audio_core: Add interfaces for Sink and SinkStream.

src/audio_core/CMakeLists.txt

@@ -2,8 +2,13 @@ add_library(audio_core STATIC
     audio_out.cpp
     audio_out.h
     buffer.h
+    null_sink.h
     stream.cpp
     stream.h
+    sink.h
+    sink_details.cpp
+    sink_details.h
+    sink_stream.h
 )
 
 create_target_directory_groups(audio_core)

src/audio_core/null_sink.h

@@ -0,0 +1,27 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "audio_core/sink.h"
+
+namespace AudioCore {
+
+class NullSink final : public Sink {
+public:
+    explicit NullSink(std::string){};
+    ~NullSink() override = default;
+
+    SinkStream& AcquireSinkStream(u32 /*sample_rate*/, u32 /*num_channels*/) override {
+        return null_sink_stream;
+    }
+
+private:
+    struct NullSinkStreamImpl final : SinkStream {
+        void EnqueueSamples(u32 /*num_channels*/, const s16* /*samples*/,
+                            size_t /*sample_count*/) override {}
+    } null_sink_stream;
+};
+
+} // namespace AudioCore

src/audio_core/sink.h

@@ -0,0 +1,29 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+
+#include "audio_core/sink_stream.h"
+#include "common/common_types.h"
+
+namespace AudioCore {
+
+constexpr char auto_device_name[] = "auto";
+
+/**
+ * This class is an interface for an audio sink. An audio sink accepts samples in stereo signed
+ * PCM16 format to be output. Sinks *do not* handle resampling and expect the correct sample rate.
+ * They are dumb outputs.
+ */
+class Sink {
+public:
+    virtual ~Sink() = default;
+    virtual SinkStream& AcquireSinkStream(u32 sample_rate, u32 num_channels) = 0;
+};
+
+using SinkPtr = std::unique_ptr<Sink>;
+
+} // namespace AudioCore

src/audio_core/sink_details.cpp

@@ -0,0 +1,38 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <memory>
+#include <string>
+#include <vector>
+#include "audio_core/null_sink.h"
+#include "audio_core/sink_details.h"
+#include "common/logging/log.h"
+
+namespace AudioCore {
+
+// g_sink_details is ordered in terms of desirability, with the best choice at the top.
+const std::vector<SinkDetails> g_sink_details = {
+    SinkDetails{"null", &std::make_unique<NullSink, std::string>,
+                [] { return std::vector<std::string>{"null"}; }},
+};
+
+const SinkDetails& GetSinkDetails(std::string sink_id) {
+    auto iter =
+        std::find_if(g_sink_details.begin(), g_sink_details.end(),
+                     [sink_id](const auto& sink_detail) { return sink_detail.id == sink_id; });
+
+    if (sink_id == "auto" || iter == g_sink_details.end()) {
+        if (sink_id != "auto") {
+            LOG_ERROR(Audio, "AudioCore::SelectSink given invalid sink_id {}", sink_id);
+        }
+        // Auto-select.
+        // g_sink_details is ordered in terms of desirability, with the best choice at the front.
+        iter = g_sink_details.begin();
+    }
+
+    return *iter;
+}
+
+} // namespace AudioCore

src/audio_core/sink_details.h

@@ -0,0 +1,32 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <functional>
+#include <memory>
+#include <vector>
+
+namespace AudioCore {
+
+class Sink;
+
+struct SinkDetails {
+    SinkDetails(const char* id_, std::function<std::unique_ptr<Sink>(std::string)> factory_,
+                std::function<std::vector<std::string>()> list_devices_)
+        : id(id_), factory(factory_), list_devices(list_devices_) {}
+
+    /// Name for this sink.
+    const char* id;
+    /// A method to call to construct an instance of this type of sink.
+    std::function<std::unique_ptr<Sink>(std::string device_id)> factory;
+    /// A method to call to list available devices.
+    std::function<std::vector<std::string>()> list_devices;
+};
+
+extern const std::vector<SinkDetails> g_sink_details;
+
+const SinkDetails& GetSinkDetails(std::string sink_id);
+
+} // namespace AudioCore

src/audio_core/sink_stream.h

@@ -0,0 +1,32 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+
+#include "common/common_types.h"
+
+namespace AudioCore {
+
+/**
+ * Accepts samples in stereo signed PCM16 format to be output. Sinks *do not* handle resampling and
+ * expect the correct sample rate. They are dumb outputs.
+ */
+class SinkStream {
+public:
+    virtual ~SinkStream() = default;
+
+    /**
+     * Feed stereo samples to sink.
+     * @param num_channels Number of channels used.
+     * @param samples Samples in interleaved stereo PCM16 format.
+     * @param sample_count Number of samples.
+     */
+    virtual void EnqueueSamples(u32 num_channels, const s16* samples, size_t sample_count) = 0;
+};
+
+using SinkStreamPtr = std::unique_ptr<SinkStream>;
+
+} // namespace AudioCore