EGLDevice

This topic describes EGL mechanisms that you can use to implement a pure EGL display. Such a display does not use a window system.

EGLDevice provides a mechanism to access graphics functionality in the absence of or without reference to a native window system. It is a method to initialize EGL displays and surfaces directly on top of GPUs/devices rather than native window system objects. It is a cross-platform method to discover media devices like displays, GPUs, etc. The set of EGLDevice extensions boot strap EGL, without the use of any native APIs.

EGLOutput

EGLOutput is to graphical outputs what EGLDevice is to devices. It allows enumeration of outputs on a device. EGLOutput allows rendering directly to a screen in the absence of a window system. Additionally, it allows applications to bypass native window systems for direct rendering. It defines certain EGL resources for referencing display control hardware associated with an EGL device. EGLOutput provides a binding between GL, NVIDIA® CUDA®, and multimedia rendering and the display output. In a typical Embedded setting, the outputs are often initialized to a fixed state at system startup. But in cases where they are configurable, other interfaces such as DRM must be used.

EGLStream

EGLStream is a mechanism to share data efficiently between different APIs without copying data. APIs could be OpenGL, CUDA, Multimedia, etc. A producer and a consumer are attached to two ends of a stream object:

Producer adds content into the stream.
Consumer retrieves this content.

EGLOutput instances can also be specified as consumers, allowing APIs to direct their output to the screen.