diff --git a/spine-cpp/include/spine/PhysicsConstraintTimeline.h b/spine-cpp/include/spine/PhysicsConstraintTimeline.h
index 2eb7ea4f4..94c6dbe37 100644
--- a/spine-cpp/include/spine/PhysicsConstraintTimeline.h
+++ b/spine-cpp/include/spine/PhysicsConstraintTimeline.h
@@ -67,6 +67,7 @@ namespace spine {
 		virtual bool global(PhysicsConstraintData &constraintData) = 0;
 
 		int _constraintIndex;
+		bool _additive;
 	};
 
 	/// Changes a physics constraint's PhysicsConstraintPose::getInertia().
@@ -184,7 +185,7 @@ namespace spine {
 
 	public:
 		explicit PhysicsConstraintWindTimeline(size_t frameCount, size_t bezierCount, int physicsConstraintIndex)
-			: PhysicsConstraintTimeline(frameCount, bezierCount, physicsConstraintIndex, Property_PhysicsConstraintWind) {};
+			: PhysicsConstraintTimeline(frameCount, bezierCount, physicsConstraintIndex, Property_PhysicsConstraintWind) { _additive = true; };
 
 	protected:
 		float get(PhysicsConstraintPose &pose) override {
@@ -210,7 +211,7 @@ namespace spine {
 
 	public:
 		explicit PhysicsConstraintGravityTimeline(size_t frameCount, size_t bezierCount, int physicsConstraintIndex)
-			: PhysicsConstraintTimeline(frameCount, bezierCount, physicsConstraintIndex, Property_PhysicsConstraintGravity) {};
+			: PhysicsConstraintTimeline(frameCount, bezierCount, physicsConstraintIndex, Property_PhysicsConstraintGravity) { _additive = true; };
 
 	protected:
 		float get(PhysicsConstraintPose &pose) override {
diff --git a/spine-cpp/src/spine/ColorTimeline.cpp b/spine-cpp/src/spine/ColorTimeline.cpp
index 999a2c755..49a837ae4 100644
--- a/spine-cpp/src/spine/ColorTimeline.cpp
+++ b/spine-cpp/src/spine/ColorTimeline.cpp
@@ -136,6 +136,7 @@ void RGBTimeline::setFrame(int frame, float time, float r, float g, float b) {
 
 void RGBTimeline::_apply(Slot &slot, SlotPose &pose, float time, float alpha, MixBlend blend) {
 	Color &color = pose._color;
+	float r, g, b;
 	if (time < _frames[0]) {
 		Color &setup = slot._data._setup._color;
 		switch (blend) {
@@ -145,59 +146,58 @@ void RGBTimeline::_apply(Slot &slot, SlotPose &pose, float time, float alpha, Mi
 				color.b = setup.b;
 				return;
 			case MixBlend_First:
-				color.r += (setup.r - color.r) * alpha;
-				color.g += (setup.g - color.g) * alpha;
-				color.b += (setup.b - color.b) * alpha;
-				return;
+				r = color.r + (setup.r - color.r) * alpha;
+				g = color.g + (setup.g - color.g) * alpha;
+				b = color.b + (setup.b - color.b) * alpha;
+				break;
 			default:
 				return;
 		}
-	}
-
-	float r, g, b;
-	int i = Animation::search(_frames, time, ENTRIES);
-	int curveType = (int) _curves[i >> 2];
-	switch (curveType) {
-		case LINEAR: {
-			float before = _frames[i];
-			r = _frames[i + R];
-			g = _frames[i + G];
-			b = _frames[i + B];
-			float t = (time - before) / (_frames[i + ENTRIES] - before);
-			r += (_frames[i + ENTRIES + R] - r) * t;
-			g += (_frames[i + ENTRIES + G] - g) * t;
-			b += (_frames[i + ENTRIES + B] - b) * t;
-			break;
-		}
-		case STEPPED: {
-			r = _frames[i + R];
-			g = _frames[i + G];
-			b = _frames[i + B];
-			break;
-		}
-		default: {
-			r = getBezierValue(time, i, R, curveType - BEZIER);
-			g = getBezierValue(time, i, G, curveType + BEZIER_SIZE - BEZIER);
-			b = getBezierValue(time, i, B, curveType + BEZIER_SIZE * 2 - BEZIER);
-			break;
-		}
-	}
-
-	if (alpha == 1) {
-		color.r = r;
-		color.g = g;
-		color.b = b;
 	} else {
-		if (blend == MixBlend_Setup) {
-			Color &setup = slot._data._setup._color;
-			color.r = setup.r;
-			color.g = setup.g;
-			color.b = setup.b;
+		int i = Animation::search(_frames, time, ENTRIES);
+		int curveType = (int) _curves[i >> 2];
+		switch (curveType) {
+			case LINEAR: {
+				float before = _frames[i];
+				r = _frames[i + R];
+				g = _frames[i + G];
+				b = _frames[i + B];
+				float t = (time - before) / (_frames[i + ENTRIES] - before);
+				r += (_frames[i + ENTRIES + R] - r) * t;
+				g += (_frames[i + ENTRIES + G] - g) * t;
+				b += (_frames[i + ENTRIES + B] - b) * t;
+				break;
+			}
+			case STEPPED: {
+				r = _frames[i + R];
+				g = _frames[i + G];
+				b = _frames[i + B];
+				break;
+			}
+			default: {
+				r = getBezierValue(time, i, R, curveType - BEZIER);
+				g = getBezierValue(time, i, G, curveType + BEZIER_SIZE - BEZIER);
+				b = getBezierValue(time, i, B, curveType + BEZIER_SIZE * 2 - BEZIER);
+				break;
+			}
+		}
+
+		if (alpha != 1) {
+			if (blend == MixBlend_Setup) {
+				Color &setup = slot._data._setup._color;
+				r = setup.r + (r - setup.r) * alpha;
+				g = setup.g + (g - setup.g) * alpha;
+				b = setup.b + (b - setup.b) * alpha;
+			} else {
+				r = color.r + (r - color.r) * alpha;
+				g = color.g + (g - color.g) * alpha;
+				b = color.b + (b - color.b) * alpha;
+			}
 		}
-		color.r += (r - color.r) * alpha;
-		color.g += (g - color.g) * alpha;
-		color.b += (b - color.b) * alpha;
 	}
+	color.r = r < 0 ? 0 : (r > 1 ? 1 : r);
+	color.g = g < 0 ? 0 : (g > 1 ? 1 : g);
+	color.b = b < 0 ? 0 : (b > 1 ? 1 : b);
 }
 
 RTTI_IMPL(AlphaTimeline, SlotCurveTimeline)
@@ -229,6 +229,7 @@ void AlphaTimeline::apply(Skeleton &skeleton, float lastTime, float time, Array<
 	if (!slot->_bone._active) return;
 
 	Color &color = (appliedPose ? *slot->_applied : slot->_pose)._color;
+	float a;
 	if (time < _frames[0]) {
 		Color &setup = slot->_data._setup._color;
 		switch (blend) {
@@ -236,20 +237,22 @@ void AlphaTimeline::apply(Skeleton &skeleton, float lastTime, float time, Array<
 				color.a = setup.a;
 				return;
 			case MixBlend_First:
-				color.a += (setup.a - color.a) * alpha;
-				return;
+				a = color.a + (setup.a - color.a) * alpha;
+				break;
 			default:
 				return;
 		}
+	} else {
+		a = getCurveValue(time);
+		if (alpha != 1) {
+			if (blend == MixBlend_Setup) {
+				Color &setup = slot->_data._setup._color;
+				a = setup.a + (a - setup.a) * alpha;
+			} else
+				a = color.a + (a - color.a) * alpha;
+		}
 	}
-
-	float a = getCurveValue(time);
-	if (alpha == 1)
-		color.a = a;
-	else {
-		if (blend == MixBlend_Setup) color.a = slot->_data._setup._color.a;
-		color.a += (a - color.a) * alpha;
-	}
+	color.a = a < 0 ? 0 : (a > 1 ? 1 : a);
 }
 
 RTTI_IMPL(RGBA2Timeline, SlotCurveTimeline)
diff --git a/spine-cpp/src/spine/IkConstraintTimeline.cpp b/spine-cpp/src/spine/IkConstraintTimeline.cpp
index 0f2ef415e..07e1707b9 100644
--- a/spine-cpp/src/spine/IkConstraintTimeline.cpp
+++ b/spine-cpp/src/spine/IkConstraintTimeline.cpp
@@ -108,30 +108,20 @@ void IkConstraintTimeline::apply(Skeleton &skeleton, float lastTime, float time,
 		}
 	}
 
-	switch (blend) {
-		case MixBlend_Setup: {
-			IkConstraintPose &setup = constraint->_data._setup;
-			pose._mix = setup._mix + (mix - setup._mix) * alpha;
-			pose._softness = setup._softness + (softness - setup._softness) * alpha;
-			if (direction == MixDirection_Out) {
-				pose._bendDirection = setup._bendDirection;
-				pose._compress = setup._compress;
-				pose._stretch = setup._stretch;
-				return;
-			}
-			break;
+	if (blend == MixBlend_Setup) {
+		IkConstraintPose &setup = constraint->_data._setup;
+		pose._mix = setup._mix + (mix - setup._mix) * alpha;
+		pose._softness = setup._softness + (softness - setup._softness) * alpha;
+		if (direction == MixDirection_Out) {
+			pose._bendDirection = setup._bendDirection;
+			pose._compress = setup._compress;
+			pose._stretch = setup._stretch;
+			return;
 		}
-		case MixBlend_First:
-		case MixBlend_Replace:
-			pose._mix += (mix - pose._mix) * alpha;
-			pose._softness += (softness - pose._softness) * alpha;
-			if (direction == MixDirection_Out) return;
-			break;
-		case MixBlend_Add:
-			pose._mix += mix * alpha;
-			pose._softness += softness * alpha;
-			if (direction == MixDirection_Out) return;
-			break;
+	} else {
+		pose._mix += (mix - pose._mix) * alpha;
+		pose._softness += (softness - pose._softness) * alpha;
+		if (direction == MixDirection_Out) return;
 	}
 	pose._bendDirection = (int) _frames[i + BEND_DIRECTION];
 	pose._compress = _frames[i + COMPRESS] != 0;
diff --git a/spine-cpp/src/spine/PathConstraintMixTimeline.cpp b/spine-cpp/src/spine/PathConstraintMixTimeline.cpp
index b812d297a..3e741e61a 100644
--- a/spine-cpp/src/spine/PathConstraintMixTimeline.cpp
+++ b/spine-cpp/src/spine/PathConstraintMixTimeline.cpp
@@ -109,25 +109,15 @@ void PathConstraintMixTimeline::apply(Skeleton &skeleton, float lastTime, float
 		}
 	}
 
-	switch (blend) {
-		case MixBlend_Setup: {
-			PathConstraintPose &setup = constraint->_data._setup;
-			pose._mixRotate = setup._mixRotate + (rotate - setup._mixRotate) * alpha;
-			pose._mixX = setup._mixX + (x - setup._mixX) * alpha;
-			pose._mixY = setup._mixY + (y - setup._mixY) * alpha;
-			break;
-		}
-		case MixBlend_First:
-		case MixBlend_Replace:
-			pose._mixRotate += (rotate - pose._mixRotate) * alpha;
-			pose._mixX += (x - pose._mixX) * alpha;
-			pose._mixY += (y - pose._mixY) * alpha;
-			break;
-		case MixBlend_Add:
-			pose._mixRotate += rotate * alpha;
-			pose._mixX += x * alpha;
-			pose._mixY += y * alpha;
-			break;
+	if (blend == MixBlend_Setup) {
+		PathConstraintPose &setup = constraint->_data._setup;
+		pose._mixRotate = setup._mixRotate + (rotate - setup._mixRotate) * alpha;
+		pose._mixX = setup._mixX + (x - setup._mixX) * alpha;
+		pose._mixY = setup._mixY + (y - setup._mixY) * alpha;
+	} else {
+		pose._mixRotate += (rotate - pose._mixRotate) * alpha;
+		pose._mixX += (x - pose._mixX) * alpha;
+		pose._mixY += (y - pose._mixY) * alpha;
 	}
 }
 
diff --git a/spine-cpp/src/spine/PathConstraintSpacingTimeline.cpp b/spine-cpp/src/spine/PathConstraintSpacingTimeline.cpp
index 4e5827b23..3e6d0c438 100644
--- a/spine-cpp/src/spine/PathConstraintSpacingTimeline.cpp
+++ b/spine-cpp/src/spine/PathConstraintSpacingTimeline.cpp
@@ -60,6 +60,6 @@ void PathConstraintSpacingTimeline::apply(Skeleton &skeleton, float lastTime, fl
 	if (constraint->isActive()) {
 		PathConstraintPose &pose = appliedPose ? *constraint->_applied : constraint->_pose;
 		PathConstraintData &data = constraint->_data;
-		pose._spacing = getAbsoluteValue(time, alpha, blend, pose._spacing, data._setup._spacing);
+		pose._spacing = getAbsoluteValue(time, alpha, blend == MixBlend_Add ? MixBlend_Replace : blend, pose._spacing, data._setup._spacing);
 	}
 }
diff --git a/spine-cpp/src/spine/PhysicsConstraintTimeline.cpp b/spine-cpp/src/spine/PhysicsConstraintTimeline.cpp
index a4c987ad0..179899b86 100644
--- a/spine-cpp/src/spine/PhysicsConstraintTimeline.cpp
+++ b/spine-cpp/src/spine/PhysicsConstraintTimeline.cpp
@@ -52,13 +52,14 @@ RTTI_IMPL(PhysicsConstraintMixTimeline, PhysicsConstraintTimeline)
 RTTI_IMPL_MULTI(PhysicsConstraintResetTimeline, Timeline, ConstraintTimeline)
 
 PhysicsConstraintTimeline::PhysicsConstraintTimeline(size_t frameCount, size_t bezierCount, int constraintIndex, Property property)
-	: CurveTimeline1(frameCount, bezierCount), ConstraintTimeline(), _constraintIndex(constraintIndex) {
+	: CurveTimeline1(frameCount, bezierCount), ConstraintTimeline(), _constraintIndex(constraintIndex), _additive(false) {
 	PropertyId ids[] = {((PropertyId) property << 32) | constraintIndex};
 	setPropertyIds(ids, 1);
 }
 
 void PhysicsConstraintTimeline::apply(Skeleton &skeleton, float, float time, Array<Event *> *, float alpha, MixBlend blend, MixDirection direction,
 									  bool appliedPose) {
+	if (blend == MixBlend_Add && !_additive) blend = MixBlend_Replace;
 	if (_constraintIndex == -1) {
 		float value = time >= _frames[0] ? getCurveValue(time) : 0;