Name

    AMD_shader_trinary_minmax

Name Strings

    GL_AMD_shader_trinary_minmax

Contact

    Graham Sellers, AMD (graham.sellers 'at' amd.com)

Status

    Shipping

Version

    Last Modified Date:         10/01/2012
    Author Revision:            2

Number

    428

Dependencies

    OpenGL 2.0 or ARB_shader_objects is required.

    This extension is written against the OpenGL Shading Language
    Specification, Version 4.30.

Overview

    This extension introduces three new trinary built-in functions to the
    OpenGL Shading Languages. These functions allow the minimum, maximum
    or median of three inputs to be found with a single function call. These
    operations may be useful for sorting and filtering operations, for example.
    By explicitly performing a trinary operation with a single built-in
    function, shader compilers and optimizers may be able to generate better
    instruction sequences for perform sorting and other multi-input functions.

IP Status

    None.

New Procedures and Functions

    None.

New Tokens

    None.

Additions to Chapter 2 of the OpenGL Shading Language (GLSL) Specification,
version 4.30, (Overview of OpenGL Shading)

    None.

Additions to Chapter 3 of the OpenGL Shading Language (GLSL) Specification,
version 4.30, (Basics)

    None.

Additions to Chapter 4 of the OpenGL Shading Language (GLSL) Specification,
version 4.30, (Variables and Types)

    None.

Additions to Chapter 5 of the OpenGL Shading Language (GLSL) Specification,
version 4.30, (Operators and Expressions)

    None.

Additions to Chapter 6 of the OpenGL Shading Language (GLSL) Specification,
version 4.30, (Statement Structure)

    None.

Additions to Chapter 7 of the OpenGL Shading Language (GLSL) Specification,
version 4.30 (Built-in variables)

    None.

Additions to Chapter 8 of the OpenGL Shading Language (GLSL) Specification,
version 4.30 (Built-in functions)

    In Section 8.3, "Common Functions", add to the table of functions, p.133:

    +---------------------------------------------------+--------------------------------------------------------+
    | Syntax                                            | Description                                            |
    +---------------------------------------------------+--------------------------------------------------------+
    | genType min3(genType x, genType y, genType z)     | Returns the per-component minimum value of x, y, and z |
    | genIType min3(genIType x, genIType y, genIType z) | Returns the per-component minimum value of x, y, and z |
    | genUType min3(genUType x, genUType y, genUType z) | Returns the per-component minimum value of x, y, and z |
    +---------------------------------------------------+--------------------------------------------------------+
    | genType max3(genType x, genType y, genType z)     | Returns the per-component maximum value of x, y, and z |
    | genIType max3(genIType x, genIType y, genIType z) | Returns the per-component maximum value of x, y, and z |
    | genUType max3(genUType x, genUType y, genUType z) | Returns the per-component maximum value of x, y, and z |
    +---------------------------------------------------+--------------------------------------------------------+
    | genType mid3(genType x, genType y, genType z)     | Returns the per-component median value of x, y, and z  |
    | genIType mid3(genIType x, genIType y, genIType z) | Returns the per-component median value of x, y, and z  |
    | genUType mid3(genUType x, genUType y, genUType z) | Returns the per-component median value of x, y, and z  |
    +---------------------------------------------------+--------------------------------------------------------+

Additions to Chapter 9 of the OpenGL Shading Language (GLSL) Specification,
version 4.30, (Shading Language Grammar)

    None.

Additions to the AGL/GLX/WGL Specifications

    None.

GLX Protocol

    None.

Errors

    None.

Issues

    1) Should the trinary min and max functions be given new names (min3, max3)
       or simply overload the existing min and max functions?

       RESOLVED: Use new names.

Revision History

    Rev.    Date      Author    Changes
    ----  --------    --------  -----------------------------------------

     2    10/01/2012  gsellers  Update to GLSL 4.30. Ready to post.
     1    11/01/2012  gsellers  Initial Revision