XNACS1Lib:
Tutorial 5: Working With Sprite Sheets

Reference: This is the fifth tutorial on how to work with the XNACS1Lib library. It is assumed you have read and understand the previous four tutorials:

• First Tutorial : XNACS1Lib application structure;
• Second Tutorial: Working with primitives; and
• Third Tutorial : Working with PrimitiveSet
• Fourth Tutorial : Working With Audio

Goals : This tutorial concentrates on describing how to work with Sprite Sheets: 

1. Obtain the example code

• Here is the zip file to the source files and compiled executable of this example.
• Here is the keyboard mapping for the XBOX 360 controller.  
• Here is the main tutorial page for working with XNACS1Lib, and here is the complete documentation of the library: html-page or compiled html help file.

2. The Source Code Files/Structure

Take a look at the ExampleProgram folder that you have unzipped and you will see a structure identicle to that of the previous tutorials.

3. The Solution Explorer:

Now double click on the *.sln file in the ExampleProgram folder, to start the project in the IDE. Notice the structure of the SolutionExplorer follows the source code folder structure we have examined:
As illustrated in the above figure, you will notice the Textures folder and the Sprites.png file. The process of including the *.png files into the project works identical to that of *.jpg Texture files, where you would right-mouse-button click on the Resources folder and add the existing Textures folder. Any *.png files can be included in this folder (and thus into your project). 

4. Examine the Predefined Emitters:

The XNACS1Rectangle.SetTextureSpriteSheet(String SpriteSheetTexture, int numColumns, int numRows, int padding) arguments are pretty straightforward.

• SpriteSheetTexture is the name of the sprite sheet you are going to be using
• numColumns is the number of columns your sprite sheet has
• numRows is the number of rows your sprite sheet has
• padding is the width of the padding between images in pixels
  

You may also notice the lines of code, "Sprite.SetTextureSpriteAnimationFrames(0, 0, 1, 0, 5, SpriteSheetAnimationMode.AnimateForward);" and "Sprite.SetTextureSpriteAnimationFrames(0, 0, 1, 0, 5, SpriteSheetAnimationMode.AnimateForward);" What the first line of code does is set the current animation of your Sprite object, to a sprite from the sprite sheet.  The second line of code enables the Sprite object to loop through animiations if you want.

The XNACS1Rectangle.SetTextureSpriteAnimationFrames(int beginX, int beginY, int endX, int endY, int ticksPerFrame, SpriteSheetAnimationMode mode) arguments are a little more confusing.

• beginX is the column you want your animation to start in
• begin Y is the row you want your animation to start in
• endX is the column you want your animation to stop
• endY is the row you want your animation to stop
• ticksPerFrame is how many ticks occur, before frames are switched
• mode is how you want your animations to occur (start to end, end to start, start to end to start)

The following is the code that causes the sprite to change directions when a direction on the dpad is pressed.  It is one example of how you can use the sprite sheet animations.

Project home page>: The Game-Themed Introductory Programming Project.

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Kelvin Sung Computing and Software Systems University of Washington, Bothell ksung@u.washington.edu

Michael Panitz Business And Information Technology Cascadia Community College mpanitz@cascadia.eduu

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	This work is supported in part by a grant from Microsoft Research under the Computer Gaming Curriculum in Computer Science RFP, Award Number 15871 and 16531.