#! /usr/bin/env python
"""
helium.py is a program which generates a 3D animation of a clasical Helium atom

Run the program and rotate the image in 3D.


Paul Eugenio
PHZ4151C
Jan 27, 2019
"""


import numpy as np
import vpython as vp
import sys



# constructing the Helium nucleous 
# 
# using  red spheres for protons and  blue 
# spheres for neutrons
#
proton1  = vp.sphere( pos=vp.vector(0.1,0,0),  radius=0.1, color=vp.color.red )
proton2  = vp.sphere( pos=vp.vector(-0.1,0,0), radius=0.1, color=vp.color.red )
neutron1 = vp.sphere( pos=vp.vector(0,0,0.1),  radius=0.1, color=vp.color.blue )
neutron2 = vp.sphere( pos=vp.vector(0,0,-0.1), radius=0.1, color=vp.color.blue )
makeTrail = False
electron1 = vp.sphere( pos=vp.vector(1,0,0), radius=0.03, color=vp.color.yellow, make_trail=makeTrail )
electron2 = vp.sphere( pos=vp.vector(0,1,0), radius=0.03, color=vp.color.yellow, make_trail=makeTrail )


rateOfTime = 50
if len(sys.argv) > 1:
    rateOfTime = int(sys.argv[1])

theta, z = 0.0, 0.0
while True:
    # Do the loop forever
    theta += 0.1
    vp.rate(rateOfTime)
    x = np.cos(theta)
    y = np.sin(theta)
    electron1.pos = vp.vector(x,y,z)
    electron2.pos = vp.vector(z,x,y)

#
#