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Re: quick comments on Matrix

From: Robert O'Callahan <robert@ocallahan.org>
Date: Sat, 16 Mar 2013 15:46:17 +1300
Message-ID: <CAOp6jLbauRK4HWkfBGSCv520Gz6pyg-My-oy7yAiLh-obtR6Zg@mail.gmail.com>
To: Dirk Schulze <dschulze@adobe.com>
Cc: "public-fx@w3.org" <public-fx@w3.org>
On Sat, Mar 16, 2013 at 12:36 AM, Dirk Schulze <dschulze@adobe.com> wrote:

> I guess what you suggest is that (x,y)^T = (0,1)^T is a rotation by 90
> degree and (1,0)^T is a rotation by 0 degree? (Note that the rotation is
> clockwise on SVG.) Maybe it is better to just specify the angle between
> (1,0)^T and the vector given by x and y. The only special case would be
> that both values are 0 (which could be defined to be a multiplication by
> the identity transform == no affect).
>

Sure.

There were similar discussions on webkit-dev mailing list[1].
>

That discussion has people arguing for floats but no-one defending
doubles...


> Usually 32bit maps better to the underlaying GPU. The difference is less
> important on desktop CPUs. With standards like OpenCL 1.1 full and others,
> GPUs are required to get better on double precision anyway. The decision
> seems to be more if we want to optimize for current hardware or look at the
> life time of the spec and assume that HW gets better. Changing the spec
> later causes incompatibility later (even if the difference is very small).
> WebIDL does not support optional datatypes it seems. That means I needed
> to choose between 64-bit and 32-bit. Upon on requests here on this list, it
> seems that there are use cases for double precision beyond graphics for the
> screen.
>

What are they?

Rob
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Received on Saturday, 16 March 2013 02:46:46 GMT

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