63 lines
1.7 KiB
C++
63 lines
1.7 KiB
C++
// Copyright 2018 yuzu Emulator Project
|
|
// Licensed under GPLv2 or any later version
|
|
// Refer to the license.txt file included.
|
|
|
|
#pragma once
|
|
|
|
#include <array>
|
|
#include <vector>
|
|
#include "common/common_types.h"
|
|
|
|
namespace AudioCore {
|
|
|
|
/// Digital biquad filter:
|
|
///
|
|
/// b0 + b1 z^-1 + b2 z^-2
|
|
/// H(z) = ------------------------
|
|
/// a0 + a1 z^-1 + b2 z^-2
|
|
class Filter {
|
|
public:
|
|
/// Creates a low-pass filter.
|
|
/// @param cutoff Determines the cutoff frequency. A value from 0.0 to 1.0.
|
|
/// @param Q Determines the quality factor of this filter.
|
|
static Filter LowPass(double cutoff, double Q = 0.7071);
|
|
|
|
/// Passthrough filter.
|
|
Filter();
|
|
|
|
Filter(double a0_, double a1_, double a2_, double b0_, double b1_, double b2_);
|
|
|
|
void Process(std::vector<s16>& signal);
|
|
|
|
private:
|
|
static constexpr std::size_t channel_count = 2;
|
|
|
|
/// Coefficients are in normalized form (a0 = 1.0).
|
|
double a1, a2, b0, b1, b2;
|
|
/// Input History
|
|
std::array<std::array<double, channel_count>, 3> in;
|
|
/// Output History
|
|
std::array<std::array<double, channel_count>, 3> out;
|
|
};
|
|
|
|
/// Cascade filters to build up higher-order filters from lower-order ones.
|
|
class CascadingFilter {
|
|
public:
|
|
/// Creates a cascading low-pass filter.
|
|
/// @param cutoff Determines the cutoff frequency. A value from 0.0 to 1.0.
|
|
/// @param cascade_size Number of biquads in cascade.
|
|
static CascadingFilter LowPass(double cutoff, std::size_t cascade_size);
|
|
|
|
/// Passthrough.
|
|
CascadingFilter();
|
|
|
|
explicit CascadingFilter(std::vector<Filter> filters_);
|
|
|
|
void Process(std::vector<s16>& signal);
|
|
|
|
private:
|
|
std::vector<Filter> filters;
|
|
};
|
|
|
|
} // namespace AudioCore
|