source: 2013/30/DenisZ/CastleMaster/CastleMaster/CastleMaster/Game.cs @ 4512

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using CastleMaster.Input;

using Keys = System.Windows.Forms.Keys;
using System.Text;
using CastleMaster.Graphics;
using CastleMaster.World;

namespace CastleMaster
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class Game : Microsoft.Xna.Framework.Game
    {
        public const int WIDTH = 800;
        public const int HEIGHT = 600;
        public const string TITLE = "Castle Master Alpha 0.1";

        private const string UPS_TEXT = " UPS: ";
        private const string FPS_TEXT = " | FPS: ";

        private GraphicsDeviceManager graphics;
        private SpriteBatch spriteBatch;
        private InputHandler input;
        private RenderHelper renderer;
        private Camera camera;
        private Level level;
        
        #region Counter
        private readonly TimeSpan ONE_SECOND = TimeSpan.FromSeconds(1.0);
        private TimeSpan currentTime = TimeSpan.Zero;
        private int frames = 0, updates = 0;
        #endregion

        public Game()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
            input = new InputHandler(Window);
        }

        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            graphics.PreferredBackBufferWidth = WIDTH;
            graphics.PreferredBackBufferHeight = HEIGHT;
            graphics.SynchronizeWithVerticalRetrace = true;
            graphics.ApplyChanges();
            Window.Title = TITLE;
            IsMouseVisible = true;

            InitializeInput();

            base.Initialize();
        }

        private void InitializeInput()
        {
            input.RegisterKeyboardKey(Keys.Escape);
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            spriteBatch = new SpriteBatch(GraphicsDevice);
            renderer = new RenderHelper(spriteBatch);

            Resources.LoadResources(Content, renderer);
        }

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// all content.
        /// </summary>
        protected override void UnloadContent()
        {
            // TODO: Unload any non ContentManager content here
        }

        protected override void BeginRun()
        {
            base.BeginRun();

            camera = new Camera();
            level = new Level(128, 128);
        }

        /// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            input.Update();
            camera.Update();

            if (InputHandler.HasKeyBeenPressed(Keys.Escape))
                this.Exit();

            updates++;
            currentTime += gameTime.ElapsedGameTime;
            if (currentTime >= ONE_SECOND)
            {
                currentTime = TimeSpan.Zero;
                Window.Title = new StringBuilder(TITLE).Append(FPS_TEXT).Append(frames).Append(UPS_TEXT).Append(updates).ToString();
                frames = updates = 0;
            }

            base.Update(gameTime);
        }

        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.Black);

            renderer.BeginRender();

            level.RenderBackground(camera, renderer);
            
            renderer.EndRender();

            frames++;
            base.Draw(gameTime);
        }
    }
}