[c][cpp] Allow negative scale and shear mix in transform constraint. See #1227.

spine-c/spine-c/src/spine/TransformConstraint.c

@@ -205,13 +205,13 @@ void _spTransformConstraint_applyAbsoluteLocal (spTransformConstraint* self) {
 		}
 
 		scaleX = bone->ascaleX, scaleY = bone->ascaleY;
-		if (scaleMix > 0) {
+		if (scaleMix != 0) {
 			if (scaleX > 0.00001) scaleX = (scaleX + (target->ascaleX - scaleX + self->data->offsetScaleX) * scaleMix) / scaleX;
 			if (scaleY > 0.00001) scaleY = (scaleY + (target->ascaleY - scaleY + self->data->offsetScaleY) * scaleMix) / scaleY;
 		}
 
 		shearY = bone->ashearY;
-		if (shearMix > 0) {
+		if (shearMix != 0) {
 			r = target->ashearY - shearY + self->data->offsetShearY;
 			r -= (16384 - (int)(16384.499999999996 - r / 360)) * 360;
 			bone->shearY += r * shearMix;
@@ -245,13 +245,13 @@ void _spTransformConstraint_applyRelativeLocal (spTransformConstraint* self) {
 
 		scaleX = bone->ascaleX;
 		scaleY = bone->ascaleY;
-		if (scaleMix > 0) {
+		if (scaleMix != 0) {
 			if (scaleX > 0.00001f) scaleX *= ((target->ascaleX - 1 + self->data->offsetScaleX) * scaleMix) + 1;
 			if (scaleY > 0.00001f) scaleY *= ((target->ascaleY - 1 + self->data->offsetScaleY) * scaleMix) + 1;
 		}
 
 		shearY = bone->ashearY;
-		if (shearMix > 0) shearY += (target->ashearY + self->data->offsetShearY) * shearMix;
+		if (shearMix != 0) shearY += (target->ashearY + self->data->offsetShearY) * shearMix;
 
 		spBone_updateWorldTransformWith(bone, x, y, rotation, scaleX, scaleY, bone->ashearX, shearY);
 	}

spine-cpp/spine-cpp/src/spine/TransformConstraint.cpp

@@ -315,7 +315,7 @@ void TransformConstraint::applyAbsoluteLocal() {
 		}
 
 		float scaleX = bone._ascaleX, scaleY = bone._ascaleY;
-		if (scaleMix > 0) {
+		if (scaleMix != 0) {
 			if (scaleX > 0.00001f) {
 				scaleX = (scaleX + (target._ascaleX - scaleX + _data._offsetScaleX) * scaleMix) / scaleX;
 			}
@@ -326,7 +326,7 @@ void TransformConstraint::applyAbsoluteLocal() {
 		}
 
 		float shearY = bone._ashearY;
-		if (shearMix > 0) {
+		if (shearMix != 0) {
 			float r = target._ashearY - shearY + _data._offsetShearY;
 			r -= (16384 - (int) (16384.499999999996 - r / 360)) * 360;
 			bone._shearY += r * shearMix;
@@ -363,7 +363,7 @@ void TransformConstraint::applyRelativeLocal() {
 		}
 
 		float scaleX = bone._ascaleX, scaleY = bone._ascaleY;
-		if (scaleMix > 0) {
+		if (scaleMix != 0) {
 			if (scaleX > 0.00001f) {
 				scaleX *= ((target._ascaleX - 1 + _data._offsetScaleX) * scaleMix) + 1;
 			}
@@ -374,7 +374,7 @@ void TransformConstraint::applyRelativeLocal() {
 		}
 
 		float shearY = bone._ashearY;
-		if (shearMix > 0) {
+		if (shearMix != 0) {
 			shearY += (target._ashearY + _data._offsetShearY) * shearMix;
 		}