EGL

EGL is a cross-platform interface defined by the Khronos Group that serves as a bridge between rendering APIs and the native windowing system. It provides the mechanisms to create and manage rendering contexts, surfaces, and synchronization objects, enabling portable graphics applications on embedded and desktop environments.

The primary objects in EGL are EGLDisplay, EGLConfig, EGLSurface, and EGLContext. Applications obtain a display handle with eglGetDisplay, initialize it with eglInitialize, choose a suitable framebuffer configuration with eglChooseConfig, and create an OpenGL ES or OpenGL context with eglCreateContext. Window or pixel buffer surfaces are created with eglCreateWindowSurface, eglCreatePixmapSurface, or eglCreatePbufferSurface, and a configured context is made current on a surface via eglMakeCurrent. Rendering results are presented with eglSwapBuffers.

EGL supports several types of surfaces: window surfaces that render to a native window, pixmap surfaces that render to a platform pixmap, and pbuffers for offscreen rendering. It interfaces with various native window systems through platform backends such as X11, Wayland, Windows, and Android, among others, providing a consistent API regardless of the underlying platform.

Typical usage involves initializing the display, selecting a compatible config, creating a rendering context and a surface, making the context current, issuing rendering commands through the bound API (for example, OpenGL ES), and swapping buffers as needed. EGL also supports synchronization primitives and resource sharing between contexts via extensions.

To extend functionality and portability, EGL exposes extensions (for example, KHR and EXT variants) that add capabilities such as advanced swap control, additional surface types, and customized context attributes. As a Khronos standard, EGL is widely implemented by GPU drivers on mobile devices, desktop GPUs, and embedded platforms and serves as a key component of graphics pipelines that rely on OpenGL ES and related APIs.