[Public WebGL] Re: WebGL 2 EXT_disjoint_timer_query in Firefox

Kenneth Russell [email protected]
Wed May 24 10:55:05 PDT 2017

That's correct, it's not supposed to be advertised.
EXT_disjoint_timer_query is for WebGL 1.0, and _webgl2 for 2.0.

The split was made fairly late in the WebGL 2.0 spec process, which is
probably why it slipped by in Firefox.

https://github.com/KhronosGroup/WebGL/pull/2405 strengthens the conformance
test. Thanks for pointing this out.


On Wed, May 24, 2017 at 10:36 AM, Kai Ninomiya <[email protected]> wrote:

> IIRC the EXT_disjoint_timer_query extension is not supposed to be
> available at all for WebGL 2 contexts. Getting that extension should fail.
> It's possible we forgot to add a conformance test for this behavior, and it
> slipped by in Firefox.
> On Wed, May 24, 2017 at 8:19 AM Tarek Sherif <[email protected]> wrote:
>> Ah, I just realized I was only using the TIME_ELAPSED_EXT and
>> GPU_DISJOINT_EXT enums on the extensions, which is why they appeared to be
>> interchangeable. The presence of the original EXT_disjoint_timer_query on a
>> WebGL 2 context does still strike me as odd, since the text from spec I
>> quoted suggests that it shouldn't be.
>> Tarek Sherif
>> http://tareksherif.net/
>> https://www.biodigital.com/
>> On Wed, May 24, 2017 at 9:29 AM, Tarek Sherif <[email protected]> wrote:
>>> I'm confused by how EXT_disjoint_timer_query is behaving with WebGL 2
>>> contexts in Firefox. It allows both WebGL 1 (e.g. ext.createQueryEXT) and
>>> WebGL 2 (gl.createQuery) usage. Is the WebGL 2 usage is guaranteed for this
>>> extension? The EXT_disjoint_timer_query spec doesn't mention the WebGL 2
>>> usage, but does state: "This version of the disjoint_timer_query extension
>>> is exposed only on on WebGL 1.0 contexts. See the _webgl2 version of the
>>> extension for how it is exposed on WebGL 2.0 contexts." Does that mean
>>> EXT_disjoint_timer_query should behave as specified in
>>> EXT_disjoint_timer_query_webgl2 when using a WebGL 2 context? If so, it
>>> would seem that the WebGL 1-like functionality that Firefox exposes on that
>>> extension is incorrect.
>>> Either way, this all seems more confusing than it needs to be...
>>> Tarek Sherif
>>> http://tareksherif.net/
>>> https://www.biodigital.com/
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