box2d之Sensor传感器
[code lang="as3"]package{
import Box2D.Collision.Shapes.b2PolygonShape;
import Box2D.Common.Math.b2Vec2;
import Box2D.Dynamics.Contacts.b2Contact;
import Box2D.Dynamics.b2Body;
import Box2D.Dynamics.b2BodyDef;
import Box2D.Dynamics.b2DebugDraw;
import Box2D.Dynamics.b2FixtureDef;
import Box2D.Dynamics.b2World;
import flash.display.Sprite;
import flash.events.Event;
import flash.events.TimerEvent;
import flash.utils.Timer;
[SWF(width="800",height="600",frameRate="32",backgroundColor="0x000000")]
public class Sensor extends Sprite{
private var world:b2World;
private var timeStep:Number;
private var iterations:uint;
private var pixelsPerMeter:Number = 30;
private var i:int = 0;
public function Sensor(){
createWorld();
makeDebugDraw();
createGround();
addEventListener(Event.ENTER_FRAME,onEnterframe);
var timer:Timer = new Timer(1000);
timer.addEventListener(TimerEvent.TIMER,onTimer);
timer.start();
}
private function createWorld():void{
var gravity:b2Vec2 = new b2Vec2(0.0,9.8);
var doSleep:Boolean = true;
world = new b2World(gravity,doSleep);
world.SetWarmStarting(true);
timeStep = 1.0/30.0;
iterations = 10;
}
private function makeDebugDraw():void{
var debugDraw:b2DebugDraw = new b2DebugDraw();
var debugSprite:Sprite = new Sprite();
addChild(debugSprite);
debugDraw.SetSprite(debugSprite);
debugDraw.SetDrawScale(30.0);
debugDraw.SetFillAlpha(0.5);
debugDraw.SetLineThickness(1.0);
debugDraw.SetFlags(b2DebugDraw.e_shapeBit);
world.SetDebugDraw(debugDraw);
}
private function createGround():void{
var bodyDef:b2BodyDef = new b2BodyDef();
bodyDef.position.Set(400/pixelsPerMeter,330/pixelsPerMeter);
var box:b2PolygonShape = new b2PolygonShape();
box.SetAsBox(400/pixelsPerMeter,15/pixelsPerMeter);
var fixtureDef:b2FixtureDef = new b2FixtureDef();
fixtureDef.shape = box;
fixtureDef.density = 0;
fixtureDef.friction = 0.3;
fixtureDef.isSensor = true;
fixtureDef.userData = "through";
var body:b2Body = world.CreateBody(bodyDef);
body.CreateFixture(fixtureDef);
bodyDef.position.Set(400/pixelsPerMeter,585/pixelsPerMeter);
box.SetAsBox(400/pixelsPerMeter,15/pixelsPerMeter);
fixtureDef = new b2FixtureDef();
fixtureDef.shape = box;
fixtureDef.density = 0;
fixtureDef.friction = 0.3;
fixtureDef.isSensor = false;
fixtureDef.userData = "ground";
body = world.CreateBody(bodyDef);
body.CreateFixture(fixtureDef);
}
private function onTimer(e:TimerEvent = null):void{
var bodyDef:b2BodyDef = new b2BodyDef();
bodyDef.type = b2Body.b2_dynamicBody;
bodyDef.position.Set((Math.random()*300+60)/pixelsPerMeter,0);
bodyDef.userData = i;
var box:b2PolygonShape = new b2PolygonShape();
box.SetAsBox((Math.random()*30+3)/pixelsPerMeter,(Math.random()*30+3)/pixelsPerMeter);
var fixtureDef:b2FixtureDef = new b2FixtureDef();
fixtureDef.shape = box;
fixtureDef.density = 1.0;
fixtureDef.friction = 0.5;
fixtureDef.restitution = 0.2;
var body:b2Body = world.CreateBody(bodyDef);
body.CreateFixture(fixtureDef);
i++;
}
private function onEnterframe(e:Event):void{
world.Step(timeStep,iterations,iterations);
world.ClearForces();
world.DrawDebugData();
if(world.GetContactList()){
var contact:b2Contact = world.GetContactList();
if(contact.GetFixtureA().GetBody().GetUserData() == "ground"){
trace(contact.GetFixtureB().GetBody().GetUserData());
}
if(contact.GetFixtureA().GetBody().GetUserData() == "through"){
var body:b2Body = contact.GetFixtureB().GetBody();
world.DestroyBody(body);
}
}
}
}
}
[/code]
<img src="http://www.everyinch.net/wp-content/uploads/2011/10/Sensor-300x225.jpg" alt="" title="Sensor" width="300" height="225" class="alignnone size-medium wp-image-295" />