HIttesting

[joshwa11]

Hey guys, i was working on rebuilding my game and i have noticed my hittests dont seem to be terribly accurate, most of the time the hittest seems to work on the maximum perimeter, for example if i have a triangle it would still be treated as a full square, anybody got any idea how i could make it more accurate?

[Draglino]

Are you using AS3 ? in as3 you can make hitTestPoint other then hitTestObject

[LonLonRanch]

I'm assuming that this is in AS2?

The problem with hitTest is that it only calculates the bounding box of the graphic and not the actual pixels. That's where specifying the pixel comes in handy. Check out the liveDocs for more information. Basically, with hitTest you can do:

hitTest(x, y, shapeFlag) : Boolean
hitTest(target) : Boolean

so instead of checking the bounding box, you can do a hitTest check for a specific point, like:

hitTest(box._x, box._y, true);

But either way, a triangle is one of the hardest objects to run a successful hitTest with, rectangles and circles are much easier. If you need something more powerful I'd search google for hitTest classes already written that could do this for you. If you use AS3 Troy Gilbert wrote an excellent PixelPerfectHitTest collision class.

[joshwa11]

Afriad im using AS2, would i have to specify every point around the triangle? Trying to avoid using alot of code, minimising lag you see

[LonLonRanch]

Unfortunately doing hitTests on objects that are not rectangles or circles takes much more work than most people want to do.

If you're still in AS2 try this: clicky

[joshwa11]

checkForCollision(Goblin_Swordsman_1,man ,alphaTolerance);
if(Collision == true){
_root.text == "hit"
}else{
}

That was my first attempt and it aint working, any idea how thats wrong?

[LonLonRanch]

Did you download the file and read the documentation? I'm guessing it's going to take a little effort to implement it into your file.

[joshwa11]

A couple of the files in the download appear to be a format i cant open but yes ive read through the documentation, the demo's also aren't fully functioning, for example CDDemo2 doesn't work like it does on the page, did a similar thing happen when you downloaded it?

[LonLonRanch]

I haven't actually used it, I used the AS3 one I mentioned earlier which worked for me, but I don't actually know much about this one, just looked like something you'd be interested in.

[asgrunt]

checkForCollision is a static of the CollisionDetection class. So you need to use it like so:

import com.gskinner.sprites.CollisionDetection;
...
CollisionDetection.checkForCollision(mc1 ,mc2);

You will either get a rectangle with the overlapping area or null if no collision did occur between the mcs with the instance names mc1 and mc2.

Of the many files in Skinners' zip you only need the CollisionDetection.as.