1 files changed, 222 insertions, 0 deletions

diff --git a/src/audio_core/renderer/command/effect/light_limiter.cpp b/src/audio_core/renderer/command/effect/light_limiter.cpp
new file mode 100644
index 000000000..e8fb0e2fc
--- /dev/null
+++ b/src/audio_core/renderer/command/effect/light_limiter.cpp
@@ -0,0 +1,222 @@
+// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "audio_core/renderer/adsp/command_list_processor.h"
+#include "audio_core/renderer/command/effect/light_limiter.h"
+
+namespace AudioCore::AudioRenderer {
+/**
+ * Update the LightLimiterInfo state according to the given parameters.
+ * A no-op.
+ *
+ * @param params - Input parameters to update the state.
+ * @param state  - State to be updated.
+ */
+static void UpdateLightLimiterEffectParameter(const LightLimiterInfo::ParameterVersion2& params,
+                                              LightLimiterInfo::State& state) {}
+
+/**
+ * Initialize a new LightLimiterInfo state according to the given parameters.
+ *
+ * @param params     - Input parameters to update the state.
+ * @param state      - State to be updated.
+ * @param workbuffer - Game-supplied memory for the state. (Unused)
+ */
+static void InitializeLightLimiterEffect(const LightLimiterInfo::ParameterVersion2& params,
+                                         LightLimiterInfo::State& state, const CpuAddr workbuffer) {
+    state = {};
+    state.samples_average.fill(0.0f);
+    state.compression_gain.fill(1.0f);
+    state.look_ahead_sample_offsets.fill(0);
+    for (u32 i = 0; i < params.channel_count; i++) {
+        state.look_ahead_sample_buffers[i].resize(params.look_ahead_samples_max, 0.0f);
+    }
+}
+
+/**
+ * Apply a light limiter effect if enabled, according to the current state, on the input mix
+ * buffers, saving the results to the output mix buffers.
+ *
+ * @param params       - Input parameters to use.
+ * @param state        - State to use, must be initialized (see InitializeLightLimiterEffect).
+ * @param enabled      - If enabled, limiter will be applied, otherwise input is copied to output.
+ * @param inputs       - Input mix buffers to perform the limiter on.
+ * @param outputs      - Output mix buffers to receive the limited samples.
+ * @param sample_count - Number of samples to process.
+ * @params statistics  - Optional output statistics, only used with version 2.
+ */
+static void ApplyLightLimiterEffect(const LightLimiterInfo::ParameterVersion2& params,
+                                    LightLimiterInfo::State& state, const bool enabled,
+                                    std::vector<std::span<const s32>>& inputs,
+                                    std::vector<std::span<s32>>& outputs, const u32 sample_count,
+                                    LightLimiterInfo::StatisticsInternal* statistics) {
+    constexpr s64 min{std::numeric_limits<s32>::min()};
+    constexpr s64 max{std::numeric_limits<s32>::max()};
+
+    const auto recip_estimate = [](f64 a) -> f64 {
+        s32 q, s;
+        f64 r;
+        q = (s32)(a * 512.0);               /* a in units of 1/512 rounded down */
+        r = 1.0 / (((f64)q + 0.5) / 512.0); /* reciprocal r */
+        s = (s32)(256.0 * r + 0.5);         /* r in units of 1/256 rounded to nearest */
+        return ((f64)s / 256.0);
+    };
+
+    if (enabled) {
+        if (statistics && params.statistics_reset_required) {
+            for (u32 i = 0; i < params.channel_count; i++) {
+                statistics->channel_compression_gain_min[i] = 1.0f;
+                statistics->channel_max_sample[i] = 0;
+            }
+        }
+
+        for (u32 sample_index = 0; sample_index < sample_count; sample_index++) {
+            for (u32 channel = 0; channel < params.channel_count; channel++) {
+                auto sample{(Common::FixedPoint<49, 15>(inputs[channel][sample_index]) /
+                             Common::FixedPoint<49, 15>::one) *
+                            params.input_gain};
+                auto abs_sample{sample};
+                if (sample < 0.0f) {
+                    abs_sample = -sample;
+                }
+                auto coeff{abs_sample > state.samples_average[channel] ? params.attack_coeff
+                                                                       : params.release_coeff};
+                state.samples_average[channel] +=
+                    ((abs_sample - state.samples_average[channel]) * coeff).to_float();
+
+                // Reciprocal estimate
+                auto new_average_sample{Common::FixedPoint<49, 15>(
+                    recip_estimate(state.samples_average[channel].to_double()))};
+                if (params.processing_mode != LightLimiterInfo::ProcessingMode::Mode1) {
+                    // Two Newton-Raphson steps
+                    auto temp{2.0 - (state.samples_average[channel] * new_average_sample)};
+                    new_average_sample = 2.0 - (state.samples_average[channel] * temp);
+                }
+
+                auto above_threshold{state.samples_average[channel] > params.threshold};
+                auto attenuation{above_threshold ? params.threshold * new_average_sample : 1.0f};
+                coeff = attenuation < state.compression_gain[channel] ? params.attack_coeff
+                                                                      : params.release_coeff;
+                state.compression_gain[channel] +=
+                    (attenuation - state.compression_gain[channel]) * coeff;
+
+                auto lookahead_sample{
+                    state.look_ahead_sample_buffers[channel]
+                                                   [state.look_ahead_sample_offsets[channel]]};
+
+                state.look_ahead_sample_buffers[channel][state.look_ahead_sample_offsets[channel]] =
+                    sample;
+                state.look_ahead_sample_offsets[channel] =
+                    (state.look_ahead_sample_offsets[channel] + 1) % params.look_ahead_samples_min;
+
+                outputs[channel][sample_index] = static_cast<s32>(
+                    std::clamp((lookahead_sample * state.compression_gain[channel] *
+                                params.output_gain * Common::FixedPoint<49, 15>::one)
+                                   .to_long(),
+                               min, max));
+
+                if (statistics) {
+                    statistics->channel_max_sample[channel] =
+                        std::max(statistics->channel_max_sample[channel], abs_sample.to_float());
+                    statistics->channel_compression_gain_min[channel] =
+                        std::min(statistics->channel_compression_gain_min[channel],
+                                 state.compression_gain[channel].to_float());
+                }
+            }
+        }
+    } else {
+        for (u32 i = 0; i < params.channel_count; i++) {
+            if (params.inputs[i] != params.outputs[i]) {
+                std::memcpy(outputs[i].data(), inputs[i].data(), outputs[i].size_bytes());
+            }
+        }
+    }
+}
+
+void LightLimiterVersion1Command::Dump([[maybe_unused]] const ADSP::CommandListProcessor& processor,
+                                       std::string& string) {
+    string += fmt::format("LightLimiterVersion1Command\n\tinputs: ");
+    for (u32 i = 0; i < MaxChannels; i++) {
+        string += fmt::format("{:02X}, ", inputs[i]);
+    }
+    string += "\n\toutputs: ";
+    for (u32 i = 0; i < MaxChannels; i++) {
+        string += fmt::format("{:02X}, ", outputs[i]);
+    }
+    string += "\n";
+}
+
+void LightLimiterVersion1Command::Process(const ADSP::CommandListProcessor& processor) {
+    std::vector<std::span<const s32>> input_buffers(parameter.channel_count);
+    std::vector<std::span<s32>> output_buffers(parameter.channel_count);
+
+    for (u32 i = 0; i < parameter.channel_count; i++) {
+        input_buffers[i] = processor.mix_buffers.subspan(inputs[i] * processor.sample_count,
+                                                         processor.sample_count);
+        output_buffers[i] = processor.mix_buffers.subspan(outputs[i] * processor.sample_count,
+                                                          processor.sample_count);
+    }
+
+    auto state_{reinterpret_cast<LightLimiterInfo::State*>(state)};
+
+    if (effect_enabled) {
+        if (parameter.state == LightLimiterInfo::ParameterState::Updating) {
+            UpdateLightLimiterEffectParameter(parameter, *state_);
+        } else if (parameter.state == LightLimiterInfo::ParameterState::Initialized) {
+            InitializeLightLimiterEffect(parameter, *state_, workbuffer);
+        }
+    }
+
+    LightLimiterInfo::StatisticsInternal* statistics{nullptr};
+    ApplyLightLimiterEffect(parameter, *state_, effect_enabled, input_buffers, output_buffers,
+                            processor.sample_count, statistics);
+}
+
+bool LightLimiterVersion1Command::Verify(const ADSP::CommandListProcessor& processor) {
+    return true;
+}
+
+void LightLimiterVersion2Command::Dump([[maybe_unused]] const ADSP::CommandListProcessor& processor,
+                                       std::string& string) {
+    string += fmt::format("LightLimiterVersion2Command\n\tinputs: \n");
+    for (u32 i = 0; i < MaxChannels; i++) {
+        string += fmt::format("{:02X}, ", inputs[i]);
+    }
+    string += "\n\toutputs: ";
+    for (u32 i = 0; i < MaxChannels; i++) {
+        string += fmt::format("{:02X}, ", outputs[i]);
+    }
+    string += "\n";
+}
+
+void LightLimiterVersion2Command::Process(const ADSP::CommandListProcessor& processor) {
+    std::vector<std::span<const s32>> input_buffers(parameter.channel_count);
+    std::vector<std::span<s32>> output_buffers(parameter.channel_count);
+
+    for (u32 i = 0; i < parameter.channel_count; i++) {
+        input_buffers[i] = processor.mix_buffers.subspan(inputs[i] * processor.sample_count,
+                                                         processor.sample_count);
+        output_buffers[i] = processor.mix_buffers.subspan(outputs[i] * processor.sample_count,
+                                                          processor.sample_count);
+    }
+
+    auto state_{reinterpret_cast<LightLimiterInfo::State*>(state)};
+
+    if (effect_enabled) {
+        if (parameter.state == LightLimiterInfo::ParameterState::Updating) {
+            UpdateLightLimiterEffectParameter(parameter, *state_);
+        } else if (parameter.state == LightLimiterInfo::ParameterState::Initialized) {
+            InitializeLightLimiterEffect(parameter, *state_, workbuffer);
+        }
+    }
+
+    auto statistics{reinterpret_cast<LightLimiterInfo::StatisticsInternal*>(result_state)};
+    ApplyLightLimiterEffect(parameter, *state_, effect_enabled, input_buffers, output_buffers,
+                            processor.sample_count, statistics);
+}
+
+bool LightLimiterVersion2Command::Verify(const ADSP::CommandListProcessor& processor) {
+    return true;
+}
+
+} // namespace AudioCore::AudioRenderer