from visual import*
from visual.graph import *

print """
Rob Salgado (salgado@physics.syr.edu) - Sept 24, 2003

This program copies objects from one display into another
with an improved copyobjects() function.

With a new function updatecopyobjects(),
I wish to update the objects in the destination display
with data from the source display.

However, to make this work, I had to understand a subtlety in the 
copyobjects() function on http://www.vpython.org/webdoc/visual/options.html .

First, run and observe the shell output. (Widen the shell output window.)

Second, note my updatecopyobjects() function 
and my revised copyobjects() function.
    The original version of copyobjects() 
    does not use the reverse() function.
    Observe what happens when that statement is commented out.

*** Essentially, I believe copyobjects() should traverse the
source-display's list in reverse as it builds up the destination-display
so that the items in the destination list of objects
are in correspondence with those of the source list.

For an example of what you can do with this,
comment out the print statements in updatecopyobjects()
[so the animations will run smoothly] and 
uncomment the updatecopyobjects() statement in the while loop.

===========
"""

scene=display(
    title="A",
    width=350,height=350,
    x=0, y=0,
    autoscale=0,
    visible=1,
    forward=(-1,-1,-1),center=vector(0,0,0)
    )

sceneB=display(
    title="B",
    width=350,height=350,
    x=350, y=0,
    autoscale=0,
    visible=1,
    forward=(0,-1,-10),center=vector(0,0,0)
    )

scene.select()


def copyobjects(scene1,scene2):
    # based on http://www.vpython.org/webdoc/visual/options.html
    # Copy all Visual objects from scene1 into scene2
    scene2.select()

    scenelist=scene1.objects
    ###
    ### reverse() is needed so that the items in the destination list of objects
    ### are in correspondence with those of the source list
    scenelist.reverse()
    
    for obj in scenelist:
        newobj = obj.__class__() # create object in scene2

        # FOR DEBUGGING
        print    obj,    obj.__class__, "\t--copy-->\t",
        print newobj, newobj.__class__

        for member in obj.__members__:
            if member == 'display': continue # avoid putting into scene1
            setattr(newobj,member,getattr(obj,member))

    # FOR DEBUGGING
    print "\n-----list of scene1 objects"
    print scene1.objects
    for obj in scene1.objects: print obj.__class__,
    print "\n-----list of scene2 objects"
    print scene2.objects
    for obj in scene2.objects: print obj.__class__,
    print "\n------------"


def updatecopyobjects(scene1,scene2):
    # Update the Visual objects copied into scene2 from scene1
    obj2_list=scene2.objects
    i=0
    for obj in scene1.objects:

        # FOR DEBUGGING
        print          obj,            obj.__class__, "\t--update-->\t",
        print obj2_list[i],   obj2_list[i].__class__

        for member in obj.__members__:
            if member == 'display': continue # avoid putting into scene1
            setattr(obj2_list[i],member,getattr(obj,member))
        i += 1    
            


### A variant of the "Simple program example"
### from http://www.vpython.org/vpythonprog.htm

floor = box (pos=(0,0,0), length=4, height=0.5, width=4, color=color.blue)
ball = sphere (pos=(0,4,0), radius=1, color=color.red)
ball.velocity = vector(0,-1,0)
dt = 0.01


copyobjects(scene,sceneB)
updatecopyobjects(scene,sceneB) # here for proof of concept
 

while 1:
    rate (100)
    ball.pos = ball.pos + ball.velocity*dt

    if ball.y < ball.radius:
        ball.velocity.y = -ball.velocity.y
    else:
        ball.velocity.y = ball.velocity.y - 9.8*dt

    #You may want to comment out the function's print statements
    #before you uncomment the next line.:
    #updatecopyobjects(scene,sceneB)