[waffle] [RFC v2] wflinfo: add GLSL version information to wflinfo

[Dylan Baker]

On Monday, November 17, 2014 10:15:54 AM Chad Versace wrote:
> On Sun 16 Nov 2014, Jordan Justen wrote:
> >On 2014-11-15 12:47:05, Emil Velikov wrote:
> >> Hi Dylan,
> >> On 14/11/14 17:39, Dylan Baker wrote:
> >> > v2: - Don't print for gles1, since gles1 doesn't have a shading language
> >> >       and will always return FLINFO_GL_ERROR
> >> >
> >> > Signed-off-by: Dylan Baker <dylanx.c.baker at intel.com>
> >> > ---
> >> >
> >> > This addresses Jordan's comments, but from the point of view of having a
> >> > parsable output not printing the string 'OpenGL shading language...'
> >> > seems suboptimal. Would it be better to add an additional block to the
> >> > assignment if and look for fixed-functions versions and set the value of
> >> > shading langauge to 'Fixed Function' or 'None' instead?
> >> >
> >> I'm not sure how Chad and Jordan feel about it but making gles1's shader
> >> langugage version return "None" sounds good imho.`
> >
> >I'd rather not give output for things that are not applicable based on
> >the platform or api.
> >
> >Maybe ... N/A for situation like this would make sense in verbose mode
> >though.
> 
> If wflinfo does print anything for the GLES1 GLSL version, I prefer it to be 
> "None". If it printed "N/A", I predict that some user will get confused 
> by over-interpreting the meaning of "N/A". On the contrary, "None" is 
> straightforward and asks for no further interpretation.
> 
> Like Emil and Dylan, I have a slight preference that wflinfo print 
> "None" for the GLES1 GLSL version rather than be silent. But it's only 
> a slight preference; it doesn't matter much to me.
> 
> Dylan, why in the original patch did you decide to print anything at all 
> for the GLES1 GLSL version? You vaguely mention parseability. Can you 
> say more about any parsing issues you forsee, and how those issues might 
> affect Piglit?
> 
> I don't want this thread to devolve into a bikeshed. I just want know if
> you have concrete concerns about the silence vs "None" decision before 
> any patch gets committed.

Sure.

Here's my thoughts on the matter. wflinfo is meant to be parsed by
external tools. If wflinfo doesn't return 'OpenGL shading language
version string' under some circumstances we force all parsers to
implement functionality to either recognize that gles 1 and gl < 2.0 do
not have shading languages, or handle not getting a shading version. On
the other hand if wflinfo handles that case then parsers don't need to.

In other words this allows complexity to be implemented once rather than
multiple times.

I also think that wflinfo is the right place to handle this because
wflinfo is guaranteed to have all of the information that is required to
make the correct decisions, where a client parser might not.

Dylan

> 
> >> > @@ -561,6 +567,10 @@ print_wflinfo(const struct options *opts)
> >> >      printf("OpenGL vendor string: %s\n", vendor);
> >> >      printf("OpenGL renderer string: %s\n", renderer);
> >> >      printf("OpenGL version string: %s\n", version_str);
> >> > +     // Do not print WFLINFO_GL_ERROR for gles1, there is not GLSL for GL ES 1.x
> >> > +     if (strcmp(api, "gles1") != 0) {
> >> > +             printf("OpenGL shading language version string: %s\n", language_str);
> >> > +     }
> >
> >How about a new function, and call it like this:
> >    if (opts->context_api != WAFFLE_CONTEXT_OPENGL_ES1) {
> >        print_glsl_info();
> >    }
> >
> >That would avoid calling glGetString(GL_SHADING_LANGUAGE_VERSION) for
> >gles1.
> 
> Agreed. If wflinfo prints no GLES1 GLSL info in the final patch, then 
> wflinfo shouldn't call glGetString(GL_SHADING_LANGUAGE_VERSION) at all 
> for GLES1. It's just a good idea to avoid producing GL errors when 
> possible.
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