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[Public WebGL] Re: texParameteri and texParameterf



(You don't mind that I re-add the list in CC, do you?)

----- Original Message -----
> On Thu, Aug 05, 2010 at 01:34:02PM -0700, Benoit Jacob wrote:
> > Ah OK. I hadn't read the desktop GL spec.
> >
> > I have read the WebGL and GL ES specs and haven't found any clue
> > about whether this should fail or not. Does someone know where this
> > is defined, or should the spec be clarified?
> 
> Need to clarify exactly what you're asking about. You said "an
> integer value". But glTexParameter* can specify either float, int, or
> enum values. For a float or int value, there are well-defined numeric
> conversions; you can specify int values for a parameter that's
> internally float, or vice-versa, and get conversions as described in
> chapter 2 of the GL/ES specs.

Thanks, but this Chapter 2 is 40 pages long; could you please refer to a more specific part of it?

> 
> For an enum value, you in principle could specify it as a float but
> it should only succeed if the conversion is lossless and the result is
> an accepted value for that parameter, per the general description of
> INVALID_ENUM errors also in ch. 2. In practice I wouldn't be surprised
> for there to be some variability in implementations as this is a
> really
> obscure case - nobody in C is likely to write something like
> 
> GLfloat enumVal = (GLfloat)GL_LINEAR;
> glTexParameterfv(GL_TEXTURE2D, GL_TEXTURE_MIN_FILTER, &enumVal);
> 
> or
> 
> glTexParameterf(GL_TEXTURE2D, GL_TEXTURE_MIN_FILTER,
> (GLfloat)GL_LINEAR);

Ah, thanks, this is exactly what I was inquiring about. I need to have a closer look at that chapter 2.

Cheers,
Benoit

> 
> Jon
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