[PATCH 5/7] glamor: compute GLSL version from GL_SHADING_LANGUAGE_VERSION

[Kenneth Graunke]

On Monday, May 11, 2015 09:23:56 PM Keith Packard wrote:
> This replaces a kludge which used the GL version as a proxy for the
> GLSL version.
> 
> Signed-off-by: Keith Packard <keithp at keithp.com>
> ---
>  glamor/glamor.c | 20 +++++++++++++-------
>  1 file changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/glamor/glamor.c b/glamor/glamor.c
> index 6f4f309..641c2e4 100644
> --- a/glamor/glamor.c
> +++ b/glamor/glamor.c
> @@ -337,6 +337,8 @@ glamor_init(ScreenPtr screen, unsigned int flags)
>      glamor_screen_private *glamor_priv;
>      int gl_version;
>      int max_viewport_size[2];
> +    const char *shading_version_string;
> +
>      PictureScreenPtr ps = GetPictureScreenIfSet(screen);
>  
>      if (flags & ~GLAMOR_VALID_FLAGS) {
> @@ -380,14 +382,18 @@ glamor_init(ScreenPtr screen, unsigned int flags)
>  
>      gl_version = epoxy_gl_version();
>  
> -    /* Would be nice to have a cleaner test for GLSL 1.30 support,
> -     * but for now this should suffice
> -     */
> -    if (glamor_priv->gl_flavor == GLAMOR_GL_DESKTOP && gl_version >= 30)
> -        glamor_priv->glsl_version = 130;
> -    else
> -        glamor_priv->glsl_version = 120;
> +    shading_version_string = (char *) glGetString(GL_SHADING_LANGUAGE_VERSION);
>  
> +    glamor_priv->glsl_version = 0;
> +    if (shading_version_string)
> +        glamor_priv->glsl_version = (int) (strtof(shading_version_string, NULL) * 100.0 + 0.5);
> +
> +    if (glamor_priv->glsl_version < 100 || glamor_priv->glsl_version > 1000) {
> +        if (glamor_priv->gl_flavor == GLAMOR_GL_DESKTOP && gl_version >= 30)
> +            glamor_priv->glsl_version = 130;
> +        else
> +            glamor_priv->glsl_version = 120;
> +    }
>  
>      /* We'd like to require GL_ARB_map_buffer_range or
>       * GL_OES_map_buffer_range, since it offers more information to
> 

Sadly, this won't work for GLES contexts.

The format of the GL_SHADING_LANGUAGE_VERSION string, on GL, is:

   <version number><space>vendor-specific information>
   i.e. "3.30 from the totally awesome X.org project"

but in GLES, it's:

   "OpenGL ES GLSL ES N.M vendor-specific information"
   i.e. "OpenGL ES GLSL ES 3.00"

If you care about making that work, I recommend swiping Piglit's
piglit_get_glsl_version() function, available here:
http://cgit.freedesktop.org/piglit/tree/tests/util/piglit-shader.c#n28
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