Index: ps/trunk/binaries/data/mods/public/simulation/components/Attack.js
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/components/Attack.js	(revision 22989)
+++ ps/trunk/binaries/data/mods/public/simulation/components/Attack.js	(revision 22990)
@@ -1,615 +1,615 @@
 function Attack() {}
 
 var g_AttackTypes = ["Melee", "Ranged", "Capture"];
 
 Attack.prototype.preferredClassesSchema =
 	"<optional>" +
 		"<element name='PreferredClasses' a:help='Space delimited list of classes preferred for attacking. If an entity has any of theses classes, it is preferred. The classes are in decending order of preference'>" +
 			"<attribute name='datatype'>" +
 				"<value>tokens</value>" +
 			"</attribute>" +
 			"<text/>" +
 		"</element>" +
 	"</optional>";
 
 Attack.prototype.restrictedClassesSchema =
 	"<optional>" +
 		"<element name='RestrictedClasses' a:help='Space delimited list of classes that cannot be attacked by this entity. If target entity has any of these classes, it cannot be attacked'>" +
 			"<attribute name='datatype'>" +
 				"<value>tokens</value>" +
 			"</attribute>" +
 			"<text/>" +
 		"</element>" +
 	"</optional>";
 
 Attack.prototype.Schema =
 	"<a:help>Controls the attack abilities and strengths of the unit.</a:help>" +
 	"<a:example>" +
 		"<Melee>" +
 			"<Damage>" +
 				"<Hack>10.0</Hack>" +
 				"<Pierce>0.0</Pierce>" +
 				"<Crush>5.0</Crush>" +
 			"</Damage>" +
 			"<MaxRange>4.0</MaxRange>" +
 			"<RepeatTime>1000</RepeatTime>" +
 			"<Bonuses>" +
 				"<Bonus1>" +
 					"<Civ>pers</Civ>" +
 					"<Classes>Infantry</Classes>" +
 					"<Multiplier>1.5</Multiplier>" +
 				"</Bonus1>" +
 				"<BonusCavMelee>" +
 					"<Classes>Cavalry Melee</Classes>" +
 					"<Multiplier>1.5</Multiplier>" +
 				"</BonusCavMelee>" +
 			"</Bonuses>" +
 			"<RestrictedClasses datatype=\"tokens\">Champion</RestrictedClasses>" +
 			"<PreferredClasses datatype=\"tokens\">Cavalry Infantry</PreferredClasses>" +
 		"</Melee>" +
 		"<Ranged>" +
 			"<Damage>" +
 				"<Hack>0.0</Hack>" +
 				"<Pierce>10.0</Pierce>" +
 				"<Crush>0.0</Crush>" +
 			"</Damage>" +
 			"<MaxRange>44.0</MaxRange>" +
 			"<MinRange>20.0</MinRange>" +
 			"<ElevationBonus>15.0</ElevationBonus>" +
 			"<PrepareTime>800</PrepareTime>" +
 			"<RepeatTime>1600</RepeatTime>" +
 			"<Delay>1000</Delay>" +
 			"<Bonuses>" +
 				"<Bonus1>" +
 					"<Classes>Cavalry</Classes>" +
 					"<Multiplier>2</Multiplier>" +
 				"</Bonus1>" +
 			"</Bonuses>" +
 			"<Projectile>" +
 				"<Speed>50.0</Speed>" +
 				"<Spread>2.5</Spread>" +
 				"<ActorName>props/units/weapons/rock_flaming.xml</ActorName>" +
 				"<ImpactActorName>props/units/weapons/rock_explosion.xml</ImpactActorName>" +
 				"<ImpactAnimationLifetime>0.1</ImpactAnimationLifetime>" +
 			"</Projectile>" +
 			"<RestrictedClasses datatype=\"tokens\">Champion</RestrictedClasses>" +
 			"<Splash>" +
 				"<Shape>Circular</Shape>" +
 				"<Range>20</Range>" +
 				"<FriendlyFire>false</FriendlyFire>" +
 				"<Damage>" +
 					"<Hack>0.0</Hack>" +
 					"<Pierce>10.0</Pierce>" +
 					"<Crush>0.0</Crush>" +
 				"</Damage>" +
 			"</Splash>" +
 		"</Ranged>" +
 		"<Slaughter>" +
 			"<Damage>" +
 				"<Hack>1000.0</Hack>" +
 				"<Pierce>0.0</Pierce>" +
 				"<Crush>0.0</Crush>" +
 			"</Damage>" +
 			"<MaxRange>4.0</MaxRange>" +
 		"</Slaughter>" +
 	"</a:example>" +
 	"<optional>" +
 		"<element name='Melee'>" +
 			"<interleave>" +
 				Attacking.BuildAttackEffectsSchema() +
 				"<element name='MaxRange' a:help='Maximum attack range (in metres)'><ref name='nonNegativeDecimal'/></element>" +
 				"<element name='PrepareTime' a:help='Time from the start of the attack command until the attack actually occurs (in milliseconds). This value relative to RepeatTime should closely match the \"event\" point in the actor&apos;s attack animation'>" +
 					"<data type='nonNegativeInteger'/>" +
 				"</element>" +
 				"<element name='RepeatTime' a:help='Time between attacks (in milliseconds). The attack animation will be stretched to match this time'>" + // TODO: it shouldn't be stretched
 					"<data type='positiveInteger'/>" +
 				"</element>" +
 				Attack.prototype.preferredClassesSchema +
 				Attack.prototype.restrictedClassesSchema +
 			"</interleave>" +
 		"</element>" +
 	"</optional>" +
 	"<optional>" +
 		"<element name='Ranged'>" +
 			"<interleave>" +
 				Attacking.BuildAttackEffectsSchema() +
 				"<element name='MaxRange' a:help='Maximum attack range (in metres)'><ref name='nonNegativeDecimal'/></element>" +
 				"<element name='MinRange' a:help='Minimum attack range (in metres)'><ref name='nonNegativeDecimal'/></element>" +
 				"<optional>"+
 					"<element name='ElevationBonus' a:help='give an elevation advantage (in meters)'><ref name='nonNegativeDecimal'/></element>" +
 				"</optional>" +
 				"<optional>" +
 					"<element name='RangeOverlay'>" +
 						"<interleave>" +
 							"<element name='LineTexture'><text/></element>" +
 							"<element name='LineTextureMask'><text/></element>" +
 							"<element name='LineThickness'><ref name='nonNegativeDecimal'/></element>" +
 						"</interleave>" +
 					"</element>" +
 				"</optional>" +
 				"<element name='PrepareTime' a:help='Time from the start of the attack command until the attack actually occurs (in milliseconds). This value relative to RepeatTime should closely match the \"event\" point in the actor&apos;s attack animation'>" +
 					"<data type='nonNegativeInteger'/>" +
 				"</element>" +
 				"<element name='RepeatTime' a:help='Time between attacks (in milliseconds). The attack animation will be stretched to match this time'>" +
 					"<data type='positiveInteger'/>" +
 				"</element>" +
 				"<element name='Delay' a:help='Delay of the damage in milliseconds'><ref name='nonNegativeDecimal'/></element>" +
 				"<optional>" +
 					"<element name='Splash'>" +
 						"<interleave>" +
 							"<element name='Shape' a:help='Shape of the splash damage, can be circular or linear'><text/></element>" +
 							"<element name='Range' a:help='Size of the area affected by the splash'><ref name='nonNegativeDecimal'/></element>" +
 							"<element name='FriendlyFire' a:help='Whether the splash damage can hurt non enemy units'><data type='boolean'/></element>" +
 							Attacking.BuildAttackEffectsSchema() +
 						"</interleave>" +
 					"</element>" +
 				"</optional>" +
 				"<element name='Projectile'>" +
 					"<interleave>" +
 						"<element name='Speed' a:help='Speed of projectiles (in meters per second).'>" +
 							"<ref name='positiveDecimal'/>" +
 						"</element>" +
 						"<element name='Spread' a:help='Standard deviation of the bivariate normal distribution of hits at 100 meters. A disk at 100 meters from the attacker with this radius (2x this radius, 3x this radius) is expected to include the landing points of 39.3% (86.5%, 98.9%) of the rounds.'><ref name='nonNegativeDecimal'/></element>" +
 						"<element name='Gravity' a:help='The gravity affecting the projectile. This affects the shape of the flight curve.'>" +
 							"<ref name='nonNegativeDecimal'/>" +
 						"</element>" +
 						"<optional>" +
 							"<element name='LaunchPoint' a:help='Delta from the unit position where to launch the projectile.'>" +
 								"<attribute name='y'>" +
 									"<data type='decimal'/>" +
 								"</attribute>" +
 							"</element>" +
 						"</optional>" +
 						"<optional>" +
 							"<element name='ActorName' a:help='actor of the projectile animation.'>" +
 								"<text/>" +
 							"</element>" +
 						"</optional>" +
 						"<optional>" +
 							"<element name='ImpactActorName' a:help='actor of the projectile impact animation'>" +
 								"<text/>" +
 							"</element>" +
 							"<element name='ImpactAnimationLifetime' a:help='length of the projectile impact animation.'>" +
 								"<ref name='positiveDecimal'/>" +
 							"</element>" +
 						"</optional>" +
 					"</interleave>" +
 				"</element>" +
 				Attack.prototype.preferredClassesSchema +
 				Attack.prototype.restrictedClassesSchema +
 			"</interleave>" +
 		"</element>" +
 	"</optional>" +
 	"<optional>" +
 		"<element name='Capture'>" +
 			"<interleave>" +
 				Attacking.BuildAttackEffectsSchema() +
 				"<element name='MaxRange' a:help='Maximum attack range (in meters)'><ref name='nonNegativeDecimal'/></element>" +
 				"<element name='RepeatTime' a:help='Time between attacks (in milliseconds). The attack animation will be stretched to match this time'>" + // TODO: it shouldn't be stretched
 					"<data type='positiveInteger'/>" +
 				"</element>" +
 				Attack.prototype.preferredClassesSchema +
 				Attack.prototype.restrictedClassesSchema +
 			"</interleave>" +
 		"</element>" +
 	"</optional>" +
 	"<optional>" +
 		"<element name='Slaughter' a:help='A special attack to kill domestic animals'>" +
 			"<interleave>" +
 				Attacking.BuildAttackEffectsSchema() +
 				"<element name='MaxRange'><ref name='nonNegativeDecimal'/></element>" + // TODO: how do these work?
 				Attack.prototype.preferredClassesSchema +
 				Attack.prototype.restrictedClassesSchema +
 			"</interleave>" +
 		"</element>" +
 	"</optional>";
 
 Attack.prototype.Init = function()
 {
 };
 
 Attack.prototype.Serialize = null; // we have no dynamic state to save
 
 Attack.prototype.GetAttackTypes = function(wantedTypes)
 {
 	let types = g_AttackTypes.filter(type => !!this.template[type]);
 	if (!wantedTypes)
 		return types;
 
 	let wantedTypesReal = wantedTypes.filter(wtype => wtype.indexOf("!") != 0);
 	return types.filter(type => wantedTypes.indexOf("!" + type) == -1 &&
 	      (!wantedTypesReal || !wantedTypesReal.length || wantedTypesReal.indexOf(type) != -1));
 };
 
 Attack.prototype.GetPreferredClasses = function(type)
 {
 	if (this.template[type] && this.template[type].PreferredClasses &&
 	    this.template[type].PreferredClasses._string)
 		return this.template[type].PreferredClasses._string.split(/\s+/);
 
 	return [];
 };
 
 Attack.prototype.GetRestrictedClasses = function(type)
 {
 	if (this.template[type] && this.template[type].RestrictedClasses &&
 	    this.template[type].RestrictedClasses._string)
 		return this.template[type].RestrictedClasses._string.split(/\s+/);
 
 	return [];
 };
 
 Attack.prototype.CanAttack = function(target, wantedTypes)
 {
 	let cmpFormation = Engine.QueryInterface(target, IID_Formation);
 	if (cmpFormation)
 		return true;
 
 	let cmpThisPosition = Engine.QueryInterface(this.entity, IID_Position);
 	let cmpTargetPosition = Engine.QueryInterface(target, IID_Position);
 	if (!cmpThisPosition || !cmpTargetPosition || !cmpThisPosition.IsInWorld() || !cmpTargetPosition.IsInWorld())
 		return false;
 
 	let cmpIdentity = QueryMiragedInterface(target, IID_Identity);
 	if (!cmpIdentity)
 		return false;
 
 	let cmpHealth = QueryMiragedInterface(target, IID_Health);
 	let targetClasses = cmpIdentity.GetClassesList();
 	if (targetClasses.indexOf("Domestic") != -1 && this.template.Slaughter && cmpHealth && cmpHealth.GetHitpoints() &&
 	   (!wantedTypes || !wantedTypes.filter(wType => wType.indexOf("!") != 0).length))
 		return true;
 
 	let cmpEntityPlayer = QueryOwnerInterface(this.entity);
 	let cmpTargetPlayer = QueryOwnerInterface(target);
 	if (!cmpTargetPlayer || !cmpEntityPlayer)
 		return false;
 
 	let types = this.GetAttackTypes(wantedTypes);
 	let entityOwner = cmpEntityPlayer.GetPlayerID();
 	let targetOwner = cmpTargetPlayer.GetPlayerID();
 	let cmpCapturable = QueryMiragedInterface(target, IID_Capturable);
 
 	// Check if the relative height difference is larger than the attack range
 	// If the relative height is bigger, it means they will never be able to
 	// reach each other, no matter how close they come.
 	let heightDiff = Math.abs(cmpThisPosition.GetHeightOffset() - cmpTargetPosition.GetHeightOffset());
 
 	for (let type of types)
 	{
 		if (type != "Capture" && (!cmpEntityPlayer.IsEnemy(targetOwner) || !cmpHealth || !cmpHealth.GetHitpoints()))
 			continue;
 
 		if (type == "Capture" && (!cmpCapturable || !cmpCapturable.CanCapture(entityOwner)))
 			continue;
 
 		if (heightDiff > this.GetRange(type).max)
 			continue;
 
 		let restrictedClasses = this.GetRestrictedClasses(type);
 		if (!restrictedClasses.length)
 			return true;
 
 		if (!MatchesClassList(targetClasses, restrictedClasses))
 			return true;
 	}
 
 	return false;
 };
 
 /**
  * Returns null if we have no preference or the lowest index of a preferred class.
  */
 Attack.prototype.GetPreference = function(target)
 {
 	let cmpIdentity = Engine.QueryInterface(target, IID_Identity);
 	if (!cmpIdentity)
 		return undefined;
 
 	let targetClasses = cmpIdentity.GetClassesList();
 
 	let minPref = null;
 	for (let type of this.GetAttackTypes())
 	{
 		let preferredClasses = this.GetPreferredClasses(type);
 		for (let targetClass of targetClasses)
 		{
 			let pref = preferredClasses.indexOf(targetClass);
 			if (pref === 0)
 				return pref;
 			if (pref != -1 && (minPref === null || minPref > pref))
 				minPref = pref;
 		}
 	}
 	return minPref;
 };
 
 /**
  * Get the full range of attack using all available attack types.
  */
 Attack.prototype.GetFullAttackRange = function()
 {
 	let ret = { "min": Infinity, "max": 0 };
 	for (let type of this.GetAttackTypes())
 	{
 		let range = this.GetRange(type);
 		ret.min = Math.min(ret.min, range.min);
 		ret.max = Math.max(ret.max, range.max);
 	}
 	return ret;
 };
 
 Attack.prototype.GetAttackEffectsData = function(type, splash)
 {
 	let template = this.template[type];
 	if (splash)
 		template = template.Splash;
 	return Attacking.GetAttackEffectsData("Attack/" + type + (splash ? "/Splash" : ""), template, this.entity);
 };
 
 /**
  * Find the best attack against a target.
  * @param {number} target - The entity-ID of the target.
  * @param {boolean} allowCapture - Whether capturing is allowed.
  * @return {string} - The preferred attack type.
  */
 Attack.prototype.GetBestAttackAgainst = function(target, allowCapture)
 {
 	let cmpFormation = Engine.QueryInterface(target, IID_Formation);
 	if (cmpFormation)
 	{
 		// TODO: Formation against formation needs review
 		let types = this.GetAttackTypes();
 		return g_AttackTypes.find(attack => types.indexOf(attack) != -1);
 	}
 
 	let cmpIdentity = Engine.QueryInterface(target, IID_Identity);
 	if (!cmpIdentity)
 		return undefined;
 
 	// Always slaughter domestic animals instead of using a normal attack
 	if (this.template.Slaughter && cmpIdentity.HasClass("Domestic"))
 		return "Slaughter";
 
 	let types = this.GetAttackTypes().filter(type => this.CanAttack(target, [type]));
 
 	// Check whether the target is capturable and prefer that when it is allowed.
 	let captureIndex = types.indexOf("Capture");
 	if (captureIndex != -1)
 	{
 		if (allowCapture)
 			return "Capture";
 		types.splice(captureIndex, 1);
 	}
 
 	let targetClasses = cmpIdentity.GetClassesList();
 	let isPreferred = attackType => MatchesClassList(targetClasses, this.GetPreferredClasses(attackType));
 
 	return types.sort((a, b) =>
 		(types.indexOf(a) + (isPreferred(a) ? types.length : 0)) -
 		(types.indexOf(b) + (isPreferred(b) ? types.length : 0))).pop();
 };
 
 Attack.prototype.CompareEntitiesByPreference = function(a, b)
 {
 	let aPreference = this.GetPreference(a);
 	let bPreference = this.GetPreference(b);
 
 	if (aPreference === null && bPreference === null) return 0;
 	if (aPreference === null) return 1;
 	if (bPreference === null) return -1;
 	return aPreference - bPreference;
 };
 
 Attack.prototype.GetTimers = function(type)
 {
 	let prepare = +(this.template[type].PrepareTime || 0);
 	prepare = ApplyValueModificationsToEntity("Attack/" + type + "/PrepareTime", prepare, this.entity);
 
 	let repeat = +(this.template[type].RepeatTime || 1000);
 	repeat = ApplyValueModificationsToEntity("Attack/" + type + "/RepeatTime", repeat, this.entity);
 
 	return { "prepare": prepare, "repeat": repeat };
 };
 
 Attack.prototype.GetSplashDamage = function(type)
 {
 	if (!this.template[type].Splash)
 		return false;
 
 	return {
 		"attackData": this.GetAttackEffectsData(type, true),
 		"friendlyFire": this.template[type].Splash.FriendlyFire != "false",
 		"shape": this.template[type].Splash.Shape,
 	};
 };
 
 Attack.prototype.GetRange = function(type)
 {
 	let max = +this.template[type].MaxRange;
 	max = ApplyValueModificationsToEntity("Attack/" + type + "/MaxRange", max, this.entity);
 
 	let min = +(this.template[type].MinRange || 0);
 	min = ApplyValueModificationsToEntity("Attack/" + type + "/MinRange", min, this.entity);
 
 	let elevationBonus = +(this.template[type].ElevationBonus || 0);
 	elevationBonus = ApplyValueModificationsToEntity("Attack/" + type + "/ElevationBonus", elevationBonus, this.entity);
 
 	return { "max": max, "min": min, "elevationBonus": elevationBonus };
 };
 
 /**
  * Attack the target entity. This should only be called after a successful range check,
  * and should only be called after GetTimers().repeat msec has passed since the last
  * call to PerformAttack.
  */
 Attack.prototype.PerformAttack = function(type, target)
 {
 	let attackerOwner = Engine.QueryInterface(this.entity, IID_Ownership).GetOwner();
 
 	// If this is a ranged attack, then launch a projectile
 	if (type == "Ranged")
 	{
 		let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
 		let turnLength = cmpTimer.GetLatestTurnLength()/1000;
 		// In the future this could be extended:
 		//  * Obstacles like trees could reduce the probability of the target being hit
 		//  * Obstacles like walls should block projectiles entirely
 
 		let horizSpeed = +this.template[type].Projectile.Speed;
 		let gravity = +this.template[type].Projectile.Gravity;
 		// horizSpeed /= 2; gravity /= 2; // slow it down for testing
 
 		let cmpPosition = Engine.QueryInterface(this.entity, IID_Position);
 		if (!cmpPosition || !cmpPosition.IsInWorld())
 			return;
 		let selfPosition = cmpPosition.GetPosition();
 		let cmpTargetPosition = Engine.QueryInterface(target, IID_Position);
 		if (!cmpTargetPosition || !cmpTargetPosition.IsInWorld())
 			return;
 		let targetPosition = cmpTargetPosition.GetPosition();
 
 		let previousTargetPosition = Engine.QueryInterface(target, IID_Position).GetPreviousPosition();
 		let targetVelocity = Vector3D.sub(targetPosition, previousTargetPosition).div(turnLength);
 
 		let timeToTarget = this.PredictTimeToTarget(selfPosition, horizSpeed, targetPosition, targetVelocity);
 		let predictedPosition = (timeToTarget !== false) ? Vector3D.mult(targetVelocity, timeToTarget).add(targetPosition) : targetPosition;
 
 		// Add inaccuracy based on spread.
 		let distanceModifiedSpread = ApplyValueModificationsToEntity("Attack/Ranged/Spread", +this.template[type].Projectile.Spread, this.entity) *
 			predictedPosition.horizDistanceTo(selfPosition) / 100;
 
 		let randNorm = randomNormal2D();
 		let offsetX = randNorm[0] * distanceModifiedSpread;
 		let offsetZ = randNorm[1] * distanceModifiedSpread;
 
 		let realTargetPosition = new Vector3D(predictedPosition.x + offsetX, targetPosition.y, predictedPosition.z + offsetZ);
 
 		// Recalculate when the missile will hit the target position.
 		let realHorizDistance = realTargetPosition.horizDistanceTo(selfPosition);
 		timeToTarget = realHorizDistance / horizSpeed;
 
 		let missileDirection = Vector3D.sub(realTargetPosition, selfPosition).div(realHorizDistance);
 
 		// Launch the graphical projectile.
 		let cmpProjectileManager = Engine.QueryInterface(SYSTEM_ENTITY, IID_ProjectileManager);
 
 		let actorName = "";
 		let impactActorName = "";
 		let impactAnimationLifetime = 0;
 
 		actorName = this.template[type].Projectile.ActorName || "";
 		impactActorName = this.template[type].Projectile.ImpactActorName || "";
 		impactAnimationLifetime = this.template[type].Projectile.ImpactAnimationLifetime || 0;
 
 		// TODO: Use unit rotation to implement x/z offsets.
-		let deltaLaunchPoint = new Vector3D(0, this.template[type].Projectile.LaunchPoint["@y"], 0.0);
+		let deltaLaunchPoint = new Vector3D(0, +this.template[type].Projectile.LaunchPoint["@y"], 0);
 		let launchPoint = Vector3D.add(selfPosition, deltaLaunchPoint);
 
 		let cmpVisual = Engine.QueryInterface(this.entity, IID_Visual);
 		if (cmpVisual)
 		{
 			// if the projectile definition is missing from the template
 			// then fallback to the projectile name and launchpoint in the visual actor
 			if (!actorName)
 				actorName = cmpVisual.GetProjectileActor();
 
 			let visualActorLaunchPoint = cmpVisual.GetProjectileLaunchPoint();
 			if (visualActorLaunchPoint.length() > 0)
 				launchPoint = visualActorLaunchPoint;
 		}
 
 		let id = cmpProjectileManager.LaunchProjectileAtPoint(launchPoint, realTargetPosition, horizSpeed, gravity, actorName, impactActorName, impactAnimationLifetime);
 
 		let attackImpactSound = "";
 		let cmpSound = Engine.QueryInterface(this.entity, IID_Sound);
 		if (cmpSound)
 			attackImpactSound = cmpSound.GetSoundGroup("attack_impact_" + type.toLowerCase());
 
 		let data = {
 			"type": type,
 			"attackData": this.GetAttackEffectsData(type),
 			"target": target,
 			"attacker": this.entity,
 			"attackerOwner": attackerOwner,
 			"position": realTargetPosition,
 			"direction": missileDirection,
 			"projectileId": id,
 			"attackImpactSound": attackImpactSound
 		};
 		if (this.template[type].Splash)
 			data.splash = {
 				"friendlyFire": this.template[type].Splash.FriendlyFire != "false",
 				"radius": +this.template[type].Splash.Range,
 				"shape": this.template[type].Splash.Shape,
 				"attackData": this.GetAttackEffectsData(type, true),
 			};
 		cmpTimer.SetTimeout(SYSTEM_ENTITY, IID_DelayedDamage, "MissileHit", +this.template[type].Delay + timeToTarget * 1000, data);
 	}
 	else
 		Attacking.HandleAttackEffects(type, this.GetAttackEffectsData(type), target, this.entity, attackerOwner);
 };
 
 /**
  * Get the predicted time of collision between a projectile (or a chaser)
  * and its target, assuming they both move in straight line at a constant speed.
  * Vertical component of movement is ignored.
  * @param {Vector3D} selfPosition - the 3D position of the projectile (or chaser).
  * @param {number} horizSpeed - the horizontal speed of the projectile (or chaser).
  * @param {Vector3D} targetPosition - the 3D position of the target.
  * @param {Vector3D} targetVelocity - the 3D velocity vector of the target.
  * @return {Vector3D|boolean} - the 3D predicted position or false if the collision will not happen.
  */
 Attack.prototype.PredictTimeToTarget = function(selfPosition, horizSpeed, targetPosition, targetVelocity)
 {
 	let relativePosition = new Vector3D.sub(targetPosition, selfPosition);
 	let a = targetVelocity.x * targetVelocity.x + targetVelocity.z * targetVelocity.z - horizSpeed * horizSpeed;
 	let b = relativePosition.x * targetVelocity.x + relativePosition.z * targetVelocity.z;
 	let c = relativePosition.x * relativePosition.x + relativePosition.z * relativePosition.z;
 	// The predicted time to reach the target is the smallest non negative solution
 	// (when it exists) of the equation a t^2 + 2 b t + c = 0.
 	// Using c>=0, we can straightly compute the right solution.
 
 	if (c == 0)
 		return 0;
 
 	let disc = b * b - a * c;
 	if (a < 0 || b < 0 && disc >= 0)
 		return c / (Math.sqrt(disc) - b);
 
 	return false;
 };
 
 Attack.prototype.OnValueModification = function(msg)
 {
 	if (msg.component != "Attack")
 		return;
 
 	let cmpUnitAI = Engine.QueryInterface(this.entity, IID_UnitAI);
 	if (!cmpUnitAI)
 		return;
 
 	if (this.GetAttackTypes().some(type =>
 	      msg.valueNames.indexOf("Attack/" + type + "/MaxRange") != -1))
 		cmpUnitAI.UpdateRangeQueries();
 };
 
 Attack.prototype.GetRangeOverlays = function()
 {
 	if (!this.template.Ranged || !this.template.Ranged.RangeOverlay)
 		return [];
 
 	let range = this.GetRange("Ranged");
 	let rangeOverlays = [];
 	for (let i in range)
 		if ((i == "min" || i == "max") && range[i])
 			rangeOverlays.push({
 				"radius": range[i],
 				"texture": this.template.Ranged.RangeOverlay.LineTexture,
 				"textureMask": this.template.Ranged.RangeOverlay.LineTextureMask,
 				"thickness": +this.template.Ranged.RangeOverlay.LineThickness,
 			});
 	return rangeOverlays;
 };
 
 Engine.RegisterComponentType(IID_Attack, "Attack", Attack);