Add SLAudio renderer for Steam Link

app/app.pro

@@ -60,15 +60,21 @@ macx {
 }
 
 unix:!macx {
-    CONFIG += link_pkgconfig soundio
+    CONFIG += link_pkgconfig
     PKGCONFIG += openssl sdl2 SDL2_ttf opus
 
-    # For libsoundio
-    packagesExist(libpulse) {
-        PKGCONFIG += libpulse
+    # SLAudio is used on Steam Link
+    !config_SL {
+        CONFIG += soundio
     }
-    packagesExist(alsa) {
-        PKGCONFIG += alsa
+
+    soundio {
+        packagesExist(libpulse) {
+            PKGCONFIG += libpulse
+        }
+        packagesExist(alsa) {
+            PKGCONFIG += alsa
+        }
     }
 
     packagesExist(libavcodec) {
@@ -208,13 +214,15 @@ libvdpau {
 config_SL {
     message(Steam Link build configuration selected)
 
-    DEFINES += STEAM_LINK HAVE_SLVIDEO
-    LIBS += -lSLVideo
+    DEFINES += STEAM_LINK HAVE_SLVIDEO HAVE_SLAUDIO
+    LIBS += -lSLVideo -lSLAudio
 
     SOURCES += \
-        streaming/video/slvid.cpp
+        streaming/video/slvid.cpp \
+        streaming/audio/renderers/slaud.cpp
     HEADERS += \
-        streaming/video/slvid.h
+        streaming/video/slvid.h \
+        streaming/audio/renderers/slaud.h
 }
 win32:!winrt {
     message(DXVA2 renderer selected)
@@ -270,7 +278,7 @@ else:unix: LIBS += -L$$OUT_PWD/../qmdnsengine/ -lqmdnsengine
 INCLUDEPATH += $$PWD/../qmdnsengine/qmdnsengine/src/include $$PWD/../qmdnsengine
 DEPENDPATH += $$PWD/../qmdnsengine/qmdnsengine/src/include $$PWD/../qmdnsengine
 
-!winrt {
+soundio {
     win32:CONFIG(release, debug|release): LIBS += -L$$OUT_PWD/../soundio/release/ -lsoundio
     else:win32:CONFIG(debug, debug|release): LIBS += -L$$OUT_PWD/../soundio/debug/ -lsoundio
     else:unix: LIBS += -L$$OUT_PWD/../soundio/ -lsoundio

app/streaming/audio/audio.cpp

@@ -5,18 +5,24 @@
 #include "renderers/soundioaudiorenderer.h"
 #endif
 
+#ifdef HAVE_SLAUDIO
+#include "renderers/slaud.h"
+#endif
+
 #include "renderers/sdl.h"
 
 #include <Limelight.h>
 
 IAudioRenderer* Session::createAudioRenderer()
 {
-#ifdef HAVE_SOUNDIO
+#if defined(HAVE_SOUNDIO)
     if (qgetenv("ML_AUDIO") == "SDL") {
         return new SdlAudioRenderer();
     }
 
     return new SoundIoAudioRenderer();
+#elif defined(HAVE_SLAUDIO)
+    return new SLAudioRenderer();
 #else
     return new SdlAudioRenderer();
 #endif

app/streaming/audio/renderers/slaud.cpp

@@ -0,0 +1,58 @@
+#include "slaud.h"
+
+#include <SDL.h>
+
+SLAudioRenderer::SLAudioRenderer()
+    : m_AudioContext(nullptr),
+      m_AudioStream(nullptr)
+{
+}
+
+bool SLAudioRenderer::prepareForPlayback(const OPUS_MULTISTREAM_CONFIGURATION* opusConfig)
+{
+    m_AudioContext = SLAudio_CreateContext();
+    if (m_AudioContext == nullptr) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                     "SLAudio_CreateContext() failed");
+        return false;
+    }
+
+    m_AudioStream = SLAudio_CreateStream(m_AudioContext,
+                                         opusConfig->sampleRate,
+                                         opusConfig->channelCount,
+                                         SAMPLES_PER_FRAME * sizeof(short) * opusConfig->channelCount,
+                                         1);
+    if (m_AudioStream == nullptr) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                     "SLAudio_CreateStream() failed");
+        return false;
+    }
+
+    SDL_LogInfo(SDL_LOG_CATEGORY_APPLICATION,
+                "Using SLAudio renderer");
+
+    return true;
+}
+
+SLAudioRenderer::~SLAudioRenderer()
+{
+    if (m_AudioStream != nullptr) {
+        SLAudio_FreeStream(m_AudioStream);
+    }
+
+    if (m_AudioContext != nullptr) {
+        SLAudio_FreeContext(m_AudioContext);
+    }
+}
+
+bool SLAudioRenderer::submitAudio(short* audioBuffer, int audioSize)
+{
+    void* outputBuffer = SLAudio_BeginFrame(m_AudioStream);
+
+    if (outputBuffer != nullptr) {
+        memcpy(outputBuffer, audioBuffer, audioSize);
+        SLAudio_SubmitFrame(m_AudioStream);
+    }
+
+    return true;
+}

app/streaming/audio/renderers/slaud.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "renderer.h"
+#include <SLAudio.h>
+
+class SLAudioRenderer : public IAudioRenderer
+{
+public:
+    SLAudioRenderer();
+
+    virtual ~SLAudioRenderer();
+
+    virtual bool prepareForPlayback(const OPUS_MULTISTREAM_CONFIGURATION* opusConfig);
+
+    virtual bool submitAudio(short* audioBuffer, int audioSize);
+
+private:
+    CSLAudioContext* m_AudioContext;
+    CSLAudioStream* m_AudioStream;
+};