Add simple, invisible instant-hit projectile

For melee attacks, machine guns and so on.

OpenRA.Mods.Common/OpenRA.Mods.Common.csproj

@@ -147,6 +147,7 @@
     <Compile Include="Effects\SpriteEffect.cs" />
     <Compile Include="Projectiles\AreaBeam.cs" />
     <Compile Include="Projectiles\Bullet.cs" />
+    <Compile Include="Projectiles\InstantHit.cs" />
     <Compile Include="Projectiles\GravityBomb.cs" />
     <Compile Include="Projectiles\LaserZap.cs" />
     <Compile Include="Projectiles\Missile.cs" />

OpenRA.Mods.Common/Projectiles/InstantHit.cs

@@ -0,0 +1,85 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2017 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using OpenRA.GameRules;
+using OpenRA.Graphics;
+using OpenRA.Mods.Common.Traits;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Projectiles
+{
+	[Desc("Simple invisible direct on target projectile.")]
+	public class InstantHitInfo : IProjectileInfo
+	{
+		[Desc("Maximum offset at the maximum range.")]
+		public readonly WDist Inaccuracy = WDist.Zero;
+
+		[Desc("Projectile can be blocked.")]
+		public readonly bool Blockable = false;
+
+		[Desc("The width of the projectile.")]
+		public readonly WDist Width = new WDist(1);
+
+		[Desc("Extra search radius beyond projectile width. Required to ensure affecting actors with large health radius.")]
+		public readonly WDist TargetExtraSearchRadius = new WDist(1536);
+
+		public IProjectile Create(ProjectileArgs args) { return new InstantHit(this, args); }
+	}
+
+	public class InstantHit : IProjectile
+	{
+		readonly ProjectileArgs args;
+		readonly InstantHitInfo info;
+
+		bool doneDamage;
+		WPos target;
+		WPos source;
+
+		public InstantHit(InstantHitInfo info, ProjectileArgs args)
+		{
+			this.args = args;
+			this.info = info;
+			target = args.PassiveTarget;
+			source = args.Source;
+		}
+
+		public void Tick(World world)
+		{
+			// Check for blocking actors
+			WPos blockedPos;
+			if (info.Blockable && BlocksProjectiles.AnyBlockingActorsBetween(world, source, target,
+				info.Width, info.TargetExtraSearchRadius, out blockedPos))
+			{
+				target = blockedPos;
+			}
+
+			if (info.Inaccuracy.Length > 0)
+			{
+				var inaccuracy = OpenRA.Mods.Common.Util.ApplyPercentageModifiers(info.Inaccuracy.Length, args.InaccuracyModifiers);
+				var maxOffset = inaccuracy * (target - source).Length / args.Weapon.Range.Length;
+				target += WVec.FromPDF(args.SourceActor.World.SharedRandom, 2) * maxOffset / 1024;
+			}
+
+			if (!doneDamage)
+			{
+				args.Weapon.Impact(Target.FromPos(target), args.SourceActor, args.DamageModifiers);
+				doneDamage = true;
+				world.AddFrameEndTask(w => w.Remove(this));
+			}
+		}
+
+		public IEnumerable<IRenderable> Render(WorldRenderer wr)
+		{
+			yield break;
+		}
+	}
+}