add ease functions

core/base/ActionTween.cpp

@@ -56,51 +56,96 @@ namespace easy2d
 		case EaseFunc::Linear:
 			ease_func_ = math::Linear;
 			break;
-		case EaseFunc::EaseIn:
+		case EaseFunc::In:
 			ease_func_ = MakeEaseIn(2.f);
 			break;
-		case EaseFunc::EaseOut:
+		case EaseFunc::Out:
 			ease_func_ = MakeEaseOut(2.f);
 			break;
-		case EaseFunc::EaseInOut:
+		case EaseFunc::InOut:
 			ease_func_ = MakeEaseInOut(2.f);
 			break;
-		case EaseFunc::EaseExponentialIn:
+		case EaseFunc::ExpoIn:
 			ease_func_ = math::EaseExponentialIn;
 			break;
-		case EaseFunc::EaseExponentialOut:
+		case EaseFunc::ExpoOut:
 			ease_func_ = math::EaseExponentialOut;
 			break;
-		case EaseFunc::EaseExponentialInOut:
+		case EaseFunc::ExpoInOut:
 			ease_func_ = math::EaseExponentialInOut;
 			break;
-		case EaseFunc::EaseBounceIn:
+		case EaseFunc::BounceIn:
 			ease_func_ = math::EaseBounceIn;
 			break;
-		case EaseFunc::EaseBounceOut:
+		case EaseFunc::BounceOut:
 			ease_func_ = math::EaseBounceOut;
 			break;
-		case EaseFunc::EaseBounceInOut:
+		case EaseFunc::BounceInOut:
 			ease_func_ = math::EaseBounceInOut;
 			break;
-		case EaseFunc::EaseElasticIn:
+		case EaseFunc::ElasticIn:
 			ease_func_ = MakeEaseElasticIn(0.3f);
 			break;
-		case EaseFunc::EaseElasticOut:
+		case EaseFunc::ElasticOut:
 			ease_func_ = MakeEaseElasticOut(0.3f);
 			break;
-		case EaseFunc::EaseElasticInOut:
+		case EaseFunc::ElasticInOut:
 			ease_func_ = MakeEaseElasticInOut(0.3f);
 			break;
-		case EaseFunc::EaseSineIn:
+		case EaseFunc::SineIn:
 			ease_func_ = math::EaseSineIn;
 			break;
-		case EaseFunc::EaseSineOut:
+		case EaseFunc::SineOut:
 			ease_func_ = math::EaseSineOut;
 			break;
-		case EaseFunc::EaseSineInOut:
+		case EaseFunc::SineInOut:
 			ease_func_ = math::EaseSineInOut;
 			break;
+		case EaseFunc::BackIn:
+			ease_func_ = math::EaseBackIn;
+			break;
+		case EaseFunc::BackOut:
+			ease_func_ = math::EaseBackOut;
+			break;
+		case EaseFunc::BackInOut:
+			ease_func_ = math::EaseBackInOut;
+			break;
+		case EaseFunc::QuadIn:
+			ease_func_ = math::EaseQuadIn;
+			break;
+		case EaseFunc::QuadOut:
+			ease_func_ = math::EaseQuadOut;
+			break;
+		case EaseFunc::QuadInOut:
+			ease_func_ = math::EaseQuadInOut;
+			break;
+		case EaseFunc::CubicIn:
+			ease_func_ = math::EaseCubicIn;
+			break;
+		case EaseFunc::CubicOut:
+			ease_func_ = math::EaseCubicOut;
+			break;
+		case EaseFunc::CubicInOut:
+			ease_func_ = math::EaseCubicInOut;
+			break;
+		case EaseFunc::QuartIn:
+			ease_func_ = math::EaseQuartIn;
+			break;
+		case EaseFunc::QuartOut:
+			ease_func_ = math::EaseQuartOut;
+			break;
+		case EaseFunc::QuartInOut:
+			ease_func_ = math::EaseQuartInOut;
+			break;
+		case EaseFunc::QuintIn:
+			ease_func_ = math::EaseQuintIn;
+			break;
+		case EaseFunc::QuintOut:
+			ease_func_ = math::EaseQuintOut;
+			break;
+		case EaseFunc::QuintInOut:
+			ease_func_ = math::EaseQuintInOut;
+			break;
 		default:
 			break;
 		}

core/base/ActionTween.h

@@ -25,26 +25,44 @@
 
 namespace easy2d
 {
+	// 缓动函数枚举
+	// More infomation about ease functions, see https://easings.net
 	enum class EaseFunc
 	{
-		Linear,					// 线性
+		Linear,			// 线性
-		EaseIn,					// 由慢变快
+		In,				// 由慢变快
-		EaseOut,				// 由快变慢
+		Out,			// 由快变慢
-		EaseInOut,				// 由慢变快, 再由快变慢
+		InOut,			// 由慢变快, 再由快变慢
-		EaseExponentialIn,		// 由慢变极快
+		ExpoIn,			// 由慢变极快
-		EaseExponentialOut,		// 由极快变慢
+		ExpoOut,		// 由极快变慢
-		EaseExponentialInOut,	// 由慢至极快, 再由极快边慢
+		ExpoInOut,		// 由慢至极快, 再由极快边慢
-		EaseBounceIn,			// 自起点赋予反弹力
+		ElasticIn,		// 自起点赋予弹性
-		EaseBounceOut,			// 自终点赋予反弹力
+		ElasticOut,		// 自终点赋予弹性
-		EaseBounceInOut,		// 在起点和终点赋予反弹力
+		ElasticInOut,	// 再起点和终点赋予弹性
-		EaseElasticIn,			// 自起点赋予弹性
+		BounceIn,		// 自起点赋予反弹力
-		EaseElasticOut,			// 自终点赋予弹性
+		BounceOut,		// 自终点赋予反弹力
-		EaseElasticInOut,		// 再起点和终点赋予弹性
+		BounceInOut,	// 在起点和终点赋予反弹力
-		EaseSineIn,				// 由快变慢, 采用正弦变换速度
+		BackIn,
-		EaseSineOut,			// 由慢变快, 采用正弦变换速度
+		BackOut,
-		EaseSineInOut,			// 由慢至快, 再由快至慢, 采用正弦变换速度
+		BackInOut,
+		QuadIn,
+		QuadOut,
+		QuadInOut,
+		CubicIn,
+		CubicOut,
+		CubicInOut,
+		QuartIn,
+		QuartOut,
+		QuartInOut,
+		QuintIn,
+		QuintOut,
+		QuintInOut,
+		SineIn,
+		SineOut,
+		SineInOut,
 	};
 
+	// 缓动函数
 	using EaseFunction = std::function<float(float)>;
 
 	inline EaseFunction MakeEaseIn(float rate) { return std::bind(math::EaseIn, std::placeholders::_1, rate); }
@@ -54,6 +72,8 @@ namespace easy2d
 	inline EaseFunction MakeEaseElasticOut(float period) { return std::bind(math::EaseElasticOut, std::placeholders::_1, period); }
 	inline EaseFunction MakeEaseElasticInOut(float period) { return std::bind(math::EaseElasticInOut, std::placeholders::_1, period); }
 
+
+	// 补间动画
 	class Tween
 		: public Action
 	{
@@ -65,12 +85,12 @@ namespace easy2d
 			EaseFunc func
 		);
 
-		// 设置速度变化曲线
+		// 设置缓动函数
 		void SetEaseFunction(
 			EaseFunc func
 		);
 
-		// 自定义速度变化曲线
+		// 自定义缓动函数
 		void SetEaseFunction(
 			EaseFunction func
 		);

core/math/ease.hpp

@@ -30,6 +30,9 @@ namespace easy2d
 			return step;
 		}
 
+
+		// Ease
+
 		inline float EaseIn(float step, float rate)
 		{
 			return math::Pow(step, rate);
@@ -47,6 +50,9 @@ namespace easy2d
 			return 1.f - .5f * math::Pow(2.f - 2 * step, rate);
 		}
 
+
+		// Exponential Ease
+
 		inline float EaseExponentialIn(float step)
 		{
 			return math::Pow(2.f, 10 * (step - 1));
@@ -64,6 +70,9 @@ namespace easy2d
 			return 0.5f * (2 - math::Pow(2, -10 * (step * 2 - 1)));
 		}
 
+
+		// Bounce Ease
+
 		inline float EaseBounceOut(float step)
 		{
 			if (step < 1 / 2.75f)
@@ -102,6 +111,9 @@ namespace easy2d
 			}
 		}
 
+
+		// Elastic Ease
+
 		inline float EaseElasticIn(float step, float period)
 		{
 			if (step == 0 || step == 1)
@@ -132,6 +144,39 @@ namespace easy2d
 			return math::Pow(2, -10 * step) * math::Sin((step - period / 4) * 360.f / period) * 0.5f + 1;
 		}
 
+
+		// Back Ease
+
+		inline float EaseBackIn(float step)
+		{
+			const float overshoot = 1.70158f;
+			return step * step * ((overshoot + 1) * step - overshoot);
+		}
+
+		inline float EaseBackOut(float step)
+		{
+			const float overshoot = 1.70158f;
+			step = step - 1;
+			return step * step * ((overshoot + 1) * step + overshoot) + 1;
+		}
+
+		inline float EaseBackInOut(float step)
+		{
+			const float overshoot = 1.70158f * 1.525f;
+
+			step = step * 2;
+			if (step < 1)
+			{
+				return (step * step * ((overshoot + 1) * step - overshoot)) / 2;
+			}
+
+			step = step - 2;
+			return (step * step * ((overshoot + 1) * step + overshoot)) / 2 + 1;
+		}
+
+
+		// Sine Ease
+
 		inline float EaseSineIn(float step)
 		{
 			return 1.f - math::Cos(step * 90);
@@ -146,5 +191,96 @@ namespace easy2d
 		{
 			return -0.5f * (math::Cos(step * 180) - 1);
 		}
+
+
+		// Quad Ease
+
+		inline float EaseQuadIn(float step)
+		{
+			return step * step;
+		}
+
+		inline float EaseQuadOut(float step)
+		{
+			return -1 * step * (step - 2);
+		}
+
+		inline float EaseQuadInOut(float step)
+		{
+			step = step * 2;
+			if (step < 1)
+				return 0.5f * step * step;
+			--step;
+			return -0.5f * (step * (step - 2) - 1);
+		}
+
+
+		// Cubic Ease
+
+		inline float EaseCubicIn(float step)
+		{
+			return step * step * step;
+		}
+
+		inline float EaseCubicOut(float step)
+		{
+			step -= 1;
+			return (step * step * step + 1);
+		}
+
+		inline float EaseCubicInOut(float step)
+		{
+			step = step * 2;
+			if (step < 1)
+				return 0.5f * step * step * step;
+			step -= 2;
+			return 0.5f * (step * step * step + 2);
+		}
+
+
+		// Quart Ease
+
+		inline float EaseQuartIn(float step)
+		{
+			return step * step * step * step;
+		}
+
+		inline float EaseQuartOut(float step)
+		{
+			step -= 1;
+			return -(step * step * step * step - 1);
+		}
+
+		inline float EaseQuartInOut(float step)
+		{
+			step = step * 2;
+			if (step < 1)
+				return 0.5f * step * step * step * step;
+			step -= 2;
+			return -0.5f * (step * step * step * step - 2);
+		}
+
+
+		// Quint Ease
+
+		inline float EaseQuintIn(float step)
+		{
+			return step * step * step * step * step;
+		}
+
+		inline float EaseQuintOut(float step)
+		{
+			step -= 1;
+			return (step * step * step * step * step + 1);
+		}
+
+		inline float EaseQuintInOut(float step)
+		{
+			step = step * 2;
+			if (step < 1)
+				return 0.5f * step * step * step * step * step;
+			step -= 2;
+			return 0.5f * (step * step * step * step * step + 2);
+		}
 	}
 }