Re: Is Apple's patent valid?

Chris Lilley wrote:
>US patent 5379129 was filed on May 8, 1992 and was
>granted on January 3, 1995. It cannot, therefore, assuming prior art
>means anything, be patenting *general* alpha compositing.

OPENGL has had a GL_ONE_MINUS_SRC_COLOR blending mode
(factor = (1,1,1,1)-(Rs, Gs, Bs, As)) at least since 1993
when it was described in the OpenGL Programming Guide.
If someone has the OPENGL spec handy, in a copy published before
May 8, 1992, there's the prior art.

This is probably getting off-topic for the patent-policy discussion except
as an example of its application.  I think W3C should be willing to invest
a fair amount of effort in looking at the validity of patents that
the candidate recommendation might infringe, overturning invalid ones,
and, as you wrote in an earlier message, provide commentary about them
in the Recommendation.  W3C should also look very hard for workarounds if
it cannot negotiate RF licensing of any patents found to be valid and that
the candidate recommendation infringes.  It should be W3C policy that
participants in a WG must offer RF licensing--to do otherwise leaves
the participant in a conflict-of-interest situation.

Glenn

Received on Thursday, 4 October 2001 10:46:39 UTC