homing weapons more or less work now

OpenRa.Game/Effects/Missile.cs

@@ -0,0 +1,89 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using OpenRa.Game.Graphics;
+using OpenRa.Game.GameRules;
+
+namespace OpenRa.Game.Effects
+{
+	class Missile : IEffect
+	{
+		readonly Player Owner;
+		readonly Actor FiredBy;
+		readonly WeaponInfo Weapon;
+		readonly ProjectileInfo Projectile;
+		readonly WarheadInfo Warhead;
+		float2 Pos;
+		readonly Actor Target;
+		readonly Animation anim;
+		int Facing;
+		int t;
+
+		public Missile(string weapon, Player owner, Actor firedBy,
+			int2 src, Actor target)
+		{
+			Weapon = Rules.WeaponInfo[weapon];
+			Projectile = Rules.ProjectileInfo[Weapon.Projectile];
+			Warhead = Rules.WarheadInfo[Weapon.Warhead];
+			FiredBy = firedBy;
+			Owner = owner;
+			Target = target;
+			Pos = src.ToFloat2();
+
+			/* todo: initial facing should be turret facing, or unit facing if we're not turreted */
+			Facing = Traits.Util.GetFacing( Target.CenterLocation - src.ToFloat2(), 0 );
+
+			if (Projectile.Image != null && Projectile.Image != "none")
+			{
+				anim = new Animation(Projectile.Image);
+
+				if (Projectile.Rotates)
+					Traits.Util.PlayFacing(anim, "idle", () => Facing);
+				else
+					anim.PlayRepeating("idle");
+			}
+		}
+
+		const int MissileCloseEnough = 7;
+		const float Scale = .3f;
+
+		public void Tick()
+		{
+			if (t == 0)
+				Sound.Play(Weapon.Report + ".aud");
+
+			t += 40;
+
+			Traits.Util.TickFacing(ref Facing, 
+				Traits.Util.GetFacing(Target.CenterLocation - Pos, Facing),
+				Projectile.ROT);
+
+			anim.Tick();
+
+			var dist = Target.CenterLocation - Pos;
+			if (dist.LengthSquared < MissileCloseEnough * MissileCloseEnough || Target.IsDead)
+			{
+				Game.world.AddFrameEndTask(w => w.Remove(this));
+
+				if (t > Projectile.Arm * 40)	/* don't blow up in our launcher's face! */
+					Combat.DoImpact(Pos.ToInt2(), Pos.ToInt2(), Weapon, Projectile, Warhead, FiredBy);
+				return;
+			}
+
+			var move = (Scale * Weapon.Speed / dist.Length) * dist;
+			Pos += move;
+
+			if (Projectile.Animates)
+				Game.world.AddFrameEndTask(w => w.Add(new Smoke((Pos - 1.5f * move).ToInt2())));
+
+			// todo: running out of fuel
+			// todo: turbo boost vs aircraft
+		}
+
+		public IEnumerable<Tuple<Sprite, float2, int>> Render()
+		{
+			yield return Tuple.New(anim.Image, Pos - 0.5f * anim.Image.size, 0);
+		}
+	}
+}