from visual import *

## ruth chabay, carnegie mellon university, 2000-06

## rings may be dragged through stuff - a little surreal

scene.width=800

scene.title="Tower of Hanoi"

print("Move the stack to the white pole.")

maxradius=2.5

thick=.5

spacing=maxradius+thick

leftpole=cylinder(pos=(-2*spacing,-3,0), radius=0.3, axis=(0,6,0))

leftpole.color=(.5,.5,.5)

midpole=cylinder(pos=(0,-3,0), radius=0.3, axis=(0,6,0))

midpole.color=(.5,.5,.5)

rightpole=cylinder(pos=(2*spacing,-3,0), radius=0.3, axis=(0,6,0))

floor=box(pos=(0,-3.5,0), size=(23,.99,5),

color=(1.0,0.5,0), material=materials.wood)

poles=[leftpole,midpole,rightpole]

rings=[]

hues=[(1,0,0), (1,1,0), (0,1,0), (.3,.3,1), (1,0,1)]

for y in arange(-2, 3,1):

rings.append(ring(pos=(poles[0].x,y,0), radius=.5*(3-y), color=hues[y+2],

thickness=thick,axis=(0,1,0)))

stack=[rings[:],[],[]] # list of rings on each pole

scene.autoscale=0

moves=0

while True:

rate(100)

if scene.mouse.events:

m = scene.mouse.getevent()

if m.drag: # identify pole clicked on

mx=m.project(normal=vector(0,0,1)).x

pole1=int((mx+floor.length/2.)/(floor.length/3.))

# pick up a ring

if len(stack[pole1])>0:

select=stack[pole1][-1] # remove ring from stack

del(stack[pole1][-1])

while not (scene.mouse.events and scene.mouse.getevent().drop): # drag ring

select.pos=scene.mouse.project(normal=vector(0,0,1))

rate(60)

mx=select.x

pole2=int((mx+floor.length/2.)/(floor.length/3.))

# put down a ring

if len(stack[pole2])>0: # stack not empty

if stack[pole2][-1].radius > select.radius: # legal move

select.x=poles[pole2].x

select.y=-2+len(stack[pole2])

stack[pole2].append(select)

moves=moves+1

else: # illegal move

select.x=poles[pole1].x

select.y=-2+len(stack[pole1])

stack[pole1].append(select)

else: # stack empty

select.x=poles[pole2].x

select.y=-2

stack[pole2].append(select)

moves=moves+1

if len(stack[2])==5: # task completed?

print("You won in ",moves," moves.")

flash=0

while flash < 6:

rightpole.color=(1,0,0)

rate(10)

rightpole.color=(1,1,1)

rate(10)

flash=flash+1

break