Flash MX 2004 Games : Art to ActionScript

Chapter 8: In tip-top condition
All Movie Clips have a number of properties you can access: ‘_x’ indicates the position across the
screen, ‘_y’ is the position down the screen. Notice how in this example we nest one ‘if ’ statement
inside another. You can do this as many times as you choose, but if nesting more than three then
you are encouraged to find another way to execute the code, since nested ‘if ’ statements are very
prone to difficult-to-detect bugs, sometimes a condition is not met and the code goes screwy.
Testing for a specific position is not recommended; one reason for this is because positions in
Flash are not integer values (whole numbers) and so the character may be at (100.1, 199.8), which
is extremely close to the target position yet the condition would still fail. One way around this
problem is to reduce the exercise to a distance away from the target.
Figure 8.1 That pesky Pythagoras
Now, you may be thinking, how can Pythagoras help with this problem? The answer is that the
relationship between the three sides of a right-angle triangle is one of the most useful devices you
will find when creating graphical games. Let’s start by reviewing the concept. If we have a triangle
ABC where side AC has length x and side BC has length y then the length of side AB must equal
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