Glowy Things

Large version.

Here's another "gotta make something" post. I'm actually pretty happy with the ethereal feel of it. Sort of ghostly, but not necessarily spooky. There are two elements at play here.

1). Glow Filter. I talked about filters in the last post. This is just adding a glow filter via actionscript. I'm adjusting the strength of the glow with the second important element of this .swf.

2). We're using TRIGONOMETRY again! Now, there are several ways to get the pulsing glow effect, but I thought about it...and...the sine wave came to my aid! If you're familiar with the sine wave, you know that it oscillates from a crest to a trough and continues this (think of a REALLY sloppy sideways "S" - that's pretty much a sine wave). Each of these full runs is called a period. So we have a curve that goes from n to 0 to -n and back to 0. Handy for a repetitive movement! I'm essentially feeding sin an increasing number (representing the x axis - in other words, we're moving RIGHT along the wave) and it's spitting back a stream of numbers that go uuuuuuup and back doooooooown and back uuuuuuup until we all vomit, we're so dang full of numbers! Er. Or something. So our glow strength is going from 10 to -10 and back again. Since a negative strength on a glow makes the glow invisible...well...we don't see it.

OH, almost forgot two little things. The spat out number (the ups and downs) are amplified by 10 to get a strong glow effect. We're upping the amplitude of the sine wave! Joy of joys! The other little thing...when the glow is negative, I'm having some fun making the origin points of the glows jump around randomly in the dark. Creepy little buggers!

NOTE: One last thing, I swear. As each origin point is created, it also randomizes the QUALITY of the glow. That's why you sometimes see nice round glows, and other times you'll see more squared off glows. In this case, I wouldn't say there's a difference in quality. Just different effects.