void Box2DWheelJoint::setLocalAnchorA(const QPointF &localAnchorA)
{
    mWheelJointDef.localAnchorA = b2Vec2(localAnchorA.x() / scaleRatio,
                                         -localAnchorA.y() / scaleRatio);
    anchorsAuto = false;
    emit localAnchorAChanged();
}
void Box2DDistanceJoint::setLocalAnchorA(const QPointF &localAnchorA)
{
    if (mOverrideLocalAnchorA && mLocalAnchorA == localAnchorA)
        return;

    mOverrideLocalAnchorA = true;
    mLocalAnchorA = localAnchorA;

    emit localAnchorAChanged();
}
void Box2DFrictionJoint::setLocalAnchorA(const QPointF &localAnchorA)
{
    mFrictionJointDef.localAnchorA = toMeters(localAnchorA);
    mAnchorsAuto = false;
    emit localAnchorAChanged();
}