README

Overview

DemoApp01 is a modular Java demo application focused on game/physics concepts, featuring scene management, entities, behaviors, and graphical rendering. It highlights an extensible and configurable architecture.

What's New

• Entity-Component-Behavior architecture (simplified ECS)
• Dynamic scene management (e.g., DemoScene)
• Rendering system with plugins (layers, debug, world, objects...)
• Simple physics engine (gravity, materials)
• Advanced keyboard input management (InputHandler)
• External configuration system (properties files)
• Internationalization (i18n/messages)
• Debug mode and multiple log levels

Project Structure

• src/main/java/core/: application core (App, entities, behaviors, physics engine, renderer, utils)
• src/main/java/demo/scenes/: demo scenes
• src/main/resources/: resources, configuration, i18n
• src/test/: test resources and configuration

Configuration

The file src/main/resources/config.properties allows you to configure:

• debug, mode, timeout, window size, available scenes, gravity, etc.

Example:

debug=2
mode=DEVELOPMENT
timeout=200
winsize=800x600
scenes=demo:demo.scenes.DemoScene
defaultscene=demo
physics.gravity=9.81

Main Entities

• App: entry point, lifecycle, services, configuration
• Scene: scene and entity manager
• Entity/GameObject/World/Camera: base entities, world objects, camera
• Behavior: attachable behaviors (gravity, player input, velocity, etc.)
• Renderer: graphics engine, layers and plugins management
• InputHandler: keyboard input management, debug shortcuts

Building the Project

Prerequisites

• Java 17+
• sdkman (for Java version management)

Build the JAR

sdk env use
chmod +x ./build
./build

Run tests

./build test

Run the project

./build run debug=2

Note You can pass as many arguments as needed after run:

• debug=[1 to 5]
• mode=[DEVELOPMENT,TESTING,PRODUCTION]
• timeout=[milliseconds]

Program help

./build run help

Help output:

Usage: java -jar app.jar [key=value]...
Available options:
 debug=<level>       Set debug level (0=none, 1=some, 2=verbose)
 mode=<mode>         Set application mode (DEVELOPMENT, TESTING, PRODUCTION)
 winsize=<WxH>       Set window size (e.g., 800x600)
 help                Show this help message

Run directly from JAR

java -jar target/build/DemoApp01-0.0.1.jar debug=2

Usage

• Keyboard controls the player entity and allows debug level adjustment (Ctrl+D).
• ESC exits the application.
• Debug mode displays extra information on screen.

Internationalization

Messages are externalized in src/main/resources/i18n/messages.properties.

Contribution

All contributions are welcome!

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Frédéric Delorme frederic.delorme@gmail.com