DSP/HLE: Implement mixer processing

src/audio_core/hle/mixers.h

@@ -0,0 +1,63 @@
+// Copyright 2016 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+
+#include "audio_core/hle/common.h"
+#include "audio_core/hle/dsp.h"
+
+namespace DSP {
+namespace HLE {
+
+class Mixers final {
+public:
+    Mixers() {
+        Reset();
+    }
+
+    void Reset();
+
+    DspStatus Tick(DspConfiguration& config,
+                   const IntermediateMixSamples& read_samples,
+                   IntermediateMixSamples& write_samples,
+                   const std::array<QuadFrame32, 3>& input);
+
+    StereoFrame16 GetOutput() const {
+        return current_frame;
+    }
+
+private:
+    StereoFrame16 current_frame = {};
+
+    using OutputFormat = DspConfiguration::OutputFormat;
+
+    struct {
+        std::array<float, 3> intermediate_mixer_volume = {};
+
+        bool mixer1_enabled = false;
+        bool mixer2_enabled = false;
+        std::array<QuadFrame32, 3> intermediate_mix_buffer = {};
+
+        OutputFormat output_format = OutputFormat::Stereo;
+
+    } state;
+
+    /// INTERNAL: Update our internal state based on the current config.
+    void ParseConfig(DspConfiguration& config);
+    /// INTERNAL: Read samples from shared memory that have been modified by the ARM11.
+    void AuxReturn(const IntermediateMixSamples& read_samples);
+    /// INTERNAL: Write samples to shared memory for the ARM11 to modify.
+    void AuxSend(IntermediateMixSamples& write_samples, const std::array<QuadFrame32, 3>& input);
+    /// INTERNAL: Mix current_frame.
+    void MixCurrentFrame();
+    /// INTERNAL: Downmix from quadraphonic to stereo based on status.output_format and accumulate into current_frame.
+    void DownmixAndMixIntoCurrentFrame(float gain, const QuadFrame32& samples);
+    /// INTERNAL: Generate DspStatus based on internal state.
+    DspStatus GetCurrentStatus() const;
+};
+
+} // namespace HLE
+} // namespace DSP