Box2D Forums

Chassis = new Sprite(450, 100, menuTextures.Chassis1);            
      
      final FixtureDef objectFixtureDef = PhysicsFactory.createFixtureDef(1.0f, 0.0f, 1.0f);
      objectFixtureDef.restitution = 0.0f;
      final FixtureDef pivotDef = PhysicsFactory.createFixtureDef(1.0f, 0.0f, 1.0f);
      pivotDef.restitution = 0.0f;
      final FixtureDef wheelDef = PhysicsFactory.createFixtureDef(1.0f, 0.0f, 5.0f);
      wheelDef.restitution = 0.0f;
      final ITriangulationAlgoritm triangulationAlgoritm = new EarClippingTriangulator();
      
      final float width = Chassis.getWidthScaled() / PIXEL_TO_METER_RATIO_DEFAULT;
      final float height = Chassis.getHeightScaled() / PIXEL_TO_METER_RATIO_DEFAULT;
      
      List<Vector2> mVertices = new ArrayList<Vector2>();
      
      mVertices.add(new Vector2(-0.39844f*width, -0.14648f*height));
      mVertices.add(new Vector2(-0.37500f*width, -0.14648f*height));
      mVertices.add(new Vector2(+0.02344f*width, -0.16406f*height));
      mVertices.add(new Vector2(+0.06152f*width, -0.17773f*height));
      mVertices.add(new Vector2(+0.06348f*width, -0.10938f*height));
      mVertices.add(new Vector2(+0.09375f*width, -0.12500f*height));
      mVertices.add(new Vector2(+0.18945f*width, -0.12305f*height));
      mVertices.add(new Vector2(+0.32812f*width, +0.07422f*height));
      mVertices.add(new Vector2(+0.21484f*width, +0.04883f*height));
      mVertices.add(new Vector2(+0.37695f*width, +0.11914f*height));
      mVertices.add(new Vector2(+0.39844f*width, +0.29688f*height));
      mVertices.add(new Vector2(+0.37793f*width, +0.29492f*height));
      mVertices.add(new Vector2(+0.39746f*width, +0.37109f*height));
      mVertices.add(new Vector2(+0.34375f*width, +0.37305f*height));
      mVertices.add(new Vector2(+0.21875f*width, +0.37500f*height));
      mVertices.add(new Vector2(+0.21875f*width, +0.41016f*height));
      mVertices.add(new Vector2(+0.02344f*width, +0.22461f*height));
      mVertices.add(new Vector2(-0.36133f*width, +0.45312f*height));
      mVertices.add(new Vector2(-0.36816f*width, +0.43750f*height));
      mVertices.add(new Vector2(-0.35547f*width, +0.40430f*height));
      mVertices.add(new Vector2(-0.35645f*width, +0.22461f*height));
      
      final List<Vector2> triangles = triangulationAlgoritm.computeTriangles(mVertices);
      
      final Body chassisBody = PhysicsFactory.createTrianglulatedBody(mPhysicsWorld, Chassis, triangles, BodyType.DynamicBody, objectFixtureDef);      
        mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(Chassis, chassisBody, true, true));

        final Shape leftJointShape = new Rectangle( Chassis.getX()+ Chassis.getWidth() - 210, Chassis.getY()+ Chassis.getHeight() - 35, 10, 25);
        final Body leftAnchorBody = PhysicsFactory.createBoxBody(this.mPhysicsWorld, leftJointShape, BodyType.DynamicBody, pivotDef);
        leftAnchorBody.setTransform( new Vector2( leftAnchorBody.getWorldCenter().x, leftAnchorBody.getWorldCenter().y ), 60f); // change rotation
       
        final Shape rightJointShape = new Rectangle(Chassis.getX()+ Chassis.getWidth() - 70, Chassis.getY()+ Chassis.getHeight() - 35, 10, 25);
        final Body rightAnchorBody = PhysicsFactory.createBoxBody(this.mPhysicsWorld, rightJointShape, BodyType.DynamicBody, pivotDef);
        rightAnchorBody.setTransform( new Vector2( rightAnchorBody.getWorldCenter().x, rightAnchorBody.getWorldCenter().y ), 125f); // change rotation
       
        this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(leftJointShape, leftAnchorBody, true, true));
        this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(rightJointShape, rightAnchorBody, true, true));
       
        final Sprite WheelLeft = new Sprite(Chassis.getX()+ Chassis.getWidth() - 215, Chassis.getY()+ Chassis.getHeight() - 25, menuTextures.Wheel1);
        final Body leftWheelBody = PhysicsFactory.createCircleBody(this.mPhysicsWorld, WheelLeft, BodyType.DynamicBody, wheelDef); 
        leftWheelBody.setSleepingAllowed(false);
      final Sprite WheelRight = new Sprite(Chassis.getX()+ Chassis.getWidth() - 70, Chassis.getY()+ Chassis.getHeight() - 25, menuTextures.Wheel1);
      final Body rightWheelBody = PhysicsFactory.createCircleBody(this.mPhysicsWorld, WheelRight, BodyType.DynamicBody, wheelDef);
      rightWheelBody.setSleepingAllowed(false);
      
      this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(WheelLeft, leftWheelBody, true, true));
        this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(WheelRight, rightWheelBody, true, true));
       
        scene.getFirstChild().attachChild(Chassis);
        scene.getFirstChild().attachChild(leftJointShape);
        scene.getFirstChild().attachChild(rightJointShape);
        scene.getFirstChild().attachChild(WheelLeft);
        scene.getFirstChild().attachChild(WheelRight);
       
        final PrismaticJointDef leftPrismaticJointDef = new PrismaticJointDef();
        //leftPrismaticJointDef.initialize(chassisBody, leftAnchorBody, new Vector2(Chassis.getWidth() - 210, Chassis.getHeight() - 25), new Vector2(0, 1.0f)); // the 3rd parameter says where the fuck
        //leftPrismaticJointDef.initialize(chassisBody, leftAnchorBody, leftAnchorBody.getWorldCenter(), new Vector2((float)Math.cos(Math.PI/3), (float)Math.sin(Math.PI/3))); // the 3rd parameter says where the fuck
        leftPrismaticJointDef.bodyA = chassisBody;
        leftPrismaticJointDef.bodyB = leftAnchorBody;
        leftPrismaticJointDef.localAnchorA.set(-2.2f, 1.6f);
        leftPrismaticJointDef.localAnchorB.set(0, 0);
        leftPrismaticJointDef.localAxis1.set(new Vector2((float)Math.cos(Math.PI/3), (float)Math.sin(Math.PI/3)));
        leftPrismaticJointDef.lowerTranslation = -0.0f;
        leftPrismaticJointDef.upperTranslation = 0.0f;
        leftPrismaticJointDef.enableLimit = true;
        leftPrismaticJointDef.enableMotor = true;
        leftPrismaticJointDef.maxMotorForce = 0;
        leftPrismaticJointDef.motorSpeed = 0;
        this.mPhysicsWorld.createJoint(leftPrismaticJointDef);
       
        final PrismaticJointDef rightPrismaticJointDef = new PrismaticJointDef();
        //rightPrismaticJointDef.initialize(chassisBody, leftAnchorBody, new Vector2(Chassis.getWidth() - 70, Chassis.getHeight() - 25), new Vector2(0, 1.0f)); // the 3rd parameter says where the fuck
        //rightPrismaticJointDef.initialize(chassisBody, rightAnchorBody, rightAnchorBody.getWorldCenter(), new Vector2((float)-Math.cos(Math.PI/3), (float)Math.sin(Math.PI/3))); // the 3rd parameter says where the fuck
        rightPrismaticJointDef.bodyA = chassisBody;
        rightPrismaticJointDef.bodyB = rightAnchorBody;
        rightPrismaticJointDef.localAnchorA.set(2.2f, 1.6f);
        rightPrismaticJointDef.localAnchorB.set(0, 0);
        rightPrismaticJointDef.localAxis1.set(new Vector2((float)-Math.cos(Math.PI/3), (float)Math.sin(Math.PI/3)));
        rightPrismaticJointDef.lowerTranslation = -0.0f;
        rightPrismaticJointDef.upperTranslation = 0.0f;
        rightPrismaticJointDef.enableLimit = true;
        rightPrismaticJointDef.enableMotor = true;
        rightPrismaticJointDef.maxMotorForce = 0;
        rightPrismaticJointDef.motorSpeed = 0;
        this.mPhysicsWorld.createJoint(rightPrismaticJointDef);
       
        final RevoluteJointDef leftRevoluteJointDef = new RevoluteJointDef();
        //leftRevoluteJointDef.initialize(leftAnchorBody, leftWheelBody, leftWheelBody.getWorldCenter());
        leftRevoluteJointDef.bodyA = leftAnchorBody;
        leftRevoluteJointDef.bodyB = leftWheelBody;
        leftRevoluteJointDef.localAnchorA.set(0,0);
        leftRevoluteJointDef.localAnchorB.set(0,-0.5f);
        leftRevoluteJointDef.enableLimit = true;
        leftRevoluteJointDef.enableMotor = true;
        leftRevoluteJointDef.maxMotorTorque = 200;
        leftRevoluteJointDef.motorSpeed = 10;       
        this.mPhysicsWorld.createJoint(leftRevoluteJointDef);
       
        final RevoluteJointDef rightRevoluteJointDef = new RevoluteJointDef();
        //rightRevoluteJointDef.initialize(rightAnchorBody, rightWheelBody, rightWheelBody.getWorldCenter());
        rightRevoluteJointDef.bodyA = rightAnchorBody;
        rightRevoluteJointDef.bodyB = rightWheelBody;
        rightRevoluteJointDef.localAnchorA.set(0,0);
        rightRevoluteJointDef.localAnchorB.set(0,-0.5f);
        rightRevoluteJointDef.enableLimit = true;
        rightRevoluteJointDef.enableMotor = true;
        rightRevoluteJointDef.maxMotorTorque = 200;
        rightRevoluteJointDef.motorSpeed = 10;
        this.mPhysicsWorld.createJoint(rightRevoluteJointDef);