EON

An easy-to-use but flexible game framework based on Raylib for Common Lisp.

Introduction

EON is a game framework built upon and cooperating with claw-raylib (my high-level bindings for Raylib), integrating commonly used facilities in game (especially old school style) development. If you are familiar with Raylib, you should find it easy to get started with EON since all interfaces of Raylib (including Raygui, Raymath, RLGL) can be used alongside EON. It is important to note that EON was spun out from one of my retro game projects, mainly focusing on optimizing and developing functionalities for console-style games without additional support for modern PC games, for instance, the framework by default simulates the keyboard as gamepad input and the built-in input events do not yet support mouse, although you can directly obtain mouse input through Raylib. This project is still under development, so APIs are subject to change. EON and all its dependencies can be loaded and run on SBCL, CCL, and ECL.

Features

Along with the rich set of features of Raylib (such as support for various image, audio, font formats, batch rendering, shape drawing, and collision detection), EON offers many useful functionalities for game development:

1. Asynchronous Support
   A suite of built-in asynchronous functions allowing for quick writing of events and logic using async / await syntax.
2. Asset Management
   Unified API for loading and unloading assets, ensuring reusable assets are not repeatedly loaded, with non-reusable assets managed by the GC automatically, though manual management is also an option.
3. Audio Management
   Context-free, unified audio control API and automatic audio stream resource management.
4. Screen Management
   Proper screen abstraction for managing scene/interface switching with transition animations.
5. Viewport Support
   Facilitates adaptation to different screen sizes and window dimensions.
6. Scene System
   Build 2D/3D scene node tree in your preferred way, transforming, rendering, and updating them together.
7. GUI System
   Based on the 2D scene system, the GUI system includes built-in widgets such as text, images, selection boxes, input boxes, dialogue boxes, and allows for easy creation of custom widgets, complete with a flexible GUI layout system and DSL for declarative UI construction.
8. Particle Effect System
   A particle effect system designed with logic and rendering separation, featuring abstract updaters and renderers for high customization and extension of particle systems.
9. Tiled Map Renderer
   An optimized built-in Tiled map renderer capable of rendering Tiled maps or any of their layers.
10. More…
    Scrolling backgrounds, key combos, focus management, shader uniform management, asynchronous job system, etc.

Dependencies

Currently, the EON framework relies solely on libraylib as its foreign library, which should be ensured correctly installed on your machine. Additionally, some libraries or their latest versions might not yet be included in the latest Quicklisp distribution. You can find them in my repositories and clone them to a location where Quicklisp can find them:

• claw-raylib
  You also need to follow the build instruction of claw-raylib to automatically generate the bindings.
• cl-universal-tween-engine
• cl-cont-optimizer
• promise-async-await
• cffi-ops
• cffi-object

Get Started

To get started, you can refer to the examples and cheatsheet to learn the interfaces of Raylib, and familiarize yourself with the usage of EON by exploring the eon-examples. Currently, most exported APIs should have docstrings to explain their arguments and usage.