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Re: [Public WebGL] problematic GetParameter pnames



On Wed, Jun 9, 2010 at 7:26 PM, Mark Callow <callow_mark@hicorp.co.jp> wrote:
> The first three are equivalent respectively to the following in Open GL 3.1:
>
> MAX_FRAGMENT_UNIFORM_COMPONENTS/4
> MAX_VERTEX_UNIFORM_COMPONENTS/4
> MAX_VARYING_COMPONENTS/4
>
> For the first 2, I'm assuming the WebGL implementation is using only the
> default uniform block.
>
> A shader compiler is required for WebGL so I think we decided to drop the
> SHADER_COMPILER query.
>
> Since readPixels is supported, IMPLEMENTATION_COLOR_READ_FORMAT and
> IMPLEMENTATION_COLOR_READ_TYPE ought to be supported by WebGL so the
> application can use the most efficient format when reading pixels. This
> seems be an oversight in the WebGL spec. There is no equivalent on desktop
> GL as typically they have format conversion hardware so any format is
> equally good. A WebGL implementation on desktop will have to emulate these.

Yes, the absence of IMPLEMENTATION_COLOR_READ_FORMAT and
IMPLEMENTATION_COLOR_READ_TYPE in the getParameter documentation is an
oversight, as is the presence of the SHADER_COMPILER enum in the spec.
I've updated the spec.

The gl-get-calls test querying SHADER_COMPILER is a bug in the test.

-Ken

> Regards
>
> -Mark
>
>
>
> On 10/06/2010 06:38, Benoit Jacob wrote:
>
> Hi,
>
> I have trouble implementing the following pnames in GetParameter:
>
> A. The following pnames are mentioned in the WebGl spec for GetParameter,
> but are seem to be absent from desktop OpenGL. How to implement them on
> desktop OpenGL systems?
>     MAX_FRAGMENT_UNIFORM_VECTORS
>     MAX_VERTEX_UNIFORM_VECTORS
>     MAX_VARYING_VECTORS
>
> B. The following pnames are mentioned in the WebGL spec only in the general
> list of constants, but not in the section on getParameter. Yet the
> gl-get-calls test is trying to pass them to getParameter. Which is right?
>     SHADER_COMPILER
>     IMPLEMENTATION_COLOR_READ_FORMAT
>     IMPLEMENTATION_COLOR_READ_TYPE
>
> Cheers,
> Benoit
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