Learning XNA 3.0

Animation

As mesmerizing as it is to sit and watch moving, bouncing XNA logos, that's not exactly the reason you're reading this book. Let's get to something a little more exciting by animating some sprites.

Tip

The code for this section of the chapter is available with the source code for the book under Chapter 2 and is titled AnimatedSprites.

As discussed earlier in this chapter, animation in 2D XNA games is done much like a cartoon flipbook. Animations are made up of a number of standalone images, and flipping through the images in a cycle causes them to appear animated.

Typically, sprite animations are laid out in a single sheet, and you pull out individual images from that sheet and draw them on the screen in a specific order. These sheets are referred to as sprite sheets. An example of a sprite sheet is included in the source for this chapter, in the AnimatedSprites\AnimatedSprites\Content\Images folder. The sprite sheet is named threerings.png and is shown in Figure 2-8.

Figure 2-8. Sample sprite sheet (threerings.png)

In each of the previous examples, you have drawn a sprite by loading the image into a Texture2D object and then drawing the entire image. With a sprite sheet, you need to be able to load the entire sheet into a Texture2D object and then pull out individual sprite frames to draw as you cycle through the animation. The overload for SpriteBatch.Draw that you've used ...