Undefined-Game-Engine

Note: JDK Version 17

Summary

Undefined is a 2D Game Engine built in Java, designed to allow users to create, edit, and play games.

How to Run Game

• To run the program, run app/Main
• IMPORTANT: need to include "UNSPLASH_ACCESS_KEY=OSHzuf4ybMZXfL1ddpzvxGCZ-yMMfcb2TmY2ys7VpTM" in environment variables for Unsplash API to work

Game Engine Capabilities Guide

1. Asset Management (Adding Images)

You can import images to be used as sprites for your game objects.

What you can do:

• Import Local Files: Load images (.png, .jpg, .jpeg) from your computer.
• Import from Unsplash: Search for and download images directly from the Unsplash API.
• Manage Assets: View a list of imported sprites in the "Assets" panel.

How to do it (in the Editor):

1. Look for the "Assets" panel on the left sidebar.
2. Click the "+" (Add) button in the Sprites header.
3. Select either "Import from Local" to browse files or "Import from Unsplash" to search online.
4. Once imported, the sprite appears as a card in the list. Clicking it adds it to the scene as a new GameObject.

2. Game Object Properties

You can modify the physical and visual attributes of Game Objects in the scene.

What you can do:

• Transform: Change position (X, Y), rotation, and scale.
• Sprite Rendering: Change the sprite image, toggle visibility, adjust opacity, and set Z-Index (layering).

How to do it:

1. Select a GameObject in the Scene view (center panel) by clicking on it.
2. The Properties Panel on the right side will update.
3. Edit the fields in the Transform section to move/resize the object.
4. Use the Sprite Renderer section to swap the image or change opacity.

3. Game Logic (Scripting)

You can define interactive behavior using a Trigger system without writing raw code.

What you can do:

• Create Triggers: Define "When [Event] happens, if [Condition] is true, do [Actions]".
• Events: On Click, On Key Press.
• Conditions: Compare numbers (>, =, etc.) or booleans to decide if actions should run.
• Actions:
  • Wait: Pause execution.
  • Assign: Change variable values.
  • Change Position: Move objects.
  • Change Visibility: Hide/show objects.

How to do it:

1. With an object selected, look at the Trigger Manager in the Properties Panel.
2. Click "+" to add a new Trigger.
3. Select an Event (e.g., "On Click").
4. Add Conditions (optional) and Actions using their respective "+" buttons.
5. Click the Edit (Pencil) button on an action/condition to open the script editor dialog and define the logic.

4. Variables

You can store data (like health, score, or flags) to manage game state.

What you can do:

• Global Variables: Shared across the entire game (e.g., PlayerScore).
• Local Variables: Specific to a single object (e.g., MyHealth).
• Types: Supports Numeric (doubles) and Boolean (true/false).

How to do it:

1. In the Properties Panel, scroll to the Variable Section.
2. Click the "+" button next to "Global Variables" or "Local Variables".
3. Enter a name and initial value.

5. Preview & Testing

You can play the game instantly to test your logic.

What you can do:

• Launch a standalone window running the current scene.
• Interact with objects using the defined Events (Click, Key Press).
• Switch between Sprite Mode (visuals) and Button Mode (debug buttons).

How to do it:

1. Click the Green Play Button (▶) in the top toolbar of the editor.
2. A new window will open running the game loop.
3. Click the Stop Button (■) to close the preview.

Core Project Data Hierarchy

• Project: The root container, managing Scenes, Assets, and a Global Environment.
• Scene: Contains a list of GameObjects.
• GameObject: The fundamental entity representing items in the game. Each has:
  • Transform: Position (X, Y), Rotation, and Scale.
  • SpriteRenderer: Renders images (sprites) with properties like visibility, opacity, and Z-index.
  • TriggerManager: Handles game logic via scripts.
  • Environment: Stores local variables specific to the object.

List of User Stories

• User story 1: As a user, I want to be able to create my own unique sprites, so that I can customize my game’s characters and objects to my liking.
• User story 2: As a user, I want game objects to be interactable during gameplay, so that I can create a more diverse and interactive experience for players.
• User story 3: As a user, I want to be able to change and adjust the properties of the components so that I can customize the appearance and behavior according to my preference.
• User story 4: As a user, I want to add different scenes to my game.
• User story 5: As a user, I want to be able to test my game before releasing / publishing it.
• User story 6: As a user, I want my game to autosave, so I can work on my project at another time.

API Information

• This project utilizes the Unsplash API to fetch images that can be used within the game engine.
  • Link to documentation: Unsplash API Documentation.
  • DONT FORGET TO CONFIGURE YOUR API KEY SO THAT ALL FEATURES WORK AS INTENDED

Software Design Principles

1. Open–Closed Principle (OCP) & Extensibility

Goal: Enable future developers to add gameplay capabilities (Conditions, Actions, Expressions) without modifying existing code.

• Abstract Base Classes: The system uses abstract classes to define the required behavior for all gameplay logic elements.

  • Implementation: Every specific logic type inherits from one of these base abstractions:
    • Condition (e.g., NumericComparisonCondition)
    • Action (e.g., WaitAction, ChangeVisibilityAction)
    • Expression (e.g., NumericExpression)

• Factory Design Pattern: Factories are used to manage the creation of these objects dynamically.

  • Registry Map: Each factory (ConditionFactory, ActionFactory, DefaultVariableFactoryRegistry) maintains a map pairing a unique name (key) with a supplier function (value).
  • Functionality:
    • Automatically lists available types for the Editor UI to populate menus.
    • Constructs the correct instance based on user selection without hardcoded switch statements in the client code.
  • Reference: See ConditionFactory and ActionFactory.

• Workflow for New Features:

  1. Inherit: Create a new subclass extending the appropriate abstract base class.
  2. Register: Add the new type to the Factory’s registry map.
  • Result: The system is open for extension (new features can be added) but closed for modification (core logic remains untouched).

2. Single Responsibility Principle (SRP) & Architecture

Context: Adherence to SRP is a direct result of implementing Clean Architecture.

• Separation of Concerns: Business logic is strictly separated into distinct Use Case classes, preventing "God classes" that handle too many responsibilities.
• Granular Use Cases: Operations are broken down into specific classes:
  • Trigger Management: Handled by specific interactors like TriggerCreateInteractor and TriggerDeleteInteractor.
  • Scene Management: Split into isolated actions such as CreateSceneInteractor, ListScenesInteractor, and SelectSceneInteractor.

Screenshots/DEMO