Homework 3 Information, ECS50 Summer 2008

All parts of the assignment are due by noon on Wednesday, September 10th

Assignment:

Snake
The purpose of this assignment is to learn more about the use of interrupts, and to write a larger program in assembly language. Both are skills that can come in handy in the future. In order to develop these skills, you are going to design a game similar to the QBasic Nibbles game; it’s also known as Snakes. There are specifications which everyone's games must follow, and a list of options of which you must complete (2). You can complete additional options for extra credit.

Game Description:

In this game you are a snake which collects items (the numbers 1 – 9) in each level. Each number is generated after the previous is collected (e.g. 3 is collected by the snake and then 4 is generated), and the numbers are randomly placed on the game board (but not where the snake currently resides.) The head of the snake will be represented by a capital ‘S’, while the body is made of small letter s's. As each number is collected the snake will grow in length by one ASCII character. Further, the snake is continually moving, and cannot touch itself, or the edge of the game board. The edge of the game board will be represented by an ‘*’ - this character represents a solid barrier that the snake cannot go through. The snake will be moved via the following keys: • • •

•
 I – Up K – Down J – Left L – Right

If you attempt to reverse direction (e.g. you are going up and you press ‘K’) you essentially run into yourself and die. In other words you are only allowed to make 90 degree turns. After collecting all numbers 1 – 9 the player wins the game/level.

Here is a very crude asci drawing of what your screen might look like during play.


*************************
*                       *
*    ssssss             *
*         s             *
*         ssS   4       *
*                       *
*                       *
*************************

In essence you are doing the version of the game in the bottom right hand of the welcome screen at http://www.snakegame.net/, and then adding as many cool new things as you want.
Here are the specifications that are required:

Screen must be drawn correctly
Border of screen and all obstacles must be made of '*'
The Snake must be able to change directions
The Snake moves at a constant pace
The snake must die if it encounters any obstacle (wall, itself, etc.)
Items to collect must appear in random places in order (1-9) after they have been consumed
The snake must increase in length by one after each item is ingested
The head of the snake should be an 'S', and the body built out of 's'
Upon collecting the last number (9) the level is won, the next level will start and the Snakes speed will increase by 10% from the previous level.

Here are the options which you need to choose two or more:

Increase the speed of the Snakes movements by 50% when an 'I' is run over
Decrease the speed of the Snakes movements by 50% when a 'D' is run over
Warp the Snake to a random point on the screen when a 'W' is run over
Shrink the Snake by one ASCII character when an 'X' is run over (The I, D, W, and/or X should appear randomly on the screen after a random amount of time ranging from 20 to 30 seconds, and then disappear after 5 seconds. These effects cease after a level is won.)
Point system - the faster you beat a level the more points you get, until you die and/or you try to pick up additional items for points.
Additional levels (must look different, you can use the '*' character to generate obstacles)
Think of your own option and check if it will be okay.