void Transform::RotateTowards(const Kiwi::Vector3& target, float maxRotation)
{
if(m_position == target) return;
//calculate the vector between the current position and the target
Kiwi::Vector3 vectorBetween(target.x - m_position.x, target.y - m_position.y, target.z - m_position.z);
vectorBetween = vectorBetween.Normalized();
Kiwi::Vector3 forward = this->GetForward();
Kiwi::Vector3 up = this->GetUp();
float dot = forward.Dot(vectorBetween);
if( dot < -0.999999f )
{
//currently pointing in exactly opposite directions so rotate 180 degrees about the up axis
this->Rotate(up, 3.141592f);
return;
}else if( dot > 0.9999f )
{
//already facing each other, do nothing
return;
}
Kiwi::Vector3 rotationAxis = forward.Cross(vectorBetween);
float angle = std::acos( forward.Dot(vectorBetween) );
//angle = ToDegrees(angle);
if(maxRotation != 0.0f && angle > maxRotation)
{
angle = maxRotation;
}
this->Rotate(rotationAxis, angle);
//now the quaternion is facing the target, but it may be rotated around the z-axis
//need to rotate around the z-axis to the desired up direction
Kiwi::Vector3 eulerAngles = m_rotation.GetEulerAngles();
if(eulerAngles.z != 0.0f)
{
this->Rotate(this->GetForward(),-eulerAngles.z);
}
}
double const squaredDistanceBetween(Point3D const & a0, Point3D const & a1){
return squaredOf(vectorBetween(a0, a1));
}
double const distanceBetween(Point3D const & a0, Point3D const & a1){
return absoluteOf(vectorBetween(a0, a1));
}
