feat(mechanics): Make stray projectiles not hit disabled fighters

source/AI.cpp

@@ -675,7 +675,8 @@ void AI::Step(Command &activeCommands)
 			// Each ship only switches targets twice a second, so that it can
 			// focus on damaging one particular ship.
 			targetTurn = (targetTurn + 1) & 31;
-			if(targetTurn == step || !target || target->IsDestroyed() || (target->IsDisabled() && personality.Disables())
+			if(targetTurn == step || !target || target->IsDestroyed() || (target->IsDisabled() &&
+					(personality.Disables() || target->CanBeCarried()))
 					|| (target->IsFleeing() && personality.IsMerciful()) || !target->IsTargetable())
 			{
 				target = FindTarget(*it);

source/CollisionSet.cpp

@@ -39,34 +39,6 @@ namespace {
 	constexpr int USED_MAX_VELOCITY = MAX_VELOCITY - 1;
 	// Warn the user only once about too-large projectile velocities.
 	bool warned = false;
-
-
-	// Keep track of the closest collision found so far. If an external "closest
-	// hit" value was given, there is no need to check collisions farther out
-	// than that.
-	class Closest {
-	public:
-		explicit Closest(double closestHit)
-			: closest_dist(closestHit)
-			, closest_body(nullptr)
-		{}
-
-		void TryNearer(double new_closest, Body *new_body)
-		{
-			if(new_closest >= closest_dist)
-				return;
-
-			closest_dist = new_closest;
-			closest_body = new_body;
-		}
-
-		double GetClosestDistance() const { return closest_dist; }
-		Body *GetClosestBody() const { return closest_body; }
-
-	private:
-		double closest_dist;
-		Body *closest_body;
-	};
 }
 
 
@@ -166,9 +138,8 @@ void CollisionSet::Finish()
 
 
 
-// Get all collisions for the given projectile. Collisions are not necessarily
-// sorted by distance. If the projectile is incapable if impacting multiple ships
-// in the same frame then only the closest collision is returned.
+// Get all possible collisions for the given projectile. Collisions are not necessarily
+// sorted by distance.
 const vector<Collision> &CollisionSet::Line(const Projectile &projectile) const
 {
 	// What objects the projectile hits depends on its government.
@@ -177,15 +148,15 @@ const vector<Collision> &CollisionSet::Line(const Projectile &projectile) const
 	// Convert the projectile to a line represented by its start and end points.
 	Point from = projectile.Position();
 	Point to = from + projectile.Velocity();
-	return Line(from, to, pGov, projectile.Target(), projectile.HitsRemaining() != 1);
+	return Line(from, to, pGov, projectile.Target());
 }
 
 
 
-// Get all collisions along a line. Collisions are not necessarily sorted by
-// distance. If the all variable is false then only the closest collision is returned.
+// Get all possible collisions along a line. Collisions are not necessarily sorted by
+// distance.
 const vector<Collision> &CollisionSet::Line(const Point &from, const Point &to,
-		const Government *pGov, const Body *target, bool all) const
+		const Government *pGov, const Body *target) const
 {
 	const int x = from.X();
 	const int y = from.Y();
@@ -198,7 +169,6 @@ const vector<Collision> &CollisionSet::Line(const Point &from, const Point &to,
 	const int endGX = endX >> SHIFT;
 	const int endGY = endY >> SHIFT;
 
-	Closest closer_result(1.);
 	lineResult.clear();
 
 	// Special case, very common: the projectile is contained in one grid cell.
@@ -226,13 +196,10 @@ const vector<Collision> &CollisionSet::Line(const Point &from, const Point &to,
 			Point offset = from - it->body->Position();
 			const double range = mask.Collide(offset, to - from, it->body->Facing());
 
-			closer_result.TryNearer(range, it->body);
-			if(range < 1. && all)
+			if(range < 1.)
 				lineResult.emplace_back(it->body, collisionType, range);
 		}
 
-		if(!all && closer_result.GetClosestDistance() < 1.)
-			lineResult.emplace_back(closer_result.GetClosestBody(), collisionType, closer_result.GetClosestDistance());
 		return lineResult;
 	}
 
@@ -247,7 +214,7 @@ const vector<Collision> &CollisionSet::Line(const Point &from, const Point &to,
 		}
 		Point newEnd = from + pVelocity.Unit() * USED_MAX_VELOCITY;
 
-		return Line(from, newEnd, pGov, target, all);
+		return Line(from, newEnd, pGov, target);
 	}
 
 	// When stepping from one grid cell to the next, we'll go in this direction.
@@ -300,13 +267,12 @@ const vector<Collision> &CollisionSet::Line(const Point &from, const Point &to,
 			Point offset = from - it->body->Position();
 			const double range = mask.Collide(offset, to - from, it->body->Facing());
 
-			closer_result.TryNearer(range, it->body);
-			if(range < 1. && all)
+			if(range < 1.)
 				lineResult.emplace_back(it->body, collisionType, range);
 		}
 
-		// Check if we've found a collision or reached the final grid cell.
-		if((closer_result.GetClosestBody() && !all) || (gx == endGX && gy == endGY))
+		// Check if we've reached the final grid cell.
+		if(gx == endGX && gy == endGY)
 			break;
 		// If not, move to the next one. Check whether rx / mx < ry / my.
 		const int64_t diff = rx * my - ry * mx;
@@ -342,8 +308,6 @@ const vector<Collision> &CollisionSet::Line(const Point &from, const Point &to,
 		}
 	}
 
-	if(!all && closer_result.GetClosestBody())
-		lineResult.emplace_back(closer_result.GetClosestBody(), collisionType, closer_result.GetClosestDistance());
 	return lineResult;
 }
 

source/CollisionSet.h

@@ -45,15 +45,14 @@ class CollisionSet {
 	// Finish adding objects (and organize them into the final lookup table).
 	void Finish();
 
-	// Get all collisions for the given projectile. Collisions are not necessarily
-	// sorted by distance. If the projectile is incapable if impacting multiple ships
-	// in the same frame then only the closest collision is returned.
+	// Get all possible collisions for the given projectile. Collisions are not necessarily
+	// sorted by distance.
 	const std::vector<Collision> &Line(const Projectile &projectile) const;
 
-	// Get all collisions along a line. Collisions are not necessarily sorted by
-	// distance. If the all variable is false then only the closest collision is returned.
+	// Get all possible collisions along a line. Collisions are not necessarily sorted by
+	// distance.
 	const std::vector<Collision> &Line(const Point &from, const Point &to,
-		const Government *pGov = nullptr, const Body *target = nullptr, bool all = true) const;
+		const Government *pGov = nullptr, const Body *target = nullptr) const;
 
 	// Get all objects within the given range of the given point.
 	const std::vector<Body *> &Circle(const Point &center, double radius) const;

source/Engine.cpp

@@ -2213,6 +2213,11 @@ void Engine::DoCollisions(Projectile &projectile)
 		if(hit && collisionType == CollisionType::SHIP)
 			shipHit = reinterpret_cast<Ship *>(hit)->shared_from_this();
 
+		// Don't collide with carried ships that are disabled and not directly targeted.
+		if(shipHit && hit != projectile.Target()
+				&& shipHit->CanBeCarried() && shipHit->IsDisabled())
+			continue;
+
 		// Create the explosion the given distance along the projectile's
 		// motion path for this step.
 		projectile.Explode(visuals, range, hit ? hit->Velocity() : Point());

source/Projectile.cpp

@@ -60,7 +60,10 @@ Projectile::Projectile(const Ship &parent, Point position, Angle angle, const We
 
 	cachedTarget = TargetPtr().get();
 	if(cachedTarget)
+	{
 		targetGovernment = cachedTarget->GetGovernment();
+		targetDisabled = cachedTarget->IsDisabled();
+	}
 
 	dV = this->angle.Unit() * (weapon->Velocity() + Random::Real() * weapon->RandomVelocity());
 	velocity += dV;
@@ -82,6 +85,8 @@ Projectile::Projectile(const Projectile &parent, const Point &offset, const Angl
 	hitsRemaining = weapon->PenetrationCount();
 
 	cachedTarget = TargetPtr().get();
+	if(cachedTarget)
+		targetDisabled = cachedTarget->IsDisabled();
 
 	// Given that submunitions inherit the velocity of the parent projectile,
 	// it is often the case that submunitions don't add any additional velocity.
@@ -137,14 +142,15 @@ void Projectile::Move(vector<Visual> &visuals, vector<Projectile> &projectiles)
 
 	// If the target has left the system, stop following it. Also stop if the
 	// target has been captured by a different government.
+	// Also stop targeting disabled ships, unless requested.
 	const Ship *target = cachedTarget;
 	if(target)
 	{
 		target = TargetPtr().get();
-		if(!target || !target->IsTargetable() || target->GetGovernment() != targetGovernment)
+		if(!target || !target->IsTargetable() || target->GetGovernment() != targetGovernment ||
+				(!targetDisabled && target->IsDisabled()))
 		{
-			targetShip.reset();
-			cachedTarget = nullptr;
+			BreakTarget();
 			target = nullptr;
 		}
 	}
@@ -380,6 +386,7 @@ void Projectile::BreakTarget()
 	targetShip.reset();
 	cachedTarget = nullptr;
 	targetGovernment = nullptr;
+	targetDisabled = false;
 }
 
 

source/Projectile.h

@@ -114,6 +114,7 @@ class Projectile : public Body {
 
 	std::weak_ptr<Ship> targetShip;
 	const Ship *cachedTarget = nullptr;
+	bool targetDisabled = false;
 	const Government *targetGovernment = nullptr;
 
 	// The change in velocity of all stages of this projectile