コード例 #1
0
ファイル: AI.cpp プロジェクト: balachia/endless-sky
void AI::Attack(Ship &ship, Command &command, const Ship &target)
{
	Point d = target.Position() - ship.Position();
	
	// First, figure out what your shortest-range weapon is.
	double shortestRange = 4000.;
	for(const Armament::Weapon &weapon : ship.Weapons())
	{
		const Outfit *outfit = weapon.GetOutfit();
		if(outfit && !weapon.IsAntiMissile())
			shortestRange = min(outfit->Range(), shortestRange);
	}
	
	// Deploy any fighters you are carrying.
	if(!ship.IsYours())
		command |= Command::DEPLOY;
	// If this ship only has long-range weapons, it should keep its distance
	// instead of trying to close with the target ship.
	if(shortestRange > 1000. && d.Length() < .5 * shortestRange)
	{
		command.SetTurn(TurnToward(ship, -d));
		if(ship.Facing().Unit().Dot(d) <= 0.)
			command |= Command::FORWARD;
		return;
	}
	
	// First of all, aim in the direction that will hit this target.
	command.SetTurn(TurnToward(ship, TargetAim(ship)));
	
	// Calculate this ship's "turning radius; that is, the smallest circle it
	// can make while at full speed.
	double stepsInFullTurn = 360. / ship.TurnRate();
	double circumference = stepsInFullTurn * ship.Velocity().Length();
	double diameter = max(200., circumference / PI);
	
	// This isn't perfect, but it works well enough.
	if((ship.Facing().Unit().Dot(d) >= 0. && d.Length() > diameter)
			|| (ship.Velocity().Dot(d) < 0. && ship.Facing().Unit().Dot(d.Unit()) >= .9))
		command |= Command::FORWARD;
}
コード例 #2
0
ファイル: Armament.cpp プロジェクト: Arnogax/endless-sky
// Fire this weapon. If it is a turret, it automatically points toward
// the given ship's target. If the weapon requires ammunition, it will
// be subtracted from the given ship.
void Armament::Weapon::Fire(Ship &ship, list<Projectile> &projectiles, list<Effect> &effects)
{
	// Since this is only called internally by Armament (no one else has non-
	// const access), assume Armament checked that this is a valid call.
	Angle aim = ship.Facing();
	
	// Get projectiles to start at the right position. They are drawn at an
	// offset of (.5 * velocity) and that velocity includes the velocity of the
	// ship that fired them.
	Point start = ship.Position() + aim.Rotate(point) - .5 * ship.Velocity();
	
	shared_ptr<const Ship> target = ship.GetTargetShip();
	// If you are boarding your target, do not fire on it.
	if(ship.IsBoarding() || ship.Commands().Has(Command::BOARD))
		target.reset();
	
	if(!isTurret || !target || target->GetSystem() != ship.GetSystem())
		aim += angle;
	else
	{
		Point p = target->Position() - start + ship.GetPersonality().Confusion();
		Point v = target->Velocity() - ship.Velocity();
		double steps = RendezvousTime(p, v, outfit->Velocity());
		
		// Special case: RendezvousTime() may return NaN. But in that case, this
		// comparison will return false.
		if(!(steps < outfit->TotalLifetime()))
			steps = outfit->TotalLifetime();
		
		p += steps * v;
		
		aim = Angle(TO_DEG * atan2(p.X(), -p.Y()));
	}
	
	projectiles.emplace_back(ship, start, aim, outfit);
	if(outfit->WeaponSound())
		Audio::Play(outfit->WeaponSound(), start);
	double force = outfit->FiringForce();
	if(force)
		ship.ApplyForce(aim.Unit() * -force);
	
	for(const auto &eit : outfit->FireEffects())
		for(int i = 0; i < eit.second; ++i)
		{
			effects.push_back(*eit.first);
			effects.back().Place(start, ship.Velocity(), aim);
		}
	
	Fire(ship);
}
コード例 #3
0
ファイル: AI.cpp プロジェクト: balachia/endless-sky
bool AI::Stop(Ship &ship, Command &command, double slow)
{
	const Point &velocity = ship.Velocity();
	const Angle &angle = ship.Facing();
	
	double speed = velocity.Length();
	
	if(speed <= slow)
		return true;
	
	command.SetTurn(TurnBackward(ship));
	if(velocity.Unit().Dot(angle.Unit()) < -.8)
		command |= Command::FORWARD;
	
	return false;
}
コード例 #4
0
ファイル: AI.cpp プロジェクト: balachia/endless-sky
double AI::TurnToward(const Ship &ship, const Point &vector)
{
	static const double RAD_TO_DEG = 180. / 3.14159265358979;
	Point facing = ship.Facing().Unit();
	double cross = vector.Cross(facing);
	
	if(vector.Dot(facing) > 0.)
	{
		double angle = asin(cross / vector.Length()) * RAD_TO_DEG;
		if(fabs(angle) <= ship.TurnRate())
			return -angle / ship.TurnRate();
	}
	
	bool left = cross < 0.;
	return left - !left;
}
コード例 #5
0
ファイル: AI.cpp プロジェクト: balachia/endless-sky
double AI::TurnBackward(const Ship &ship)
{
	Angle angle = ship.Facing();
	bool left = ship.Velocity().Cross(angle.Unit()) > 0.;
	double turn = left - !left;
	
	// Check if the ship will still be pointing to the same side of the target
	// angle if it turns by this amount.
	angle += ship.TurnRate() * turn;
	bool stillLeft = ship.Velocity().Cross(angle.Unit()) > 0.;
	if(left == stillLeft)
		return turn;
	
	// If we're within one step of the correct direction, stop turning.
	return 0.;
}
コード例 #6
0
ファイル: Armament.cpp プロジェクト: Arnogax/endless-sky
// Fire an anti-missile. Returns true if the missile should be killed.
bool Armament::Weapon::FireAntiMissile(Ship &ship, const Projectile &projectile, list<Effect> &effects)
{
	int strength = outfit->AntiMissile();
	if(!strength)
		return false;
	
	double range = outfit->Velocity();
	
	// Check if the missile is in range.
	Point start = ship.Position() + ship.Facing().Rotate(point);
	Point offset = projectile.Position() - start;
	if(offset.Length() > range)
		return false;
	
	// Firing effects are displayed at the anti-missile that just fired.
	Angle aim = TO_DEG * atan2(offset.X(), -offset.Y());
	for(const auto &eit : outfit->FireEffects())
		for(int i = 0; i < eit.second; ++i)
		{
			effects.push_back(*eit.first);
			effects.back().Place(start, ship.Velocity(), aim);
		}
	
	// Figure out where the effect should be placed. Anti-missiles do not create
	// projectiles; they just create a blast animation.
	start += (.5 * range) * offset.Unit();
	for(const auto &eit : outfit->HitEffects())
		for(int i = 0; i < eit.second; ++i)
		{
			effects.push_back(*eit.first);
			effects.back().Place(start, ship.Velocity(), aim);
		}
	
	// Die effects are displayed at the projectile, whether or not it actually "dies."
	for(const auto &eit : outfit->DieEffects())
		for(int i = 0; i < eit.second; ++i)
		{
			effects.push_back(*eit.first);
			effects.back().Place(projectile.Position(), projectile.Velocity(), aim);
		}
	
	Fire(ship);
	
	return (Random::Int(strength) > Random::Int(projectile.MissileStrength()));
}
コード例 #7
0
ファイル: AI.cpp プロジェクト: balachia/endless-sky
bool AI::MoveTo(Ship &ship, Command &command, const Point &target, double radius, double slow)
{
	const Point &position = ship.Position();
	const Point &velocity = ship.Velocity();
	const Angle &angle = ship.Facing();
	Point distance = target - position;
	
	double speed = velocity.Length();
	
	bool isClose = (distance.Length() < radius);
	if(isClose && speed < slow)
		return true;
	
	distance = target - StoppingPoint(ship);
	bool isFacing = (distance.Unit().Dot(angle.Unit()) > .8);
	if(!isClose || !isFacing)
		command.SetTurn(TurnToward(ship, distance));
	if(isFacing)
		command |= Command::FORWARD;
	
	return false;
}
コード例 #8
0
ファイル: AI.cpp プロジェクト: balachia/endless-sky
Point AI::StoppingPoint(const Ship &ship)
{
	const Point &position = ship.Position();
	const Point &velocity = ship.Velocity();
	const Angle &angle = ship.Facing();
	double acceleration = ship.Acceleration();
	double turnRate = ship.TurnRate();
	
	// If I were to turn around and stop now, where would that put me?
	double v = velocity.Length();
	if(!v)
		return position;
	
	// This assumes you're facing exactly the wrong way.
	double degreesToTurn = TO_DEG * acos(-velocity.Unit().Dot(angle.Unit()));
	double stopDistance = v * (degreesToTurn / turnRate);
	// Sum of: v + (v - a) + (v - 2a) + ... + 0.
	// The number of terms will be v / a.
	// The average term's value will be v / 2. So:
	stopDistance += .5 * v * v / acceleration;
	
	return position + stopDistance * velocity.Unit();
}
コード例 #9
0
ファイル: Projectile.cpp プロジェクト: Phezzan/endless-sky
// Check if the given ship is within this projectile's blast radius. (The
// projectile will not explode unless it is also within the trigger radius.)
bool Projectile::InBlastRadius(const Ship &ship, int step) const
{
	const Mask &mask = ship.GetSprite().GetMask(step);
	return mask.WithinRange(position - ship.Position(), ship.Facing(), weapon->BlastRadius());
}
コード例 #10
0
ファイル: AI.cpp プロジェクト: balachia/endless-sky
void AI::MoveIndependent(Ship &ship, Command &command) const
{
	if(ship.Position().Length() >= 10000.)
	{
		MoveTo(ship, command, Point(), 40., .8);
		return;
	}
	shared_ptr<const Ship> target = ship.GetTargetShip();
	if(target && (ship.GetGovernment()->IsEnemy(target->GetGovernment())
			|| (ship.IsYours() && target == sharedTarget.lock())))
	{
		bool shouldBoard = ship.Cargo().Free() && ship.GetPersonality().Plunders();
		bool hasBoarded = Has(ship, target, ShipEvent::BOARD);
		if(shouldBoard && target->IsDisabled() && !hasBoarded)
		{
			if(ship.IsBoarding())
				return;
			MoveTo(ship, command, target->Position(), 40., .8);
			command |= Command::BOARD;
		}
		else
			Attack(ship, command, *target);
		return;
	}
	else if(target)
	{
		bool cargoScan = ship.Attributes().Get("cargo scan");
		bool outfitScan = ship.Attributes().Get("outfit scan");
		if((!cargoScan || Has(ship, target, ShipEvent::SCAN_CARGO))
				&& (!outfitScan || Has(ship, target, ShipEvent::SCAN_OUTFITS)))
			target.reset();
		else
		{
			CircleAround(ship, command, *target);
			if(!ship.GetGovernment()->IsPlayer())
				command |= Command::SCAN;
		}
		return;
	}
	
	// If this ship is moving independently because it has a target, not because
	// it has no parent, don't let it make travel plans.
	if(ship.GetParent() && !ship.GetPersonality().IsStaying())
		return;
	
	if(!ship.GetTargetSystem() && !ship.GetTargetPlanet() && !ship.GetPersonality().IsStaying())
	{
		int jumps = ship.JumpsRemaining();
		// Each destination system has an average priority of 10.
		// If you only have one jump left, landing should be high priority.
		int planetWeight = jumps ? (1 + 40 / jumps) : 1;
		
		vector<int> systemWeights;
		int totalWeight = 0;
		const vector<const System *> &links = ship.Attributes().Get("jump drive")
			? ship.GetSystem()->Neighbors() : ship.GetSystem()->Links();
		if(jumps)
		{
			for(const System *link : links)
			{
				// Prefer systems in the direction we're facing.
				Point direction = link->Position() - ship.GetSystem()->Position();
				int weight = static_cast<int>(
					11. + 10. * ship.Facing().Unit().Dot(direction.Unit()));
				
				systemWeights.push_back(weight);
				totalWeight += weight;
			}
		}
		int systemTotalWeight = totalWeight;
		
		// Anywhere you can land that has a port has the same weight. Ships will
		// not land anywhere without a port.
		vector<const StellarObject *> planets;
		for(const StellarObject &object : ship.GetSystem()->Objects())
			if(object.GetPlanet() && object.GetPlanet()->HasSpaceport()
					&& object.GetPlanet()->CanLand(ship))
			{
				planets.push_back(&object);
				totalWeight += planetWeight;
			}
		if(!totalWeight)
			return;
		
		int choice = Random::Int(totalWeight);
		if(choice < systemTotalWeight)
		{
			for(unsigned i = 0; i < systemWeights.size(); ++i)
			{
				choice -= systemWeights[i];
				if(choice < 0)
				{
					ship.SetTargetSystem(links[i]);
					break;
				}
			}
		}
		else
		{
			choice = (choice - systemTotalWeight) / planetWeight;
			ship.SetTargetPlanet(planets[choice]);
		}
	}
	
	if(ship.GetTargetSystem())
	{
		PrepareForHyperspace(ship, command);
		bool mustWait = false;
		for(const weak_ptr<const Ship> &escort : ship.GetEscorts())
		{
			shared_ptr<const Ship> locked = escort.lock();
			mustWait = locked && locked->CanBeCarried();
		}
		
		if(!mustWait)
			command |= Command::JUMP;
	}
	else if(ship.GetTargetPlanet())
	{
		MoveToPlanet(ship, command);
		if(!ship.GetPersonality().IsStaying())
			command |= Command::LAND;
		else if(ship.Position().Distance(ship.GetTargetPlanet()->Position()) < 100.)
			ship.SetTargetPlanet(nullptr);
	}
	else if(ship.GetPersonality().IsStaying() && ship.GetSystem()->Objects().size())
	{
		unsigned i = Random::Int(ship.GetSystem()->Objects().size());
		ship.SetTargetPlanet(&ship.GetSystem()->Objects()[i]);
	}
}
コード例 #11
0
ファイル: AI.cpp プロジェクト: balachia/endless-sky
void AI::MovePlayer(Ship &ship, const PlayerInfo &player, const list<shared_ptr<Ship>> &ships)
{
	Command command;
	
	if(player.HasTravelPlan())
	{
		const System *system = player.TravelPlan().back();
		ship.SetTargetSystem(system);
		// Check if there's a particular planet there we want to visit.
		for(const Mission &mission : player.Missions())
			if(mission.Destination() && mission.Destination()->GetSystem() == system)
			{
				ship.SetDestination(mission.Destination());
				break;
			}
	}
	
	if(keyDown.Has(Command::NEAREST))
	{
		double closest = numeric_limits<double>::infinity();
		int closeState = 0;
		for(const shared_ptr<Ship> &other : ships)
			if(other.get() != &ship && other->IsTargetable())
			{
				// Sort ships into one of three priority states:
				// 0 = friendly, 1 = disabled enemy, 2 = active enemy.
				int state = other->GetGovernment()->IsEnemy(ship.GetGovernment());
				// Do not let "target nearest" select a friendly ship, so that
				// if the player is repeatedly targeting nearest to, say, target
				// a bunch of fighters, they won't start firing on friendly
				// ships as soon as the last one is gone.
				if((!state && !shift) || other->GetGovernment()->IsPlayer())
					continue;
				
				state += state * !other->IsDisabled();
				
				double d = other->Position().Distance(ship.Position());
				
				if(state > closeState || (state == closeState && d < closest))
				{
					ship.SetTargetShip(other);
					closest = d;
					closeState = state;
				}
			}
	}
	else if(keyDown.Has(Command::TARGET))
	{
		shared_ptr<const Ship> target = ship.GetTargetShip();
		bool selectNext = !target || !target->IsTargetable();
		for(const shared_ptr<Ship> &other : ships)
		{
			bool isPlayer = other->GetGovernment()->IsPlayer() || other->GetPersonality().IsEscort();
			if(other == target)
				selectNext = true;
			else if(other.get() != &ship && selectNext && other->IsTargetable() && isPlayer == shift)
			{
				ship.SetTargetShip(other);
				selectNext = false;
				break;
			}
		}
		if(selectNext)
			ship.SetTargetShip(shared_ptr<Ship>());
	}
	else if(keyDown.Has(Command::BOARD))
	{
		shared_ptr<const Ship> target = ship.GetTargetShip();
		if(!target || !target->IsDisabled() || target->IsDestroyed() || target->GetSystem() != ship.GetSystem())
		{
			double closest = numeric_limits<double>::infinity();
			bool foundEnemy = false;
			bool foundAnything = false;
			for(const shared_ptr<Ship> &other : ships)
				if(other->IsTargetable() && other->IsDisabled() && !other->IsDestroyed())
				{
					bool isEnemy = other->GetGovernment()->IsEnemy(ship.GetGovernment());
					double d = other->Position().Distance(ship.Position());
					if((isEnemy && !foundEnemy) || d < closest)
					{
						closest = d;
						foundEnemy = isEnemy;
						foundAnything = true;
						ship.SetTargetShip(other);
					}
				}
			if(!foundAnything)
				keyDown.Clear(Command::BOARD);
		}
	}
	else if(keyDown.Has(Command::LAND))
	{
		// If the player is right over an uninhabited planet, display a message
		// explaining why they cannot land there.
		string message;
		for(const StellarObject &object : ship.GetSystem()->Objects())
			if(!object.GetPlanet() && !object.GetSprite().IsEmpty())
			{
				double distance = ship.Position().Distance(object.Position());
				if(distance < object.Radius())
					message = object.LandingMessage();
			}
		const StellarObject *target = ship.GetTargetPlanet();
		if(target && ship.Position().Distance(target->Position()) < target->Radius())
		{
			// Special case: if there are two planets in system and you have one
			// selected, then press "land" again, do not toggle to the other if
			// you are within landing range of the one you have selected.
		}
		else if(message.empty() && target)
		{
			bool found = false;
			const StellarObject *next = nullptr;
			for(const StellarObject &object : ship.GetSystem()->Objects())
				if(object.GetPlanet())
				{
					if(found)
					{
						next = &object;
						break;
					}
					else if(&object == ship.GetTargetPlanet())
						found = true;
				}
			if(!next)
			{
				for(const StellarObject &object : ship.GetSystem()->Objects())
					if(object.GetPlanet())
					{
						next = &object;
						break;
					}
			}
			ship.SetTargetPlanet(next);
			if(next->GetPlanet() && !next->GetPlanet()->CanLand())
				message = "The authorities on this planet refuse to clear you to land here.";
		}
		else if(message.empty())
		{
			double closest = numeric_limits<double>::infinity();
			int count = 0;
			for(const StellarObject &object : ship.GetSystem()->Objects())
				if(object.GetPlanet())
				{
					++count;
					double distance = ship.Position().Distance(object.Position());
					const Planet *planet = object.GetPlanet();
					if(planet == ship.GetDestination())
						distance = 0.;
					else if(!planet->HasSpaceport() && !planet->IsWormhole())
						distance += 10000.;
					
					if(distance < closest)
					{
						ship.SetTargetPlanet(&object);
						closest = distance;
					}
				}
			if(!ship.GetTargetPlanet())
				message = "There are no planets in this system that you can land on.";
			else if(!ship.GetTargetPlanet()->GetPlanet()->CanLand())
				message = "The authorities on this planet refuse to clear you to land here.";
			else if(count > 1)
			{
				message = "You can land on more than one planet in this system. Landing on ";
				if(ship.GetTargetPlanet()->Name().empty())
					message += "???.";
				else
					message += ship.GetTargetPlanet()->Name() + ".";
			}
		}
		if(!message.empty())
			Messages::Add(message);
	}
	else if(keyDown.Has(Command::JUMP))
	{
		if(!ship.GetTargetSystem())
		{
			double bestMatch = -2.;
			const auto &links = (ship.Attributes().Get("jump drive") ?
				ship.GetSystem()->Neighbors() : ship.GetSystem()->Links());
			for(const System *link : links)
			{
				Point direction = link->Position() - ship.GetSystem()->Position();
				double match = ship.Facing().Unit().Dot(direction.Unit());
				if(match > bestMatch)
				{
					bestMatch = match;
					ship.SetTargetSystem(link);
				}
			}
		}
	}
	else if(keyDown.Has(Command::SCAN))
		command |= Command::SCAN;
	
	bool hasGuns = Preferences::Has("Automatic firing") && !ship.IsBoarding()
		&& !(keyStuck | keyHeld).Has(Command::LAND | Command::JUMP | Command::BOARD);
	if(hasGuns)
		command |= AutoFire(ship, ships, false);
	hasGuns |= keyHeld.Has(Command::PRIMARY);
	if(keyHeld)
	{
		if(keyHeld.Has(Command::RIGHT | Command::LEFT))
			command.SetTurn(keyHeld.Has(Command::RIGHT) - keyHeld.Has(Command::LEFT));
		else if(keyHeld.Has(Command::BACK))
		{
			if(ship.Attributes().Get("reverse thrust"))
				command |= Command::BACK;
			else
				command.SetTurn(TurnBackward(ship));
		}
		
		if(keyHeld.Has(Command::FORWARD))
			command |= Command::FORWARD;
		if(keyHeld.Has(Command::PRIMARY))
		{
			int index = 0;
			for(const Armament::Weapon &weapon : ship.Weapons())
			{
				const Outfit *outfit = weapon.GetOutfit();
				if(outfit && !outfit->Icon())
				{
					command.SetFire(index);
					hasGuns |= !weapon.IsTurret();
				}
				++index;
			}
		}
		if(keyHeld.Has(Command::SECONDARY))
		{
			int index = 0;
			for(const Armament::Weapon &weapon : ship.Weapons())
			{
				const Outfit *outfit = weapon.GetOutfit();
				if(outfit && outfit == player.SelectedWeapon())
					command.SetFire(index);
				++index;
			}
		}
		if(keyHeld.Has(Command::AFTERBURNER))
			command |= Command::AFTERBURNER;
		
		if(keyHeld.Has(AutopilotCancelKeys()))
			keyStuck = keyHeld;
	}
	if(hasGuns && Preferences::Has("Automatic aiming") && !command.Turn()
			&& ship.GetTargetShip() && ship.GetTargetShip()->GetSystem() == ship.GetSystem()
			&& !keyStuck.Has(Command::LAND | Command::JUMP | Command::BOARD))
	{
		Point distance = ship.GetTargetShip()->Position() - ship.Position();
		if(distance.Unit().Dot(ship.Facing().Unit()) >= .8)
			command.SetTurn(TurnToward(ship, TargetAim(ship)));
	}
	
	if(ship.IsBoarding())
		keyStuck.Clear();
	else if(keyStuck.Has(Command::LAND) && ship.GetTargetPlanet())
	{
		if(ship.GetPlanet())
			keyStuck.Clear();
		else
		{
			MoveToPlanet(ship, command);
			command |= Command::LAND;
		}
	}
	else if(keyStuck.Has(Command::JUMP) && ship.GetTargetSystem())
	{
		if(!ship.Attributes().Get("hyperdrive") && !ship.Attributes().Get("jump drive"))
		{
			Messages::Add("You do not have a hyperdrive installed.");
			keyStuck.Clear();
		}
		else if(!ship.HyperspaceType())
		{
			Messages::Add("You cannot jump to the selected system.");
			keyStuck.Clear();
		}
		else if(!ship.JumpsRemaining() && !ship.IsEnteringHyperspace())
		{
			Messages::Add("You do not have enough fuel to make a hyperspace jump.");
			keyStuck.Clear();
		}
		else if(!ship.GetTargetSystem())
			keyStuck.Clear();
		else
		{
			PrepareForHyperspace(ship, command);
			command |= Command::JUMP;
			if(keyHeld.Has(Command::JUMP))
				command |= Command::WAIT;
		}
	}
	else if(keyStuck.Has(Command::BOARD) && ship.GetTargetShip())
	{
		shared_ptr<const Ship> target = ship.GetTargetShip();
		if(!target || !target->IsTargetable() || !target->IsDisabled() || target->IsDestroyed())
			keyStuck.Clear(Command::BOARD);
		else
		{
			MoveTo(ship, command, target->Position(), 40., .8);
			command |= Command::BOARD;
		}
	}
	
	if(isLaunching)
		command |= Command::DEPLOY;
	if(isCloaking)
		command |= Command::CLOAK;
	
	ship.SetCommands(command);
}
コード例 #12
0
ファイル: AI.cpp プロジェクト: balachia/endless-sky
// Fire whichever of the given ship's weapons can hit a hostile target.
Command AI::AutoFire(const Ship &ship, const list<shared_ptr<Ship>> &ships, bool secondary) const
{
	Command command;
	int index = -1;
	
	// Special case: your target is not your enemy. Do not fire, because you do
	// not want to risk damaging that target. The only time a ship other than
	// the player will target a friendly ship is if the player has asked a ship
	// for assistance.
	shared_ptr<Ship> currentTarget = ship.GetTargetShip();
	const Government *gov = ship.GetGovernment();
	bool isSharingTarget = ship.IsYours() && currentTarget == sharedTarget.lock();
	bool currentIsEnemy = currentTarget
		&& currentTarget->GetGovernment()->IsEnemy(gov)
		&& currentTarget->GetSystem() == ship.GetSystem();
	if(currentTarget && !(currentIsEnemy || isSharingTarget))
		currentTarget.reset();
	
	// Only fire on disabled targets if you don't want to plunder them.
	bool spareDisabled = (ship.GetPersonality().Disables() || ship.GetPersonality().Plunders());
	
	// Find the longest range of any of your non-homing weapons.
	double maxRange = 0.;
	for(const Armament::Weapon &weapon : ship.Weapons())
		if(weapon.IsReady() && !weapon.IsHoming() && (secondary || !weapon.GetOutfit()->Icon()))
			maxRange = max(maxRange, weapon.GetOutfit()->Range());
	// Extend the weapon range slightly to account for velocity differences.
	maxRange *= 1.5;
	
	// Find all enemy ships within range of at least one weapon.
	vector<shared_ptr<const Ship>> enemies;
	if(currentTarget)
		enemies.push_back(currentTarget);
	for(auto target : ships)
		if(target->IsTargetable() && gov->IsEnemy(target->GetGovernment())
				&& target->Velocity().Length() < 20.
				&& target->GetSystem() == ship.GetSystem()
				&& target->Position().Distance(ship.Position()) < maxRange
				&& target != currentTarget)
			enemies.push_back(target);
	
	for(const Armament::Weapon &weapon : ship.Weapons())
	{
		++index;
		// Skip weapons that are not ready to fire. Also skip homing weapons if
		// no target is selected, and secondary weapons if only firing primaries.
		if(!weapon.IsReady() || (!currentTarget && weapon.IsHoming()))
			continue;
		if(!secondary && weapon.GetOutfit()->Icon())
			continue;
		
		// Special case: if the weapon uses fuel, be careful not to spend so much
		// fuel that you cannot leave the system if necessary.
		if(weapon.GetOutfit()->FiringFuel())
		{
			double fuel = ship.Fuel() * ship.Attributes().Get("fuel capacity");
			fuel -= weapon.GetOutfit()->FiringFuel();
			// If the ship is not ever leaving this system, it does not need to
			// reserve any fuel.
			bool isStaying = ship.GetPersonality().IsStaying();
			if(!secondary || fuel < (isStaying ? 0. : ship.JumpFuel()))
				continue;
		}
		// Figure out where this weapon will fire from, but add some randomness
		// depending on how accurate this ship's pilot is.
		Point start = ship.Position() + ship.Facing().Rotate(weapon.GetPoint());
		start += ship.GetPersonality().Confusion();
		
		const Outfit *outfit = weapon.GetOutfit();
		double vp = outfit->Velocity();
		double lifetime = outfit->TotalLifetime();
		
		if(currentTarget && (weapon.IsHoming() || weapon.IsTurret()))
		{
			bool hasBoarded = Has(ship, currentTarget, ShipEvent::BOARD);
			if(currentTarget->IsDisabled() && spareDisabled && !hasBoarded)
				continue;
			
			Point p = currentTarget->Position() - start;
			Point v = currentTarget->Velocity() - ship.Velocity();
			// By the time this action is performed, the ships will have moved
			// forward one time step.
			p += v;
			
			if(p.Length() < outfit->BlastRadius())
				continue;
			
			double steps = Armament::RendevousTime(p, v, vp);
			if(steps == steps && steps <= lifetime)
			{
				command.SetFire(index);
				continue;
			}
		}
		// Don't fire homing weapons with no target.
		if(weapon.IsHoming())
			continue;
		
		for(const shared_ptr<const Ship> &target : enemies)
		{
			if(!target->IsTargetable()
					|| target->Velocity().Length() > 20.
					|| target->GetSystem() != ship.GetSystem())
				continue;
			
			// Don't shoot ships we want to plunder.
			bool hasBoarded = Has(ship, target, ShipEvent::BOARD);
			if(target->IsDisabled() && spareDisabled && !hasBoarded)
				continue;
			
			Point p = target->Position() - start;
			Point v = target->Velocity() - ship.Velocity();
			// By the time this action is performed, the ships will have moved
			// forward one time step.
			p += v;
			
			// Get the vector the weapon will travel along.
			v = (ship.Facing() + weapon.GetAngle()).Unit() * vp - v;
			// Extrapolate over the lifetime of the projectile.
			v *= lifetime;
			
			const Mask &mask = target->GetSprite().GetMask(step);
			if(mask.Collide(-p, v, target->Facing()) < 1.)
			{
				command.SetFire(index);
				break;
			}
		}
	}
	
	return command;
}