COMP 1010 Fall 2011 Assignment 1CS3413 Winter 2023 Assignment 2 Page 1 of 6CS3413 Winter 2023 Assignment 2 Due: Mar. 03th, 11:59PM Notes and Style • must be written in C. No C++ • The...

You will make a text version of the classic video game “centipede.” The rules for the game are simple: kill all the caterpillars before they kill you. The problem is, these are space caterpillars (and you are in a space ship) – when you shoot them, they split at the point they were hit, and now you have two smaller caterpillars!


COMP 1010 Fall 2011 Assignment 1 CS3413 Winter 2023 Assignment 2 Page 1 of 6 CS3413 Winter 2023 Assignment 2 Due: Mar. 03th, 11:59PM Notes and Style • must be written in C. No C++ • The prof has provided a working demo in D2l (a2demo executable <- change="" permissions="" when="" copied="" to="" your="" fcs="" machine="" with="" chmod="" u+x="">) • your assignment code must be handed in electronically using the D2L drop box. Try early and re-submit later. • Include a Makefile. If “make” doesn’t compile and produce an executable, your assignment will not be marked • You make file should also include a “make run” and “make clean” command that runs your executable and removes all files resulting from compilation • Your program must run. Programs that do not run, or segfault before working at all, will lose 50%. Save early and often, and use version control. Submit often, only submit working versions. • Your program must compile with –Wall, with no warnings showing. You will lose marks for warnings and lose marks for not compiling with -Wall in your makefile • Include a “listing” file, a single .txt file with all your source files concatenated into it. Good header text in EACH file is imperative here. E.g. cat *.h *.c | listing.txt • Use common-sense commenting and good style, practices. Provide function headers, comment regions, etc. No particular format or style is required but bad programming practices will result in marks docked (e.g., huge complicated functions, unreadable code, magic numbers, bad variable names, etc). • Error checking is extremely important in real world OS work, and you must do it rigorously. Error handing, however, is hard in C. Try to handle gracefully when you can, but for hard errors (out of memory, etc.), hard fail (exit) is OK. • Test on FCS computers with their version of gcc, make sure your Makefile uses the one you tested. • Your assignment will be tested on FCS computers. Attack of the Poisonous Fredericton Caterpillars You will make a text version of the classic video game “centipede.” The rules for the game are simple: kill all the caterpillars before they kill you. The problem is, these are space caterpillars (and you are in a space ship) – when you shoot them, they split at the point they were hit, and now you have two smaller caterpillars! To save explanation, try running a sample of the program (how yours will act) on AN FCS computer using the precompiled executable on D2L. (a3demo). When you copy it over you will probably need to give it executable permissions (chmod u+x a3demo) wasd controls for up/left/down/right), space to fire, and q quits. This assignment seems large, but can be broken down into many small components that are, on their own, easy to create. The tough part will be making them all run together with threads and managing resources with mutexes! Take your time reading through this, tackle one small problem at a time, and review this document throughout your work! Synopsis: CS3413 Winter 2023 Assignment 2 Page 2 of 6 - Have a player spaceship that the player can control using w, a, s, d, around a restricted space at the bottom of the screen. The player spaceship must animate. - Generate caterpillars starting at the top of the screen, at some random interval. They go left to right (or opposite), and when they hit an end, they go to the next row and change direction. Note in the sample how they wrap around (tricky logic). Caterpillars must animate graphics in addition to move. - If the player presses space, a bullet fires from the player toward the top of the screen. If it goes off the screen, it is destroyed. If it hits a caterpillar, the caterpillar splits into two at that spot, and you now have two caterpillars, with the new one going faster than the old one by some multiple. If one of the two caterpillars is below a minimum size (e.g., 5), it dies. The player has a reasonable maximum fire rate (e.g., once per n ticks). - The caterpillars randomly shoot from their head at the player. - When the player is hit, pause the game briefly and kill all the bullets (but leave the caterpillars) to avoid unfair re-spawn deaths. If the player is hit, they lose a life. When no lives are left, the game is over. - The player wins if there are no caterpillars left on screen. - The program must quit properly by joining all threads, until only the main one is left, and freeing memory, and quickly. The final “Done” text must appear on the console as in the provided main and sample. This is to highlight that you did not just use an exit() call. Every time you create a thread, you MUST think: who will join it and when? This is to make scalable, reusable programs. For the same reasons, you must free all memory properly. - There must be no evident race conditions or deadlock conditions. - Game mechanics will not be a major concern, e.g., left-over dead aliens, exact speeds, etc. Collision detection (e.g., bullets hitting the player or caterpillars) must be perfect to help test for race conditions. REQUIRED programming components: As this is a threading assignment, you need the following (to make it hard enough!)  You will create (at least) the following threads. You may find it useful to make additional ones to help you. Threads must be joinable (default), and cannot be detached (man pthread_create). ➢ a thread for the player. This handles the player animation and other things, e.g., what happens when the player is shot. ➢ a thread for the keyboard. This requires its own thread so it can block while the rest of the program runs. This is quite tricky because you will have to use the “select” command (man select): it blocks until there is data on a stream, or on a timeout. Here is the problem: if you use getchar, it blocks. While it is blocking, the game may end (you get shot). However, until getchar unblocks that thread cannot end. Using select, you can time out regularly to check if the game is over before blocking again. I have provided a working example using the command, but you should try to understand it by reading the man page for pselect. ➢ a thread to re-draw the screen / perform a refresh using the command in the provided console code. Do not do refreshes each time you draw, only here. CS3413 Winter 2023 Assignment 2 Page 3 of 6 ➢ An upkeep thread, that puts updated score and player lives to screen, checks if there are no enemies left, and does regular cleanup (such as delete memory left behind for dead bullets and caterpillars, maybe). ➢ A thread that spawns new caterpillars at a regular (but somewhat random) interval. ➢ a new thread for EACH caterpillar. The thread lives until the caterpillar is shot and killed. Using a single thread for all the caterpillars is not acceptable. When a caterpillar splits, a new thread is started for the new caterpillar. ➢ a new thread for each bullet (yours and caterpillars’!), which lives until the bullet gets consumed into an enemy or you, or until it leaves the screen. ➢ a main program (not in main.c!) that starts everything and then sleeps using a condition variable (pthread_cond_wait). When the game ends this thread is woken up (pthread_cond_signal) and cleans up. You must use a condition variable and signal here for the assignment.  Dynamically managed (malloc/free) linked lists: these are very thread un-friendly. At least one list for the bullets, and one list for the caterpillars. No storing in arrays, etc. In a real game engine, you would likely have fewer threads, e.g., one thread for enemy AI, one thread for input, etc. However, games are highly multithreaded and have a lot of concurrency issues. Making a game engine is a lot like making a simple OS as well: there is a core set of functions that control access to game resources and keeps track of states of other parts. Then, the actual game components (player, enemies, etc) will access those through the engine. This assignment should require more thinking about the engineering and planning of your solution than normal, but it is perhaps algorithmically more straight forward than A1, as each individual component (e.g., make a player move) is relatively simple. Have fun! There’s a lot up to you (redesign the spaceship or enemy look, manage difficulty, etc). Your caterpillars may just be simple chains of ascii characters that animate a bit, or they may be more like as seen in the example, larger and stranger looking. Want to add other enemy types? Go for it! There are no game aesthetic or marks for “fun” factor, but it can feel good to make something you’re proud of. Handout: You have been provided with a console.h/console.c library that provides text- mode functions for you and a sample program. Be sure to compile with the –lcurses flag to link to the curses (text graphics) library, and the –pthread flag to link to the posix-threads library. Console.h has a lot of comments to explain how to use each function. Definitely use these in your solution. They are provided so you don’t have to worry about “graphics” and drawing to screen here. An example and main.c (in “distribute” with console.h/c) will help you see how this is used.  This library is simple to use (see the examples included in my distribute sample code). There is a screen buffer off screen. You draw to the buffer using the commands detailed in the library. To have the changes reflected to screen, use the refresh command. To move, e.g., the player, you first draw a blank square where the player WAS and then draw the player at its new location.  This library contains a sleep function that sleeps for the given number of ticks, where a tick is 10ms. Use this in your thread loops, e.g., to set the speed of CS3413 Winter 2023 Assignment 2 Page 4 of 6 screen redraw (1 tick?), alien animation, movements, etc. Most of your threads will be loops that sleep before checking for more work.  note that you can alter speeds simply by making each sleep longer or shorter.  this library is not thread safe! (e.g., it is non-re-entrant) Create a mutex and make sure to lock it before using ANY screen calls. Not ensuring mutual exclusion will yield funny results.  You shouldn’t really need to look at the Console.c file, and there are limited comments in it. All information you need is documented in the .h file. Distribute I have included a “distribute” package which includes multiple files. There is a rough make and sample set up to get you started – feel free to use and edit these as necessary (though, as mentioned, you shouldn’t need to read or edit Console.c…you will need to compile it into your program, so I am including it here). The main example file contains a sample enemy, gameboard, and 3 examples of how to perform basic tasks in this environment. They are NOT thread safe examples necessarily, so they are commented out. Uncomment the example you want to see run, make, and try it out! Some will break, to showcase why mutexing, especially the screen resource (a shared, critical resource) is important, and how it could make nonsensical output when race conditions occur. These examples should be either useful or fixable (and then useful) for you. You can use them, delete them, or reference them in your final code. In other words, they should help act as building blocks or simple examples for your final assignment. They are designed after looking at common problem points getting started for students in my prior sections of this course. If you need help understanding them, send me an email or come talk in office hours. Hints: - KEEP FINE-GRAINED MUTEXING, e.g., only lock each caterpillar, the player, the screen, a list, etc.,