[Mesa-dev] [PATCH] mesa: expose EXT_texture_compression_s3tc on GLES

[Erik Faye-Lund]

On Tue, 2018-10-30 at 07:44 -0400, Ilia Mirkin wrote:
> On Thu, Oct 25, 2018 at 6:59 AM Erik Faye-Lund
> <erik.faye-lund at collabora.com> wrote:
> > 
> > From: Marek Olšák <marek.olsak at amd.com>
> > 
> > The spec was modified to support GLES.
> > 
> > Tested-by: Erik Faye-Lund <erik.faye-lund at collabora.com>
> > ---
> > This replaces this patch:
> > https://patchwork.freedesktop.org/patch/257423/
> > 
> >  docs/relnotes/18.3.0.html        |  1 +
> >  src/mesa/main/extensions_table.h |  2 +-
> >  src/mesa/main/glformats.c        | 11 +++++++++++
> >  3 files changed, 13 insertions(+), 1 deletion(-)
> > 
> > diff --git a/docs/relnotes/18.3.0.html b/docs/relnotes/18.3.0.html
> > index 5874d3fa330..e0061872de4 100644
> > --- a/docs/relnotes/18.3.0.html
> > +++ b/docs/relnotes/18.3.0.html
> > @@ -57,6 +57,7 @@ Note: some of the new features are only available
> > with certain drivers.
> >  <li>GL_AMD_multi_draw_indirect on all GL 4.x drivers.</li>
> >  <li>GL_AMD_query_buffer_object on i965, nvc0, r600, radeonsi.</li>
> >  <li>GL_EXT_disjoint_timer_query on radeonsi and most other Gallium
> > drivers (ES extension)</li>
> > +<li>GL_EXT_texture_compression_s3tc on all drivers (ES
> > extension)<li>
> >  <li>GL_EXT_vertex_attrib_64bit on i965, nvc0, radeonsi.</li>
> >  <li>GL_EXT_window_rectangles on radeonsi.</li>
> >  <li>GL_KHR_texture_compression_astc_sliced_3d on radeonsi.</li>
> > diff --git a/src/mesa/main/extensions_table.h
> > b/src/mesa/main/extensions_table.h
> > index 09bf923bd0e..47db1583135 100644
> > --- a/src/mesa/main/extensions_table.h
> > +++ b/src/mesa/main/extensions_table.h
> > @@ -278,7 +278,7 @@ EXT(EXT_texture_buffer                      ,
> > OES_texture_buffer
> >  EXT(EXT_texture_compression_dxt1            ,
> > ANGLE_texture_compression_dxt          , GLL, GLC, ES1, ES2, 2004)
> >  EXT(EXT_texture_compression_latc            ,
> > EXT_texture_compression_latc           , GLL,  x ,  x ,  x , 2006)
> >  EXT(EXT_texture_compression_rgtc            ,
> > ARB_texture_compression_rgtc           , GLL, GLC,  x ,  x , 2004)
> > -EXT(EXT_texture_compression_s3tc            ,
> > EXT_texture_compression_s3tc           , GLL, GLC,  x ,  x , 2000)
> > +EXT(EXT_texture_compression_s3tc            ,
> > EXT_texture_compression_s3tc           , GLL, GLC,  x , ES2, 2000)
> >  EXT(EXT_texture_cube_map                    ,
> > ARB_texture_cube_map                   , GLL,  x ,  x ,  x , 2001)
> >  EXT(EXT_texture_cube_map_array              ,
> > OES_texture_cube_map_array             ,  x ,  x ,  x ,  31, 2014)
> >  EXT(EXT_texture_edge_clamp                  ,
> > dummy_true                             , GLL,  x ,  x ,  x , 1997)
> > diff --git a/src/mesa/main/glformats.c b/src/mesa/main/glformats.c
> > index 6cb3435dea2..f8fc36e9311 100644
> > --- a/src/mesa/main/glformats.c
> > +++ b/src/mesa/main/glformats.c
> > @@ -2803,6 +2803,17 @@ _mesa_es3_error_check_format_and_type(const
> > struct gl_context *ctx,
> >        internalFormat = effectiveInternalFormat;
> >     }
> > 
> > +   /* The GLES variant of EXT_texture_compression_s3tc is very
> > vague and
> > +    * doesn't list valid types. Just do exactly what the spec
> > says.
> > +    */
> > +   if (ctx->Extensions.EXT_texture_compression_s3tc &&
> > +       (internalFormat == GL_COMPRESSED_RGB_S3TC_DXT1_EXT ||
> > +        internalFormat == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT ||
> > +        internalFormat == GL_COMPRESSED_RGBA_S3TC_DXT3_EXT ||
> > +        internalFormat == GL_COMPRESSED_RGBA_S3TC_DXT5_EXT))
> > +      return format == GL_RGB || format == GL_RGBA ? GL_NO_ERROR :
> > +                                                     GL_INVALID_OP
> > ERATION;
> 
> Presumably GL_RGB only for GL_COMPRESSED_RGB_S3TC_DXT1_EXT and
> GL_RGBA
> for the others?
> 

Actually, this is AFAICT what the comment refers to. The extension spec
says:

"
    Components are then selected from the resulting R, G, B, or A    
    values to obtain a texture with the base internal format specified 
    by <internalformat>, which must match <format> except when <target>
    is TEXTURE_2D and <internalformat> is one of the following
    compressed formats: COMPRESSED_RGB_S3TC_DXT1_EXT,
    COMPRESSED_RGBA_S3TC_DXT1_EXT, COMPRESSED_RGBA_S3TC_DXT3_EXT, or
    COMPRESSED_RGBA_S3TC_DXT5_EXT. In this case, conversion from only
    RGB and RGBA formats are supported during texture image processing.
    <format> values other than RBA or RGBA will result in the
    INVALID_OPERATION error. In all other cases where <internalformat>
    does not match <format>, the error INVALID_OPERATION is generated.
"

This implies, as far as I can read, that RGB <-> RGBA is allowed. It's
a bit strange, I must admit, but it seems to be what the spec says.

> > +
> >     switch (format) {
> >     case GL_BGRA_EXT:
> >        if (type != GL_UNSIGNED_BYTE || internalFormat != GL_BGRA)
> > --
> > 2.17.2
> > 
> > _______________________________________________
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> > mesa-dev at lists.freedesktop.org
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> 
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