MonoGame.Samples/RockRain/Core/MeteorsManager.cs

using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using RockRain.Core;


namespace RockRain
{
    /// <summary>
    /// This game component implements a manager for all Meteors in the game.
    /// </summary>
    public class MeteorsManager : DrawableGameComponent
    {
        // List of active meteors
        protected List<Meteor> meteors;
        // Constant for initial meteor count
        private const int STARTMETEORCOUNT = 5;
        // Time for a new meteor
        private const int ADDMETEORTIME = 6000;

        protected Texture2D meteorTexture;
        protected TimeSpan elapsedTime = TimeSpan.Zero;
        protected AudioLibrary audio;

        public MeteorsManager(Game game, ref Texture2D theTexture)
            : base(game)
        {
            meteorTexture = theTexture;
            meteors = new List<Meteor>();
        }

        /// <summary>
        /// Allows the game component to perform any initialization it needs to 
        /// before starting to run.  This is where it can query for any required
        /// services and load content.
        /// </summary>
        public override void Initialize()
        {
            // Get the current audiocomponent and play the background music
            audio = (AudioLibrary)Game.Services.GetService(typeof(AudioLibrary));

            meteors.Clear();

            Start();

            for (int i = 0; i < meteors.Count; i++)
            {
                meteors[i].Initialize();
            }

            base.Initialize();
        }

        /// <summary>
        /// Start the Meteors Rain
        /// </summary>
        public void Start()
        {
            // Initialize a counter
            elapsedTime = TimeSpan.Zero;

            // Add the meteors
            for (int i = 0; i < STARTMETEORCOUNT; i++)
            {
                AddNewMeteor();
            }
        }

        /// <summary>
        /// All Meteors in the game
        /// </summary>
        public List<Meteor> AllMeteors
        {
            get { return meteors; }
        }

        /// <summary>
        /// Check if is a moment for a new meteor
        /// </summary>
        private void CheckforNewMeteor(GameTime gameTime)
        {
            // Add a rock each ADDMETEORTIME
            elapsedTime += gameTime.ElapsedGameTime;

            if (elapsedTime > TimeSpan.FromMilliseconds(ADDMETEORTIME))
            {
                elapsedTime -= TimeSpan.FromMilliseconds(ADDMETEORTIME);

                AddNewMeteor();
                // Play a sound for a new meteor
                audio.NewMeteor.Play();
            }
        }

        /// <summary>
        /// Add a new meteor in the scene
        /// </summary>
        private Meteor AddNewMeteor()
        {
            Meteor newMeteor = new Meteor(Game, ref meteorTexture);
            newMeteor.Initialize();
            meteors.Add(newMeteor);
            // Set the meteor identifier
            newMeteor.Index = meteors.Count - 1;

            return newMeteor;
        }

        /// <summary>
        /// Allows the game component to update itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        public override void Update(GameTime gameTime)
        {
            CheckforNewMeteor(gameTime);

            // Update Meteors
            for (int i = 0; i < meteors.Count; i++)
            {
                meteors[i].Update(gameTime);
            }

            base.Update(gameTime);
        }

        /// <summary>
        /// Check if the ship collide with a meteor
        /// <returns>true, if has a collision</returns>
        /// </summary>
        public bool CheckForCollisions(Rectangle rect)
        {
            for (int i = 0; i < meteors.Count; i++)
            {
                if (meteors[i].CheckCollision(rect))
                {
                    // BOM !!
                    audio.Explosion.Play();

                    // Put the meteor back to your initial position
                    meteors[i].PutinStartPosition();

                    return true;
                }
            }
            return false;
        }

        /// <summary>
        /// Allows the game component draw your content in game screen
        /// </summary>
        public override void Draw(GameTime gameTime)
        {
            // Draw the meteors
            for (int i = 0; i < meteors.Count; i++)
            {
                meteors[i].Draw(gameTime);
            }

            base.Draw(gameTime);
        }
    }
}