kc3-lang/angle/extensions/ANGLE_request_extension.txt

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• Author : James Darpinian
  Date : 2019-10-03 13:46:28
  Hash : c42da4e5
  Message : Extend ANGLE_request_extension with DisableExtension ARB_texture_rectangle is the only currently supported disablable extension. This allows us to use ARB_texture_rectangle in WebGL implementations without exposing it to WebGL user shaders. Bug: angleproject:3956 Bug: angleproject:3770 Change-Id: I80b10d2e9c9feebe545ce15195721487165ecc51 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1838418 Commit-Queue: James Darpinian <jdarpinian@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>

• 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.
  
  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