[Mesa-dev] [PATCH] glsl: properly setting var->data.binding if explicit_binding is true

[Timothy Arceri]

On Sun, 2015-04-26 at 15:23 +0200, Alejandro Piñeiro wrote:
On 26/04/15 00:08, Timothy Arceri wrote:
> > On Sat, 2015-04-25 at 18:46 +0200, Alejandro Piñeiro wrote:
> >> There was a typo on commit c0cd5b, doing it when explicit_binding
> >> was false. This prevented to use any binding point different to 0.
> >> ---
> >>
> >> Taking into account the explanation on the header about the
> >> variable binding (ast.h:553)
> >>
> >>    /**
> >>     * Binding specified via GL_ARB_shading_language_420pack's
"binding" keyword.
> >>     *
> >>     * \note
> >>     * This field is only valid if \c explicit_binding is set.
> >>     */
> >>    int binding;
> >>
> >> The binding is correct (and should be updated) if explicit_binding
is true.
> >> But the current behaviour was updating it if it was false. 
> >>
> >> This was not detected by piglit because all the calls to
> >> glBindBufferBase(GL_ATOMIC_COUNTER_BUFFER are using 0.
> >>
> >> I tested this patch by running all piglit on my system, and I
didn't
> >> detect regression. I also runned make check without issues.
> >>
> >> https://bugs.freedesktop.org/show_bug.cgi?id=90175
> > You should probably convert your test program to a piglit test also
so
> > this bug can be detected if it happens again in the future.
> 
> There are several piglit tests at spec/arb_shader_atomic_counters
> testing that you get what you expect while using atomic counters.
> Probably it would be enough to just modify some of the already
existing
> tests, using a non-zero binding point (for example at semantics.c).
> 
> But I don't have too much experience tweaking/creating piglit tests.
> What option would be preferred for this case? A new test or just
modify
> a little one of the already available?
>

Take a look at buffer-binding.c it would probably make sense to add your
subtest to this test.

Your test would probably look something like this:

static bool
run_test_explicit_binding(test params here)
{

	/* test code */

	if (explict_binding_set_incorrectly)
		return false;

	return true;
}

And you would add something like this to piglit_init()*/

if (piglit_is_extension_supported("GL_ARB_shading_language_420pack"))

        atomic_counters_subtest(&status, GL_NONE,
                                "Atomic buffer explicit binding"
                                run_test_explicit_binding, 
}

You would also need to update the comment at the top of the file.