Dogcows Code - chaz/carfire/blob - CarFire/CarFire/CarFire/Trigger.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.Linq;
   4 using System.Text;
   5 using Microsoft.Xna.Framework;
   6 using Microsoft.Xna.Framework.Graphics;
   7 using Microsoft.Xna.Framework.Content;
   8
   9 namespace CarFire
  10 {
  11     /// <summary>
  12     /// A trigger is an invisible entity whose only purpose is
  13     /// to check a condition and run a script when the condition
  14     /// is right.
  15     /// </summary>
  16     public class Trigger : IEntity
  17     {
  18         #region Public Methods
  19
  20         /// <summary>
  21         /// Construct a trigger entity.
  22         /// </summary>
  23         /// <param name="identifier">The entity identifier.</param>
  24         /// <param name="position">The position.</param>
  25         /// <param name="info">The key-value pairs.</param>
  26         /// <param name="game">The game reference.</param>
  27         public Trigger(char identifier, Point position, Dictionary<string, string> info, Game game)
  28         {
  29             mGame = game;
  30             mPrevCondition = false;
  31             mCoordinates = position;
  32
  33             string condition;
  34             if (info.TryGetValue("condition", out condition))
  35             {
  36                 mCondition = new Script(condition, game);
  37             }
  38             else throw new Exception("Triggers must define a condition script.");
  39
  40             string eventt;
  41             if (info.TryGetValue("event", out eventt))
  42             {
  43                 mEvent = new Script(eventt, game);
  44             }
  45             else throw new Exception("Triggers must define an event script.");
  46         }
  47
  48         /// <summary>
  49         /// Check the trigger condition and execute the event if the
  50         /// condition evaluates to true.
  51         /// </summary>
  52         public void Call()
  53         {
  54             Player player = mGame.GetPlayerAtCoordinates(mCoordinates);
  55             if (player != null)
  56             {
  57                 bool condition = mCondition.Run(player);
  58                 if (condition && condition != mPrevCondition)
  59                 {
  60                     mEvent.Run(player);
  61                 }
  62                 mPrevCondition = condition;
  63             }
  64             else
  65             {
  66                 mPrevCondition = false;
  67             }
  68         }
  69
  70
  71         /// <summary>
  72         /// Calls the trigger.
  73         /// </summary>
  74         /// <param name="timeSpan">Unused.</param>
  75         public virtual void Update(TimeSpan timeSpan)
  76         {
  77             Call();
  78         }
  79
  80         public virtual void LoadContent(ContentManager contentManager)
  81         {
  82             // No implementation needed.
  83         }
  84
  85         public virtual void Draw(SpriteBatch spriteBatch)
  86         {
  87             // No implementation needed.
  88         }
  89
  90         public Vector2 Position
  91         {
  92             get { return Vector2.Zero; }
  93         }
  94
  95         public Point Coordinates
  96         {
  97             get { return new Point(-1, -1); }
  98         }
  99
 100         #endregion
 101
 102
 103         #region Private Variables
 104
 105         Script mCondition;
 106         Script mEvent;
 107         Game mGame;
 108         bool mPrevCondition;
 109         Point mCoordinates;
 110
 111         #endregion
 112     }
 113 }