0.14 Xna0126-using oop - a simple sprite class

Revised: Mon May 09 13:00:37 CDT 2016

This page is part of a Book titled XNA Game Studio .

Table of Contents

• Table of Contents
• Preface
  • Viewing tip
    • Figures
    • Listings
• General background information
  • The three pillars of OOP
  • Wanted, lots of sprites
  • Encapsulation to the rescue
• Preview
  • Demonstrate how to use the Sprite class
  • Instantiate Sprite objects on the move
  • Seven Sprite objects
  • Move to the right and down
• Discussion and sample code
  • The Sprite class
    • Two instance variables and a property accessor method
    • Two overloaded constructors
      • No image when instantiated
      • Image loaded during construction
        • The first parameter
        • The second parameter
        • Loading the image
    • The SetImage method
      • Load an image into a Sprite object
      • The parameters and the body
    • The Draw method of the Sprite class
      • A single parameter
      • The body of the Sprite.Draw method
    • The end of the class
  • The Game1 class
    • The generic List class
    • The modified Game1 constructor
    • The overridden LoadContent method
      • A new Sprite object
      • List capacity considerations
      • Assign an image to the Sprite object
    • The overridden Update method
      • The Count property of the List object
      • The remaining 23 Sprite objects
      • Adding Sprite object references to the list
      • Instantiate new Sprite objects
        • The modulus operator
        • Every eighth iteration
        • Even and odd sprite images
      • Make all the existing sprites move
        • Use a for loop
        • Put a new value in the Position property
      • Load a green ball image in the topmost Sprite object
      • Maintain the frame counter
      • The end of the overridden Update method
    • The overridden Game1.Draw method
      • Draw all Sprite objects
      • Call the SpriteBatch.Draw method
      • The end of the Game1.Draw method
• Run the program
• Run my program
• Summary
• Miscellaneous
• Complete program listing

Preface

This module is one in a collection of modules designed primarily for teaching GAME 1343 Game and Simulation Programming I at Austin Community College in Austin, TX. These modules are intended tosupplement and not to replace the textbook.

An earlier module titled Getting Started provided information on how to get started programming with Microsoft's XNA Game Studio.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the Figuresand Listings while you are reading about them.

Figures

• Figure 1 . Seven Sprite objects.
• Figure 2 . Twenty-four Sprite objects with a green one at the top.

Listings

• Listing 1 . Beginning of the Sprite class.
• Listing 2 . Two overloaded constructors.
• Listing 3 . The SetImage method.
• Listing 4 . The Draw method of the Sprite class.
• Listing 5 . Beginning of the class named Game1.
• Listing 6 . The modified constructor for the Game1 class.
• Listing 7 . The overridden LoadContent method.
• Listing 8 . Beginning of the overridden Update method.
• Listing 9 . Instantiate new Sprite objects.
• Listing 10 . Make all the existing sprites move.
• Listing 11 . Load a green ball image in the topmost Sprite object.
• Listing 12 . Maintain the frame counter.
• Listing 13 . The overridden Game1.Draw method.
• Listing 14 . Contents of the file named Sprite.cs
• Listing 15 . Contents of the file named Game1.cs.