audio_core: Remove global state

src/audio_core/dsp_interface.cpp

@@ -0,0 +1,75 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cstddef>
+#include "audio_core/dsp_interface.h"
+#include "audio_core/sink.h"
+#include "audio_core/sink_details.h"
+#include "common/assert.h"
+
+namespace AudioCore {
+
+DspInterface::DspInterface() = default;
+
+DspInterface::~DspInterface() {
+    if (perform_time_stretching) {
+        FlushResidualStretcherAudio();
+    }
+}
+
+void DspInterface::SetSink(const std::string& sink_id) {
+    const SinkDetails& sink_details = GetSinkDetails(sink_id);
+    sink = sink_details.factory();
+    time_stretcher.SetOutputSampleRate(sink->GetNativeSampleRate());
+}
+
+Sink& DspInterface::GetSink() {
+    ASSERT(sink);
+    return *sink.get();
+}
+
+void DspInterface::EnableStretching(bool enable) {
+    if (perform_time_stretching == enable)
+        return;
+
+    if (!enable) {
+        FlushResidualStretcherAudio();
+    }
+    perform_time_stretching = enable;
+}
+
+void DspInterface::OutputFrame(const StereoFrame16& frame) {
+    if (!sink)
+        return;
+
+    if (perform_time_stretching) {
+        time_stretcher.AddSamples(&frame[0][0], frame.size());
+        std::vector<s16> stretched_samples = time_stretcher.Process(sink->SamplesInQueue());
+        sink->EnqueueSamples(stretched_samples.data(), stretched_samples.size() / 2);
+    } else {
+        constexpr size_t maximum_sample_latency = 2048; // about 64 miliseconds
+        if (sink->SamplesInQueue() > maximum_sample_latency) {
+            // This can occur if we're running too fast and samples are starting to back up.
+            // Just drop the samples.
+            return;
+        }
+
+        sink->EnqueueSamples(&frame[0][0], frame.size());
+    }
+}
+
+void DspInterface::FlushResidualStretcherAudio() {
+    if (!sink)
+        return;
+
+    time_stretcher.Flush();
+    while (true) {
+        std::vector<s16> residual_audio = time_stretcher.Process(sink->SamplesInQueue());
+        if (residual_audio.empty())
+            break;
+        sink->EnqueueSamples(residual_audio.data(), residual_audio.size() / 2);
+    }
+}
+
+} // namespace AudioCore