GTA IV - Homing Missile Script

/**
 * Homing Missile Script for GTA IV
 * Copyright (C) 2011 Morten T. Pedersen
 *
 * This program is free software: you can redistribute it and/or modify
 * it 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.*/
**/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using GTA;

namespace LCPD
{
    public class HomingMissiles : Script
    {
        public HomingMissiles()
        {
            Interval = 25;

            this.Tick += new EventHandler(HomingMissiles_Tick);
            if (Player.Character.Weapons.RocketLauncher.isPresent)
                _lastAmmo = Player.Character.Weapons.RocketLauncher.Ammo;
            BindConsoleCommand("createrocket", Command_CreateRocket);
        }

        private const int rocketHash = 1516578222;
        private const int fireHash = 1443084780;

        private void Command_CreateRocket(ParameterCollection parameters)
        {
            GTA.Object obj = World.CreateObject(new Model(rocketHash), Player.Character.GetOffsetPosition(new Vector3(0, 3, 0)));
            if (!Exists(obj))
                return;
            obj.Heading = Player.Character.Heading;

            GTA.Object fire = World.CreateObject(new Model(fireHash), obj.Position);
        }

        private int _lastAmmo = -1;
        private GTA.Object _rocket;
        private Vehicle _target;

        public int LastAmmo
        {
            get { return _lastAmmo; }
            set { _lastAmmo = value; }
        }
        public GTA.Object Rocket
        {
            get { return _rocket; }
            set { _rocket = value; }
        }
        public Vehicle Target
        {
            get { return _target; }
            private set { _target = value; }
        }

        void HomingMissiles_Tick(object sender, EventArgs e)
        {
            try
            {
                if (Target != null)
                {
                    //We have a target. Destroy it!! >:D
                    if (!Rocket.Exists() || !Target.Exists())
                    {
                        Rocket = null;
                        Target = null;
                    }
                    Vector3 rot = Target.Position - ((GTA.Object)Rocket).Position;
                    Rocket.Velocity = Vector3.Normalize(rot) * 100;
                }

                if (Player.Character.Weapons.CurrentType != Weapon.Heavy_RocketLauncher)
                    return;

                if (Player.Character.Weapons.Current.Ammo < LastAmmo)
                {
                    GTA.Object rocket = FindRocket();
                    Vehicle target = FindTarget();
                    if (Exists(rocket) && Exists(target))
                    {
                        Rocket = rocket;
                        Target = target;
                    }
                }
                LastAmmo = Player.Character.Weapons.Current.Ammo;
            }
            catch (Exception)
            {
            }
        }

        private Vehicle FindTarget()
        {
            return Helpers.Math.Choose(World.GetVehicles(Player.Character.Position, 10000));
        }

        private GTA.Object FindRocket()
        {
            List<GTA.Object> qualifiedObjects = new List<GTA.Object>();
            GTA.Object[] objects = World.GetAllObjects();
            foreach (GTA.Object obj in objects)
            {
                if (obj.Model.isVehicle)
                    continue;
                if (obj.Position.DistanceTo2D(Player.Character.Position) > 25)
                    continue;
                if (obj.isAttachedSomewhere)
                    continue;
                qualifiedObjects.Add(obj);
            }

            foreach (GTA.Object obj in qualifiedObjects)
            {
                int hash = obj.Model.Hash;
                if (hash == rocketHash)
                    return obj;
            }

            return null;
        }
    }
}