calculate method

@override Vector3 calculate(Vehicle vehicle, Vector3 force, [ double? delta ])

Calculates the steering force for a single simulation step.

Implementation

@override
Vector3 calculate(Vehicle vehicle, Vector3 force, [double? delta]) {
	final entity1 = this.entity1!;
	final entity2 = this.entity2!;

	// first we need to figure out where the two entities are going to be
	// in the future. This is approximated by determining the time
	// taken to reach the mid way point at the current time at max speed
	midPoint.addVectors( entity1.position, entity2.position ).multiplyScalar( 0.5 );
	final time = vehicle.position.distanceTo( midPoint ) / vehicle.maxSpeed;

	// now we have the time, we assume that entity 1 and entity 2 will
	// continue on a straight trajectory and extrapolate to get their future positions
	translation.copy( entity1.velocity ).multiplyScalar( time );
	predictedPosition1.addVectors( entity1.position, translation );

	translation.copy( entity2.velocity ).multiplyScalar( time );
	predictedPosition2.addVectors( entity2.position, translation );

	// calculate the mid point of these predicted positions
	midPoint.addVectors( predictedPosition1, predictedPosition2 ).multiplyScalar( 0.5 );

	// then steer to arrive at it
	_arrive.deceleration = deceleration;
	_arrive.target = midPoint;
	_arrive.calculate( vehicle, force );

	return force;
}