ARDA (Autonomous Rabbits Dream of ARDA)

A Middle-earth-simulating cellular automaton.

Getting Things Running

Terminal Execution

While in this directory, next to src/, compile the source via makefile:

make

Then, execute the compiled program:

make run

Unit Testing

To set up testing via Eclipse, follow the steps below. Please note that the tests assume that all values in config/silmarillion.cfg are left at their published defaults, and will therefore almost certainly fail if the configuration is altered.

1. In Eclipse, create a new Java Project
2. Give it a nice, memorable, Tolkien-esque name, then click Finish
3. In the dialog offering to create modules, click Don't Create
4. Right-click the new project and select Import...
5. In the dialog, choose General > File System and click Next
6. Browse to THIS folder as the source and click Open
7. Click Select All, then Finish
8. In the Eclipse Package Explorer, open any test in src/ (e.g. test.arda.entity/EntityTest.java)
9. Hover over the red-underlined org.junit import
10. Choose the option Fix project setup
11. In the dialog offering to add JUnit to the build path, select the JUnit option and click OK
12. Run tests (any test.arda path) and profit

Design Discussion

The simulation is an interaction between Entities, who can hold Items, and move about a World.

If we think of the World as a game board, then Entities are the pieces on that board. These pieces can be either Creatures or Shrubbery (Bushes and Stones). There are also Items, but unlike Entity pieces, Items do not exist physically on the board, instead existing virtually in the Inventories of Entities. Because Items cannot exist in the physical World, there is no mechanic by which Items are “dropped”. Instead, Items simply pass from one Entity’s Inventory to another’s. Whether the receiving Entity can utilize a given Item is not guaranteed.

An Entity might be a Hobbit. A Hobbit, through Entity, has an Inventory. Inside that Inventory might be Apples, Meat, or even a Ring or some Mithril armor. Apples and Meat, being food items, restore health upon consumption by the Hobbit. The Mithril buffs defense. The Ring increases the detection range of the Hobbit, at the cost of reduced maximum health. Hobbits lose nourishment with each tick of the World, and need to eat food Items whenever they get hungry enough or else risk starving to death. Looting Bushes and slain Rabbits gives the Hobbits food to sustain themselves. Hobbits can teleport from one edge of the World to the opposite edge as if by "tunneling" or passing through a shadow realm, as it were. To complicate their existence, Hobbits are the prey of Nazgul and therefore prioritize running away from them above all other actions. Hobbits cannot attack Nazgul, nor would they loot them.

Nazgul attack Hobbits, the act of which replenishes their health. They can replicate and roam around, but need to attack Hobbits in order to avoid starving to death.

Rabbits move randomly and reproduce. Inside Rabbit’s Inventory might be some Meat. When the Rabbit is slain by a Hobbit, the Meat passes from the Rabbit’s Inventory to the Hobbit’s. Rabbits are not attacked by any other Creature.

Ents move randomly and at random intervals. They are able to move multiple spaces at a time due to their significant height. Occasionally, each Ent will spawn a Bush near its position, repopulating the World with Shrubbery.

Finally, Shrubbery Entities like Bush or Stone do not move, but still have Inventories. Inside the Inventory of a Bush might be an Apple. Inside the Inventory of a Stone might be a random powerful Item, such as the aforementioned Mithril armor. By interacting with these objects, Creatures can obtain loot to aid them in their quests. Bushes, particularly, decay over time and eventually die out. This, in combination with Ent-based Bush spawning, keeps the World comfortably vegetated.

App

• The entry point to the application and home to the main() method, this class kicks off the program by calling the Render class.

Render

• Handles the drawing of the visual simulation, ticking the World with each step of its Timer.

• Color of cells on the board signify the type of each Entity.

  • Hobbits are blue.
  • Nazgul are red.
  • Rabbits are brown.
  • Ents are bright green.
  • Stones are gray.
  • Bushes are dark green.

World

• Keeps track of all Entities on the board.
• Randomly seeds the board at the beginning of the simulation.
• Removes dead Entities from the board after they have decayed.

Entity

• Has a Coordinate, placing it in the World, as well as an Inventory to hold Items.

Creature

• Is an Entity and handles many standard operational decisions common to all Creature sub-types.

Originally written in Spring 2020