## Parameters for the model solar system
## Used by the main program theplanets.py
##
## Each planet needs to be defined AND AT THE END
## all planets must be put into the list 'planets'
##     - All objects that exert gravity need a mass.
##     - All objects subject to gravity need a curve attribute named
##       'track' for tracing the orbit, a velocity velocity named 'vel',
##       and list of objects that exert gravity on them ('others')

from visual import *

####################### sun ### (fixed in space by assumption)
sun = sphere(pos=(0.,0.,0.), radius=0.2, color=color.yellow)
sun.mass = 1

####################### bigmars ### (this object will affect Earth,
#######################              but is not affected by the Earth.)
##### note that the z-position is not zero - its orbit will be tilted
##### relative to the unperturbed orbit of the Earth. Set
##### starting position, velocity, mass, and color of track.
bigmars = sphere(radius=0.1, color=color.magenta, pos=(3,0,0.2))
bigmars.vel = vector(0,0.5,0)
bigmars.mass = 0.0
bigmars.others=[sun]            ### sun affects the bigmars
bigmars.track=curve(color=color.red)

earth = sphere(radius = 0.1, color=color.blue, pos = (2,0,0))
earth.vel = vector(0,0.6,0)
earth.others=[sun,bigmars]      ### bigmars and sun affect the earth
earth.track=curve(color=color.cyan)

## list of the planets - things with tracks and dynamics - sun is fixed
planets = [bigmars, earth]