Simple Quickbox2d Sensors

Jesse — Mon, 14 Jun 2010 16:12:00 +0000

Hey, wouldn’t be nice if you could make sensors easily in quickbox2d (which is already fantastic and easy). Well, you can, and here’s how, really easily. I’d post the source code, but if you haven’t figured it out by yourself, you might need the practice tinkering (besides Zevan will add it soon, I’m sure). This is painless, I promise.

If you don’t know what a sensor is, or why you’d want one – think of it as a physics object that detects collision but doesn’t actually affect the movement of anything its collides with – like passing through a ghost. No category or mask bits needed here, just a simple “true” or ”false”.

here’s how to add it to quickbox2d:

OVERVIEW:

you are going to open and add one tiny line of code to 3 files.

Step 1) open com.actionsnippet.QuickObject.as

Step) find the function “defineDefaults” should look something like this:

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private function defineDefaults():void{
defaults = {x:3, y:3, linearDamping:0,
angularDamping:0, isBullet:false,
fixedRotation:false,
allowSleep: true,
isSleeping:false,
scaleSkin:true,
density:1.0, friction:0.5, restitution:0.2, angle:0.0,
maskBits:0xFFFF, categoryBits:1, groupIndex:0,
draggable: true,
lineColor:0x000000, lineAlpha:1,
lineThickness:0,
fillColor:0xCCCCCC, fillAlpha:1
}

When you create an object, you pass parameters. these are the default parameters and we need to do as add “, isSensor:false” at the end so it looks like this

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1 of 3 completed. Now lets add a couple of tiny bits of code to the “BoxObject.as” and “CircleObject.as” files as well

BoxObject code: “boxDef.isSensor = p.isSensor;” see example below

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override protected function build():void{
var p:Object = params;

if(p.skin is DisplayObject){
bodyDef.userData = p.skin;
var t:Number = p.skin.rotation;

p.skin.rotation = 0;
if (!p.width){
p.width = p.skin.width / 30;
}
if (!p.height){
p.height = p.skin.height / 30;
}
p.skin.rotation = t;
}

if (!p.width) p.width = 1;
if (!p.height) p.height = 1;

var boxDef:b2PolygonDef = new b2PolygonDef();
shapeDef = boxDef;
var hw:Number = p.width / 2;
var hh:Number = p.height / 2;
boxDef.SetAsBox(hw, hh);

boxDef.density = p.density;
boxDef.friction = p.friction;
boxDef.restitution = p.restitution;
boxDef.filter.maskBits = p.maskBits;
boxDef.filter.categoryBits = p.categoryBits;
boxDef.filter.groupIndex = p.groupIndex;
boxDef.isSensor = p.isSensor; // <------ HERE IT IS!

CircleObject code: “circDef.isSensor = p.isSensor;” see example below

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protected override function build():void{

var p:Object = params;

var circDef:b2CircleDef = new b2CircleDef();
shapeDef = circDef;

if (p.skin is DisplayObject){
bodyDef.userData = p.skin;
if (!p.radius){
p.radius = p.skin.width/60;
}
}
if (!p.radius) p.radius = .5;

circDef.radius = p.radius;
circDef.density = p.density;
circDef.friction = p.friction;
circDef.restitution = p.restitution;
circDef.filter.maskBits = p.maskBits;
circDef.filter.categoryBits = p.categoryBits;
circDef.filter.groupIndex = p.groupIndex;
circDef.isSensor = p.isSensor; // HERE IT IS!!!

so, now, anytime you want an object to be a sensor, just tell it so on creation.
Examples:

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sim.addBox({x:someNumber, y:someNumber, width: x:someNumber, height: x:someNumber, density:0, isSensor:true});

sim.addCircle({x: x:someNumber, y: x:someNumber, radius: x:someNumber, density: 0, isSensor:true});

Fix for papervision 3ds parser

Jesse — Thu, 09 Apr 2009 15:58:56 +0000

If you are having problems with the 3ds parser in papervision & you are using CS4 this might help you.

download here

To use it, just unzip the parsers.zip and copy everything over in your papervision3d/objects/parsers folder. It’ll replace some files, this should be ok, and it’ll add one with some helper files.

CONTEXT (since code will change and, hopefully, this will be made useless soon by the papervision guys)

I have been using the 3ds parser without problem in CS3 for months. I’ve recently started using it in FLARTOOLKIT experiments, again with no problem. I then switched to FLARmanager, which required both CS4 and a recent papervision (i’ve been using an older one). My 3ds imports broke, even test code I downloaded broke. I updated to the latest papervision (INFO: Papervision3D Public Beta 2.0 – Great White (December 3rd, 2008)) and it was still broke, and then I went back and reintegrated everything with new papervision and CS3 – no problems. So CS4 does something weird.

A solution (which Josh L posted in a comment at drawlogic) was suggested and I followed it. Thanks for the advice! Considering I had never made custom classes before and had a few little issues doing it, I zipped up the solution for everything to share.

download here

Jesse Gomez » code stuffs

Simple Quickbox2d Sensors

Fix for papervision 3ds parser