Add acceleration.

OpenRA.Mods.RA2/Activities/BallisticMissileFly.cs

@@ -22,17 +22,17 @@ public class BallisticMissileFly : Activity
 		readonly BallisticMissile missile;
 		readonly WPos initPos;
 		readonly WPos targetPos;
-		readonly int length;
 		readonly int facing;
 
+		int length;
 		int ticks;
 
 		public BallisticMissileFly(Actor self, Target target, BallisticMissile missile)
 		{
 			this.missile = missile;
 			initPos = self.CenterPosition;
 			targetPos = target.CenterPosition;
-			length = Math.Max((targetPos - initPos).Length / missile.Info.Speed, 1);
+			length = Math.Max((targetPos - initPos).Length / missile.MovementSpeed, 1);
 			facing = (targetPos - initPos).Yaw.Facing;
 			missile.Facing = facing;
 		}
@@ -50,6 +50,7 @@ public override bool Tick(Actor self)
 				return true;
 			}
 
+			length = Math.Max((targetPos - initPos).Length / missile.MovementSpeed, 1);
 			var pos = WPos.LerpQuadratic(initPos, targetPos, missile.Info.LaunchAngle, ticks, length);
 			missile.SetPosition(self, pos);
 

OpenRA.Mods.RA2/Traits/BallisticMissile.cs

@@ -23,15 +23,18 @@ namespace OpenRA.Mods.RA2.Traits
 	[Desc("This unit, when ordered to move, will fly in ballistic path then will detonate itself upon reaching target.")]
 	public class BallisticMissileInfo : ITraitInfo, IMoveInfo, IPositionableInfo, IFacingInfo
 	{
-		[Desc("Projectile speed in WDist / tick, two values indicate variable velocity.")]
-		public readonly int Speed = 17;
+		[Desc("Initial projectile speed in WDist / tick.")]
+		public readonly int Speed = 1;
 
 		[Desc("In angle. Missile is launched at this pitch and the intial tangential line of the ballistic path will be this.")]
 		public readonly WAngle LaunchAngle = WAngle.Zero;
 
 		[Desc("Minimum altitude where this missile is considered airborne")]
 		public readonly int MinAirborneAltitude = 5;
 
+		[Desc("Speed gain in WDist / tick.")]
+		public readonly int Acceleration = 3;
+
 		[Desc("Types of damage missile explosion is triggered with. Leave empty for no damage types.")]
 		public readonly BitSet<DamageType> DamageTypes = default(BitSet<DamageType>);
 
@@ -78,6 +81,8 @@ public class BallisticMissile : ISync, IFacing, IMove, IPositionable,
 		bool airborne;
 		int airborneToken = ConditionManager.InvalidConditionToken;
 
+		int acceleration;
+
 		public BallisticMissile(ActorInitializer init, BallisticMissileInfo info)
 		{
 			Info = info;
@@ -123,7 +128,7 @@ Pair<CPos, SubCell>[] IOccupySpace.OccupiedCells()
 
 		public int MovementSpeed
 		{
-			get { return Util.ApplyPercentageModifiers(Info.Speed, speedModifiers); }
+			get { return Util.ApplyPercentageModifiers(Info.Speed, speedModifiers) + acceleration; }
 		}
 
 		public WVec FlyStep(int facing)
@@ -163,6 +168,8 @@ public void SetPosition(Actor self, WPos pos)
 			if (!self.IsInWorld)
 				return;
 
+			acceleration += Info.Acceleration;
+
 			self.World.UpdateMaps(self, this);
 
 			var altitude = self.World.Map.DistanceAboveTerrain(CenterPosition);
@@ -228,8 +235,7 @@ public Activity VisualMove(Actor self, WPos fromPos, WPos toPos)
 
 		public int EstimatedMoveDuration(Actor self, WPos fromPos, WPos toPos)
 		{
-			var speed = MovementSpeed;
-			return speed > 0 ? (toPos - fromPos).Length / speed : 0;
+			return MovementSpeed > 0 ? (toPos - fromPos).Length / MovementSpeed : 0;
 		}
 
 		public CPos NearestMoveableCell(CPos cell) { return cell; }