kc3-lang/angle/extensions/ANGLE_request_extension.txt

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• Hash : a1665d2f
  Author :
  Date : 2024-05-10T00:15:31
  

  Reland "Document thread-unsafe iterator access to resource maps"
  
  This is a reland of commit d1bb6ed8399dd12e79484f30f9e9ded95c25625a
  
  The crash was due to another issue (disabling EGL validation in
  Chrome)
  
  Original change's description:
  > Document thread-unsafe iterator access to resource maps
  >
  > By using a proxy type, everywhere resource maps are iterated are clearly
  > marked as not being thread safe.  In most cases, only destruction and
  > capture/replay iterate over these maps, which means thread safety is not
  > an issue (or is externally enforced).
  >
  > The only case where iterators are used in the presence of other contexts
  > is with ANGLE_request_extension, which is changed to explicitly require
  > the application to ensure thread safety.  In practice, the user is
  > Chrome which already guarantees this.
  >
  > Bug: angleproject:8667
  > Change-Id: I7af13c6433b6955d9c36f9088b3aa4c065e1cfc1
  > Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5526428
  > Reviewed-by: Charlie Lao <cclao@google.com>
  > Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
  > Reviewed-by: Geoff Lang <geofflang@chromium.org>
  
  Bug: angleproject:8667
  Change-Id: Id539cabac01df5f242150f6684222577003eef3f
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5531278
  Reviewed-by: Charlie Lao <cclao@google.com>
  Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
  Reviewed-by: Geoff Lang <geofflang@chromium.org>
  

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• extensions/ANGLE_request_extension.txt

• Name
  
      ANGLE_request_extension
  
  Name Strings
  
      GL_ANGLE_request_extension
  
  Contributors
  
      Geoff Lang
      James Darpinian
  
  Contact
  
      Geoff Lang (geofflang 'at' google.com)
  
  Notice
  
      Copyright (c) 2016 The Khronos Group Inc. Copyright terms at
          http://www.khronos.org/registry/speccopyright.html
  
  Status
  
      Draft
  
  Version
  
      Version 2, October 4, 2019
  
  Number
  
      OpenGL ES Extension #??
  
  Dependencies
  
      Requires OpenGL ES 2.0
  
      Written against the OpenGL ES 3.0 specification.
  
  Overview
  
      This extension allows the client to query extensions that can be enabled and
      explicitly request that an extension be enabled or disabled.
  
  New Procedures and Functions
  
      void RequestExtension(const char *name)
  
      void DisableExtension(const char *name)
  
  New Tokens
  
      Accepted by the <name> parameter of GetString and GetStringi:
  
          REQUESTABLE_EXTENSIONS_ANGLE      0x93A8
  
      Accepted by the <value> parameter of the GetInteger* functions:
  
          NUM_REQUESTABLE_EXTENSIONS_ANGLE  0x93A9
  
  Additions to the OpenGL ES 3.0 Specification
  
      Add the following paragraph to the end paragraph 4 of section 6.1.6, String
      Queries:
  
      "REQUESTABLE_EXTENSIONS_ANGLE returns a list of extensions that can be
      enabled at runtime by calling RequestExtension."
  
      Change the following section of paragraph 6 of section 6.1.6, String Queries:
  
      - "name may only be EXTENSIONS, indicating that the extension name
      - corresponding to the indexth supported extension should be returned.
      - <index> may range from zero to the value of NUM_EXTENSIONS minus one"
      + "name may be EXTENSIONS or REQUESTABLE_EXTENSIONS_ANGLE, indicating that
      + the extension name corresponding to the indexth supported or requestable
      + extension should be returned. <index> may range from zero to the value of
      + NUM_EXTENSIONS and NUM_REQUESTABLE_EXTENSIONS_ANGLE minus one"
  
      The commands
  
         void RequestExtension(const char *name)
         void DisableExtension(const char *name)
  
      enable or disable the requestable OpenGL ES extension named <name>. If the
      requested extension was not requestable or disablable, INVALID_OPERATION is
      generated. Not all requestable extensions can be disabled. There is
      currently no query for disablable extensions.  This operation is not thread
      safe, and the application is responsible for ensuring no other context in
      the share group is accessed by another thread during this operation.
  
  New State
  
      Add to Table 6.30 (Implementation Dependent Version and Extension Support)
  
      Get value                        Type Get Cmd     Min Value Description                      Sec.
      -------------------------------- ---- ----------- --------- -------------------------------- -----
      NUM_REQUESTABLE_EXTENSIONS_ANGLE Z+   GetIntegerv -         Number of individual requestable 6.1.6
                                                                  extension names
  
  Interactions with the OpenGL ES 2.0 specification:
  
      Remove all references to GetStringi and NUM_REQUESTABLE_EXTENSIONS_ANGLE.
  
  Issues
  
      (1) How can the user determine which extensions can be enabled without
          potentially generating errors?
  
        This can be solved by:
        a) Never generate an error in EnableExtensions, simply return false when
           the extension is not recognized or cannot be enabled.
        b) Add another query for the extensions that the context supports
           enabling.
  
        RESOLVED: Use (b) because it allows the context to explicity advertise
        which extensions support enabling and doesn't generate errors in the
        normal use case.
  
  Revision History
  
      Rev.    Date         Author     Changes
      ----  -------------  ---------  ----------------------------------------
        1    Nov 28, 2016  geofflang  Initial version
        2    Oct 4, 2019   jdarpinian Add DisableExtension
  

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