1 files changed, 201 insertions, 0 deletions
diff --git a/src/audio_core/hle/mixers.cpp b/src/audio_core/hle/mixers.cpp
new file mode 100644
index 000000000..18335f7f0
--- /dev/null
+++ b/src/audio_core/hle/mixers.cpp
@@ -0,0 +1,201 @@
+// Copyright 2016 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cstddef>
+
+#include "audio_core/hle/common.h"
+#include "audio_core/hle/dsp.h"
+#include "audio_core/hle/mixers.h"
+
+#include "common/assert.h"
+#include "common/logging/log.h"
+#include "common/math_util.h"
+
+namespace DSP {
+namespace HLE {
+
+void Mixers::Reset() {
+    current_frame.fill({});
+    state = {};
+}
+
+DspStatus Mixers::Tick(DspConfiguration& config,
+        const IntermediateMixSamples& read_samples,
+        IntermediateMixSamples& write_samples,
+        const std::array<QuadFrame32, 3>& input)
+{
+    ParseConfig(config);
+
+    AuxReturn(read_samples);
+    AuxSend(write_samples, input);
+
+    MixCurrentFrame();
+
+    return GetCurrentStatus();
+}
+
+void Mixers::ParseConfig(DspConfiguration& config) {
+    if (!config.dirty_raw) {
+        return;
+    }
+
+    if (config.mixer1_enabled_dirty) {
+        config.mixer1_enabled_dirty.Assign(0);
+        state.mixer1_enabled = config.mixer1_enabled != 0;
+        LOG_TRACE(Audio_DSP, "mixers mixer1_enabled = %hu", config.mixer1_enabled);
+    }
+
+    if (config.mixer2_enabled_dirty) {
+        config.mixer2_enabled_dirty.Assign(0);
+        state.mixer2_enabled = config.mixer2_enabled != 0;
+        LOG_TRACE(Audio_DSP, "mixers mixer2_enabled = %hu", config.mixer2_enabled);
+    }
+
+    if (config.volume_0_dirty) {
+        config.volume_0_dirty.Assign(0);
+        state.intermediate_mixer_volume[0] = config.volume[0];
+        LOG_TRACE(Audio_DSP, "mixers volume[0] = %f", config.volume[0]);
+    }
+
+    if (config.volume_1_dirty) {
+        config.volume_1_dirty.Assign(0);
+        state.intermediate_mixer_volume[1] = config.volume[1];
+        LOG_TRACE(Audio_DSP, "mixers volume[1] = %f", config.volume[1]);
+    }
+
+    if (config.volume_2_dirty) {
+        config.volume_2_dirty.Assign(0);
+        state.intermediate_mixer_volume[2] = config.volume[2];
+        LOG_TRACE(Audio_DSP, "mixers volume[2] = %f", config.volume[2]);
+    }
+
+    if (config.output_format_dirty) {
+        config.output_format_dirty.Assign(0);
+        state.output_format = config.output_format;
+        LOG_TRACE(Audio_DSP, "mixers output_format = %zu", static_cast<size_t>(config.output_format));
+    }
+
+    if (config.headphones_connected_dirty) {
+        config.headphones_connected_dirty.Assign(0);
+        // Do nothing.
+        // (Note: Whether headphones are connected does affect coefficients used for surround sound.)
+        LOG_TRACE(Audio_DSP, "mixers headphones_connected=%hu", config.headphones_connected);
+    }
+
+    if (config.dirty_raw) {
+        LOG_DEBUG(Audio_DSP, "mixers remaining_dirty=%x", config.dirty_raw);
+    }
+
+    config.dirty_raw = 0;
+}
+
+static s16 ClampToS16(s32 value) {
+    return static_cast<s16>(MathUtil::Clamp(value, -32768, 32767));
+}
+
+static std::array<s16, 2> AddAndClampToS16(const std::array<s16, 2>& a, const std::array<s16, 2>& b) {
+    return {
+        ClampToS16(static_cast<s32>(a[0]) + static_cast<s32>(b[0])),
+        ClampToS16(static_cast<s32>(a[1]) + static_cast<s32>(b[1]))
+    };
+}
+
+void Mixers::DownmixAndMixIntoCurrentFrame(float gain, const QuadFrame32& samples) {
+    // TODO(merry): Limiter. (Currently we're performing final mixing assuming a disabled limiter.)
+
+    switch (state.output_format) {
+    case OutputFormat::Mono:
+        std::transform(current_frame.begin(), current_frame.end(), samples.begin(), current_frame.begin(),
+            [gain](const std::array<s16, 2>& accumulator, const std::array<s32, 4>& sample) -> std::array<s16, 2> {
+                // Downmix to mono
+                s16 mono = ClampToS16(static_cast<s32>((gain * sample[0] + gain * sample[1] + gain * sample[2] + gain * sample[3]) / 2));
+                // Mix into current frame
+                return AddAndClampToS16(accumulator, { mono, mono });
+            });
+        return;
+
+    case OutputFormat::Surround:
+        // TODO(merry): Implement surround sound.
+        // fallthrough
+
+    case OutputFormat::Stereo:
+        std::transform(current_frame.begin(), current_frame.end(), samples.begin(), current_frame.begin(),
+            [gain](const std::array<s16, 2>& accumulator, const std::array<s32, 4>& sample) -> std::array<s16, 2> {
+                // Downmix to stereo
+                s16 left = ClampToS16(static_cast<s32>(gain * sample[0] + gain * sample[2]));
+                s16 right = ClampToS16(static_cast<s32>(gain * sample[1] + gain * sample[3]));
+                // Mix into current frame
+                return AddAndClampToS16(accumulator, { left, right });
+            });
+        return;
+    }
+
+    UNREACHABLE_MSG("Invalid output_format %zu", static_cast<size_t>(state.output_format));
+}
+
+void Mixers::AuxReturn(const IntermediateMixSamples& read_samples) {
+    // NOTE: read_samples.mix{1,2}.pcm32 annoyingly have their dimensions in reverse order to QuadFrame32.
+
+    if (state.mixer1_enabled) {
+        for (size_t sample = 0; sample < samples_per_frame; sample++) {
+            for (size_t channel = 0; channel < 4; channel++) {
+                state.intermediate_mix_buffer[1][sample][channel] = read_samples.mix1.pcm32[channel][sample];
+            }
+        }
+    }
+
+    if (state.mixer2_enabled) {
+        for (size_t sample = 0; sample < samples_per_frame; sample++) {
+            for (size_t channel = 0; channel < 4; channel++) {
+                state.intermediate_mix_buffer[2][sample][channel] = read_samples.mix2.pcm32[channel][sample];
+            }
+        }
+    }
+}
+
+void Mixers::AuxSend(IntermediateMixSamples& write_samples, const std::array<QuadFrame32, 3>& input) {
+    // NOTE: read_samples.mix{1,2}.pcm32 annoyingly have their dimensions in reverse order to QuadFrame32.
+
+    state.intermediate_mix_buffer[0] = input[0];
+
+    if (state.mixer1_enabled) {
+        for (size_t sample = 0; sample < samples_per_frame; sample++) {
+            for (size_t channel = 0; channel < 4; channel++) {
+                write_samples.mix1.pcm32[channel][sample] = input[1][sample][channel];
+            }
+        }
+    } else {
+        state.intermediate_mix_buffer[1] = input[1];
+    }
+
+    if (state.mixer2_enabled) {
+        for (size_t sample = 0; sample < samples_per_frame; sample++) {
+            for (size_t channel = 0; channel < 4; channel++) {
+                write_samples.mix2.pcm32[channel][sample] = input[2][sample][channel];
+            }
+        }
+    } else {
+        state.intermediate_mix_buffer[2] = input[2];
+    }
+}
+
+void Mixers::MixCurrentFrame() {
+    current_frame.fill({});
+
+    for (size_t mix = 0; mix < 3; mix++) {
+        DownmixAndMixIntoCurrentFrame(state.intermediate_mixer_volume[mix], state.intermediate_mix_buffer[mix]);
+    }
+
+    // TODO(merry): Compressor. (We currently assume a disabled compressor.)
+}
+
+DspStatus Mixers::GetCurrentStatus() const {
+    DspStatus status;
+    status.unknown = 0;
+    status.dropped_frames = 0;
+    return status;
+}
+
+} // namespace HLE
+} // namespace DSP