winamp/Src/external_dependencies/openmpt-trunk/common/Dither.h

/*
 * Dither.h
 * --------
 * Purpose: Dithering when converting to lower resolution sample formats.
 * Notes  : (currently none)
 * Authors: Olivier Lapicque
 *          OpenMPT Devs
 * The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
 */


#pragma once

#include "openmpt/all/BuildSettings.hpp"

#include "mpt/base/macros.hpp"
#include "mpt/string/types.hpp"
#include "openmpt/soundbase/Dither.hpp"
#include "openmpt/soundbase/DitherModPlug.hpp"
#include "openmpt/soundbase/DitherNone.hpp"
#include "openmpt/soundbase/DitherSimple.hpp"

#include "mptRandom.h"

#include <vector>
#include <variant>

#include <cstddef>


OPENMPT_NAMESPACE_BEGIN


using Dither_Default = Dither_Simple;


class DitherNamesOpenMPT
{
public:
	static mpt::ustring GetModeName(std::size_t mode)
	{
		mpt::ustring result;
		switch(mode)
		{
			case 0:
				// no dither
				result = MPT_USTRING("no");
				break;
			case 1:
				// chosen by OpenMPT code, might change
				result = MPT_USTRING("default");
				break;
			case 2:
				// rectangular, 0.5 bit depth, no noise shaping (original ModPlug Tracker)
				result = MPT_USTRING("0.5 bit");
				break;
			case 3:
				// rectangular, 1 bit depth, simple 1st order noise shaping
				result = MPT_USTRING("1 bit");
				break;
			default:
				result = MPT_USTRING("");
				break;
		}
		return result;
	}
};


using DithersOpenMPT =
	Dithers<std::variant<MultiChannelDither<Dither_None>, MultiChannelDither<Dither_Default>, MultiChannelDither<Dither_ModPlug>, MultiChannelDither<Dither_Simple>>, DitherNamesOpenMPT, 4, 1, 0, mpt::good_prng>;


struct DithersWrapperOpenMPT
	: DithersOpenMPT
{
	template <typename Trd>
	DithersWrapperOpenMPT(Trd &rd, std::size_t mode = DithersOpenMPT::DefaultDither, std::size_t channels = DithersOpenMPT::DefaultChannels)
		: DithersOpenMPT(rd, mode, channels)
	{
		return;
	}
};


OPENMPT_NAMESPACE_END