EXT_texture_sRGB_RG8

GL_EXT_texture_sRGB_RG8

Sam Holmes
Maurice Ribble
Tobias Hector
Jan-Harald Fredriksen
Dylan Perks
Contributors to EXT_texture_sRGB_R8, on which this is based.

Tobias Hector (tobias.hector 'at' imgtec.com)

Complete.

Last Modified Date: December 11, 2020
Revision: 4

OpenGL ES Extension #223
OpenGL Extension #555

OpenGL ES 3.0 or OpenGL 1.2 is required.

This extension is written against the OpenGL ES 3.1 and
OpenGL 4.6 (Core Profile) specifications.

This extension interacts with ARB_texture_view.

This extension interacts with EXT_texture_view.

This extension interacts with OES_texture_view.

This extension interacts with ARB_direct_state_access.

This extension introduces SRG8_EXT as an acceptable internal format.
This allows efficient sRGB sampling for source images stored with 2
channels.

None

Accepted by the <internalformat> parameters of TexImage3D, TexImage2D,
TexImage1D, TexStorage3D, TexStorage2D, TexStorage1D, TextureStorage3D,
TextureStorage2D, and TextureStorage1D:

    SRG8_EXT    0x8FBE

The following table entry is added to Table 8.2 (Valid combinations of
format, type and sized internalformat):

    Format    Type             External Bytes per Pixel    Internal Format
    ------    ----             ------------------------    ---------------
    RG        UNSIGNED_BYTE    2                           SRG8_EXT

The following table entry is added to Table 8.13 (Correspondence of sized
internal color formats to base internal formats):

    Sized Internal Format    Base Internal Format    R    G    B    A    S    CR    TF    Req. rend.    Req. tex.
    ---------------------    --------------------    -    -    -    -    -    --    --    ----------    ---------
    SRG8_EXT                 RG                      8    8                         X                   X

The following table entry is added to Table 8.24 (sRGB texture internal
formats):

    Internal Format
    ---------------
    SRG8_EXT

The following table entry is added to Table 8.2 (Valid combinations of
format, type and sized internalformat):

    Format    Type             External Bytes per Pixel    Internal Format
    ------    ----             ------------------------    ---------------
    RG        UNSIGNED_BYTE    2                           SRG8_EXT

The following table entry is added to Table 8.12 (Correspondence of sized
internal color formats to base internal formats):

    Sized Internal Format    Base Internal Format    R    G    B    A    S    CR    TF    Req. rend.    Req. tex.
    ---------------------    --------------------    -    -    -    -    -    --    --    ----------    ---------
    SRG8_EXT                 RG                      8    8                         X                   X

The following table entry is added to Table 8.22 (Compatible internal
formats for TextureView):

    Class              Internal formats
    ---------------    ----------------
    VIEW_CLASS_16_BITS  SRG8_EXT

The following table entry is added to Table 8.24 (sRGB texture internal
formats):

    Internal Format
    ---------------
    SRG8_EXT

If OpenGL is not supported, ignore all references to 1D textures,
including TexImage1D, TexStorage1D, and TextureStorage1D.

If neither OpenGL 4.5 nor ARB_direct_state_access are supported,
ignore all references to TextureStorage3D, TextureStorage2D, and
TextureStorage1D.

If ARB_texture_view is supported, add SRG8_EXT to the Internal formats
column of the VIEW_CLASS_16_BITS row in Table 3.X.2.

If EXT_texture_view is supported, add SRG8_EXT to the Internal formats
column of the VIEW_CLASS_16_BITS row in Table 8.X.2.

If OES_texture_view is supported, add SRG8_EXT to the Internal formats
column of the VIEW_CLASS_16_BITS row in Table 8.X.2.

None

None

#01    2/5/2015    Tobias Hector      Initial revision.
#02    2/5/2015    Tobias Hector      Fixed Table 8.13 entry and whitespace issues.
#03    2/17/2015   Tobias Hector      Fixed Table 8.2 entry to correctly say 2 bytes.
#04    12/11/2020  Dylan Perks        Add GL interactions and register for GL