CS 61B Data Structures - Project 3: BYOW
FAQ
Each assignment will have an FAQ linked at the top. You can also access it by adding “/faq” to the end of the URL. The FAQ for Project 3 is located here.
Introduction
In Project 3, you will create an engine for generating explorable worlds. This is a large design project that will require you and one partner to work through every stage of development from ideation to presentation. The goal of this project is to teach you how to handle a larger piece of code with little starter code in the hopes of emulating something like a product development cycle. In accordance with this, the grading of this project will be different from other projects. Since there is no notion of “the correct answer” when it comes to world design and implementation, you will be assessed much like a performance review you might receive at an internship or job in addition to a very general autograder. While this means you will be graded slightly subjectively, we promise to be pretty nice bosses and will respect you as any boss should respect their hardworking employees. Please talk to us if you feel the grading scheme feels unfair.
This project will require you a great deal of exploration and experimentation. Searching the web for answers (not solutions from past semesters) should be a regular activity throughout this process. Please know that there are no right and wrong answers, as this is a very open-ended project. However, there are some implementations and ideas that are better than others. It is ok and expected that you will go through several iterations before settling on something that you deem good. That is, this project is about software engineering.
You’re not required to use any of the fancy data structures or concepts from class (A*, MSTs, Disjoint Sets, etc.). This project is about software engineering, not about data structures or algorithms. The data structures and algorithms we’ve learned about in class will make your code significantly simpler and more efficient, but please don’t use things just because we learned about them in class. Only use these tools if you feel comfortable using them in your implementation.
A video playlist (from Spring 2018) discussing tips for working on this project can be found at this link. A walkthrough of the new skeleton code is also available here.
Please also note that since the structure of the project has been changed, Phase 1 will refer to part 3A of the project.
There are several key deadlines for this assignment:
- Team formation: You must submit the Project 3 Partnerships Form by Friday, November 3rd at 4:59 PM. You will not be able to change your partner later. Read and understand the partnership guidelines before starting the assignment.
- Project 3A - World Generation: Due on Gradescope by 11/13 at 11:59 PM.
- Project 3B - Interactivity: Due on Gradescope by 11/27 at 11:59 PM.
- Project 3C - Ambition & Demos: Due at Ambition Checkoff Form by 11/27 at 11:59 PM. Demos will be in lab in that week of.
Although, Project 3B & 3C are due same day, since you need to be manually checked off for “Ambition” part, we made a division between “Interactivity” and “Ambition & Demos”. Once you submit to Gradescope for 3B, your code should also have “Ambition” features because we will be asking your Gradescope submission ID from 3B in 3C Form.
You cannot submit Project 3B & 3C late, as it will be graded during a lab checkoff with a TA. While in theory you could submit 3A and the supporting labs (Lab 11 and Lab 12) late, Project 3B & 3C builds upon these assignments, so it is unlikely that you will be able to submit these assignments late and still complete Project 3B on time.
For convenience, here are the form links for this project:
- Partnerships Form
- Project 3A Reflection
- Project 3A Checkoff
- Project 3B & 3C Reflection
- Project 3C Checkoff
Now on to the assignment spec!
Overview
Your task for the next few weeks is to design and implement a 2D tile-based world exploration engine. By “tile-based”, we mean the worlds you generate will consist of a 2D grid of tiles. By “world exploration engine” we mean that your software will build a world, which the user will be able to explore by walking around and interacting with objects in that world. Your world will have an overhead perspective. As an example of a much more sophisticated system than you will build, the NES game “Zelda II” is (sometimes) a tile based world exploration engine that happens to be a video game:
The system you build can either use graphical tiles (as shown above), or it can use text based tiles, like the game shown below:
We will provide a tile renderer, a small set of starter tiles, and the headers for a few required methods that must be implemented for your world engine and that will be used by the autograder. The project will have two major deadlines. By the first deadline, you should be able to generate random worlds that meet the criteria below. By the second deadline, a user should be able to explore and interact with the world.
The major goal of this project is to give you a chance to attempt to manage the complexity that comes with building a large system. Be warned: The system you build probably isn’t going to be that fun for users! Three weeks is simply not enough time, particularly for novice programmers. However, we do hope you will find it to be a fulfilling project, and the worlds you generate might even be beautiful.
Project Setup
THE SETUP FOR THIS PROJECT IS DIFFERENT THAN THE OTHER LABS / PROJECTS. PLEASE DO NOT SKIP THIS STEP!
Group Repository Setup
You’ll be working exclusively in a group repository for this portion of the project. To set this group repo up on your local computer, follow the instructions below (these are also in the spec):
- Go to your email and accept the GitHub repo invite that you should have received.
- Log in to Beacon, and click on the “Groups” tab. You should have a group listed here.
- Click the “View Repository on GitHub” link.
- You’ll now be taken to your new repository on GitHub. You will have an empty repository. Copy the clone link shown in the text bar (blacked out in the screenshot).
- Open a new Terminal window, and navigate to the directory that you store your CS 61B files in (usually, students have a directory called
cs61b).
IMPORTANT: Do not cd into your fa23-s**** repo! You should not be cloning the group repo inside of your personal 61b one.
- Type the following commands into your terminal, and hit Enter after each one:
git clone <paste your link from GitHub here>
cd fa23-proj3-g*** // Replace the *** here with your group repo number
git remote add skeleton https://github.com/Berkeley-CS61B/proj3-skeleton-fa23.git
git pull skeleton main --allow-unrelated-histories
Once you’ve completed the above steps, you should see your new group repo called fa23-proj3-g***in your local files, and if you open this repo, you’ll see the proj3 skeleton folder. From here, you and your partner can proceed as normal, by adding, committing, pushing, and pulling from this repo as you would otherwise.
Skeleton Code
Use git pull skeleton main in your group repo to pull the skeleton code. The skeleton code contains two key packages that you’ll be using: TileEngine, Core and Utils. TileEngineprovides some basic methods for rendering, as well as basic code structure for tiles, and contains:
TERenderer.java- contains rendering-related methods.TETile.java- the type used for representing tiles in the world.Tileset.java- a library of provided tiles.
IMPORTANT NOTE: Do NOT change TETile.java’s character field or character() method as it may lead to bad autograder results.
The other package Core contains everything unrelated to tiles. We recommend that you put all of your code for this project in the Core package, though this not required. The Core package comes with the following classes:
AutograderBuddy.java- Provides two method for interacting with your system.TETile[][] getWorldFromInput(String input)simulates the game without rendering by returning the world that would result if the input string had been typed on the keyboard. You should fill this out for autograder.Main.java- How the user starts the entire system. Reads command line arguments and calls the appropriate function inWorld.java.World.java- YOUR WORLD!
This is a open ended project. As you can see, we gave you just one file called World.java where you can do necessary things to create your world! The aim of this project to give you freedom to create your own world with different desing choices. You can create any other classes if you want. Primarly, you can use World.java for the logic behind your world creation.
The last package Utils contains everything that you might need to implement your World.javaclass.
RandomUtils.java- Provides handful of functions that might be useful.FileUtils.java- Library of simple file operations. You can find related APIs here and here.
This project makes heavy use of StdDraw, which is a package that has basic graphics rendering capabilities. Additionally, it supports user interaction with keyboard and mouse clicks. You will likely need to consult the API specification for StdDraw at some points in the project, which can be found here.
Your project should only use standard java libraries (imported from java.*) or any libraries we provided with your repo. Your final submission for 3B and 3C should not use any external libraries other than the ones provided in the skeleton.
IMPORTANT NOTE: Do NOT use static variables unless they have the final keyword! In 2018, many students ran into major debugging issues by trying to use static variables. Static non-final variables add a huge amount of complexity to a system. Additionally, do not call System.exit() in getWorldFromInput as this will cause the autograder to exit and fail.
3A: World Generation
As mentioned above, the first goal of the project will be to write a world generator. The requirements for your world are listed below:
- The world must be a 2D grid, drawn using our tile engine. The tile engine is described in lab11.
- The world must be pseudo-randomly generated. Pseudo-randomness is discussed in lab 11.
- The generated world must include distinct rooms and hallways, though it may also include outdoor spaces.
- At least some rooms should be rectangular, though you may support other shapes as well.
- Your world generator must be capable of generating hallways that include turns (or equivalently, straight hallways that intersect).
- All rooms should be reachable, i.e. there should be no rooms with no way to enter
- The world should be substantially different each time, i.e. you should NOT have the same basic layout with easily predictable features. FAQ will have a description of what “substantially different” means.
As an example of a world that meets all of these requirements (click for higher resolution), see the image below. In this image, # represents a wall tile, a dot represents a floor tile, and there is also one golden colored wall segment that represents a locked door. All unused spaces are left blank.
Once you’ve completed lab 11, you can start working on your world generation algorithm.
It is very likely that you will end up throwing away your first world generation algorithm. This is normal! In real world systems, it is common to build several completely new versions before getting something you’re happy with. The room generation algorithm above was my 3rd one, and was ultimately much simpler than either of my first two.
You’re welcome to search the web for cool world generation algorithms. You should not copy and paste code from existing games or graphical demos online, but you’re welcome to draw inspiration from code on the web. Make sure to cite your sources using @source tags. For inspiration, you can try playing existing 2D tile based games. Brogue is an example of a particularly elegant, beautiful game. Dwarf Fortress is an example of an incredibly byzantine, absurdly complex world generation engine.
Tileset and Tile Rendering
The tile rendering engine we provide takes in a 2D array of TETile objects and draws it to the screen. Let’s call this TETile[][] world for now. world[0][0] corresponds to the bottom left tile of the world. The first coordinate is the x coordinate, e.g. world[9][0] refers to the tile 9 spaces over to the right from the bottom left tile. The second coordinate is the y coordinate, and the value increases as we move upwards, e.g. world[0][5] is 5 tiles up from the bottom left tile. All values should be non-null, i.e. make sure to fill them all in before calling renderFrame. Make sure you understand the orientation of the world grid! If you’re unsure, write short sample programs that draw to the grid to deepen your understanding. If you mix up x vs. y or up vs. down, you’re going to have an incredibly confusing time debugging.
We have provided a small set of default tiles in Tileset.java and these should serve as a good example of how to create TETile objects. We strongly recommend adding your own tiles as well.
The tile engine also supports graphical tiles!
Any TETile object you create should be given a unique character that other tiles do not use. Even if you are using your own images for rendering the tile, each TETile should still have its own character representation.
If you do not supply a filename, or the file cannot be opened, then the tile engine will use the unicode character provided instead. This means that if someone else does not have the image file locally in the same location you specified, your world will still be displayed, but using unicode characters instead of textures you chose.
The tile rendering engine relies on StdDraw. We recommend against using StdDraw commands like setXScale or setYScale unless you really know what you’re doing, as you may considerably alter or damage the a e s t h e t i c of the system otherwise.
Starting Your Program
Your program will be started by running the main method of the Main class. You will see that this method will render your program and will provide interactivity for you in the future. On top of that, in order to test your world, for 3A, your project must support getWorldFromInput. Specifically, you should be able to handle an input of the format "N#######S" where each # is a digit and there can be an arbitrary number of #s. This corresponds to requesting a new world (N), providing a seed (#s), and then pressing S to indicate that the seed has been completely entered. The logic between your world generation in Main class and getWorldFromInput method should be similar. While you should render your program in Main, you should not do that in getWorldFromInput since this will be used for Autograder.
Finally, we recommend that you make minimal modifications to the core.Main class. It is a much better idea to delegate all the work of the program to other classes you will create.
When your core.Main.main() method is run, your program must display a Main Menu that provides at LEAST the options to start a new world, load a previously saved world, and quit. The Main Menu should be fully navigable via the keyboard, using N for “new world”, L for “load world”, and Q for quit. You may include additional options or methods of navigation if you so choose.
After pressing N on the keyboard for “new world”, the user should be prompted to enter a “random seed”, which is a long value of their choosing. This long data type will be used to generate the world randomly (as described later and in lab 12). 9,223,372,036,854,775,807. There is no defined behavior for seeds larger than this.
The behavior of the “Load” command is described later in this specification call getWorldFromInput("N3412S"), your program should generate a world with seed 3412 and return the generated 2D tile array. Note that letters in the input string can be upper or lower case and your engine should be able to accept either keypress (i.e. “N” and “n” should both initiate the process of world generation). You should ** NOT** render any tiles or play any sound when using getWorldFromInput.
If you want to allow the user to have additional options, e.g. the ability to pick attributes of their character, specify world generation parameters, etc., you should create additional options. For example, you might add a fourth option “S” to the main menu for “select creature and create new world” if you want the user to be able to pick what sort of creature to play as. These additional options may have arbitrary behavior of your choosing, however, the behavior of N, L, and Q must be exactly as described in the spec!
Requirements
For 3A, you should be able to run Main.main by providing an input String, and have your program create a world, that adhere to the requirements mentioned above along with our randomness requirements mentioned in the Submission and Grading section below. Note that you should render the world to check your code by writing your own main method, but for the autograder, getWorldFromInput should not render the world, only returning the world as a TETile array. Worlds should be visibly different for different seeds provided to the program.
Design Document
Since we did not provide you with any significant skeleton code for Project 3, and since the project is very open-ended, we expect that BYOW implementations will vary a fair amount between students. We recommend that you have a design document that reflects the current state of your project.
Before you begin writing any code, use the guidelines listed here to create a plan for every feature of your BYOW program, and convince yourself that your design is correct. Writing a design document is an iterative process. After coming up with your initial design, you may find some flaws in it, requiring you to revisit your design and update its description according to your new findings.
Note: Your design document will NOT be graded.
Design Document Guidelines
You may use the following format for your BYOW design document.
Design Document Sections
1. Classes and Data Structures
Include here any class definitions. For each class, list the instance variables (if any). Include a brief description of each variable and its purpose in the class.
2. Algorithms
This is where you describe how your code works. For each class, include a high-level description of the methods in that class. That is, do not include a line-by-line breakdown of your code, but something you would write in a javadoc comment above a method, including any edge cases you are accounting for.
3. Persistence
You should only tackle this section after you are done with 3A. This section should describe how you are going to save the state of a world, and load it again, following the requirements in the spec. Again, try to keep your explanations clear and short. Include all the components your program interacts with - classes, specific methods, and files you may create. You can check out lab 11.
3B: Interactivity
In the second part of the project, you’ll add the ability for the user to actually interact with the world, and will also add user interface (UI) elements to your world to make it feel more immersive and informative.
The requirements for interactivity are as follows:
- The user must be able to control some sort of “avatar” that can moved around using the W, A, S, and D keys. By “avatar”, we just mean some sort of on-screen representation controlled by the user. For example, in my project, I used an “@” that could be moved around.
- The avatar must be able to interact with the world in some way.
- Your system must be deterministic in that the same sequence of key-presses from the same seed must result in exactly the same behavior every time. Note that a
Randomobject is guaranteed to output the same random numbers every time. - In order to support saving and loading, your program will need to create some files in your
proj3directory (more details later in the spec and in the skeleton code). The only files you may create must have the suffix “.txt” (for example “save-file.txt”). You will get autograder issues if you do not do this.
Optionally, you may also include game mechanics that allow the user to win or lose. Aside from these feature requirements, there will be a few technical requirements for your system, described in more detail below.
UI (User Interface) Appearance
After the user has entered a seed and pressed S, the world should be displayed with a user interface. The user interface of your project must include:
- A 2D grid of tiles showing the current state of the world.
- A “Heads Up Display” (HUD) that provides additional information that maybe useful to the user. At the bare minimum, this should include Text that describes the tile currently under the mouse pointer. This should not be flickering, if it flickers you won’t be able to receive credit.
As an example of the bare minimum, the simple interface below displays a grid of tiles and a HUD that displays the description of the tile under the mouse pointer (click image for higher resolution):
As an example, the game below (click image for higher resolution) uses the GUI to list additional valid key presses, and provides more verbose information when the user mouses-over a tile (“You see grass-like fungus.”). The image shown below is a professional game, so we do not expect your project to have this level of detail (but we encourage you to try for some interesting visuals).
For information about how to specify the location of the HUD, see the initialize(int width, int height, int xOffset, int yOffset) method of TERenderer or see lab 11.
UI Behavior
After the world has been generated, the user must be in control of some sort of avatar that is displayed in the world. The user must be able to move up, left, down, and right using the W, A, S, and Dkeys, respectively. These keys may also do additional things, e.g. pushing objects. You may include additional keys in your engine. The avatar should not move when attempting to move into a wall and the program should not error.
The system must behave pseudo-randomly. That is, given a certain seed, the same set of key presses must yield the exact same results!
In addition to movement keys, if the user enters :Q (note the colon), the program should quit and save. The description of the saving (and loading) function is described in the next section. “quit/saving”. This command is not case-sensitive, so :q should work as well. Additionally, :followed by any other letter should not do anything.
This project uses StdDraw to handle user input. This results in a couple of important limitations:
StdDrawdoes not support key combinations. When we say:Q, we mean:followed byQ.- It can only register key presses that result in a char. This means any unicode character will be fine but keys such as the arrow keys and escape will not work.
- On some computers, it may not support holding down of keys without some significant modifications; i.e. you can’t hold down the e key and keep moving east. If you can figure out how to support holding down of keys in a way that is compatible with
getWorldFromInput, you’re welcome to do so.
Because of the requirement that your system must handle String input (via getWorldFromInput), your engine cannot make use of real time, i.e. your system cannot have any mechanic which depends on a certain amount of time passing in real life, since that would not be captured in an input string and would not lead to deterministic behavior when using that string vs. providing input with the keyboard. Keeping track of the number of turns that have elapsed is a perfectly reasonable mechanic, and might be an interesting thing to include in your world, e.g. maybe the world grows steadily darker with each step. You’re welcome to include other key presses like allowing the user to press space bar in order to wait one turn.
Saving and Loading
Sometimes, you’ll be exploring your world, and you suddenly notice that it’s time to go to watch a CS 61B lecture. For times like these, being able to save your progress and load it later, is very handy. Your system must have the ability to save the state of the world while exploring, as well as to subsequently load the world into the exact state it was in when last saved.
Within a running Java program, we use variables to store and load values. Keep in mind that when your program ends, all the variables will go out of scope. Thus, you will need to persist the state of your program on some files that your program should create.
When the user restarts core.Main and presses L, the world should be in exactly the same state as it was before the project was terminated. This state includes the state of the random number generator! More on this in the next section. In the case that a user attempts to load but there is no previous save, your system should simply quit and the UI interface should close with no errors produced.
In the base requirements, the command :Q should save and completely terminate the program. This means an input string that contains :Q should not have any more characters after it and loading a world would require the program to be run again with an input string starting with L.
Interacting With Input Strings
Your getWorldFromInput(String input) must be able to handle input strings that include movement.
For example, the string N543SWWWWAA corresponds to the user creating a world with the seed 543, then moving up four times, then left twice. If we called getWorldFromInput("N543SWWWWAA"), your system would return a TETile[][] representing the world EXACTLY as it would be if we’d used main and typed these keys in manually. Since the system must be deterministic given a seed and a string of inputs, this will allow users to replay exactly what happened for a given sequence of inputs. This will also be handy for testing out your code, as well as for our autograder.
getWorldFromInput(String s) must also be able to handle saving and loading in a replay string, e.g. N25SDDWD:Q would correspond to starting a new world with seed 25, then moving right, right, up, right, then quit/saving. then return the 2D TETile[][] array after the fourth move.
Your world should not change in any way between saves, i.e. the same exact TETile[][] should be returned by the last call to getWorldFromInput for all the following scenarios:
getWorldFromInput(N999SDDDWWWDDD)getWorldFromInput(N999SDDD:Q),thengetWorldFromInput(LWWWDDDthengetWorldFromInput(L:Q)thengetWorldFromInput(LWWWDDD)
we then called getWorldFromInput with input L:Q, we’d expect the exact same world state to be saved and returned as TETile[][] as with the previous call where we provided LDDDD.
You do not need to worry about replay strings that contain multiple saves, i.e. N5SDD:QD:QDD:Q is not considered a valid replay string, since the program should have terminated before the second :Q. You do not need to worry about invalid replay strings, i.e. you can assume that every replay string provided by the autograder starts with either N#S or L, where # represents the user entered seed.
The return value of the getWorldFromInput method should not depend on whether the input string ends with :Q or not. The only difference is whether the world state is saved or not as a side effect of the method.
3C: Ambition & Demos
28 points of your project score will be based on features of your choosing, which we call your “ambition score”. The big idea is that beyond the base requirements of this project, we want you to try to polish your product a bit more and add some cool features. This “ambition” category is only worth 28 points. If you do, e.g., 35 points worth, you do not get extra credit. However, feel free to add as many features as you’d like if you have the time and inclination.
Under the description of some primary features, we’ve provided some GIFS that would score full points on their respective ambition point items to help clear any confusions. Yours do not need to look exactly like the examples given.
21 Points Primary Features
- Create a system so that the tile renderer only displays tiles on the screen that are within the line of sight of the avatar. The line of sight must be able to be toggled on and off with a keypress. (The line of sight GIF below is a more complex version that involves bending around corners; we have also seen versions where it is just a square of light around the avatar).
- Add the ability for light sources to affect how the world is rendered, with at least one light source that can be turned on and off with a keypress.
- Add entities which chase the avatar/other entities by use of a search algorithm from class, with a toggle to display their projected path.
- Create a system for “encounters”, where a new interface appears when the avatar interacts with entities in the world, returning the avatar to the original interface when the encounter ends (e.g. Pokémon).
- Add the ability for the user to “replay” their most recent save, visually displaying all the actions taken since the last time a new world was created. This must result in the same final state as would occur if the user had loaded the most recent save. This means that the game should be playable once the replay is complete.
- Add the ability for the user to change the perspective of their view (first-person, isometric 2.5D, 3D, etc.) (We’ve never seen anyone do isometric 2.5D or full 3D before! The Nintendo 64 game ‘Kirby 64 - The Crystal Shards’ is an example of what an isometric 2.5D world looks like). One particularly interesting example is Dorottya Urmossy and David Yang’s Fall 2022 submission, which is a 2.5D first-person view, i.e. the world is 3D but the entities are 2D.
7 Points Secondary Features
- Add multiple save slots that can be accessed with a new menu option, and a new keyboard shortcut to save to a slot other than slot 1. You should be careful to still support the default behavior of saving and loading in order to be consistent with the replay string requirements.
- Add the ability to create a new world without closing and reopening the project, either as a special option you can press while exploring, or when you reach a “game over” state if you’ve turned your world into a game.
- Add a menu option to change all text in the interface to a different language. English should be the default and there should be a way to switch it back to English.
- Add support for mouse clicks on the main menu for anything that can be done with a keypress on the main menu.
- Add ability to rotate the world, i.e. turn the board 90 degrees and adjust movement keys accordingly.
- Add a display of real date and time in the Heads-Up Display.
- Add support for movement with mouse clicks on any visible square. You’ll need to implement some sort of algorithm for pathfinding.
- Add support for 2 users to interact at the same time. This will require that you have two avatars on screen which can move around, and they should have separate control schemes.
- Add support for undoing a movement (even moves that occurred in a previous save before the current one was loaded). Undoing a movement should reset the world back to before the most recent keypress but should add to the replay string instead of removing a character (i.e. undo command should be logged in the replay string).
Requirements Summary
Here is a list of the requirements and restrictions on your project. Please note that this section does not substitute reading the entire spec since there are a lot of details which are not captured here.
- When using
main, your program must have a menu screen that has New World (N), Load (L), and Quit (Q) options, navigable by the keyboard, which are all not case-sensitive. - When entering New World, the user should enter an integer seed followed by the S key. Upon pressing S, the world should be generated and displayed.
- The UI should show the numbers entered so far when the user is giving the seed.
- Users must be able to press “:Q” to quit, and after starting the program up again, the L option on the main menu should load the world state exactly as it was before.
- All random events should be pseudorandom. That is, your program gives deterministic behavior given a seed.
- Users must be able to interact using
getWorldFromInput, and behavior other than accepting input and drawing to the screen should be identical tomain. getWorldFromInputmust return aTETile[][]array of the world at the time after the last character in the string is processed.getWorldFromInputmust be able to handle saving and loading, just likemain.- Your program must use our
TileEngineandStdDrawfor displaying graphics. - Your program must have a HUD, which displays relevant information somewhere outside the area displaying the world/tiles.
- HUD must display a description of tile upon hovering over the tile.
- Your program must not use real time. Nothing should be moving if no input is being received.
- Your program must include features that make up 28 points from the Ambition categories, with at least one primary feature.
