/// <summary>
/// separationBehavior.Update infuences the owning animal to move away from
/// the otherAnimal is it’s too close, in this case if it’s inside
/// AIParameters.separationDistance.
/// </summary>
/// <param name="otherAnimal">the Animal to react to</param>
/// <param name="aiParams">the Behaviors' parameters</param>
public override void Update(Animal otherAnimal, AIParameters aiParams)
{
base.ResetReaction();
Vector2 pushDirection = Vector2.Zero;
float weight = aiParams.PerMemberWeight;
if (Animal.ReactionDistance > 0.0f &&
Animal.ReactionDistance <= aiParams.SeparationDistance)
{
//The otherAnimal is too close so we figure out a pushDirection
//vector in the opposite direction of the otherAnimal and then weight
//that reaction based on how close it is vs. our separationDistance
pushDirection = Animal.Location - Animal.ReactionLocation;
Vector2.Normalize(ref pushDirection, out pushDirection);
//push away
weight *= (1 -
(float)Animal.ReactionDistance / aiParams.SeparationDistance);
pushDirection *= weight;
reacted = true;
reaction += pushDirection;
}
}
/// <summary>
/// CohesionBehavior.Update infuences the owning animal to move towards the
/// otherAnimal that it sees as long as it isn’t too close, in this case
/// that means inside the separationDist in the passed in AIParameters.
/// </summary>
/// <param name="otherAnimal">the Animal to react to</param>
/// <param name="aiParams">the Behaviors' parameters</param>
public override void Update(Animal otherAnimal, AIParameters aiParams)
{
base.ResetReaction();
Vector2 pullDirection = Vector2.Zero;
float weight = aiParams.PerMemberWeight;
//if the otherAnimal is too close we dont' want to fly any
//closer to it
if (Animal.ReactionDistance > 0.0f
&& Animal.ReactionDistance > aiParams.SeparationDistance)
{
//We want to make the animal move closer the the otherAnimal so we
//create a pullDirection vector pointing to the otherAnimal bird and
//weigh it based on how close the otherAnimal is relative to the
//AIParameters.separationDistance.
pullDirection = -(Animal.Location - Animal.ReactionLocation);
Vector2.Normalize(ref pullDirection, out pullDirection);
weight *= (float)Math.Pow((double)
(Animal.ReactionDistance - aiParams.SeparationDistance) /
(aiParams.DetectionDistance - aiParams.SeparationDistance), 2);
pullDirection *= weight;
reacted = true;
reaction = pullDirection;
}
}
public override void Update(Animal otherAnimal, AIParameters aiParams)
{
base.ResetReaction();
Vector2 dangerDirection = Vector2.Zero;
//Vector2.Dot will return a negative result in this case if the
//otherAnimal is behind the animal, in that case we don’t have to
//worry about it because we’re already moving away from it.
if (Vector2.Dot(
Animal.Location, Animal.ReactionLocation) >= -(Math.PI / 2))
{
//set the animal to fleeing so that it flashes red
Animal.Fleeing = true;
reacted = true;
dangerDirection = Animal.Location - Animal.ReactionLocation;
Vector2.Normalize(ref dangerDirection, out dangerDirection);
reaction = (aiParams.PerDangerWeight * dangerDirection);
}
}
/// <summary> /// Abstract function that the subclass must impliment. Figure out the /// Behavior reaction here. /// </summary> /// <param name="otherAnimal">the Animal to react to</param> /// <param name="aiParams">the Behaviors' parameters</param> public abstract void Update(Animal otherAnimal, AIParameters aiParams);
protected Behavior(Animal animal)
{
this.animal = animal;
}
public CohesionBehavior(Animal animal)
: base(animal)
{
}
/// <summary>
/// React to an Animal based on it's type
/// </summary>
/// <param name="animal"></param>
public void ReactTo(Animal animal, ref AIParameters AIparams)
{
if (animal != null)
{
//setting the the reactionLocation and reactionDistance here is
//an optimization, many of the possible reactions use the distance
//and location of theAnimal, so we might as well figure them out
//only once !
Vector2 otherLocation = animal.Location;
ClosestLocation(ref location, ref otherLocation,
out reactionLocation);
reactionDistance = Vector2.Distance(location, reactionLocation);
//we only react if theAnimal is close enough that we can see it
if (reactionDistance < AIparams.DetectionDistance)
{
Behaviors reactions = behaviors[animal.AnimalType];
foreach (Behavior reaction in reactions)
{
reaction.Update(animal, AIparams);
if (reaction.Reacted)
{
aiNewDir += reaction.Reaction;
aiNumSeen++;
}
}
}
}
}
public FleeBehavior(Animal animal)
: base(animal)
{
}
public SeparationBehavior(Animal animal)
: base(animal)
{
}