Code:

import sysimport direct.directbase.DirectStartfrom direct.showbase.DirectObject import DirectObjectfrom direct.showbase.InputStateGlobal import inputStatefrom panda3d.core import *from panda3d.bullet import *#from GameObject import *class Game(DirectObject):    def __init__(self):        base.setBackgroundColor(0.5, 0.5, 0.5, 1)        base.setFrameRateMeter(True)        base.cam.setPos(0, 0, 32)        base.cam.setP(-90)        base.cam.lookAt(0, 0, 0)        # Light        aLight = AmbientLight('ambientLight')        aLight.setColor(Vec4(0.5, 0.5, 0.5, 1))        aLightNP = render.attachNewNode(aLight)        dLight = DirectionalLight('directionalLight')        dLight.setDirection(Vec3(1, 1, -1))        dLight.setColor(Vec4(1, 1, 1, 1))        dLightNP = render.attachNewNode(dLight)        render.clearLight()        render.setLight(aLightNP)        render.setLight(dLightNP)        # Task        taskMgr.add(self.update, 'updateWorld')        # defines input vars        self.wsad = {"w" : False, "s" : False, "a" : False, "d" : False}        self.arrows = {"arrow_up" : False, "arrow_down" : False, "arrow_left" : False, "arrow_right" : False}        # updates input vars        for i in self.wsad:            self.accept(i, self.updateKeyMap, [i, True])            self.accept(i + "-up", self.updateKeyMap, [i, False])        for i in self.arrows:            self.accept(i, self.updateKeyMap, [i, True])            self.accept(i + "-up", self.updateKeyMap, [i, False])         # Physics        self.setup()    def update(self, task):        dt = globalClock.getDt()                # update input forces for each box that existes        self.updateBox(dt, self.box[0], self.wsad, 0.2)        self.updateBox(dt, self.box[1], self.arrows, 0.2)        self.world.doPhysics(dt, 5, 1.0/180.0)        return task.cont    def updateKeyMap(self, controlName, controlState):        self.wsad[controlName] = controlState        self.arrows[controlName] = controlState        def setup(self):        self.worldNP = render.attachNewNode('World')        self.world = BulletWorld()        self.world.setGravity(Vec3(0, 0, -9.81))        # Ground (static)        shape = BulletPlaneShape(Vec3(0, 0, 1), 1)        self.groundNP = self.worldNP.attachNewNode(BulletRigidBodyNode('Ground'))        self.groundNP.node().addShape(shape)        self.groundNP.setPos(0, 0, -2)        self.groundNP.setCollideMask(BitMask32.allOn())        self.world.attachRigidBody(self.groundNP.node())        # creates a list of adressable boxes and balls        self.box = []        self.ball = []        self.createBox(4,0,0)        self.createBox(-4,0,0)        self.createBall(0,0,0)        def createBox(self, x, y, z):        # Box (dynamic)        shape = BulletBoxShape(Vec3(0.5, 0.5, 0.5))        boxNP = self.worldNP.attachNewNode(BulletRigidBodyNode('Box'))        boxNP.node().setMass(1.0)        boxNP.node().addShape(shape)        boxNP.setPos(x, y, z)        #self.boxNP.setScale(2, 1, 0.5)        boxNP.setCollideMask(BitMask32.allOn())        #self.boxNP.node().setDeactivationEnabled(False)        self.world.attachRigidBody(boxNP.node())        visualNP = loader.loadModel('Models/Box/plainbox.egg')        visualNP.clearModelNodes()        visualNP.reparentTo(boxNP)        self.box.append(boxNP)    def updateBox(self, dt, NP, keys, speed):        force = Vec3(0, 0, 0)        torque = Vec3(0, 0, 0)                k=list(keys.keys())        if keys[k[0]]:            force.setY(speed)        if keys[k[1]]:            force.setY(-speed)        if keys[k[2]]:            force.setX(-speed)        if keys[k[3]]:            force.setX(speed)                force *= 30.0        torque *= 10.0        force = render.getRelativeVector(NP, force)        torque = render.getRelativeVector(NP, torque)        NP.node().setActive(True)        NP.node().applyCentralForce(force)        NP.node().applyTorque(torque)    def createBall(self, x, y, z):        # Ball (dynamic)        shape = BulletSphereShape(1)        ballNP = self.worldNP.attachNewNode(BulletRigidBodyNode('Ball'))        ballNP.node().setMass(1.0)        ballNP.node().addShape(shape)        ballNP.setPos(x, y, z)        #self.ballNP.setScale(2, 1, 0.5)        ballNP.setCollideMask(BitMask32.allOn())        #self.ballNP.node().setDeactivationEnabled(False)        self.world.attachRigidBody(ballNP.node())        visualNP = loader.loadModel('Models/Ball/ball.egg')        visualNP.clearModelNodes()        visualNP.reparentTo(ballNP)        self.ball.append(ballNP)game = Game()run()