42 lines
1.5 KiB
C++
42 lines
1.5 KiB
C++
// The cubic bezier easing implementation is a C++ version of the following javascript code:
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/**
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* https://github.com/gre/bezier-easing
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* BezierEasing - use bezier curve for transition easing function
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* by Gaëtan Renaudeau 2014 - 2015 – MIT License
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*/
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#pragma once
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#include <array>
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#include <Eigen/Dense>
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class BezierEasing {
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public:
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BezierEasing(Eigen::Vector4f c);
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BezierEasing(float x1, float y1, float x2, float y2);
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float operator() (float x) const;
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static BezierEasing linear;
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private:
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static constexpr unsigned NEWTON_ITERATIONS = 4;
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static constexpr float NEWTON_MIN_SLOPE = 0.001;
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static constexpr float SUBDIVISION_PRECISION = 0.0000001;
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static constexpr unsigned SUBDIVISION_MAX_ITERATIONS = 10;
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static constexpr unsigned KSPLINE_TABLE_SIZE = 11;
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static constexpr unsigned KSPLINE_TABLE_LAST = KSPLINE_TABLE_SIZE - 1;
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static constexpr float KSAMPLE_STEP_SIZE = 1.0 / (KSPLINE_TABLE_SIZE - 1.0);
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float A(float aA1, float aA2) const;
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float B(float aA1, float aA2) const;
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float C(float aA1) const;
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float calc_bezier(float aT, float aA1, float aA2) const;
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float get_slope(float aT, float aA1, float aA2) const;
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float binary_subdivide(float aX, float aA, float aB) const;
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float newton_raphson_iterate(float aX, float aGuessT) const;
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float get_t_for_x(float aX) const;
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float mX1;
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float mY1;
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float mX2;
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float mY2;
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std::array<float, KSPLINE_TABLE_SIZE> sampleValues;
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};
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