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



The whole string, I believe -- basically the thing that you'd pass to getUniformLocation().

    - Vlad

----- Original Message -----
> OK - so we have:
> 
> abcdefg.hijklmnop.qrstuv.wxyz
> 
> Are we talking about the length of the whole thing - or just the
> length
> of one part (like 'qrstuv' in the example above)?
> 
> * If it's the latter, then (IMHO) a 64 character limit is fine -
> nobody
> likes to type 64 character variable names!
> * If it's the former then 64 is perhaps a little tight and we should
> consider requiring 128...although I guess I could live with 64 if it
> were absolutely necessary.
> 
> -- Steve
> 
> Vladimir Vukicevic wrote:
> > I would be fine with a 128 character limit; 64 might also be fine,
> > but I worry that someone making extensive use of structs could end
> > up with some fairly lengthy identifiers. 64 is still a good bit even
> > with structs though; does anyone have any experience with long
> > identifiers in actual real-world GLSL?
> >
> >     - Vlad
> >
> > ----- Original Message -----
> >
> >> 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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