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Re: [Public WebGL] GLSL loops and constant expressions



On 12/07/2010 08:59 PM, Mark Callow wrote:
>> Not having the possibility to use "while" loops or "for" loops with
>> non-constant expressions is very, very sad.
>> As with some other things, like multiple rendering targets and depth
>> texture formats, I knew the specs say that, but I hoped in some loose
>> validation whenever the underlying GL implementation allows them.
>> Maybe these features (and others) deserve their extensions?
>> For example, the gl_FragData[i] is accepted only if i is zero, as the
>> specs say that there is only a COLOR0_ATTACHMENT. But can we actually
>> relax these limitations whenever the system is capable?
>> Sure, they won't work on all GL|ES 2.0 systems, but, as usual, a
>> developer can ask the capabilities before going on.
>>
>> Marco.
>>     
> The issue I see is, and this applies to the whole extension registry
> thing, is that  many webgl applications will fail to run on all
> implementations. This is because not all developers will provide
> fall-backs, due to lack of knowledge, the sheer complexity of dealing
> with an increasingly large number of extensions, laziness, 'thoughts
> like "I'm just making this to amuse myself" and similar reasons.
>
> In the early days of WebGL this could be a death knell. I think the
> extension registry is premature. We should wait until WebGL establishes
> a reputation for 'just working' before we create opportunities for
> fragmentation.
>   
It's a tough call.  Sure, having extensions and features that aren't
always there (eg vertex textures) will result in more 'amateur' efforts
failing on more machines - but shipping without any really compelling,
professional titles because the feature set is just too limited is also
"A Bad Thing".  One really good "killer app" title would serve to
convince developers that this can work - and the tidal wave that would
ensue would convince the nay-sayers.  I think we're doing a reasonable
job of balancing those two extremes...but there are one or two
extensions that would REALLY help - I agree with Marco that Multiple
Render Targets would get the most bang-for-buck of any addition - and
strictly, it's not even an extension - just a glGet to tell you the max
number of render targets you're allowed to use would suffice.   I'm not
sure what percentage of hardware out there can support it though.

 -- Steve

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