kc3-lang/angle/extensions/EGL_ANGLE_prepare_swap_buffers.txt

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• Hash : 926b43e7
  Author :
  Date : 2022-01-06T13:31:54
  

  Reland: Frontend: separate lock in swap prep
  
  Swapchain-based backends like Vulkan might block a lot in
  vkAcquireNextImageKHR, which is bad for overall fast progress if we also
  hold the global EGL lock there.
  
  This CL starts to split the global EGL lock. We release the EGL lock
  when performing vkAcquireNextImageKHR, and only maintain a lock for
  surfaces.
  
  This is done via a new custom entry point, EGL_PrepareSwapBuffers, so
  that we can control how the global lock is used throughout the entire
  call.
  
  Bug: angleproject:6851
  Change-Id: I095cd8b3bdbb13c842cab0a46148e2122582cdfd
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3373426
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
  Commit-Queue: Lingfeng Yang <lfy@google.com>
  

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• 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
  

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