[Mesa-dev] [PATCH 1/4] mesa: Add a Version field to the context with VersionMajor*10+VersionMinor.

[Jordan Justen]

On Thu, Jul 26, 2012 at 11:52 PM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> On 07/26/2012 05:54 PM, Jordan Justen wrote:
>> On Thu, Jul 26, 2012 at 5:27 PM, Eric Anholt <eric at anholt.net> wrote:
>>> As we get into supporting GL 3.x core, we come across more and more features
>>> of the API that depend on the version number as opposed to just the extension
>>> list.  This will let us more sanely do version checks than "(VersionMajor == 3
>>> && VersionMinor >= 2) || VersionMajor >= 4".
>>> ---
>>>  src/mesa/main/mtypes.h  |    2 ++
>>>  src/mesa/main/version.c |    6 ++++++
>>>  2 files changed, 8 insertions(+)
>>>
>>> diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
>>> index 3d59dc6..23d32a6 100644
>>> --- a/src/mesa/main/mtypes.h
>>> +++ b/src/mesa/main/mtypes.h
>>> @@ -3427,6 +3427,8 @@ struct gl_context
>>>
>>>     /** Version info */
>>>     GLuint VersionMajor, VersionMinor;
>>> +   /** VersionMajor * 10 + VersionMinor, so 31 for GL 3.1. */
>>> +   GLuint Version;
>>>     char *VersionString;
>>>
>>>     /** \name State attribute stack (for glPush/PopAttrib) */
>>> diff --git a/src/mesa/main/version.c b/src/mesa/main/version.c
>>> index efaaf58..697758e 100644
>>> --- a/src/mesa/main/version.c
>>> +++ b/src/mesa/main/version.c
>>> @@ -223,6 +223,8 @@ compute_version(struct gl_context *ctx)
>>>
>>>     override_version(ctx, &ctx->VersionMajor, &ctx->VersionMinor);
>>>
>>> +   ctx->Version = ctx->VersionMajor * 10 + ctx->VersionMinor;
>>
>> How about a macro rather than coding the *10 everywhere?
>> #define UINT_VERSION(major, minor) ((10*(major)) + (minor))

I'm not too happy with UINT_VERSION, so maybe GLVER could be a less
verbose option.

> Personally I like the major * 10 + minor version, as its clear what it
> does.  But I wouldn't object too strongly to a macro or inline function
> either.

I guess history would seem to indicate that a minor > 9 is unlikely,
but is this guaranteed?

Personally, I would prefer:
  if (ctx->Version < GLVER(major, minor))
over
  if (ctx->Version < major * 10 + minor)

And, I would prefer:
  if (ctx->Version < GLVER(3, 1))
over
  if (ctx->Version < 31)

> Also, I like Brian's idea of getting rid of VersionMajor and
> VersionMinor.  In almost all cases, the combined Version field is nicer
> to work with (as this series demonstrates), and if we need major/minor,
> extracting those is trivial.  I almost always prefer to have one copy of
> data, rather than two copies stored in different forms with code to
> synchronize them.

Agreed.

> This series is:
> Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

Same here,
Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>