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/* SPDX-License-Identifier: BSD-3-Clause */
/* SPDX-FileCopyrightText: OpenMPT Project Developers and Contributors */
#pragma once
#include "openmpt/all/BuildSettings.hpp"
#include "mpt/base/macros.hpp"
#include "mpt/random/default_engines.hpp"
#include "mpt/random/engine.hpp"
#include "openmpt/soundbase/MixSample.hpp"
#include <vector>
#include <variant>
#include <cstddef>
OPENMPT_NAMESPACE_BEGIN
template <typename Tdither>
class MultiChannelDither
{
private:
std::vector<Tdither> DitherChannels;
typename Tdither::prng_type prng;
public:
template <typename Trd>
MultiChannelDither(Trd &rd, std::size_t channels)
: DitherChannels(channels)
, prng(Tdither::prng_init(rd))
{
return;
}
void Reset()
{
for(std::size_t channel = 0; channel < DitherChannels.size(); ++channel)
{
DitherChannels[channel] = Tdither{};
}
}
std::size_t GetChannels() const
{
return DitherChannels.size();
}
template <uint32 targetbits>
MPT_FORCEINLINE MixSampleInt process(std::size_t channel, MixSampleInt sample)
{
return DitherChannels[channel].template process<targetbits>(sample, prng);
}
template <uint32 targetbits>
MPT_FORCEINLINE MixSampleFloat process(std::size_t channel, MixSampleFloat sample)
{
return DitherChannels[channel].template process<targetbits>(sample, prng);
}
};
template <typename AvailableDithers, typename DitherNames, std::size_t defaultChannels, std::size_t defaultDither, std::size_t noDither, typename seeding_random_engine = mpt::good_engine>
class Dithers
: public DitherNames
{
public:
static constexpr std::size_t NoDither = noDither;
static constexpr std::size_t DefaultDither = defaultDither;
static constexpr std::size_t DefaultChannels = defaultChannels;
private:
seeding_random_engine m_PRNG;
AvailableDithers m_Dithers;
public:
template <typename Trd>
Dithers(Trd &rd, std::size_t mode = defaultDither, std::size_t channels = defaultChannels)
: m_PRNG(mpt::make_prng<seeding_random_engine>(rd))
, m_Dithers(std::in_place_index<defaultDither>, m_PRNG, channels)
{
SetMode(mode, channels);
}
AvailableDithers &Variant()
{
return m_Dithers;
}
static std::size_t GetNumDithers()
{
return std::variant_size<AvailableDithers>::value;
}
static std::size_t GetDefaultDither()
{
return defaultDither;
}
static std::size_t GetNoDither()
{
return noDither;
}
private:
template <std::size_t i = 0>
void set_mode(std::size_t mode, std::size_t channels)
{
if constexpr(i < std::variant_size<AvailableDithers>::value)
{
if(mode == i)
{
m_Dithers.template emplace<i>(m_PRNG, channels);
} else
{
this->template set_mode<i + 1>(mode, channels);
}
} else
{
MPT_UNUSED(mode);
m_Dithers.template emplace<defaultDither>(m_PRNG, channels);
}
}
public:
void SetMode(std::size_t mode, std::size_t channels)
{
if((mode == GetMode()) && (channels == GetChannels()))
{
std::visit([](auto &dither)
{ return dither.Reset(); },
m_Dithers);
return;
}
set_mode(mode, channels);
}
void SetMode(std::size_t mode)
{
if(mode == GetMode())
{
std::visit([](auto &dither)
{ return dither.Reset(); },
m_Dithers);
return;
}
set_mode(mode, GetChannels());
}
void SetChannels(std::size_t channels)
{
if(channels == GetChannels())
{
return;
}
set_mode(GetMode(), channels);
}
void Reset()
{
std::visit([](auto &dither)
{ return dither.Reset(); },
m_Dithers);
}
std::size_t GetMode() const
{
return m_Dithers.index();
}
std::size_t GetChannels() const
{
return std::visit([](auto &dither)
{ return dither.GetChannels(); },
m_Dithers);
}
};
OPENMPT_NAMESPACE_END
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