From fa52e7c1b74aaf07a9e446cf53bd0625decb9436 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Sat, 29 Sep 2018 22:19:41 -0700
Subject: [PATCH] Fix audio device error with PA renderer (and constify some
 methods)

---
 .../audio/renderers/portaudiorenderer.cpp     | 40 +++++++++++++++----
 .../audio/renderers/portaudiorenderer.h       |  4 +-
 app/streaming/audio/renderers/renderer.h      |  4 +-
 app/streaming/audio/renderers/sdl.h           |  4 +-
 app/streaming/audio/renderers/sdlaud.cpp      |  4 +-
 5 files changed, 40 insertions(+), 16 deletions(-)

diff --git a/app/streaming/audio/renderers/portaudiorenderer.cpp b/app/streaming/audio/renderers/portaudiorenderer.cpp
index abc057ce..076ef4b5 100644
--- a/app/streaming/audio/renderers/portaudiorenderer.cpp
+++ b/app/streaming/audio/renderers/portaudiorenderer.cpp
@@ -109,7 +109,7 @@ void PortAudioRenderer::submitAudio(short* audioBuffer, int audioSize)
     }
 }
 
-bool PortAudioRenderer::testAudio(int audioConfiguration)
+bool PortAudioRenderer::testAudio(int audioConfiguration) const
 {
     PaStreamParameters params = {};
 
@@ -120,6 +120,13 @@ bool PortAudioRenderer::testAudio(int audioConfiguration)
         return false;
     }
 
+    const PaDeviceInfo* deviceInfo = Pa_GetDeviceInfo(outputDeviceIndex);
+    if (deviceInfo == nullptr) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                     "Pa_GetDeviceInfo() failed");
+        return false;
+    }
+
     switch (audioConfiguration)
     {
     case AUDIO_CONFIGURATION_STEREO:
@@ -135,20 +142,37 @@ bool PortAudioRenderer::testAudio(int audioConfiguration)
 
     params.sampleFormat = paInt16;
     params.device = outputDeviceIndex;
+    params.suggestedLatency = deviceInfo->defaultLowOutputLatency;
 
-    PaError error = Pa_IsFormatSupported(nullptr, &params, 48000);
-    if (error == paFormatIsSupported) {
-        return true;
-    }
-    else {
+    // We used to just use Pa_IsFormatSupported() but there are cases
+    // where Pa_IsFormatSupported() will fail but when we actually
+    // call Pa_OpenStream(), it fails with device unavailable.
+    PaStream* stream;
+    PaError error = Pa_OpenStream(&stream, nullptr, &params,
+                                  48000,
+                                  SAMPLES_PER_FRAME,
+                                  paNoFlag,
+                                  nullptr, nullptr);
+    if (error != paNoError) {
         SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
-                     "Pa_IsFormatSupported() failed: %s",
+                     "Pa_OpenStream() failed: %s",
                      Pa_GetErrorText(error));
         return false;
     }
+
+    error = Pa_StartStream(m_Stream);
+    if (error != paNoError) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                     "Pa_StartStream() failed: %s",
+                     Pa_GetErrorText(error));
+    }
+
+    Pa_CloseStream(stream);
+
+    return error == paNoError;
 }
 
-int PortAudioRenderer::detectAudioConfiguration()
+int PortAudioRenderer::detectAudioConfiguration() const
 {
     const PaDeviceInfo* deviceInfo = Pa_GetDeviceInfo(Pa_GetDefaultOutputDevice());
     if (deviceInfo == nullptr) {
diff --git a/app/streaming/audio/renderers/portaudiorenderer.h b/app/streaming/audio/renderers/portaudiorenderer.h
index 8c203329..d1a08b2e 100644
--- a/app/streaming/audio/renderers/portaudiorenderer.h
+++ b/app/streaming/audio/renderers/portaudiorenderer.h
@@ -20,9 +20,9 @@ public:
 
     virtual void submitAudio(short* audioBuffer, int audioSize);
 
-    virtual bool testAudio(int audioConfiguration);
+    virtual bool testAudio(int audioConfiguration) const;
 
-    virtual int detectAudioConfiguration();
+    virtual int detectAudioConfiguration() const;
 
     static int paStreamCallback(const void *input,
                                 void *output,
diff --git a/app/streaming/audio/renderers/renderer.h b/app/streaming/audio/renderers/renderer.h
index 95bc7f40..e67687e2 100644
--- a/app/streaming/audio/renderers/renderer.h
+++ b/app/streaming/audio/renderers/renderer.h
@@ -14,7 +14,7 @@ public:
 
     virtual void submitAudio(short* audioBuffer, int audioSize) = 0;
 
-    virtual bool testAudio(int audioConfiguration) = 0;
+    virtual bool testAudio(int audioConfiguration) const = 0;
 
-    virtual int detectAudioConfiguration() = 0;
+    virtual int detectAudioConfiguration() const = 0;
 };
diff --git a/app/streaming/audio/renderers/sdl.h b/app/streaming/audio/renderers/sdl.h
index b210a4c2..1d22e9ff 100644
--- a/app/streaming/audio/renderers/sdl.h
+++ b/app/streaming/audio/renderers/sdl.h
@@ -19,9 +19,9 @@ public:
 
     virtual void submitAudio(short* audioBuffer, int audioSize);
 
-    virtual bool testAudio(int audioConfiguration);
+    virtual bool testAudio(int audioConfiguration) const;
 
-    virtual int detectAudioConfiguration();
+    virtual int detectAudioConfiguration() const;
 
 private:
     SDL_AudioDeviceID m_AudioDevice;
diff --git a/app/streaming/audio/renderers/sdlaud.cpp b/app/streaming/audio/renderers/sdlaud.cpp
index e7f505f0..dc888c80 100644
--- a/app/streaming/audio/renderers/sdlaud.cpp
+++ b/app/streaming/audio/renderers/sdlaud.cpp
@@ -13,7 +13,7 @@
 // This isn't accurate on macOS and Linux (PulseAudio),
 // since they both report supporting a large number of
 // channels, regardless of the actual output device.
-int SdlAudioRenderer::detectAudioConfiguration()
+int SdlAudioRenderer::detectAudioConfiguration() const
 {
     SDL_AudioSpec want, have;
     SDL_AudioDeviceID dev;
@@ -51,7 +51,7 @@ int SdlAudioRenderer::detectAudioConfiguration()
     }
 }
 
-bool SdlAudioRenderer::testAudio(int audioConfiguration)
+bool SdlAudioRenderer::testAudio(int audioConfiguration) const
 {
     SDL_AudioSpec want, have;
     SDL_AudioDeviceID dev;