raylib architecture

raylib is a highly modular library. Everything is contained within a small number of well defined, specific and self-contained modules, each organized according to its primary functionality (nicely avoiding the huge tree of recursive dependencies, typical of other C libraries).

raylib has seven main modules:

• core: Window / Graphic Context / Inputs management.
• rlgl: Graphic API (OpenGL) wrapper and pseudo-OpenGL 1.1 translation layer.
• shapes: Basic 2D shapes drawing functions.
• textures: Textures / Image loading and management.
• text: Font data loading and text drawing.
• models: 3D models loading and drawing.
• raudio: Audio device management and sounds / music loading and playing.

Those seven modules share a common header, named raylib.h. All API functions are defined in that header, despite being internally divided into seven modules, so the user only needs to include raylib.h to access all of the raylib functionality. Other libraries often use a header for every module (so users can select the ones they need), but this complicates the dependencies. The simple approach that raylib adopts is just easier for novice (and expert) users.

Apart from those seven main modules, some other modules have been implemented with additional features:

• raymath: Vector2, Vector3, Matrix and Quaternion math related functions
• camera: 3D Camera system (free, 1st person, 3rd person, custom)
• gestures: Touch gestures detection and processing (Tap, Swipe, Drag, Pinch)
• raygui: Simple IMGUI system with several controls for tools development
• easings: Easing functions for animations (based on Robert Penner implementation)
• physac: 2D physics library (collision detection, resolution, dinamics...)

Most of the modules were designed to allow them to be as decoupled as possible from the other modules. In fact, some modules can be used as standalone libraries, independently of raylib, including the rlgl (example) and audio (example) modules.

Most of the secondary modules can also be used as standalone libraries: raymath, camera, gestures, raygui, easings, physac. All those modules are distributed as configurable single-file header-only libraries to be independently added to any project. Being header-only means the header also contains function implementations; that's extremely useful if you have a library (a bunch of functions) that you only want to drop on your code-base to cover a very specific functionality. However, creating a header-only module is not trivial. That module has to minimize external dependencies and global variables and give a very specific functionality; let's say it has to be completely portable.

NOTE: raymath, camera and gestures are compiled by default with raylib.

raylib also uses some external libraries—most of them included as single-file header-only libraries, like the well-known stb libraries and similar ones.

And that's currently the raylib internal structure.