[Mesa-dev] [PATCH] mesa: remove erroneous check for API_OPENGL_CORE in _mesa_TexBuffer

[Ian Romanick]

On 01/28/2013 02:43 PM, Christoph Bumiller wrote:
> On 28.01.2013 23:37, Chad Versace wrote:
>> On 01/28/2013 02:01 PM, Christoph Bumiller wrote:
>>> From: Christoph Bumiller <christoph.bumiller at speed.at>
>>>
>>> Only the test of the extension enable should be relevant.
>> I don't think this change is correct.
>
> So, maybe I misinterpreted the advice in the "mesa: implement
> GL_ARB_texture_buffer_range v5" thread ?
>
> In my opinion this check *should* be removed, it is driver specific and
> prevents other drivers from exposing the extension in non-core contexts.
> It simply doesn't seem to belong here.

It seems we had a bit of a miscommunication.  We should keep these API 
checks.  GL_ARB_texture_buffer_object has interactions with 
compatibility profile that are not implemented in Mesa.  If any Mesa 
driver exposes this extension, it will be broken.  We (Marek, Brian, and 
I) had some discussion about this back in December.  We decided to just 
implement this extension for core profiles.

http://lists.freedesktop.org/archives/mesa-dev/2012-December/031349.html

I think there was additional discussion on #dri-devel.  I can probably 
find the logs if that would be helpful.

>> For most extensions, including GL_ARB_texture_buffer_object, the Intel driver
>> enables the extension flags according only to hardware capabilities. That is,
>> the decision to enable a flag is independent of the context API. See
>> intel_extensions.c.
>>
>> Removing this API check may incorrectly allow glTexBufferARB on Intel drivers
>> in a non-core GL context. I could be wrong (I don't fully understand how
>> GL dispatch works), but this change still makes me uncomfortable.
>>
>>> ---
>>>   src/mesa/main/teximage.c |    3 +--
>>>   1 files changed, 1 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/src/mesa/main/teximage.c b/src/mesa/main/teximage.c
>>> index 31a559e..5a27797 100644
>>> --- a/src/mesa/main/teximage.c
>>> +++ b/src/mesa/main/teximage.c
>>> @@ -4005,8 +4005,7 @@ _mesa_TexBuffer(GLenum target, GLenum internalFormat, GLuint buffer)
>>>      GET_CURRENT_CONTEXT(ctx);
>>>      FLUSH_VERTICES(ctx, 0);
>>>
>>> -   if (!(ctx->API == API_OPENGL_CORE &&
>>> -         ctx->Extensions.ARB_texture_buffer_object)) {
>>> +   if (!ctx->Extensions.ARB_texture_buffer_object) {
>>>         _mesa_error(ctx, GL_INVALID_OPERATION, "glTexBuffer");
>>>         return;
>>>      }
>>>
>
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