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Re: [Public WebGL] Re: maximum length of identifiers in WebGL GLSL



2 cents:

* a fixed specified limit is good.

* it should be a generous limit, since some devs will probably
machine-generate their shaders (think C++ name mangling etc).  On the
other hand, a huge limit won't be exercised much.  How about 256
chars?  That should encompass all human-written shaders, and then
some.  For machine-written shaders, it could be exceeded but it's
plenty of chars to generate a unique ID by hashing down a very long
id.

-T

On Mon, Aug 2, 2010 at 4:39 PM, Gregg Tavares (wrk) <gman@google.com> wrote:
> ping.
> Anyone have an opinion on this?
> There are 2 issues.
> Issue #1: It's possible a GL driver could be exploited by passing it giant
> identifiers.  Examples.
> ctx.bindAttribLocation(program, 4MegIdentifier, location);
> ctx.shaderSource(shader, shaderWith4MegIdentifiers, ...);
> Issue #2: Having a Min/Max identifier size of WebGL means programs will be
> more likely to work across platforms.
> Right now one platform might have a 64 character limit, another a 128
> character limit. If you're developing on the 128 character limit system you
> won't know your WebGL program is not going to work on some other system.  If
> instead the spec says it must support 128 characters to be WebGL conformance
> than an system who's OpenGL driver does not support 128 character will
> either need a new driver or the WebGL implementation will need to alias the
> ids. In either case WebGL becomes more compatible across system.
> Note that the GLSL translator everyone is currently using already has a 128
> character limit but it would be nice if that limit (or some limit) was
> formalized in the spec.
>
>
>
> On Thu, Jul 29, 2010 at 3:11 PM, Gregg Tavares (wrk) <gman@google.com>
> wrote:
>>
>> Do we want to specify a maximum identifier length for WebGL GLSL?
>> I didn't see one in the GLSL spec.  I was going to write a test with
>> really long identifiers (4meg) to see if I could find some drivers that had
>> problems with them but it might be better to just require WebGL to enforce
>> some maximum length.  64 chars? 128 chars? 256 chars which will make shaders
>> less likely to fail on some drivers.
>> Thoughts?
>

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