GLSL_EXT_buffer_reference_uvec2

Name

    EXT_buffer_reference_uvec2

Name Strings

    GL_EXT_buffer_reference_uvec2

Contact

    John Kessenich, Google Inc. (johnkessenich 'at' google.com)

Status

    Draft

Version

    Last Modified Date:         September 1, 2019
    Revision:                   1

Number

    TBD

Dependencies

    This extension can be applied to OpenGL GLSL versions 4.50
    (#version 450) and higher.

    This extension can be applied to OpenGL ES ESSL versions 3.20
    (#version 320) and higher.

    This extension is written against the OpenGL Shading Language
    Specification, version 4.60, dated July 23, 2017.

    This extension requires GL_EXT_buffer_reference.

Overview

    This extension adds additional constructor support to
    GL_EXT_buffer_reference to enable conversion of references to and from a
    *uvec2*. That is, the 64 bits of address from the reference are constructed
    to and from two 32-bit unsigned integers, represented as a vector of two
    uints.

    The intent is to not require 64-bit integer support to manipulate the
    64-bits of address in a reference. E.g., a shader can use uaddCarry() to
    add an offset to a reference address via *uvec2* objects, or compare an
    address to 0, using a 'uvec2(0)' value.

New Procedures and Functions

    None.

New Tokens

    None.

Modifications to the OpenGL Shading Language Specification, Version 4.60

    Including the following line in a shader can be used to control the
    language features described in this extension:

      #extension GL_EXT_buffer_reference_uvec2 : 

    where  is as specified in section 3.3. If
    GL_EXT_buffer_reference_uvec2 is enabled, the
    GL_EXT_buffer_reference extension is also implicitly enabled.

    New preprocessor #defines are added to the OpenGL Shading Language:

      #define GL_EXT_buffer_reference_uvec2    1

    Modify section 5.4.1 (Conversion and Scalar Constructors)

    Add to the end of the section, right after the EXT_buffer_reference addition
    for constructing to and from a uint64_t():

      Buffer reference types can also be constructed from a *uvec2* value, and
      a *uvec2* value can be constructed from a buffer reference type value.
      The low-order 32 bits of the reference map to and from the 'x' component
      of the *uvec2*.

Errors

    None.

Issues

    None.

Revision History

    Revision 1
      - Internal revisions.