/// <summary>
/// GameObject update method
/// </summary>
/// <param name="gameTime"></param>
public override void Update(GameTime gameTime)
{
// track the player, just for now.
var toTarget = Player.GetWorldPosition() - RigidBody.GetPosition();
var distToTarget = Vec2.Distance(Player.GetWorldPosition(), RigidBody.GetPosition());
if (distToTarget > 10 && !Active)
{
return;
}
if (!Active)
{
ActiveEffect.Play();
}
Active = true;
var rot = GameUtils.Vec2ToRotation(toTarget);
RigidBody.SetXForm(RigidBody.GetPosition(), (float)(rot * System.Math.PI / 180.0f));
Rotation = (float)(rot * System.Math.PI / 180.0f);
toTarget.Normalize();
_lastDecision = DateTime.UtcNow;
var targetVelocity = Player.RigidBody.GetLinearVelocity();
var myVelocity = RigidBody.GetLinearVelocity();
//velocityAngle will tell us if the alien and player are moving in different directions
//180 degrees means they are moving opposite
//0 means they are moving in the same direction
//90, etc..
//if(velocityAngle > 0)
//{
//}
//getting further away?
if (_lastDistanceToTarget < distToTarget)
{
if (myVelocity.Length() > 1)
{
var velocityAngle = System.Math.Abs(System.Math.Acos(Vec2.Dot(targetVelocity, myVelocity) / (targetVelocity.Length() * myVelocity.Length())));
//if we're not going in the same direction, start slowing down
if (velocityAngle >= System.Math.PI / (2 * 60))
{
//start slowing down so we can pursue the player
GoToStopping();
}
else
{
GoToMoving(distToTarget, toTarget);
}
}
else
{
GoToMoving(distToTarget, toTarget);
}
}
else
{
//distance hasn't changed
if (distToTarget > 1)
{
GoToMoving(distToTarget, toTarget);
}
else
{
GoToStopping();
}
}
if (distToTarget <= 5)
{
var attackDiff = DateTime.UtcNow - LastAttackTime;
if (attackDiff.TotalMilliseconds >= 500)
{
LastAttackTime = DateTime.UtcNow;
ShootingEffect.Play();
SpawnProjectile("GreenLaser-small", ProjectileSource.Alien);
}
}
/*if (distToTarget > 1 && distToTarget <= 3)
* {
* // if the target is stopped
* if (Player.RigidBody.GetLinearVelocity().Length() < 0.05)
* {
* if (_moveState == MoveState.Stopping)
* {
* GoToStopping();
* }
* else
* {
* GoToMoving(toTarget);
* }
* }
* else if (Player.Instance.RigidBody.GetLinearVelocity().Length() > RigidBody.GetLinearVelocity().Length())
* {
* GoToMoving(toTarget);
* }
* }
* else if (distToTarget > 3 && targetVelocity <= 0.05)
* {
* if (myVelocity >= 0.05)
* {
* GoToStopping();
* }
* else if(_moveState == MoveState.Stopped)
* {
* RigidBody.SetLinearVelocity(Vec2.Zero);
* GoToMoving(toTarget);
* }
* }
*/
//if we're getting close enough to the player, decrease our impulse
//if (_lastDistanceToPlayer.Length() > distToPlayer && distToPlayer)
//{
//}
//if (Vec2.Distance(Player.Instance.GetWorldPosition(), RigidBody.GetPosition()) > 1 &&
// Vec2.Distance(Vec2.Zero, RigidBody.GetLinearVelocity()) < _definition.MaxSpeed)
//{
// RigidBody.ApplyImpulse(toPlayer * _definition.MoveImpulse, RigidBody.GetPosition());
// }
/*else if (GameUtils.DistanceFrom(Player.Instance.GetWorldPosition(), RigidBody.GetPosition()) > 1)
* {
* RigidBody.ApplyImpulse(toPlayer * _definition.MoveImpulse, RigidBody.GetPosition());
* }
*/
//else
//{
// DecreaseLinearVelocity(_definition.AlienTurnVelocityDecrement, 0);
// RigidBody.SetAngularVelocity(0);
//}
_lastDistanceToTarget = distToTarget;
base.Update(gameTime);
}
