|
|
COMP2720 — Lab 6 — Week 11 (16th and 17th October 2008)
Visual Python (VPython)
IMPORTANT
You should be familiar with the basics of
Visual Python by having looked at the
slides from lecture VPython-1
and the simple example program
bounce.py, and having read the Tutorial
Introduction on the
VPython Web site.
Objectives
Create simple 3D animations using Visual Python.
Marks and submission
- You will get one mark if you attend this lab, and another mark
when you show and demonstrate your working to your tutor.
- Note that we will not give you an attendance mark if you only
come to the lab for a short while.
- The mark for your lab workings will only be awarded in the lab. You
can show your workings only in this lab (as this is the last lab).
You will not receive a mark for this lab if you show it to your tutor
after the lab, unless you have a medical certificate (or similar
document) stating that you were unable to attend the normal lab.
- Please do NOT e-mail your lab workings to your tutor — we will
NOT mark e-mailed lab workings. You can only get the mark for
workings in the labs.
IMPORTANT
Note that this lab is the LAST OPPORTUNITY for you to show (and get
marks for) any lab workings. We will not consider any lab workings after
lab 6 (unless you have a medical certificate (or similar document)
stating that you were unable to attend the normal lab).
The workload in this lab is smaller that in previous labs, which should
allow you to catch up and finish your previous lab workings.
|
Preliminaries
- Once logged onto a computer, create a sub-folder called
lab6 in your folder comp2720.
- Download the lab-template.txt
and save it in your lab6 folder under the name
lab-6-diary.txt.
Please only save your lab diary as simple text file, not in RTF
or DOC format (as you will have to include your lab diaries into
your portfolio, and we will not be looking at RTF or DOC files
when assessing your
portfolio).
- Open this file lab-6-diary.txt with a text editor, and
complete the header with your details. Keep this file open and
continue writing down your workings and paste your programs
into it.
- Now copy the following file into your lab6 folder:
- Running VPython on Linux:
- Start the Konsole (aka terminal) application, by selecting
it from the Application → System
Tools → Konsole on KDE front panel menu at the bottom.
(For future ease of opening the Konsole, you can add its icon to the
front panel by double-clicking on the the front panel bar, selecting
"Add to Panel...", then choosing "Application Launcher...", the scrolling down
to "System Tools" tree node, opening it, and selecting "Konsole" icon and
pressing "Add" button.)
- In the
Terminal window, type in the command:
u1234567% idle &
which will open the IDLE shell, which will look
similar to this:
Instead of IDLE one can use any text editor, like
Kate. In this case you do not have access to the package/class
browser, and you cannot run the scripts by simply pressing "F5",
but the documentation on any available Python package
can be accessed by typing on the command-line (in Terminal window):
pydoc package_name
and the VPython scripts can be run on the command-line, like
any other Python scripts (see
below)
- In the
IDLE shell, type in the following commands:
>>> import sys
>>> sys.path.append('/sw/lib/python2.3/site-packages/visual')
>>> from visual import *
>>> sphere() # Quick test
A window with the white sphere displayed will open (a scene
in VPython). You can change and add to the displayed
"stuff" by typing VPython commands in the
IDLE shell (see examples in the lecture notes, and
in the VPython on-line tutorials and documentations).
- You can load a Python program using File.. and then
Open. A new window containing the program will open.
- You can use F5 (in the program window) to start
(run) a program (or see the Run menu).
- Once you close the scene window,
the
from visual import * declaration is gone,
and has to be retyped again if you want to continue.
This is awkward (but not my fault). The IDLE
shell also has no history mechanism (the one you've got
accustomed to while using the JES's command area).
Therefore, you can alternatively
run VPython programs, by calling the Python
interpreter on the command-line ( in Terminal window) as follows:
u1234567% cd ~/comp2720/labs/lab6
u1234567% python bounce.py
and edit your VPython scripts by using an ordinary plain text
(as suggested above) editor.
Part 1: More bouncing objects
You should spend around 70 minutes on this part of the lab.
- Open the program
bounce2.py into your favourite text editor
(NOT into JES!). Read the program and try to understand it, then
run it with VPython. See the Tutorial
Introduction on the
VPython Web site which
explains parts of this program in more details.
- Now add a yellow box to the program, with dimensions
(1, 1/3, 2/3), and a starting position different from the green
ball. The mass of the box should be 2, and it's initial
direction of movement should be different from the green ball's
movement.
- Re-run your program and debug it until the yellow box is also
correctly reflected (i.e. bouncing back) by all walls.
- Now make the yellow box rotate slowly while moving around. Set
the rotation rate to around half a full turn every second.
- Finally, add a purple ellipsoid with dimensions (1,2,3)
which rotates twice per second around its shortest dimension
and also bounces around in the box.
Part 2: Show your workings to your tutor
You should spend around 10 minutes on this part of the lab.
- Explain and show to your tutor what you have done in part 1 of
the lab, show the resulting 3D animation created, and the
programs you have developed.
- Please also show your tutor your lab diary.
Further programming ideas
|
In each lab we will provide a last section that contains ideas
for people who want to dig deeper, who are hooked on
Python or media programming. This section is not part
of the assessable lab material, but rather provides some more
problems for students who love a programming 'challenge'.
|
- Design a figure made of a head, body, arms and legs, using
different objects and the frame capabilities in
VPython (which allows you to 'glue' together different
objects into one), and make it bounce around the box.
- You might also want to try and add rotation in all thee dimensions
to the bouncing figure.
- Finally, try to add collision detection between the walls of
the box and your figure!
Last modified: 5/08/2008, 13:14
|
