Difference between revisions of "Game Programming Class2"

esse quam videri
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(Time and Timespan)
(Time corrected sprite movement)
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Understanding GameTime We'll revisit game time when we talk about performance profiling.
Understanding GameTime We'll revisit game time when we talk about performance profiling.
==Time corrected sprite movement==
# Draw(GameTime gameTime)
Console And Trace
We will build a console class later and debug in game.
==Texture2D and SpriteBatches==
==Texture2D and SpriteBatches==

Revision as of 17:37, 9 September 2016


free game fonts XNA Redistributable Font Pack

Fun with Fonts in XNA

note this font pack is now included in XNA 4

SVN Checkout

All of the examples for this class and the basic game library we wil be building is in our SVN repo this week we'll practice checking out a folder from the repo.


Repo for Spring 2016

Trunk : this contains all the old student work as well as my demos so you probably don't want this at least not quite yet


Just the Jeff folder


Demos Projects : this is the link to my demos in SVN


tortoisesvn http://tortoisesvn.tigris.org/

ankhsvn http://ankhsvn.open.collab.net/

SNV checkout demo.

In the coming weeks we'll learn how to commit to the SNV. Until then all you need to know is how to checkout.

Monogame Structures

Game Class

The MonogameGame class has two private properties

  • GraphicsDeviceManager graphics;
  • ContentManager content;
Graphics for windows and xbox are 60 fps. XBOx supports NTSC resolutions (480i, 480p, 720p, 1080i and 1080p 1080p is only on newer hdmi models).
//the game constuctor can be used to set some graphics settings.
graphics.PreferredBackBufferHeight = 768;
graphics.PreferredBackBufferWidth = 1024;
//graphics.PreferredBackBufferHeight = 1080;
//graphics.PreferredBackBufferWidth = 1920;
//graphics.IsFullScreen = true;
Graphics for Mobile Game is 30 fps and 480 x 800.
    // Frame rate is 30 fps by default for Windows Phone.  
    TargetElapsedTime = TimeSpan.FromTicks(333333);  
    // Pre-autoscale settings.  
    graphics.PreferredBackBufferWidth = 480;  
    graphics.PreferredBackBufferHeight = 800;

  1. Declare SpriteBatch spriteBatch;
  2. Initialize()
  3. LoadContent()
  4. UnloadContent()
  5. Update(GameTime gameTime)


FrameRate and GameTime

Time and Timespan

Example of update using GameTime to calculate elapsed time


Understanding GameTime We'll revisit game time when we talk about performance profiling.

Texture2D and SpriteBatches

simple pacmac bouncing back and forth

using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;

namespace GameUpdate
    /// <summary>
    /// This is the main type for your game.
    /// </summar>
public class Game1 : Microsoft.Xna.Framework.Game
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;

        Texture2D PacMan;
        Vector2 PacManLoc;      //Pacman location
        Vector2 PacManDir;      //Pacman direction
        float PacManSpeed;              //speed for the PacMan Sprite in pixels per frame per second

        public Game1()
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";

            //Change the frame fate to 30 Frames per second the default is 60fps
            //TargetElapsedTime = TimeSpan.FromTicks(333333); // you may need to add using System; to get the TimeSpan function

        /// <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


        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);

            // TODO: use this.Content to load your game content here
            PacMan = Content.Load<Texture2D>("pacmanSingle");
            //Center PacMan
            PacManLoc = new Vector2(graphics.GraphicsDevice.Viewport.Width / 2,
                graphics.GraphicsDevice.Viewport.Height / 2); //Start with PacManLoc in the center of the screen
            PacManDir = new Vector2(1, 0); //start moving left

            PacManSpeed = 20;          //initial pacman speed


        /// <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

        /// <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)

            // TODO: Add your update logic here

            //Elapsed time since last update will be used to correct movement speed
            float time = (float)gameTime.ElapsedGameTime.TotalMilliseconds;

            //Turn PacMan Around if it hits the edge of the screen
            if ((PacManLoc.X > graphics.GraphicsDevice.Viewport.Width - PacMan.Width)
                || (PacManLoc.X < 0)
                PacManDir = Vector2.Negate(PacManDir);

            //Move PacMan
            //Simple move Moves PacMac by PacManDiv on every update
            PacManLoc = PacManLoc + PacManDir * PacManSpeed;      //no good not time corrected

            //Time corrected move. MOves PacMan By PacManDiv every Second
            //PacManLoc = PacManLoc + ((PacManDir * PacManSpeed) * (time/1000));      //Simple Move PacMan by PacManDir


        /// <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)

            // TODO: Add your drawing code here
            spriteBatch.Draw(PacMan, PacManLoc, Color.White);


2D Graphics Overview

About textures and Batching

Displays, ViewPorts, Client Bounds

Alpha channels



demo project

  • IntroSimpleSpriteBatchOptionsWindows.zip



  1. Options SpriteBlendMode
  2. Additive Enable additive blending. http://blogs.msdn.com/etayrien/archive/2006/12/19/alpha-blending-part-3.aspx
  3. AlphaBlend Enable alpha blending. http://blogs.msdn.com/etayrien/archive/2006/12/19/alpha-blending-part-2.aspx
  4. None No blending specified.

Other Projects

IntroSimpleSpriteUpdateGravityWindows.zip IntroSimpleSpriteUpdateWindows.zip


  • XNA Picture With Update
Update your picture to include some movement with the update method. Use the keyboard or mouse to interact with something on the screen
  • Read Chapter 2 in XNA 3.0
  • Read Chapter 4 in XNA 3.0 (yes we skipped 3 we'll come back)