DUE: WEDNESDAY, FEBRUARY 29

PRESENTED BY: JAMES AHLUM

CSE 348 AI Game Programming

Project 2: Pathfinding in Games

The Framework

Pac-Man Developed at UC Berkeley Very well tested and documented The instructions are excellent We will focus on the search application of the

framework

The Project

Search in Pac-Man5 Tasks

Depth-first Search Breadth-first Search A* Search Transition Tables A* Food Search

Find a path to eat all dots in the map as fast as possible In-class competition to determine the winner

Setup

Download the Pac-Man Framework You can get the zip file here or from the website Unpack the zip file and store it in your desired

locationDownload Python

You want Python version 2.7.2 Download it for various OS here Select the desired installation location

Default for Windows is C:\Python27

Setup

Add Python to your Path Windows: Computer > Properties > Advanced System

Settings > Environment Variables (under Advanced Tab) Find “Path” under System Variables > Edit it and *APPEND*

C:\Python27 (or the directory where you installed Python) Note: Do not replace the Path variable with C:\Python27, just

append it using a semicolon

You should now be able to invoke the Python interpreter from the command line Open a Command Prompt, switch to the “search” directory

where you unpacked the zip file Type “python pacman.py” to test your setup

It should open a GUI where you can use arrow keys to control Pac-Man

Development

Pseudocode for the algorithms will be presented in the next lecture

The only files you should need to edit are search.py and searchAgents.py They are well commented and make it very clear

where your code needs to goAn important note from the project website:

“Each algorithm is very similar. Algorithms for DFS, BFS, and A* differ only in the details of how the fringe is managed. So, concentrate on getting DFS right and the rest should be relatively straightforward.”

Development

I recommend using the data structures in util.py Stack will be useful for depth-first search Queue will be useful for breadth-first search Priority Queue will be useful for A*

If you don’t know Python, learning it might take some time The Pac-Man projects has a tutorial that goes over the

basics and key things you’ll need to know for this project

There’s also an official Python tutorial and full documentation

Python

Data Structures Lists: list = [2, ‘a’, “string”], list[0] == 2 Tuples: pair = (1,2), pair[0] == 1 Sets: mySet = set(), mySet.add(1), 1 in mySet ==

True Dictionaries (associative arrays): f = {}, f[state] = 1.0,

where state = (x,y)Finding the length of a structure

len(“abc”) == 3, len(list) == 3Comments:

#single line comment, “””multi line comment”””

Debugging

Print to the command prompt print “message” for state in answer: print str(state)

Notice the str() method to print string representation

Log to a file file = open(‘log.txt’, ‘w’) file.write(‘log message \n’) file.close()

Deliverables

Code Email search.py and searchAgents.py to

jfa306@lehigh.edu by midnight, Wednesday, February 29

If you create any additional files (i.e. for your own data structures) or modify any existing files, also send those along with a detailed description of the additions/modifications

Presentation & Report As explained in the project description, due Thursday,

March 1

That’s All

Questions? Email jfa306@lehigh.edu with CSE348 in the subject,

CC munoz@cse.lehigh.edu