xref: /third_party/openGLES/extensions/EXT/EXT_texture_norm16.txt

Name

     EXT_texture_norm16

Name Strings

     GL_EXT_texture_norm16

Contributors

     Contributors to EXT_texture_snorm
     Daniel Koch, NVIDIA
     Jan-Harald Fredriksen, ARM

Contact

     Mathias Heyer, NVIDIA (mheyer [at] nvidia.com)

Status

     Complete

Version

     Last Modified Date:  2014-10-24
     Revision:            5

Number

    OpenGL ES Extension #207

Dependencies

     OpenGL ES 3.1 is required.

     This extension is written against the OpenGL ES 3.1 (June 4, 2014)
     specification.

     This extension interacts with EXT_texture_buffer.

     This extension interacts with EXT_texture_view.

     This extension interacts with OES_texture_storage_multisample_2d_array.

     This extension interacts with EXT_copy_image.

     This extension interacts with EXT_texture_compression_s3tc.

     This extension interacts with EXT_texture_compression_rgtc.

     This extension interacts with NV_texture_compression_s3tc.

     This extension interacts with NV_sRGB_formats.

Overview

     OpenGL ES 3.1 supports 8-bit (signed) normalized textures.

     This extension provides a set of new 16 bit signed normalized and
     unsigned normalized fixed point texture, renderbuffer and
     texture buffer formats.


New Procedures and Functions

     None

New Tokens


     Accepted by the <internalFormat> parameter of TexImage2D,TexImage3D,
     TexStorage2D, TexStorage3D and TexStorage2DMultisample,
     TexStorage3DMultisampleOES, TexBufferEXT, TexBufferRangeEXT,
     TextureViewEXT, RenderbufferStorage and RenderbufferStorageMultisample:

        R16_EXT                                     0x822A
        RG16_EXT                                    0x822C
        RGBA16_EXT                                  0x805B

     Accepted by the <internalFormat> parameter of TexImage2D,TexImage3D,
     TexStorage2D, TexStorage3D, TexStorage2DMultisample,
     TexStorage3DMultisampleOES and TextureViewEXT:

        RGB16_EXT                                   0x8054

        R16_SNORM_EXT                               0x8F98
        RG16_SNORM_EXT                              0x8F99
        RGB16_SNORM_EXT                             0x8F9A
        RGBA16_SNORM_EXT                            0x8F9B


Additions to Chapter 8 of the OpenGL  ES 3.1 Specification
(Textures and Samplers)

    Add to Table 4.X.1 (introduced by EXT_copy_image) "Compatible internal
    Formats  for copying between compressed and uncompressed...."

        ------------------------------------------------------------------------------
        | 64-bit  | RGBA16_EXT,          | COMPRESSED_RGB_S3TC_DXT1_EXT,             |
        |         | RGBA16_SNORM_EXT     | COMPRESSED_SRGB_S3TC_DXT1_NV,             |
        |         |                      | COMPRESSED_RGBA_S3TC_DXT1_EXT,            |
        |         |                      | COMPRESSED_SRGB_ALPHA_S3TC_DXT1_NV,       |
        |         |                      | COMPRESSED_RED_RGTC1_EXT,                 |
        |         |                      | COMPRESSED_SIGNED_RED_RGTC1_EXT,          |
        |         |                      | COMPRESSED_RGB8_ETC2,                     |
        |         |                      | COMPRESSED_SRGB8_ETC2,                    |
        |         |                      | COMPRESSED_R11_EAC,                       |
        |         |                      | COMPRESSED_SIGNED_R11_EAC,                |
        |         |                      | COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2, |
        |         |                      | COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2 |
        ------------------------------------------------------------------------------

    Add a row to Table 8.2 "Valid combinations of format, type and sized
    internal formats":

        Format          Type            External Bytes  Internal Format
                                        per Pixel
        --------------- --------------- --------------- ---------------
        RED             UNSIGNED_SHORT  2               R16_EXT
        RG              UNSIGNED_SHORT  4               RG16_EXT
        RGB             UNSIGNED_SHORT  6               RGB16_EXT
        RGBA            UNSIGNED_SHORT  8               RGBA16_EXT

        RED             SHORT           2               R16_SNORM_EXT
        RG              SHORT           4               RG16_SNORM_EXT
        RGB             SHORT           6               RGB16_SNORM_EXT
        RGBA            SHORT           8               RGBA16_SNORM_EXT


    Add to Table 8.13 "Correspondence of sized internal formats to base
    internal formats,...":

        Sized            Base            Bits/component              CR   TF  Req.  Req.
        Internal         Internal        S are shared bits                    rend. tex.
        Format           Format          R     G    B    A    S
        ------------     -----------     ----  ---- ---- ---  ----   ---  --- ----  ---
        R16_EXT          RED             16                           X    X   X     X
        RG16_EXT         RG              16    16                     X    X   X     X
        RGB16_EXT        RGB             16    16   16                -    X   -     X
        RGBA16_EXT       RGBA            16    16   16   16           X    X   X     X

        R16_SNORM_EXT    RED             s16                          -    X   -     X
        RG16_SNORM_EXT   RG              s16   s16                    -    X   -     X
        RGB16_SNORM_EXT  RGB             s16   s16  s16               -    X   -     X
        RGBA16_SNORM_EXT RGBA            s16   s16  s16  s16          -    X   -     X

    Add to Table 8.15: "ReadPixels format and type used during CopyTex*."

        Read Buffer Format                     format  type
        -------------------------------------  ------  --------------
        16bit Unsigned Normalized Fixed-point  RGBA    UNSIGNED_SHORT


    Add to Table 8.X.2 "Compatible internal formats for TextureViewEXT. ..."

        --------------------------------------------------------------------------
        | Class                      | Internal formats                          |
        --------------------------------------------------------------------------
        | VIEW_CLASS_64_BITS         | RGBA16_EXT, RGBA16_SNORM_EXT              |
        --------------------------------------------------------------------------
        | VIEW_CLASS_48_BITS         | RGB16_EXT, RGB16_SNORM_EXT                |
        --------------------------------------------------------------------------
        | VIEW_CLASS_32_BITS         | RG16_EXT, RG16_SNORM_EXT                  |
        --------------------------------------------------------------------------
        | VIEW_CLASS_16_BITS         | R16_EXT, R16_SNORM_EXT                    |
        --------------------------------------------------------------------------

        (If EXT_texture_view is not supported, this additions will apply to
        Table 4.X.2 "Compatible internal formats for CopyImageSubDataEXT" as
        introduced by EXT_copy_image)


    Add to Table texbo1, "Internal Formats for Buffer Textures. ..."

                                                            Component
        Sized Internal Format Base Type  Components  Norm    0 1 2 3
        --------------------- ---------  ----------  ----   ---------
        R16_EXT               ushort      1           Yes    R 0 0 1
        RG16_EXT              ushort      2           Yes    R G 0 1
        RGBA16_EXT            ushort      4           Yes    R G B A


Additions to Chapter 15 of the OpenGL ES 3.1 Specification
(Writing Fragments and Samples to the Framebuffer)

        Add to the second paragraph of Section 16.1.2 "ReadPixels":

        "For 16bit unsigned normalized fixed-point rendering surfaces,
         the combination format RGBA and type UNSIGNED_SHORT is accepted."

Errors

    No new errors.

Interactions with EXT_texture_buffer

    If EXT_texture_buffer is not supported, remove references to TexBufferEXT
    and TexBufferRangeEXT. Also remove additions to Table textbo1.


Interactions with EXT_texture_view

    If EXT_texture_view is not supported, remove references to TextureViewEXT.
    Also remove additions to Table 8.X.2.

Interactions with OES_texture_storage_multisample_2d_array

    If OES_texture_storage_multisample_2d_array is not supported, remove
    references to TexStorage3DMultisampleOES

Interactions with EXT_copy_image

    If EXT_copy_image is not supported, remove additions to Table 8.X.2.
    (If EXT_texture_view is not supported remove references to Table 4.X.2)

Interactions with EXT_texture_compression_s3tc (or equivalent):

    If EXT_texture_compression_s3tc or similar functionality (i.e.
    NV_texture_compression_s3tc etc) is not supported, ignore references
    to the following texture formats: COMPRESSED_RGB_S3TC_DXT1_EXT and
    COMPRESSED_RGBA_S3TC_DXT1_EXT.

Interactions with NV_sRGB_formats (or equivalent):

    If NV_sRGB_formats or similar functionality is not
    supported, ignore references to the following texture formats:
    COMPRESSED_SRGB_S3TC_DXT1_NV and COMPRESSED_SRGB_ALPHA_S3TC_DXT1_NV.

Interactions with EXT_texture_compression_rgtc (or equivalent):

    If EXT_texture_compression_rgtc or equivalent functionality is not
    supported, ignore references to the following texture formats:
    COMPRESSED_RED_RGTC1_EXT, COMPRESSED_SIGNED_RED_RGTC1_EXT.

Issues

    None yet.

Revision History:

   Revision 1 2014-07-03 (mheyer)
        initial revision
   Revision 2 2014-07-18 (mheyer)
        add EXT_texture_buffer, EXT_texture_view, EXT_copy_image and
        OES_texture_storage_multisample_2d_array interactions
   Revision 3 2014-07-18 (mheyer)
        rename to NV_texture_norm16, mark SNORM formats as non color-renderable
   Revision 4 2014-08-05 (mheyer)
        rename to EXT_texture_norm16, added interactions with compressed
        texture format extensions
   Revision: 5 2014-10-24 (dkoch)
        mark complete, publishing cleanup