Custom Controller Example: Having an Turret Gun Aim and Fire at the Player

void SpinController::Move(void)
{
	World *world = TheWorldMgr->GetWorld();
	// Calculate the new spin angle based on how much time has passed
	float angle = spinAngle + spinRate * TheTimeMgr->GetFloatDeltaTime();
 
	if (angle > 100.0F) angle -= 200.0F;
	else if (angle < -100.0F) angle += 200.0F;
 
	spinAngle = angle;
 
	Node *target = GetTargetNode();
 
        //You could also search for a subnode of the Entity - eg just the barrel of the gun would then move.
	//Entity *myEntity = (Entity *)GetTargetNode();
        //Node *target = myEntity->FindNode("Barrel");
 
	const GamePlayer *player = static_cast<const GamePlayer *>(TheMessageMgr->GetLocalPlayer());
	FighterController *controller = player->GetPlayerController();
	Point3D point = controller->GetColliderPosition();
 
	Vector3D view = (point - target->GetNodePosition());
 
	float x = view.x;
	float y = view.y;
	float z = view.z;
	float distance = Sqrt(x * x + y * y + z * z);
 
	view = view.Normalize();
 
	if (distance < 50.0f) {// && view.z >=0.0f) {//ie if also above turret gun
 
        //interpolate between the current viewing direction and the target viewing direction. 
        //If you use say 40.0 instead of 20.0 then it will move twice as slowly.
	Vector3D updatedView = Vector3D(originalView.x+(view.x-originalView.x)/20.0f,originalView.y+(view.y-originalView.y)/20.0f,originalView.z+(view.z-originalView.z)/20.0f);
 
	originalView = updatedView;
 
	x = updatedView.x;
	y = updatedView.y;
 
	float f = InverseSqrt(x * x + y * y);
	Vector3D right(y * f, -x * f, 0.0F);
 
	Vector3D down = updatedView % right;
	target->SetNodeMatrix3D(updatedView, -right, -down);
 
	Point3D startPos = target->GetNodePosition();
 
	//you dont want the ammo to start inside the enemy - this is just in front of the enemy
	//you can vary 4.0f to be say 1.5f or 3.0f, depending on your model
        //better still would be to use a marker on the model to be the point where the projectile exits (-> next version!!)
	startPos.x += 4.0f * updatedView.x;
	startPos.y += 4.0f * updatedView.y;
	startPos.z += 4.0f * updatedView.z;
 
        //The projectile velocity is reduced by a factor of 15.0f here to slow it down
	//otherwise the player has no chance at all!
	Point3D objectVelocity = Point3D(updatedView.x/15.0f, updatedView.y/15.0f, updatedView.z/15.0f);
 
	//Firing
	if (world)
	{
	  Controller	*controller;	
	  Entity *entity = nullptr;
 
	  //Fire on some condition - here is just an example for a quick test
          //So this is true about once every few seconds - increase (or decrease) "40" 
          //for longer (or shorter) pauses between shots
	  if ((((int)angle) % 40) == 0) //angle > -60.0F && angle < -0.0F && 
	  {
		//create fireball!!
		controller = new FireballController(startPos, objectVelocity);
		entity = Entity::Get(kEntityFireball);
 
		if (entity)
		{
			entity->SetController(controller);
 
			Zone *zone = world->FindZone(startPos);
 
			Point3D zonePosition = zone->GetInverseWorldTransform() * startPos;
			entity->SetNodePosition(zonePosition);
			zone->AddNewSubnode(entity);
			entity->Update();
 
			controller->EnterWorld(zone, zonePosition);
		}
	  }
    }
    // Invalidate the target node so that it gets updated properly
    target->Invalidate();
 
  }//if distance
 
}