XNA: A Beginner's Introduction

#region Using Statements
using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Storage;
#endregion

namespace xnaIntro
{
	/// <summary>
	/// This is the main type for your game
	/// </summary>
	public class Game1 : Microsoft.Xna.Framework.Game
	{
		GraphicsDeviceManager graphics;
		ContentManager content;

		protected float aspectRatio;
		protected Vector3 modelPosition = Vector3.Zero;
		protected Vector3 cameraPosition = new Vector3(0.0f, 0.0f, 10.0f);
		protected Model myModel;
		protected float modelRotation = 0.0f;
		protected Matrix lookAt;
		protected Matrix projection;

		public Game1()
		{
			graphics = new GraphicsDeviceManager(this);
			content = new ContentManager(Services);
		}


		/// <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()
		{
			// TODO: Add your initialization logic here

			base.Initialize();
		}


		/// <summary>
		/// Load your graphics content.  If loadAllContent is true, you should
		/// load content from both ResourceManagementMode pools.  Otherwise, just
		/// load ResourceManagementMode.Manual content.
		/// </summary>
		/// <param name="loadAllContent">Which type of content to load.</param>
		protected override void LoadGraphicsContent(bool loadAllContent)
		{
			if (loadAllContent)
			{
				myModel = content.Load<Model>("Content\\Models\\cube");
			}

			aspectRatio = ((float)graphics.GraphicsDevice.Viewport.Width) / ((float)graphics.GraphicsDevice.Viewport.Height);
			lookAt = Matrix.CreateLookAt(cameraPosition, Vector3.Zero, Vector3.Up);
			projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), aspectRatio, 1.0f, 10000.0f);
		}


		/// <summary>
		/// Unload your graphics content.  If unloadAllContent is true, you should
		/// unload content from both ResourceManagementMode pools.  Otherwise, just
		/// unload ResourceManagementMode.Manual content.  Manual content will get
		/// Disposed by the GraphicsDevice during a Reset.
		/// </summary>
		/// <param name="unloadAllContent">Which type of content to unload.</param>
		protected override void UnloadGraphicsContent(bool unloadAllContent)
		{
			if (unloadAllContent)
			{
				// TODO: Unload any ResourceManagementMode.Automatic content
				content.Unload();
			}

			// TODO: Unload any ResourceManagementMode.Manual content
		}


		/// <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)
		{
			// Allows the game to exit
			if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
				this.Exit();

			modelRotation += (float)gameTime.ElapsedGameTime.TotalMilliseconds * MathHelper.ToRadians(0.1f);
			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)
		{
			graphics.GraphicsDevice.Clear(Color.CornflowerBlue);

			Matrix[] transforms = new Matrix[myModel.Bones.Count];
			myModel.CopyAbsoluteBoneTransformsTo(transforms);

			// Draw the model. A model can have multiple meshes, so loop.
			foreach (ModelMesh mesh in myModel.Meshes)
			{
				foreach (BasicEffect effect in mesh.Effects)
				{
					effect.EnableDefaultLighting();
					effect.World = transforms[mesh.ParentBone.Index] * Matrix.CreateRotationX(modelRotation) * Matrix.CreateRotationY(modelRotation);
					effect.View = lookAt;
					effect.Projection = projection;
				}

				// Draw the mesh, using the effects set above.
				mesh.Draw();
			}

			base.Draw(gameTime);
		}
	}
}