Comments on: Pixel Perfect Collision Detection in Actionscript 3

By: Max

Max — Sat, 24 Jul 2010 01:53:01 +0000

I believe based on the code for pixel perfect collision, there is no need to do a hitTestObject, as it's essentially comparing bounding boxes, and if there is not intersection of bounding boxes then it doesn't do pixel perfect test.

So, unless I'm reading this code wrong, in the case that there is a bounding box collision, there is a double check for bounding box collision -- once in your code, once in the pixelperfect code.

if you look in the getCollisionRect function , at the first if statement , you'll see what i mean.

By: Anthony

Anthony — Wed, 26 May 2010 00:22:46 +0000

Hey, I am using this but there's one thing I just cant figure out how to do!! how do I do it? - I'm frustrated now.

I want to target a movie clip (separate from the objects colliding)in my library and move it wen the two objects collide. For instance, if block 1 and 2 collides, then move block 3.

What I had done is in the part of the pixelperfectcollission.as where it detects if there is a collision, I changed the "return true" and put return bushmc += 20; and the error gotten is that access of undefined property. (I gave the bush an instance name of bushmc)

I tried using import.flash.display.MovieClip at the top of the class file. Didn't work.

I must admit though, I am not that advanced in actionscript as yet so.. Help plzz ! :p

By: aschearer

aschearer — Sat, 08 Aug 2009 23:30:45 +0000

Yep, like you say it’s often not enough to simply get a boolean for a collision. I’ll definitely have to check out that library for my next project, thanks! But in cases where a boolean result is sufficient I think this is a pretty good method.

By: Max

Max — Sat, 08 Aug 2009 23:23:33 +0000

Clever, very clever. There’s not much point to detecting if two things collide with no resolution to the collision though.

Ah, but here’s the bad news. This library does both. http://code.google.com/p/collisiondetectionkit/ From what little I know about it you may have a faster technique though.