4 /* This file is part of: */
5 /* GODOT ENGINE */
6 /* https://godotengine.org */
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8 /* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur. */
9 /* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md) */
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17 /* the following conditions: */
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21 /* */
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24 /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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29 /*************************************************************************/
30 #include "audio_driver_alsa.h"
31
32 #ifdef ALSA_ENABLED
33
34 #include "globals.h"
35 #include <errno.h>
36
init()37 Error AudioDriverALSA::init() {
38
39 active = false;
40 thread_exited = false;
41 exit_thread = false;
42 pcm_open = false;
43 samples_in = NULL;
44 samples_out = NULL;
45
46 mix_rate = GLOBAL_DEF("audio/mix_rate", 44100);
47 output_format = OUTPUT_STEREO;
48 channels = 2;
49
50 int status;
51 snd_pcm_hw_params_t *hwparams;
52 snd_pcm_sw_params_t *swparams;
53
54 #define CHECK_FAIL(m_cond) \
55 if (m_cond) { \
56 fprintf(stderr, "ALSA ERR: %s\n", snd_strerror(status)); \
57 snd_pcm_close(pcm_handle); \
58 ERR_FAIL_COND_V(m_cond, ERR_CANT_OPEN); \
59 }
60
61 //todo, add
62 //6 chans - "plug:surround51"
63 //4 chans - "plug:surround40";
64
65 status = snd_pcm_open(&pcm_handle, "default", SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
66
67 ERR_FAIL_COND_V(status < 0, ERR_CANT_OPEN);
68
69 snd_pcm_hw_params_alloca(&hwparams);
70
71 status = snd_pcm_hw_params_any(pcm_handle, hwparams);
72 CHECK_FAIL(status < 0);
73
74 status = snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED);
75 CHECK_FAIL(status < 0);
76
77 //not interested in anything else
78 status = snd_pcm_hw_params_set_format(pcm_handle, hwparams, SND_PCM_FORMAT_S16_LE);
79 CHECK_FAIL(status < 0);
80
81 //todo: support 4 and 6
82 status = snd_pcm_hw_params_set_channels(pcm_handle, hwparams, 2);
83 CHECK_FAIL(status < 0);
84
85 status = snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, &mix_rate, NULL);
86 CHECK_FAIL(status < 0);
87
88 int latency = GLOBAL_DEF("audio/output_latency", 25);
89 buffer_size = closest_power_of_2(latency * mix_rate / 1000);
90
91 // set buffer size from project settings
92 status = snd_pcm_hw_params_set_buffer_size_near(pcm_handle, hwparams, &buffer_size);
93 CHECK_FAIL(status < 0);
94
95 // make period size 1/8
96 period_size = buffer_size >> 3;
97 status = snd_pcm_hw_params_set_period_size_near(pcm_handle, hwparams, &period_size, NULL);
98 CHECK_FAIL(status < 0);
99
100 unsigned int periods = 2;
101 status = snd_pcm_hw_params_set_periods_near(pcm_handle, hwparams, &periods, NULL);
102 CHECK_FAIL(status < 0);
103
104 status = snd_pcm_hw_params(pcm_handle, hwparams);
105 CHECK_FAIL(status < 0);
106
107 //snd_pcm_hw_params_free(&hwparams);
108
109 snd_pcm_sw_params_alloca(&swparams);
110
111 status = snd_pcm_sw_params_current(pcm_handle, swparams);
112 CHECK_FAIL(status < 0);
113
114 status = snd_pcm_sw_params_set_avail_min(pcm_handle, swparams, period_size);
115 CHECK_FAIL(status < 0);
116
117 status = snd_pcm_sw_params_set_start_threshold(pcm_handle, swparams, 1);
118 CHECK_FAIL(status < 0);
119
120 status = snd_pcm_sw_params(pcm_handle, swparams);
121 CHECK_FAIL(status < 0);
122
123 samples_in = memnew_arr(int32_t, period_size * channels);
124 samples_out = memnew_arr(int16_t, period_size * channels);
125
126 snd_pcm_nonblock(pcm_handle, 0);
127
128 mutex = Mutex::create();
129 thread = Thread::create(AudioDriverALSA::thread_func, this);
130
131 return OK;
132 };
133
thread_func(void * p_udata)134 void AudioDriverALSA::thread_func(void *p_udata) {
135
136 AudioDriverALSA *ad = (AudioDriverALSA *)p_udata;
137
138 while (!ad->exit_thread) {
139 if (!ad->active) {
140 for (unsigned int i = 0; i < ad->period_size * ad->channels; i++) {
141 ad->samples_out[i] = 0;
142 };
143 } else {
144 ad->lock();
145
146 ad->audio_server_process(ad->period_size, ad->samples_in);
147
148 ad->unlock();
149
150 for (unsigned int i = 0; i < ad->period_size * ad->channels; i++) {
151 ad->samples_out[i] = ad->samples_in[i] >> 16;
152 }
153 };
154
155 int todo = ad->period_size;
156 int total = 0;
157
158 while (todo) {
159 if (ad->exit_thread)
160 break;
161 uint8_t *src = (uint8_t *)ad->samples_out;
162 int wrote = snd_pcm_writei(ad->pcm_handle, (void *)(src + (total * ad->channels)), todo);
163
164 if (wrote < 0) {
165 if (ad->exit_thread)
166 break;
167
168 if (wrote == -EAGAIN) {
169 //can't write yet (though this is blocking..)
170 usleep(1000);
171 continue;
172 }
173 wrote = snd_pcm_recover(ad->pcm_handle, wrote, 0);
174 if (wrote < 0) {
175 //absolute fail
176 fprintf(stderr, "ALSA failed and can't recover: %s\n", snd_strerror(wrote));
177 ad->active = false;
178 ad->exit_thread = true;
179 break;
180 }
181 continue;
182 };
183
184 total += wrote;
185 todo -= wrote;
186 };
187 };
188
189 ad->thread_exited = true;
190 };
191
start()192 void AudioDriverALSA::start() {
193
194 active = true;
195 };
196
get_mix_rate() const197 int AudioDriverALSA::get_mix_rate() const {
198
199 return mix_rate;
200 };
201
get_output_format() const202 AudioDriverSW::OutputFormat AudioDriverALSA::get_output_format() const {
203
204 return output_format;
205 };
lock()206 void AudioDriverALSA::lock() {
207
208 if (!thread || !mutex)
209 return;
210 mutex->lock();
211 };
unlock()212 void AudioDriverALSA::unlock() {
213
214 if (!thread || !mutex)
215 return;
216 mutex->unlock();
217 };
218
finish()219 void AudioDriverALSA::finish() {
220
221 if (!thread)
222 return;
223
224 exit_thread = true;
225 Thread::wait_to_finish(thread);
226
227 if (pcm_open)
228 snd_pcm_close(pcm_handle);
229
230 if (samples_in) {
231 memdelete_arr(samples_in);
232 memdelete_arr(samples_out);
233 };
234
235 memdelete(thread);
236 if (mutex)
237 memdelete(mutex);
238 thread = NULL;
239 };
240
AudioDriverALSA()241 AudioDriverALSA::AudioDriverALSA() {
242
243 mutex = NULL;
244 thread = NULL;
245 pcm_handle = NULL;
246 };
247
~AudioDriverALSA()248 AudioDriverALSA::~AudioDriverALSA(){
249
250 };
251
252 #endif
253