extensions/EGL_ANGLE_prepare_swap_buffers.txt

Name

    ANGLE_prepare_swap_buffers

Name Strings

    EGL_ANGLE_prepare_swap_buffers

Contributors

    Jamie Madill
    Shahbaz Youssefi
    Lingfeng Yang

Contacts

    Jamie Madill, Google Inc. (jmadill 'at' google.com)
    Shahbaz Youssefi, Google Inc. (syoussefi 'at' google.com)
    Lingfeng Yang, Google Inc. (lfy 'at' google.com)

Status

    Draft

Version

    Version 1, January 10, 2022

Number

    EGL Extension #??

Dependencies

    This extension is written against the wording of the EGL 1.5
    Specification.

Overview

    The EGL implementation often relies on a swapchain to present backbuffer
    rendering results. Images are dequeued from the swapchain, then written in
    the course of rendering, and then queued back to the swapchain for
    presentation.  It can be advantageous to provide a hint API that performs
    the dequeue operation and other operations necessary to prepare the
    swapchain image for rendering, without also queueing it for present,
    especially if there is going to be a long or variable wait associated with
    the dequeue.  This extension provides that api, eglPrepareSwapBuffers.

New Types

    None.

New Procedures and Functions

    EGLBoolean eglPrepareSwapBuffersANGLE(
        EGLDisplay dpy,
        EGLSurface surface);

New Tokens

    None

Additions to the EGL 1.5 Specification

    Add the following to section 3.10.1 "Posting to a Window":

    An application can encourage the EGL implementation to dequeue and
    otherwise prepare a swapchain image earlier before presenting via calling

        EGLBoolean eglPrepareSwapBuffersANGLE(
            EGLDisplay dpy,
            EGLSurface surface);

    The behaviour of eglPrepareSwapBuffers can be a no-op. It is not necessary
    to call eglSwapBuffers after calling. Conversely, it's also not necessary
    to call eglPrepareSwapBuffersANGLE for eglSwapBuffers to work.

Issues

    None yet.

Revision History

    Rev.    Date         Author     Changes
    ----  -------------  ---------  ----------------------------------------
      1   Jan 10, 2022   lfy        Initial version