[Mesa-dev] [PATCH 01/17] mesa: consolidate definitions of max texture image units

[Marek Olšák]

Ping. Can I push this commit, Eric?

Also, I don't think it's important what the
MAX_COMBINED_TEXTURE_IMAGE_UNITS limit is right now, because a program
object cannot have more than 16 samplers *combined* anyway
(Elements(gl_shader_program::SamplerUnits) == 16), so the old limit
was wrong too.

We have some fixing to do before we can actually support 32 combined
samplers as required by GL 3.0.

Marek

On Wed, May 8, 2013 at 12:22 PM, Marek Olšák <maraeo at gmail.com> wrote:
> On Thu, May 2, 2013 at 7:12 PM, Eric Anholt <eric at anholt.net> wrote:
>> Marek Olšák <maraeo at gmail.com> writes:
>>
>>> Shaders are unified on most hardware (= same limits in all stages).
>>> No idea what the assertion was good for.
>>> ---
>>>  src/mesa/main/config.h                 |    6 ++----
>>>  src/mesa/main/context.c                |    6 ++----
>>>  src/mesa/state_tracker/st_extensions.c |    2 +-
>>>  3 files changed, 5 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/src/mesa/main/config.h b/src/mesa/main/config.h
>>> index 33b5ab0..76863bf 100644
>>> --- a/src/mesa/main/config.h
>>> +++ b/src/mesa/main/config.h
>>
>>> -   assert(MAX_COMBINED_TEXTURE_IMAGE_UNITS <= 8 * sizeof(GLbitfield));
>>> -
>>
>> I think this assert is asserting that _EnabledUnits of gl_texture_attrib
>> can fit the size of the Unit[] array, which seems important.
>
> With Gallium drivers, _EnabledUnits is only used for the
> fixed-function vertex program, where the number of texture coord units
> is limited to 8. The fixed-function vertex program doesn't even use
> the bits of _EnabledUnits, it only checks if the variable is non-zero,
> so it could just be a boolean.
>
> However, swrast uses _EnabledUnits, though the variable seems to be
> used for fixed-function only.
>
> Is this explanation satisfactory that _EnabledUnits doesn't need to
> have more than 32 bits or am I missing something else?
>
> Marek