2006 March 26th by todd anderson
Well, i said i was gonna get into switching action policies for the user-controlled sprite, but i thought it might be cool if i gave a visual clue if the sprite was disabled ( unable to switch actions ). Then i thought, ‘What better clue than a ring of stars around its head?’. Created a rotating-ring particle system. Done…
Damn… It rotates, but not around the sprite. I’ve been placing particle systems in their own movieclip – somtimes behind, sometimes atop the sprite… I wasn’t rendering everything in a ‘world’ view with z-buffering, because everything was 2d and i thought ‘…just layer it, jerk’. i still do.
Let’s see… do i throw a particle system in with the sprite class and swap depths based on z position of particles? No i just want a sprite to be a sprite and not worry about managing anything. Should i have a special particle system that sandwiches movieclips around the emission node, then create and dipose based on z-position? Now with AS3, i could fashion something like that because of the DisplayList ( as Sam so eloquiantly showed… though i he didn’t strip off an article clothing after every audience question – which was promised ), but in AS2 that would just be too confusing.
So i went back to my PixelCollision class and decided to poke around. Well, i did… and royally screwed up that code (that’s what svn is for!), but came out with a nice solution for replacing pixels in one bitmapdata object based on non-alpha collisions.
In the movie link above you can see what’s happening (well kind of, i made it too small i think). It’s actually a rotating-ring system in a layer above the sprite, and it’s applying alpha transparency to the stars based on collision – and/or also pixel replacement of sprite if you click on the stage (that’s my favorite part). It’s a shame it gets a little skippish in a browser, i’ll have to do a little cleaning and see what happens.