From 8b00d67febf133e89f6a0bfabc41feed555dc4a9 Mon Sep 17 00:00:00 2001
From: chai <chaifix@163.com>
Date: Sat, 12 Jan 2019 21:48:33 +0800
Subject: =?UTF-8?q?*=E5=8E=BB=E6=8E=89=E6=96=87=E4=BB=B6=E5=89=8D=E7=BC=80?=
 =?UTF-8?q?je=5F?=
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---
 src/libjin/audio/SDL/sdl_audio.cpp | 146 +++++++++++++++++++++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 src/libjin/audio/SDL/sdl_audio.cpp

(limited to 'src/libjin/audio/SDL/sdl_audio.cpp')

diff --git a/src/libjin/audio/SDL/sdl_audio.cpp b/src/libjin/audio/SDL/sdl_audio.cpp
new file mode 100644
index 0000000..4c4bcc2
--- /dev/null
+++ b/src/libjin/audio/SDL/sdl_audio.cpp
@@ -0,0 +1,146 @@
+#include "../../core/configuration.h"
+#if defined(jin_audio) && (jin_audio == jin_audio_sdl)
+
+#include <iostream>
+
+#include "../../math/math.h"
+#include "../../utils/log.h"
+
+#include "sdl_audio.h"
+#include "sdl_source.h"
+
+using namespace JinEngine::Math;
+
+namespace JinEngine
+{
+    namespace Audio
+    {
+        namespace SDL
+        {
+
+            /* 注意callback是在音频线程调用 */
+            static void defaultCallback(void *userdata, Uint8 *stream, int size)
+            {
+                static SDLAudio* audio = static_cast<SDLAudio*>(userdata);
+                if (!audio->goOnProcess())
+                    return;
+                audio->lock();
+                audio->processCommands();
+                audio->processSources(stream, size);
+                audio->processBuffer(stream, size);
+                audio->unlock();
+            }
+
+            /*call only once*/ bool SDLAudio::startSystem(const SettingBase* s)
+            {
+                jin_log_info("Initialize audio system.");
+
+                if (SDL_Init(SDL_INIT_AUDIO) < 0)
+                    return false;
+
+                SDL_AudioSpec spec;
+                Setting* setting = (Setting*)s;
+                if (setting == nullptr)
+                    return false;
+
+                unsigned int samplerate = setting->samplerate;
+                unsigned int samples = clamp<int>(setting->samples, 1, setting->samplerate);
+
+                spec.freq = samplerate;        // 每秒采样的sample数,常用的有 11025, 22050, 44100 and 48000 Hz. 
+                spec.format = AUDIO_S16SYS;      // signed 16-bit samples in native byte order
+                spec.channels = SDLAUDIO_CHANNELS; // 立体声
+                spec.samples = samples;           // 每次采样时都一次性填充好，如果=setting->samplerate则每秒只调用1次
+                spec.userdata = this;
+                spec.callback = defaultCallback;
+
+                audioDevice = SDL_OpenAudioDevice(NULL, 0, &spec, NULL, 0);
+                if (audioDevice == 0)
+                    return false;
+                /* start audio */
+                SDL_PauseAudioDevice(audioDevice, 0);
+                return true;
+            }
+
+            /*call only once*/ void SDLAudio::quitSystem()
+            {
+                jin_log_info("Quit audio system.");
+                SDL_CloseAudio();
+            }
+
+            void SDLAudio::lock()
+            {
+                SDL_LockAudioDevice(audioDevice);
+            }
+
+            void SDLAudio::unlock()
+            {
+                SDL_UnlockAudioDevice(audioDevice);
+            }
+
+            bool SDLAudio::goOnProcess()
+            {
+                if (state == SDLAudio::State::STOP)
+                {
+                    SDLSourceManager::get()->removeAllSource();
+                    pause();
+                    return false;
+                }
+                else if (state == SDLAudio::State::PAUSE)
+                    return false;
+                else
+                    return true;
+            }
+
+            void SDLAudio::processCommands()
+            {
+                SDLSourceManager::get()->processCommands();
+            }
+
+            void SDLAudio::processSources(void* buffer, size_t len)
+            {
+                SDLSourceManager::get()->processSources(buffer, len);
+            }
+
+            void SDLAudio::processBuffer(void* buff, size_t len)
+            {
+                short* buffer = (short*)buff;
+                int samples = (len / SDLAUDIO_BYTEDEPTH) >> 1; // 双声道
+                const char L = 0, R = 1;
+                for (int i = 0; i < samples; ++i)
+                {
+                    short* clip = buffer + (i << 1);
+                    clip[L] *= volume;
+                    clip[R] *= volume;
+                }
+            }
+
+            void SDLAudio::play()
+            {
+                state = State::PLAY;
+            }
+
+            void SDLAudio::stop()
+            {
+                state = State::STOP;
+            }
+
+            void SDLAudio::pause()
+            {
+                state = State::PAUSE;
+            }
+
+            void SDLAudio::resume()
+            {
+                state = State::PLAY;
+            }
+
+            void SDLAudio::setVolume(float volume)
+            {
+                this->volume = clamp(volume, 0.0f, 1.0f);
+            }
+
+        } // namespace SDL
+    } // namespace Audio
+} // namespace JinEngine
+
+#endif // (jin_audio) && (jin_audio == jin_audio_sdl)
\ No newline at end of file
-- 
cgit v1.1-26-g67d0