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RE: [filters] Shading language recommendation

From: Sylvain Galineau <sylvaing@microsoft.com>
Date: Wed, 22 Aug 2012 18:00:04 +0000
To: Chris Marrin <cmarrin@apple.com>
CC: Dirk Schulze <dschulze@adobe.com>, "public-fx@w3.org" <public-fx@w3.org>
Message-ID: <3C4041FF83E1E04A986B6DC50F0178291BE2D68C@TK5EX14MBXC227.redmond.corp.microsoft.com>
[Chris Marrin:]

>>I would like to resolve this before FPWD.

>I'd like to return to the questions put forth in previous posts:

>1) Is your objection technical or something else?

1) We believe the conformance of a Filter Effects implementation should not depend on its use of GL SL ES i.e. if a UA wants to support this functionality with a different technology they should be able to do so.
2) Generally speaking, we do not believe a CSS feature should require, recommend or depend on a specific low-level technology such as a shading language. We are not aware of any such dependencies to date and believe such architectural concerns should be kept orthogonal. As CSS specifications generally avoid even taking a dependency on a specific document language it is very unusual for a module to recommend a technology which, from a CSS standpoint, has been an implementation detail to date. A clear compelling reason to do so should at least be explicitly articulated in the specification. 
3) More specifically, if the feature aims to provide an entry point to lower level capabilities for extensibility purposes e.g. custom CSS shaders, we believe there should be a mechanism to support alternative languages; this would also future-proof the platform.
4) We are concerned that including GL SL as a RECOMMENDED feature makes it an essential feature under the W3C Patent Policy. We don't believe the shading language itself is within the scope of the CSS WG charter and we didn't carry out the  comprehensive IP review that would be necessary for us to participate on that basis. We suspect that other organizations also didn't do this.

>2) If your objection is based on the issue of "my platform does not support GLSL", what about ANGLE and the fact that 
>WebGL (which is the basis for the shading language specified) is designed to be implemented on Direct3D, and in fact 
>there are currently multiple such implementations available?

See above.

>3) If the spec were written with no recommended shading language, wouldn't that inhibit widespread adoption? 
>How would we deal with that?

The widespread adoption of what? Do canned effects such as grayscale, sepia, saturate etc. need a specific shading
language recommendation to achieve interop? 
Received on Wednesday, 22 August 2012 18:00:47 UTC

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