from vpython import *
#GlowScript 2.7 VPython
ball = sphere(pos=vector(-5,0,0), radius=0.5, color=color.cyan, make_trail=True)  
wallR = box(pos=vector(6,0,0), size=vector(0.2,12,12), color=color.green) 
wallL = box(pos=vector(-6,0,0), size=vector(0.2,12,12), color=color.green) 
wallT = box(pos=vector(0,6,0), size=vector(12,0.2,12), color=color.blue)
wallB = box(pos=vector(0,-6,0), size=vector(12,0.2,12), color=color.blue)
wallBa = box(pos=vector(0,0,-6), size=vector(12,12,0.2), color=color.red)
ball.velocity = vector(5,5,0)
deltat = 0.005  
t = 0  
#ball.pos = ball.pos + ball.velocity*deltat 
vscale = 0.1  
varr = arrow(pos=ball.pos, axis=vscale*ball.velocity, color=color.yellow) 




while t >= 0:     
    rate(100)
    if ball.pos.x > wallR.pos.x or ball.pos.x < wallL.pos.x: 
       # ball.velocity.x = -ball.velocity.x  
        print("game over")
        break
    if ball.pos.y > wallT.pos.y or ball.pos.y < wallB.pos.y: 
        #ball.velocity.y = -ball.velocity.y
        print("game over")
        break
    if ball.pos.z < wallBa.pos.z:
        #ball.velocity.z = -ball.velocity.z
    #ball.pos = ball.pos + ball.velocity*deltat 
    varr.pos = ball.pos
    varr.axis = vscale*ball.velocity
    t=t+deltat

def onpress(event):
    s=event.key
    if s='up':
        ball.velocity.y+=1
    else if s='down':
        ball.velocity.y-=1
    else if s='left':
        ball.velocity.x-=1
    else if s='right':
        ball.velocity.x+=1
scene.bind('keydown',onpress)