/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
 *                                                                                       *
 * Copyright (c) 2014-2021                                                               *
 *                                                                                       *
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 * permit persons to whom the Software is furnished to do so, subject to the following   *
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 * or substantial portions of the Software.                                              *
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#ifndef __OPENSPACE_CORE___DELAYEDVARIABLE___H__
#define __OPENSPACE_CORE___DELAYEDVARIABLE___H__

namespace openspace::interaction {

/**
 * Class that acts as a smoothing filter to a variable. The filter has a step
 * response on a form that resembles the function y = 1-e^(-t/scale). The variable
 * will be updated as soon as it is set to a value (calling the set() function).
 */
template <typename T, typename ScaleType>
class DelayedVariable {
public:
    DelayedVariable(ScaleType scaleFactor, ScaleType friction);
    void set(T value, double dt);
    void decelerate(double dt);
    void setHard(T value);
    void setFriction(ScaleType friction);
    void setScaleFactor(ScaleType scaleFactor);
    T get() const;

private:
    ScaleType _scaleFactor;
    ScaleType _friction;
    T _targetValue = T(0);
    T _currentValue = T(0);
};

} // namespace openspace::interaction

#include "delayedvariable.inl"

#endif // __OPENSPACE_CORE___DELAYEDVARIABLE___H__