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Introduction

What is OpenBOR?

OpenBOR is a royalty-free, open-source engine for sprite-based games. It combines a complete native game framework - including controls, movement, combat, artificial intelligence, levels, audio, menus, saving, and local multiplayer - with an integrated C-like scripting language that can extend or replace nearly every system.

OpenBOR specializes in side-scrolling action games such as Double Dragon and Streets of Rage, but its three-dimensional game world, configurable simulation, declarative object system, and scriptable graphics pipeline also support platformers, shooters, role-playing games, puzzle games, and other genres.

Beginners can build complete games primarily from assets and configuration. Advanced creators can manipulate engine objects, replace native behavior, construct rendering pipelines, and even compile new script programs while a module is running.

Why OpenBOR?

What sets OpenBOR apart is how we define its scope. Some engines concentrate on a particular result: role-playing games, one-on-one fighters, shoot-’em-ups, real-time strategy, or puzzles. Others attempt to support every technical medium, leaving developers to build most game-specific functionality themselves. Both are valid approaches. We take a third path by specializing in a technical medium without prescribing the result.

OpenBOR deliberately limits itself to the simulation and presentation of flat, two-dimensional visual assets in an effectively limitless three-dimensional world. No polygons. No meshes. No skeletal rigs. Just raster graphics moving through three axes. Within that foundation, virtually any sprite-powered concept is possible.

That focus means we spend our development resources on performance and depth: butter-smooth motion, asset handling, controls, gravity, collision, combat, blocking, grabbing, throwing, artificial intelligence, cameras, level trees, audio, menus, HUDs, saving, and local multiplayer are integrated and ready to use. Everything works together out of the box, with no need to build these foundations or assemble them from plugins.

Then we layer beat ’em up-oriented behavior over those systems as the default starting point. Supply the necessary assets and configuration, and characters can already move, fight, react, navigate depth, cooperate, and progress through levels. You can have a functional game running within hours, but those defaults don't dictate the finished product.

Configuration and script expose the same engine objects, properties, and low-level primitives beneath that native behavior. Creators can inspect runtime state, customize selected operations, replace complete subsystems, or combine the primitives into something we never anticipated. The same technical model can support platformers, shooters, role-playing games, puzzles, and other designs far removed from the default.

The result is a deliberately bounded medium, a complete starting point, and an ending defined only by your imagination.

• Complete native gameplay - Controls, movement, gravity, level trees, platforms, combat, blocking, grabbing, throwing, artificial intelligence, cameras, audio, menus, HUDs, and saving work without custom code.
• Engine-wide scripting - Object APIs and more than 70 event hooks expose input, animation, movement, collision, damage, spawning, audio, drawing, and other runtime systems for inspection, modification, or replacement.
• High-resolution simulation - The configurable logical clock runs at 200 Hz by default and remains independent of display updates.
• Three-dimensional sprite worlds - Floating-point X, Y, and Z geometry provides subpixel movement, terrain, altitude, and depth sorting. Set an area's Z axis to bounded values and the engine natively assumes 2D world behaviors.
• Declarative combat collision - Indexed three-dimensional attack and body boxes carry damage, reaction, motion, status, and presentation behavior.
• Composable relationships - Four independent 52-bit faction masks provide hardware-speed membership, hostility, direct-damage, and indirect-damage rules.
• Recursive graphics composition - Script-created subscreens support nested rendering, layer capture, transformations, masks, split screens, and feedback effects.
• Runtime metaprogramming - Modules can load and combine source files, compile them into independently owned programs, retain persistent state, execute them repeatedly, and replace them during play.
• Optimized performance - Native systems, high-frequency simulation, and script integration are engineered to maintain steady frame rates and seamless motion with dozens or hundreds of active objects.

Getting Started

Download OpenBOR | Start Building | Browse the Reference | Visit the Community | View the Source

This wiki is the comprehensive technical reference for OpenBOR, but please note it is not intended as a walk-through. For more in-depth instruction, consult the tutorials and guides available through the ChronoCrash community.

Guides and Resources

• OpenBOR Overview – General overview of OpenBOR functionality and runtime layout.
• OpenBOR Hub – Main jumping off point for categories and individual wiki articles.
• OpenBOR Index – Simple index of OpenBOR commands, settings, and functions.
• Legacy Manual – Archival monolithic manual.
• ChronoCrash – OpenBOR’s home community, including its help forum, downloadable games, and in-depth tutorials.
• OpenBOR Repository – Public-facing OpenBOR code base.

Development Environment

Essential Tools

The following tools are needed to begin building games with OpenBOR. You will need a ChronoCrash community account to download some resources.

• OpenBOR engine executable – The latest stable engine release.
• Edit Pack – Tools for packing and unpacking OpenBOR game modules.
• Development environment – OpenBOR uses a combination of text files and optional script files to configure game functionality. Any text editor may be used. Visual Studio Code is recommended, together with Git or another version-control system for managing project files.
• Graphics software – Any graphics-editing application capable of exporting .png images. Adobe Photoshop or GIMP are recommended.
• Audio software – An audio-editing application capable of exporting .wav files for sound effects and, optionally, .ogg files for music. Adobe Audition or Audacity are recommended.

Optional Tools

These tools are optional but highly recommended.

• ChronoCrash Modders Tools (CMT) – Visual editing application for building OpenBOR games.
• PalApply – Applies a palette to one or more images and exports optimized .png files ready for use with OpenBOR.

What Open Source Means

Because the term has caused confusion and disputes in the past, it is important to clarify what open source means in the context of OpenBOR.

OpenBOR’s existing codebase is available under a permissive BSD-derived license. Creators may use the engine to make, license, and sell games and other content they rightfully own. The OpenBOR license does not claim or control that content.

Open source does not mean a free-for-all. It provides no implied permission to modify or redistribute another creator’s work without consent. The license also permits binary distribution without requiring source disclosure - it does not compel the team to release existing or future source code, and by extension it does not entitle anyone to the source code of closed-source extensions or obligate the development team to release it. The public repository is provided and maintained as a voluntary act of good faith, not as an obligation imposed by the license.

The OpenBOR development team may produce proprietary features, such as encrypted pack handling, and license them separately at its discretion.