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Click here to download a zip file containing my version of the program. Extract the folder named XNA0124Proj from the zip file and save it somewhere on your disk. Start Visual C# 2010 Express and select Open Project... from the File menu. Navigate to that folder and select the file with the extension of .sln . This should cause the project to open and be ready to run or debug as described in the earlier module titled Getting Started .
You learned about the following major topics in this module:
This section contains a variety of miscellaneous information.
Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.
I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.
In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.
Affiliation : I: I am a professor of Computer Information Technology at Austin Community College in Austin, TX.
A complete listing of the XNA program discussed in this module is provided in Listing 11 . Note the changes that were made in the calls to the SpriteBatch.Begin method to upgrade the program from XNA 3.1 to XNA 4.0. Blending was turned offin the first call just in case there were pixels in the background image having a color that matches the key color value.
Listing 11 . The class named Game1 for the project named XNA0124Proj.
/*Project XNA0124Proj
* Illustrates displaying a sprite with color key* transparency in front of a background image.
* Must modify the color key property value for the ufo* sprite, changing the key color from the default of
* 255,0,255 (magenta or magic pink) to 0,255,0 (green).* The scale and the origin of the background image is
* changed over time giving the illusion of a ufo* flying over a planet.
********************************************************/using System;
using Microsoft.Xna.Framework;using Microsoft.Xna.Framework.Graphics;
namespace XNA0124Proj {public class Game1 : Microsoft.Xna.Framework.Game {
GraphicsDeviceManager graphics;SpriteBatch spriteBatch;
private Viewport viewport;private Vector2 ufoPosition;
private float backgroundScale;private float backgroundBaseScale;
private float dynamicScale = 0.0f;int msElapsed;//Time since last new frame.
int msPerFrame = 83;//30 updates per secondTexture2D spaceTexture;//background image
Texture2D ufoTexture;//ufo imageVector2 spaceOrigin;//origin for drawing background
public Game1() {//constructorgraphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";//Set the size of the game window, causing the
// aspect ratio of the game window to match the// aspect ratio of the background image, which is
// 640 wide by 480 high.graphics.PreferredBackBufferWidth = 450;
graphics.PreferredBackBufferHeight =(int)(450.0*480/640);
}//end constructor//-------------------------------------------------//
protected override void Initialize() {// No initialization required
base.Initialize();}//end Initialize
//-------------------------------------------------//protected override void LoadContent() {
// Create a new SpriteBatch, which can be used to// draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);//Load the two images.
spaceTexture = Content.Load<Texture2D>("space");
ufoTexture = Content.Load<Texture2D>("ufo");
//Get a reference to the viewport.viewport = graphics.GraphicsDevice.Viewport;
//Compute the position of the ufo relative to the// game window.
ufoPosition.X = viewport.Width / 2;ufoPosition.Y = viewport.Height - 70;
//Set the backgroundBaseScale factor such that// the entire background image will fit in the
// game window. Note that the aspect ratio of the// game window was set to match the aspect ratio
// of the background image in the constructor.backgroundBaseScale = (float)(450.0 / 640.0);
}//end LoadContent//-------------------------------------------------//
protected override void UnloadContent() {// No unload required
}//end UnloadContent//-------------------------------------------------//
protected override void Update(GameTime gameTime) {//Compute the elapsed time since the last update.
// Draw new data only if this time exceeds the// desired frame interval given by msPerFrame
msElapsed += gameTime.ElapsedGameTime.Milliseconds;if(msElapsed>msPerFrame) {
//Reset the elapsed time and draw the frame with// new data.
msElapsed = 0;//Reset the animation if the dynamicScale factor
// is greater than 10.if(dynamicScale>10) {
dynamicScale = 0.0f;} else {
//Increase the dynamicScale factor and use it// to compute a new scale factor that will be
// applied to the background image in the next// call to the Draw method.
dynamicScale += 0.03f;backgroundScale =
backgroundBaseScale * (1 + dynamicScale);}//end if-else on dynamicScale
//Also use the dynamicScale factor to compute a// new value for the origin of the background.
// The origin is the point in the image that is// drawn at the point in the game window that is
// passed as the second (position) parameter in// the call to the SpriteBatch.Draw method. This
// has the effect of causing the background// image to slide up and to the left at the same
// time that it is getting larger.spaceOrigin =
new Vector2((float)(450 * (dynamicScale) / 12),(float)(338 * (dynamicScale) / 10));
}//end if on msElapsedbase.Update(gameTime);
}//end Update//-------------------------------------------------//
protected override void Draw(GameTime gameTime) {// Turn off blending to draw the planet in the
// background. Note the update for XNA 4.0.// spriteBatch.Begin(SpriteBlendMode.None);
spriteBatch.Begin(SpriteSortMode.Immediate, BlendState.Opaque);//Draw the background.
spriteBatch.Draw(spaceTexture,//spriteVector2.Zero,//position re window
null,//rectangleColor.White,//tint
0,//rotationspaceOrigin,//origin
backgroundScale,//scaleSpriteEffects.None,
1.0f);//layer, near the backspriteBatch.End();
// Turn on blending to draw the UFO in the// foreground. Note the update for XNA 4.0.
// spriteBatch.Begin(SpriteBlendMode.AlphaBlend);spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend);
//Center the UFO at the point in the window// identified as UFO position. The UFO image is
// 64x33 pixels.Vector2 origin = new Vector2(32,16);
spriteBatch.Draw(ufoTexture,//spriteufoPosition,//position re window
null,//rectangleColor.White,//tine
0,//rotationorigin,//origin
1,//scaleSpriteEffects.None,
0f);//layer, 0 is in frontspriteBatch.End();
base.Draw(gameTime);}//end Draw method
}//end class}//end namespace -end-
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