EGL_KHR_swap_buffers_with_damage

Supported Hardware

Series6, Series6XE, Series6XT

Valid APIs

EGL 1.4

Description

This extension provides a means to issue a swap buffers request to display the contents of the current back buffer and also specify a list of damage rectangles that can be passed to a system compositor so it can minimize how much it has to recompose.

This should be used in situations where an application is only animating a small portion of a surface since it enables the compositor to avoid wasting time recomposing parts of the surface that haven't changed.

Note

Requires EGL 1.4 This extension is written against the wording of the EGL 1.4 Specification. Different with EGL_KHR_partial_update. EGL_KHR_swap_buffers_with_damage concerns the area of the surface that changes between frames for that surface. It concerns the differences between two buffers - the current back buffer and the current front buffer. It is useful only to the consumer.

Surface Damage Example

The surface damage for frame n is the difference between frame n and frame (n-1) and represents the area that a compositor must recompose.

  Frame 0     Frame 1     Frame 2     Frame 3     Frame 4 
+---------+ +---------+ +---------+ +---------+ +---------+ 
|         | |#########| |#########| |#########| |#########| 
|         | |         | |#########| |#########| |#########| Final surface 
|         | |         | |         | |#########| |#########|   content 
|         | |         | |         | |         | |#########| 
+---------+ +---------+ +---------+ +---------+ +---------+ 
+---------+ +---------+ +---------+ +---------+ +---------+ 
|@@@@@@@@@| |@@@@@@@@@| |         | |         | |         | 
|@@@@@@@@@| |         | |@@@@@@@@@| |         | |         | Surface damage 
|@@@@@@@@@| |         | |         | |@@@@@@@@@| |         | 
|@@@@@@@@@| |         | |         | |         | |@@@@@@@@@| 
+---------+ +---------+ +---------+ +---------+ +---------+

Registry Link

https://www.khronos.org/registry/egl/extensions/KHR/EGL_KHR_swap_buffers_with_damage.txt

Example

//As an alternative to eglSwapBuffers
eglSwapBuffersWithDamageKHR(eglDisplay, eglSurface, rects, n_rects);