# Visual Python Prelab Exercise September 24 2009
# 
# Thornton Vaseltarps first visual python graph
#
# Run this program on any of the computers in H204,
# the KINSC computer lab more or less directly above 
# the introductory lab where we meet.
#
# Go to Start -> All Programs-> VIDLE for Vpython and open VIDLE
#
# Go to File -> Open in the VIDLE menu and navigate to this program
#
# In the VIDLE menu go to Run -> Run Module to run the program
#
# You will see a window with a plot in it
# The window will be labelled ``Thornton Vaseltarp's first vpython graph''
#
# Now read through the program and change the variable graphtitle so that 
# Thornton vaseltarp is replaced by your name - make sure you leave the quote marks " "
# alone
#
# Change the value of parameter to any number between 4 and 10
#
# Now run the program again and you will see a window labelled with your name,
# and a slightly different graph.
# 
# Click on this window and press Alt-PrintScreen together to perform a screengrab of the window
# 
# Open a blank Microsoft word document and hit ctrl-V to paste your screengrab into the document
#
# Adjust the size of the image in Word so it fits on the page
#
# Print out your graph and bruing it to lab with you.

from visual import *
from visual.graph import *  # import graphing features

# set up some parameters

graphtitle = "Thornton Vaseltarp's first visual python graph"
parameter = 6


#set up some other parameters

t_start = 0
t_end = 10*2*pi
dt = 0.01

linecolor = color.black

#and some other parameters


#create a graph
graph1 = gdisplay(x=50, y=500, width=1200, height=600,
          title=graphtitle, xtitle='t', ytitle='Position',
          foreground=color.black, background=color.white)

funct1 = gcurve(color=linecolor) 

for n in range(int((t_end-t_start)/dt)):
    t = n*dt
    funct1.plot(pos=(t-parameter*sin(t),parameter*(1-cos(t)) ))   # curve