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Re: [Public WebGL] WebGL Extensions




On Jun 3, 2010, at 9:24 AM, Gregg Tavares wrote:



On Thu, Jun 3, 2010 at 5:12 AM, Oliver Hunt <oliver@apple.com> wrote:

On Jun 3, 2010, at 4:47 AM, Steve Baker wrote:

> Vladimir Vukicevic wrote:
>> Hm, I thought we didn't have this which is where the confusion came from, but looks like Chris put it in a while ago:
>>
>> https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/WebGL-spec.html#5.14.14
>>
>> Maybe it's just missing a sentence or two at the end explaining that extensions are WebGL specific, and if WebGL is built on top of an underlying OpenGL driver, that driver's extensions will not necessarily be exposed?
>>
> IMHO, it is essential that WebGL does NOT expose underlying driver
> extensions by default.  The reason being one of security.

For what it's worth the way that the JS/DOM bindings work in most (all?) browsers require every exposed function to be defined and implemented explicitly -- it would not be possible for an implementation to automate the exposure of an arbitrary set of unknown extensions.

Plenty of extensions only enable new ENUMs and new features to GLSL. No changes to the API are required so it's very possible to automate the exposure of an arbitrary set of unknown extensions unless WebGL specifically prevents that exposure.

How does the runtime _know_ that an extension is only exposing an new enum? How would the glsl validator _know_ what glsl features existed due to an arbitrary extension?  The implementation needs to handle every extension itself -- it can't do it automatically through the glGetExtensions API (or whatever it's called)

--Oliver

 

--Oliver

>
>  -- Steve
>
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