Graphics Reference
In-Depth Information
Chapter 3
In Chapter 2, “Hello Triangle: An OpenGL ES 3.0 Example,” we drew a
triangle into a window using OpenGL ES 3.0, but we used some custom
functions of our own design to open and manage the window. Although
that technique simplifies our examples, it obscures how you might need
to work with OpenGL ES 3.0 on your own systems.
As part of the family of APIs provided by the Khronos Group for
developing content, a (mostly) platform-independent API, EGL, is
available for managing
drawing surfaces
(windows are just one type;
we will talk about others later). EGL provides the mechanisms for the
following:
• Communicating with the native windowing system of your device
• Querying the available types and configurations of drawing surfaces
• Creating drawing surfaces
• Synchronizing rendering between OpenGL ES 3.0 and other graphics-
rendering APIs (such as desktop OpenGL and OpenVG, a cross-platform
API for hardware-accelerated vector graphics, or the native drawing
commands of your windowing system)
• Managing rendering resources such as texture maps
This chapter introduces the fundamentals required to open a window. As
we describe other operations, such as creating texture maps, we discuss
the necessary EGL commands.
