HTML and CSS Reference
In-Depth Information
Your engine starts out with
run()
to test for SVG support, then moves on to setting up all
of the game's objects. The
update()
method is responsible for removing and/or chan-
ging game assets. You'll notice that a few of the
init()
items aren't in the
update()
because they require a separate timer to fire.
Warning
Although it might seem like a good idea to use the animation timer
requestAnima-
tionFrame
here—as you did in the Canvas game in
chapter 6
—don't. Clearing an an-
imation timer is difficult, programming in polyfills for intervals and/or timeouts is very
buggy, and some browsers don't like SVG coupled with timer-based animation. Until sup-
port improves, you're better off using
setTimeout()
and
setInterval()
unless
you're working with a Canvas application.
Step 2: Integrate screen transitions
In order to make use of the Welcome and Game Over screens you created earlier, you'll
need the code in the following listing to add a few more methods for deleting SVG ele-
ments and mouse-click monitoring.
