Legend of Zelda, the Pot and Boomerang Update

Objectives

• Read and understand all of the Legend of Zelda source code from Lecture 5.
• Implement healing hearts.
• Implement pots and boomerangs that can be picked up, thrown, and damage enemies.

Getting Started

Download the distribution code for your game from cdn.cs50.net/2d/2025/x/projects/5/project5.zip and unzip project5.zip, which should yield a directory called zelda.

Then, in a terminal window (located in /Applications/Utilities on Mac or by typing cmd in the Windows task bar), move to the directory where you extracted zelda (recall that the cd command can change your current directory), and run

cd zelda

A “Pot”ent Weapon

We’ve explored the workings of a top-down adventure game in the style of Legend of Zelda and have a fair foundation for anything resembling it, be it a dungeon crawler or a vast 2D game featuring an overworld or the like. Let’s add a few pieces to this sample in order to pay homage to some of the classic Zelda titles and to give our character a shot at actually surviving his trek through the dungeon!

Specification

• Implement hearts that sometimes drop from vanquished enemies at random, which will heal the player for a full heart when picked up (consumed). Much of this we’ve already done in Super Mario Bros., so feel free to reuse some of the code in there! Recall that all Entities have a health field, including the Player. The Player’s health is measured numerically but represented via hearts; note that he can have half-hearts, which means that each individual heart should be worth 2 points of damage. Therefore, when we want to heal the Player for a full heart, be sure to increment health by 2, but be careful it doesn’t go above the visual cap of 6, lest we appear to have a bug! Defining a GameObject that has an onConsume callback is probably of interest here, which you can refer back to Super Mario Bros. to get a sense of, though feel free to implement however best you see fit!
• Add pots to the game world (from the tile sheet) at random that the player can pick up, at which point their animation will change to reflect them carrying the pot (shown in the character sprite sheets). The player should not be able to swing their sword when in this state. In most of the Zelda titles, the hero is able to lift pots over his head, which he can then walk around with and throw at walls or enemies as he chooses. Implement this same functionality; you’ll need to incorporate pot GameObjects, which should be collidable such that the Player can’t walk through them. When he presses a key in front of them, perhaps enter or return, he should lift the pot above his head with an animation and then transition into a state where he walks around with the pot above his head. This will entail not only adding some new states for the Player but also ensuring a link exists (pun intended) between a pot and the character such that the pot always tracks the player’s position so it can be rendered above his head. Be sure the Player cannot swing his sword while in this state, as his hands are full!
• When carrying a pot, the player should be able to throw the pot. When thrown, the pot will travel in a straight line based on where the player is looking. When it collides with a wall, travels more than four tiles, or collides with an enemy, it should disappear. When it collides with an enemy, it should do 1 point of damage to that enemy as well. Carrying the pot is one thing; the next step would be to be able to use the pot as a weapon! Allow the Player to throw the pot, effectively turning it into a projectile, and ensure it travels in a straight line depending on where the Player is facing when they throw it. When it collides with a wall, an enemy, or if it travels farther than four tiles in that direction, the pot should shatter, disappearing (although an actual shatter animation is optional). If it collides with an enemy, ensure the pot does 1 point of damage. There are many ways you can achieve this; think about how you can extend GameObject to fit this use case, perhaps adding a projectile field and therefore a dx or dy to the GameObject to allow it to have traveling functionality. Perhaps include a :fire method as part of GameObject that will trigger this behavior as by passing in said dx and dy instead. The choice is yours, but GameObject is flexible enough to make it work!
• Spawn a chest in the dungeon that the Player can open to acquire the Boomerang. For a change of pace, let’s give our character a staple from the series. The Boomerang is in some ways similar to the pots from the prior tasks, except now we’ll have to represent it as a piece of state, the start of a primitive inventory of sorts. The Player should not start with the Boomerang, but rather, on dungeon generation, you must decide a room for a treasure chest to spawn in that the Player can interact with to open it (for which you may feel free to highlight the room on the map, accessible by pressing “M”, for debugging), after which the Boomerang will be accessible to the Player via pressing a key on their keyboard (for this problem set, let’s be traditional and make it the “E” key). The boomerang ought to proceed out in a straight line for four blocks from the Player much like a thrown pot, but rather than disappear, the Boomerang should instead make its way back to the Player, wherever they happen to be (so it therefore needs to track their position on its way back if the Player has decided to move while the Boomerang is traveling). The choice of graphic for the Boomerang is up to you; feel free to draw a graphic for it in one of the blank tiles of the provided spritesheet or select an independent graphic at your discretion. Do be sure that the graphic rotates while in the air as the Boomerang ought to in a proper Zelda title for authenticity, of course! Ensure also that the Boomerang bounces off walls (i.e., terminates its four blocks of initial travel early) should it hit any before a full four blocks of distance traveled, and it should also inflict damage to enemies and immediately return upon doing so as well. And of course, the Player should only be able to throw the Boomerang if they have it in their inventory and it’s not currently traveling; signify as much visually on the screen once the Player has obtained it via a Boomerang icon somewhere on the screen, perhaps greying it out while in flight. Much of what allowed the pot to function in the above steps should work here as well, with a few changes; best of luck!

Errata

• 2026-04-02 13:45 EDT - It is possible (in either version of the distribution code) to softlock into a complete dead-end, potentially much earlier than intended. Not intentional on our part, but also not a bug students are expected to fix. If this happens to you during testing, reset the game and try again! You will not be penalized for this bug (so long as you didn’t introduce code that intentionally causes it, instead of incidentally having it happen as may occur from time to time with our distro.)
• 2026-03-30 18:45 EDT - An bug was introduced when entering new doorways. Distribution code was updated, please use the new distro.

How to Submit

1. Download a ZIP file containing your implementation of this project.
2. Go to CSCI E-23a’s Gradescope page.
3. Click Legend of Zelda.
4. Drag and drop your downloaded file to the area that says “Drag & Drop”.
5. Click Upload.

You should see a message that your project was submitted successfully. Contact your teaching fellow if not!