Comments on: AS 3.0 HitTest

By: InteractiveChaos

InteractiveChaos — Wed, 03 Mar 2010 01:34:24 +0000

Awesome work – I have had issues with loading a SWF into a MC, as the hittest is offset, and therefore doesnt work. By adding Pauls suggestion of

if( !target1.stage || !target2.stage || !target1.hitTestObject( target2 ) ) return new Rectangle();

// Get the bounds of each DisplayObject.
var bounds1:Rectangle = target1.getBounds( target1.stage );
var bounds2:Rectangle = target2.getBounds( target2.stage );

It now works perfectly.

Nice one people.

Happy flashing

By: Anthony Cholmondeley

Anthony Cholmondeley — Tue, 02 Mar 2010 21:20:19 +0000

Tink, you saved my sanity … Thanks for the hard work!!!

By: Christian Snodgrass

Christian Snodgrass — Wed, 24 Feb 2010 04:21:04 +0000

It may be eluding me, but why in intersectionRectangle did you build your own intersection rectangle instead of just calling bounds1.intersection(bounds2)?

Is there some performance boost, or just because you wanted to?

By: Piano Chords

Piano Chords — Mon, 01 Feb 2010 18:56:17 +0000

How do you enable “view Source” for flash projects? I did a quick google search and didn’t see anything.

By: Piano Chords

Piano Chords — Mon, 01 Feb 2010 18:51:57 +0000

Thanks a bundle! Your hit test did the trick when my client said the hitTest wasn’t accurate. It’s insane that Flash doesn’t have a built in complex hit test? Or am I missing something? In AS2 wasn’t there a shapeFlag hit test? I don’t know why they don’t have something like that built in for AS3!

By: Stesha D

Stesha D — Thu, 28 Jan 2010 01:29:02 +0000

Fantastic code! Good job.

By: Ian Reynolds

Ian Reynolds — Fri, 22 Jan 2010 21:21:35 +0000

Hi-
I posted a while back asking for permission to use this class in a game engine I was building and you might be interested in seeing how useful it was to me. Check out flyte-engine.org if you’re curious. Your class has been renamed Collision, I hope that’s all right. Thanks a lot!

By: Nick A

Nick A — Fri, 22 Jan 2010 13:45:51 +0000

I love the possibilities that are opened up with this.

I used it with an inverted track clip and a sleigh for our companies viral campaign (http://www.d2digital.co.uk/viral.aspx) to test for the sleigh crashing into the side of the road.

I posted the car/sleigh script on my blog; http://www.d2digital.co.uk/blog/actionscript_3_code_for_a_2d_driving_car.aspx

Good work and thanks for enabling us to do much more cool stuff!

Nick

By: Paul

Paul — Mon, 18 Jan 2010 19:17:00 +0000

If I use this class in a SWF (say, to hit test 2 squares) and then load that SWF into another SWF at a y or x of anything but zero, it seems to break.

Example:
var loader:Loader = new Loader();
loader.load(new URLRequest(“HitTest.swf”));
loader.y = 200;
addChild(loader);

in order to fix this I had to change
if( !target1.root || !target2.root || !target1.hitTestObject( target2 ) ) return new Rectangle();

// Get the bounds of each DisplayObject.
var bounds1:Rectangle = target1.getBounds( target1.root );
var bounds2:Rectangle = target2.getBounds( target2.root );

if( !target1.stage || !target2.stage || !target1.hitTestObject( target2 ) ) return new Rectangle();

// Get the bounds of each DisplayObject.
var bounds1:Rectangle = target1.getBounds( target1.stage );
var bounds2:Rectangle = target2.getBounds( target2.stage );

which messes up the intersectionRectangle function iff I wanted to use that for anything beyond internal use for the HitTest class. Lucky for me, I don’t need that for anything else.

I’m not going to try and fix this any further, but I thought you might be interested.

By: magicianseeker

magicianseeker — Mon, 11 Jan 2010 12:22:39 +0000

Tink, do you know how to solve this? I used two displayObject to detect either they collide or not and it returned sometimes true sometimes false. It doesn’t a problem when they are far apart–it returns true but it’s like that when they are near.

btw, the displayObject are vector image.
here is the code:

public static function isHitting(hitter:DisplayObject,hittee:DisplayObject,parent:DisplayObject,precision:Number):Boolean
{ if(hittee.hitTestObject(hitter))
{

var rect1:Rectangle = hitter.getBounds(parent);
var rect2:Rectangle = hittee.getBounds(parent);
var rectInt:Rectangle = rect1.intersection(rect2);
return searchCommon(hitter,hittee,rectInt,parent,precision)
}
else
{
return false;
}
}

public static function searchCommon(object1:DisplayObject,object2:DisplayObject,rect:Rectangle,parent:DisplayObject,precision:Number):Boolean
{
var returnValue:Boolean = false;
var p:Point = new Point();
for (var j:int = rect.y; j <= rect.y +rect.height && returnValue == false; j+=precision) {
if (returnValue == true) {
break;
}
else {
for (var i:int = rect.x; i <= rect.x + rect.width; i+=precision) {
p.x = i;
p.y = j;
p = parent.localToGlobal(p);

if(object1.hitTestPoint(p.x,p.y, true) == true && object2.hitTestPoint(p.x,p.y, true) == true)
{
returnValue = true;
break;
}
}
}
}
return returnValue;
}