[Mesa-dev] [PATCH 1/2] glsl: always enable OES_standard_derivatives features if supported

[Ilia Mirkin]

On Wed, May 16, 2018 at 8:04 AM, Timothy Arceri <tarceri at itsqueeze.com> wrote:
>
>
> On 16/05/18 21:12, Ilia Mirkin wrote:
>>
>>  From the spec,
>>
>> """
>>      The built-in derivative functions dFdx, dFdy, and fwidth are
>> optional, and
>>      must be enabled by
>>
>>      #extension GL_OES_standard_derivatives : enable
>>
>>      before being used.
>> """
>>
>> Sounds like you need an application override?
>
>
> The ES spec has no such wording is simply states:
>
> "dFdx(), dFdy(), and fwidth() are made optional."

That is under the heading of "Changes from Revision 59 of the OpenGL
Shading Language specification:", i.e. desktop GLSL.

There isn't a single other reference to those functions anywhere else
in https://www.khronos.org/files/opengles_shading_language.pdf . The
"optional" is in reference to it being moved out to an extension
rather than being part of the core language.

  -ilia