GL_EXT_texture_offset_non_const.txt

Name

    EXT_texture_offset_non_const

Name Strings

    GL_EXT_texture_offset_non_const

Contact

    Ricardo Garcia (rgarcia 'at' igalia.com), Igalia.

Contributors

    Ricardo Garcia, Igalia
    Graeme Leese, Broadcom
    Alexey Knyazev, independent contributor

Notice

    Copyright (c) 2021-2024 The Khronos Group Inc. Copyright terms at
        http://www.khronos.org/registry/speccopyright.html

Status

    Draft

Version

    Last Modified Date: 2024/10/23
    Revision: 1

Dependencies

    This extension can be applied to OpenGL GLSL versions 1.30
    (#version 130) and higher.

    This extension can be applied to OpenGL ES ESSL versions 3.00
    (#version 300) and higher.

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

Overview

    This extension removes the requirement that offset arguments to the
    texture*Offset functions must be constant.

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_texture_offset_non_const : <behavior>

    where <behavior> is as specified in section 3.3.

    New preprocessor #defines are added:

      #define GL_EXT_texture_offset_non_const    1


Modifications to Chapter 8 of the OpenGL Shading Language Specification
(Built-in Functions)

    Change to section 8.9.2, Texel Lookup Functions

    In the table row corresponding to the textureOffset functions, remove the
    sentence "The offset value must be a constant expression." from the
    Description column.
    
Issues

    (1) Are textureGatherOffsets functions, which also need constant offsets,
    affected by this extension?

    RESOLVED: No, they are out of scope.

Revision History

    Rev.  Date          Author          Changes
    ----  -----------   --------        ----------------------------------------
     1    2024/10/23    Ricardo Garcia  Initial revision.