engines/common/Fade.h

/*
 * Copyright (c) 2017 - 2019 Christian Schoenebeck
 *
 * http://www.linuxsampler.org
 *
 * This file is part of LinuxSampler and released under the same terms.
 * See README file for details.
 */

#ifndef LS_FADE_H
#define LS_FADE_H

#include "EaseInEaseOut.h"

namespace LinuxSampler {

#define DEFAULT_FADE_CURVE FADE_CURVE_EASE_IN_EASE_OUT

enum fade_curve_t {
    FADE_CURVE_LINEAR,
    FADE_CURVE_EASE_IN_EASE_OUT,
};

/** @brief Fades a value with a selected curve.
 *
 * Implements a smoothed transition from one value to another value in a
 * requested amount of time, either with an ease-in and ease-out algorithm 
 * (default), or linear.
 */
class Fade : public EaseInEaseOut {
public:
    Fade() : EaseInEaseOut() {
        curveType = DEFAULT_FADE_CURVE;
        Final = false;
    }

    /**
     * Select another curve type for this Fade and immediately prepare this
     * Fade for operation with the new curve type.
     */
    void setCurve(fade_curve_t curve, float sampleRate) {
        curveType = curve;
        fadeTo(endValue, duration, sampleRate);
    }

    /**
     * Only set the new curve type. It is your responsibility to prepare this
     * Fade for subsequent operation, i.e. by calling fadeTo() afterwards,
     * otherwise the result of render() calls will be undefined.
     */
    void setCurveOnly(fade_curve_t curve) {
        curveType = curve;
    }

    /**
     * Fade the current value in @duration seconds to the new value reflected
     * by @a endValue, assuming the given @a sampleRate.
     */
    void fadeTo(float endValue, float duration, float sampleRate) {
        if (curveType == FADE_CURVE_EASE_IN_EASE_OUT)
            return EaseInEaseOut::fadeTo(endValue, duration, sampleRate);
        else {
            if (duration <= 0.f) {
                setCurrentValue(endValue);
                return;
            }
            this->endValue = endValue;
            steps = duration * sampleRate;
            c = (endValue - value) / float(steps);
        }
    }

    /**
     * Fade the current value in the currently set default duration to the new
     * value reflected by @a endValue, assuming the given @a sampleRate.
     */
    void fadeTo(float endValue, float sampleRate) {
        fadeTo(endValue, duration, sampleRate);
    }

    /**
     * Proceed transition by exactly one sample point and return the current
     * smoothed value at this stage.
     */
    inline float render() {
        if (curveType == FADE_CURVE_EASE_IN_EASE_OUT)
            return EaseInEaseOut::render();
        if (!steps) return endValue;
        --steps;
        value += c;
        return value;
    }

    inline void setFinal(bool b) {
        Final = b;
    }

    template<typename T>
    inline void applyTo(T& dst) {
        if (Final)
            dst = currentValue();
        else
            dst *= currentValue();
    }

private:
    fade_curve_t curveType;
    bool Final;
};

} // namespace LinuxSampler

#endif // LS_FADE_H
1	schoenebeck	3246	/*
2	schoenebeck	3561	* Copyright (c) 2017 - 2019 Christian Schoenebeck
3	schoenebeck	3246	*
4			* http://www.linuxsampler.org
5			*
6			* This file is part of LinuxSampler and released under the same terms.
7			* See README file for details.
8			*/
9
10			#ifndef LS_FADE_H
11			#define LS_FADE_H
12
13			#include "EaseInEaseOut.h"
14
15			namespace LinuxSampler {
16
17			#define DEFAULT_FADE_CURVE FADE_CURVE_EASE_IN_EASE_OUT
18
19			enum fade_curve_t {
20			FADE_CURVE_LINEAR,
21			FADE_CURVE_EASE_IN_EASE_OUT,
22			};
23
24			/** @brief Fades a value with a selected curve.
25			*
26			* Implements a smoothed transition from one value to another value in a
27			* requested amount of time, either with an ease-in and ease-out algorithm
28			* (default), or linear.
29			*/
30			class Fade : public EaseInEaseOut {
31			public:
32			Fade() : EaseInEaseOut() {
33			curveType = DEFAULT_FADE_CURVE;
34	schoenebeck	3561	Final = false;
35	schoenebeck	3246	}
36
37			/**
38			* Select another curve type for this Fade and immediately prepare this
39			* Fade for operation with the new curve type.
40			*/
41			void setCurve(fade_curve_t curve, float sampleRate) {
42			curveType = curve;
43			fadeTo(endValue, duration, sampleRate);
44			}
45
46			/**
47			* Only set the new curve type. It is your responsibility to prepare this
48			* Fade for subsequent operation, i.e. by calling fadeTo() afterwards,
49			* otherwise the result of render() calls will be undefined.
50			*/
51			void setCurveOnly(fade_curve_t curve) {
52			curveType = curve;
53			}
54
55			/**
56			* Fade the current value in @duration seconds to the new value reflected
57			* by @a endValue, assuming the given @a sampleRate.
58			*/
59			void fadeTo(float endValue, float duration, float sampleRate) {
60			if (curveType == FADE_CURVE_EASE_IN_EASE_OUT)
61			return EaseInEaseOut::fadeTo(endValue, duration, sampleRate);
62			else {
63			if (duration <= 0.f) {
64			setCurrentValue(endValue);
65			return;
66			}
67			this->endValue = endValue;
68			steps = duration * sampleRate;
69			c = (endValue - value) / float(steps);
70			}
71			}
72
73			/**
74			* Fade the current value in the currently set default duration to the new
75			* value reflected by @a endValue, assuming the given @a sampleRate.
76			*/
77			void fadeTo(float endValue, float sampleRate) {
78			fadeTo(endValue, duration, sampleRate);
79			}
80
81			/**
82			* Proceed transition by exactly one sample point and return the current
83			* smoothed value at this stage.
84			*/
85			inline float render() {
86			if (curveType == FADE_CURVE_EASE_IN_EASE_OUT)
87			return EaseInEaseOut::render();
88			if (!steps) return endValue;
89			--steps;
90			value += c;
91			return value;
92			}
93
94	schoenebeck	3561	inline void setFinal(bool b) {
95			Final = b;
96			}
97
98			template<typename T>
99			inline void applyTo(T& dst) {
100			if (Final)
101			dst = currentValue();
102			else
103			dst *= currentValue();
104			}
105
106	schoenebeck	3246	private:
107			fade_curve_t curveType;
108	schoenebeck	3561	bool Final;
109	schoenebeck	3246	};
110
111			} // namespace LinuxSampler
112
113			#endif // LS_FADE_H