IAPDemo/Libraries/cocos2d/cocos/editor-support/spine/MathUtil.h

/******************************************************************************
 * Spine Runtimes License Agreement
 * Last updated January 1, 2020. Replaces all prior versions.
 *
 * Copyright (c) 2013-2020, Esoteric Software LLC
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#ifndef Spine_MathUtil_h
#define Spine_MathUtil_h

#include <spine/SpineObject.h>

#include <string.h>

namespace spine {

class SP_API MathUtil : public SpineObject {
private:
	MathUtil();

public:
	static const float Pi;
	static const float Pi_2;
	static const float Deg_Rad;
	static const float Rad_Deg;

	template<typename T>
	static inline T min(T a, T b) { return a < b ? a : b; }

	template<typename T>
	static inline T max(T a, T b) { return a > b ? a : b; }

	static float sign(float val);

	static float clamp(float x, float lower, float upper);

	static float abs(float v);

	/// Returns the sine in radians from a lookup table.
	static float sin(float radians);

	/// Returns the cosine in radians from a lookup table.
	static float cos(float radians);

	/// Returns the sine in radians from a lookup table.
	static float sinDeg(float degrees);

	/// Returns the cosine in radians from a lookup table.
	static float cosDeg(float degrees);

	/// Returns atan2 in radians, faster but less accurate than Math.Atan2. Average error of 0.00231 radians (0.1323
	/// degrees), largest error of 0.00488 radians (0.2796 degrees).
	static float atan2(float y, float x);

	static float acos(float v);

	static float sqrt(float v);

	static float fmod(float a, float b);

	static bool isNan(float v);

	static float random();

	static float randomTriangular(float min, float max);

	static float randomTriangular(float min, float max, float mode);

	static float pow(float a, float b);
};

struct SP_API Interpolation {
	virtual float apply(float a) = 0;

	virtual float interpolate(float start, float end, float a) {
		return start + (end - start) * apply(a);
	}

	virtual ~Interpolation() {};
};

struct SP_API PowInterpolation: public Interpolation {
	PowInterpolation(int power): power(power) {
	}

	float apply(float a) {
		if (a <= 0.5f) return MathUtil::pow(a * 2.0f, (float)power) / 2.0f;
		return MathUtil::pow((a - 1.0f) * 2.0f, (float)power) / (power % 2 == 0 ? -2.0f : 2.0f) + 1.0f;
	}

	int power;
};

struct SP_API PowOutInterpolation: public Interpolation {
	PowOutInterpolation(int power): power(power) {
	}

	float apply(float a) {
		return MathUtil::pow(a - 1, (float)power) * (power % 2 == 0 ? -1.0f : 1.0f) + 1.0f;
	}

	int power;
};

}

#endif /* Spine_MathUtil_h */