common/accel-natural.hpp


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#pragma once

#include <math.h>

#include "accel-base.hpp"

namespace rawaccel {

	/// <summary> Struct to hold "natural" (vanishing difference) acceleration implementation. </summary>
	struct natural_impl {
		double rate;
		double limit;

		natural_impl(const accel_args& args) :
			rate(args.accel), limit(args.limit - 1)
		{
			rate /= limit;
		}

		inline double operator()(double speed) const {
			// f(x) = k(1-e^(-mx))
			return limit - (limit * exp(-rate * speed));
		}

	};

	using accel_natural = additive_accel<natural_impl>;

}