PhysInjector game prototype translated in pure Box2D
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When I made the PhysInjector game prototype in only 100 lines of code I told you you would need a lot more lines (and work) in order to make the same thing run with pure Box2D.
Today I am showing you how much work.. this is the main class:
package {
import flash.display.Sprite;
import flash.events.MouseEvent;
import flash.events.Event;
import flash.text.TextField;
import Box2D.Dynamics.*;
import Box2D.Collision.Shapes.*;
import Box2D.Common.Math.*;
import Box2D.Dynamics.Contacts.*;
import Box2D.Dynamics.Joints.*;
public class Main extends Sprite {
private var world:b2World=new b2World(new b2Vec2(0,10),true);
private var worldScale:Number=30;
private var joint:b2RevoluteJoint;
private var bodyFloor:b2Body;
private var floor:Sprite= new Sprite();
private var colorArray:Array=[0xff0000,0x00ff00,0x0000ff,0xffff00,0xff00ff,0x00ffff,0x000000,0xffffff];
private var boxColor:Number=Math.floor(Math.random()*colorArray.length);
private var lives:Number=3;
private var score:Number=0;
private var scoreText:TextField = new TextField();
public function Main() {
var customContact:CustomContactListener=new CustomContactListener();
world.SetContactListener(customContact);
graphics.lineStyle(2,0x000000);
graphics.moveTo(0,100);
graphics.lineTo(640,100);
addChild(scoreText);
floor.x=50;
floor.y=420;
addChild(floor);
fillFloor();
var bodyDef:b2BodyDef=new b2BodyDef();
bodyDef.position.Set(320/worldScale,430/worldScale);
bodyDef.type=b2Body.b2_dynamicBody;
bodyDef.userData={name:"floor",asset:floor};
var polygonShape:b2PolygonShape=new b2PolygonShape();
polygonShape.SetAsBox(270/worldScale,10/worldScale);
var fixtureDef:b2FixtureDef=new b2FixtureDef();
fixtureDef.shape=polygonShape;
fixtureDef.density=10;
fixtureDef.restitution=0;
fixtureDef.friction=0.2;
bodyFloor=world.CreateBody(bodyDef);
bodyFloor.CreateFixture(fixtureDef);
var revoluteJointDef:b2RevoluteJointDef=new b2RevoluteJointDef();
revoluteJointDef.localAnchorA.Set(0,0);
revoluteJointDef.localAnchorB.Set(320/worldScale,430/worldScale);
revoluteJointDef.bodyA=bodyFloor;
revoluteJointDef.bodyB=world.GetGroundBody();
revoluteJointDef.enableMotor=true;
joint=world.CreateJoint(revoluteJointDef) as b2RevoluteJoint;
var sensor:Sprite=new Sprite();
sensor.graphics.beginFill(0x000000);
sensor.graphics.drawRect(-640,-10,1280,20);
sensor.graphics.endFill();
addChild(sensor);
sensor.x=-320;
sensor.y=500;
bodyDef.position.Set(320/worldScale,510/worldScale);
bodyDef.type=b2Body.b2_staticBody;
bodyDef.userData={name:"sensor",asset:sensor};
polygonShape.SetAsBox(640/worldScale,10/worldScale);
fixtureDef.shape=polygonShape;
fixtureDef.isSensor=true;
var sensorBody:b2Body=world.CreateBody(bodyDef);
sensorBody.CreateFixture(fixtureDef);
addEventListener(Event.ENTER_FRAME,update);
stage.addEventListener(MouseEvent.CLICK,addBox);
}
private function fillFloor():void {
floor.graphics.clear();
floor.graphics.beginFill(colorArray[boxColor]);
floor.graphics.drawRect(-270,-10,540,20);
floor.graphics.endFill();
}
private function addBox(e:MouseEvent):void {
if (mouseY<100) {
var box:Sprite = new Sprite();
box.graphics.beginFill(colorArray[boxColor]);
box.graphics.drawRect(-25,-25,50,50);
box.graphics.endFill();
box.x=mouseX-25;
box.y=mouseY-25;
addChild(box);
var bodyDef:b2BodyDef=new b2BodyDef();
bodyDef.position.Set(mouseX/worldScale,mouseY/worldScale);
bodyDef.type=b2Body.b2_dynamicBody;
bodyDef.userData={name:"box",asset:box,val:boxColor,hit:false,destroy:false};
var polygonShape:b2PolygonShape=new b2PolygonShape();
polygonShape.SetAsBox(25/worldScale,25/worldScale);
var fixtureDef:b2FixtureDef=new b2FixtureDef();
fixtureDef.shape=polygonShape;
fixtureDef.density=1+score/100;
fixtureDef.restitution=0;
fixtureDef.friction=0.2;
var body:b2Body=world.CreateBody(bodyDef);
body.CreateFixture(fixtureDef);
boxColor=Math.floor(Math.random()*colorArray.length);
fillFloor();
}
}
private function update(event:Event):void {
world.Step(1/30,10,10);
for (var currentBody:b2Body=world.GetBodyList(); currentBody; currentBody=currentBody.GetNext()) {
if (currentBody.GetUserData()) {
currentBody.GetUserData().asset.x=currentBody.GetPosition().x*worldScale;
currentBody.GetUserData().asset.y=currentBody.GetPosition().y*worldScale;
currentBody.GetUserData().asset.rotation=currentBody.GetAngle()*(180/Math.PI);
if (currentBody.GetUserData().hit) {
currentBody.GetUserData().hit=false;
score+=0.5;
currentBody.GetUserData().asset.alpha-=0.25;
if (currentBody.GetUserData().asset.alpha<=0) {
score+=2.5;
removeChild(currentBody.GetUserData().asset);
world.DestroyBody(currentBody);
}
scoreText.text=score.toString()+" - "+lives.toString()+" lives";
}
if (currentBody.GetUserData().destroy) {
removeChild(currentBody.GetUserData().asset);
world.DestroyBody(currentBody);
lives--;
scoreText.text=score.toString()+" - "+lives.toString()+" lives";
if (lives==0) {
removeEventListener(Event.ENTER_FRAME,update);
stage.removeEventListener(MouseEvent.CLICK,addBox);
}
}
}
}
joint.SetMotorSpeed(bodyFloor.GetUserData().asset.rotation);
joint.SetMaxMotorTorque(Math.abs(bodyFloor.GetUserData().asset.rotation)*100);
world.ClearForces();
}
}
}
… and this is the custom contact listener
package {
import Box2D.Dynamics.*;
import Box2D.Collision.*;
import Box2D.Dynamics.Joints.*;
import Box2D.Dynamics.Contacts.*;
import Box2D.Common.Math.b2Vec2;
class CustomContactListener extends b2ContactListener {
override public function BeginContact(contact:b2Contact):void {
var bodyA:b2Body=contact.GetFixtureA().GetBody();
var bodyB:b2Body=contact.GetFixtureB().GetBody();
if (bodyA.GetUserData().name=="box"&&bodyB.GetUserData().name=="box"&&bodyA.GetUserData().val==bodyB.GetUserData().val) {
bodyA.GetUserData().hit=true;
bodyB.GetUserData().hit=true;
}
if (bodyA.GetUserData().name=="sensor"&&bodyB.GetUserData().name=="box") {
bodyB.GetUserData().destroy=true;
}
if (bodyA.GetUserData().name=="box"&&bodyB.GetUserData().name=="sensor") {
bodyA.GetUserData().destroy=true;
}
}
}
}
As you can see, the whole script is 138+23 = 161 lines long, moreover I had to override a function, create one more class, and spend more time.
That’s why I am using PhysInjector library for a quick game I am going to release next week.
Anyway, this is the result of the Box2D version:
Click with mouse button above the black line and match boxes of the same color.
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