What is Grit?

The Grit Game Engine is a community project to build a free game engine (and pipeline tool-chain) for implementing open world 3D games, such as the those in the GTA series, Saints Row, Crysis, Fallout 3, Just Cause 2, Mafia 2, Burnout, etc. Anyone can use the engine as a foundation for their game, and anyone can read / modify / integrate the source code.

While there are many open source game engines, ours is the only one that is being optimized for open world games. We support large maps (e.g. more than 30 square km, 50000 objects) with considerable diversity in geometry and textures, because game objects and scenery consume negligible memory / CPU resources when out of visual range. We also use deferred shading, which is essential for rendering the abundance of light sources that are needed in open world scenes.

A key objective of the Grit Game Engine project is to enable ‘modders’ and other enthusiasts to build extremely diverse interactivity and gameplay into their environments. Although we support exporting from 3D Studio Max, even non-programmers find it easy to define new game object classes, materials, etc using simple definitions inside Lua scripts.

  • Code is open source and MIT licensed.
  • Large open world maps, content streamed from disk.
  • Normal / specular / gloss maps
  • Heightmap-based texture blending
  • Deferred shading
  • Soft dynamic shadows
  • 24 hour time cycle with sun, moon, clouds
  • Stars at night with real constellations
  • Procedural placement of vegetation and clutter
  • General purpose 3D physics engine.
  • Game objects are extremely scriptable via Lua.
  • Planes & cars (implemented via game object scripting).
  • Developing/debugging scripts is easy thanks to an in-game Lua console.
  • Linux and Windows ports are available.

Recent Blog Posts