public override Vector2 Calculate()
{
// The detection box is the current velocity divided by the max velocity of the entity
// range is the maximum size of the box
Vector2 viewBox = this.Entity.Velocity / this.Entity.MaxSpeed * this.range;
// Add the check points in front of the entity
IEnumerable <Vector2> checkpoints = new[]
{
this.Entity.Position,
this.Entity.Position + viewBox / 2f, // Halfway
this.Entity.Position + viewBox, // At the end
this.Entity.Position + viewBox * 2 // Double
};
foreach (Rock o in this.world.Entities.OfType <Rock>())
{
// Add a circle around the obstacle which can't be crossed
CircleF notAllowedZone = new CircleF(o.Position, o.Scale);
if (checkpoints.Any(checkpoint => notAllowedZone.Contains(checkpoint)))
{
Vector2 dist = new Vector2(o.Position.X - this.Entity.Position.X, o.Position.X - this.Entity.Position.Y);
Vector2 perpendicular = Vector2Helper.PerpendicularRightAngleOf(dist);
Vector2 perpendicularPositivePos = o.Position + perpendicular;
Vector2 perpendicularNegativePos = o.Position - perpendicular;
float perpDistPositive = Vector2.DistanceSquared(this.Entity.Position + this.Entity.Velocity, perpendicularPositivePos);
float perpDistNegative = Vector2.DistanceSquared(this.Entity.Position + this.Entity.Velocity, perpendicularNegativePos);
Vector2 targetRelative = (perpDistPositive > perpDistNegative ? perpendicularNegativePos : perpendicularPositivePos) - this.Entity.Position;
return(Vector2Helper.PerpendicularRightAngleOf(targetRelative));
}
}
// Return identity vector if there will be no collision
return(new Vector2());
}