QuickBox2D groupIndex Platforms

Hugo

Hi, first of all great work on QuickBox2D, its a great lib for those starting to play with Box2D.

I’m having an issue however, with an experiment I’m working on… I have a box that will work like a “zone”, this has density 0 so its stopped and then I have a circle which is moving. When they collide I need to catch that event BUT the catch is that I need the circle to overlap / go through the “zone” box instead of bouncing off of it. Any insight into how I can accomplish this?

Thanks and keep up the good work.

Hugo

Hi Zevan!

Thanks a lot for the quick reply, I tried your direction and it does indeed work and I’ll most likely use it in the near future on something else but it doesnt solve this specific problem.

I appologize if I didnt explain myself better but I’ll try to do so now. Lets imagine a game where there are several balls and also a “Win Zone”, this zone is nothing more then a rectangle which is a space where the balls “might” fall into (and be contained in). Now, the balls can collide with eachother but they cant collide with the “Win Zone” because this is a transparent rectangle.

First off I tried with the win zone being just a thin layer on the game’s floor but the problem is that the balls that “Win” can stack up on top of each other and therefor prevent new balls from “touching” the ground and triggering the event.

I think a good analogy would be a cup, lets say that each ping pong ball that you manage to get into the cup awards you a point. You could make the bottom of the cup trigger the score but after a couple balls the bottom of the cup would be unreachable so the win zone should be an imaginary space that represents the cup’s inside.

Anyway, thanks again for your reply it I’ll try to figure a workaround for this, just thought someone with a way better insight into Box2D then me could know an easy fix.

Andrew

This is very nice, but I’m having some problems. I get an error 1006 with GetFilterData, my code thus far:

package {
import flash.display.MovieClip;
import com.actionsnippet.qbox.*;
import flash.events.Event;
import flash.events.MouseEvent;
import com.greensock.TweenLite;
import Box2D.Common.Math.*;
import Box2D.Common.*;
import Box2D.Collision.Shapes.*;

public class err extends MovieClip {
public var myArray:Array;
public var switcher:Number;
public var _index:b2FilterData;
public var sim:QuickBox2D;

public function err():void {
sim = new QuickBox2D(this);
butt.addEventListener(MouseEvent.MOUSE_DOWN, gravitySwitch);
switcher = 2;
sim.start();
sim.mouseDrag();
init();
}

public function init():void {
myArray = [pic1, pic2, pic3, pic4];
stage.frameRate = 60;
sim.createStageWalls({width:1, fillColor:0×000000, lineAlpha:0});

for each (var i:MovieClip in myArray) {
sim.addBox( { friction:0.5, skin:i, groupIndex:_index } );
}
}

public function gravitySwitch(e:Event):void {
if (switcher == 0) {
switcher = 2;
sim.gravity.y = switcher;
collOn();
sim.stop();
sim.start();
TweenLite.to(butt, 0.25, { rotationZ: 0 } );
}
else if (switcher == 2) {
_index = myArray.GetFilterData();
switcher = 0;
sim.gravity.y = switcher;
collOff();
sim.stop();
sim.start();
TweenLite.to(butt, 0.25, { rotationZ: -45 } );
}
}

public function collOn():void {
_index = myArray.Shape.GetFilterData();
_index.groupIndex = 0;
myArray.Shape.SetFilterData(_index);
}

public function collOff():void {
_index = myArray.Shape.GetFilterData();
myArray.groupIndex = -1;
myArray.Shape.SetFilterData(_index);
}

}
}

I basically want to switch collisions on and off at will.