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[csswg-drafts] [css-transforms] [geometry-1] [webxr] Extract matrix fundamentals into a separate spec (#4076)

From: Manish Goregaokar via GitHub <sysbot+gh@w3.org>
Date: Mon, 01 Jul 2019 19:56:32 +0000
To: public-css-archive@w3.org
Message-ID: <issues.opened-462884424-1562010991-sysbot+gh@w3.org>
Manishearth has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-transforms] [geometry-1] [webxr] Extract matrix fundamentals into a separate spec ==
Various specs use the concept of matrices. CSS transforms has the most in-depth coverage, with [a whole section on the mathematical description of transform functions](https://drafts.csswg.org/css-transforms-2/#mathematical-description).

The geometry spec also uses matrices for DOMMatrix, and [uses concepts like multiplication](https://drafts.fxtf.org/geometry/#DOMMatrix). Furthermore, it refers to the parsing algorithm in css-transforms.

WebXR [also relies on matrices](https://immersive-web.github.io/webxr/#matrix) and refers to concepts like ["quaternion that describes the rotation indicated by the top left 3x3 sub-matrix"](https://immersive-web.github.io/webxr/#multiply-transforms). There was a time when it relied on matrix decomposition as well. We've had a bunch of stumbles over premultiply/postmultiply in the past, while a lot of the ambiguity has been cleaned up it would have been nice to outsource the problem to a unified spec.

I'm sure there are other specs like this.

It would be nice if we had a _single_ spec, much like the [infra spec](https://infra.spec.whatwg.org/) that defined all matrix operations in one place, including things like conventions used (I think all w3c specs use column-vector matrices). All other specs can simply refer to these for the actual algorithm.

cc @zcorpan for the geometry spec, @klausw for matrices in the WebXR spec

I'm not sure if this is the right place for this, but the transforms spec is the one with the _most_ matrix stuff, and it covers a lot of the definitions more thoroughly than others.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/4076 using your GitHub account
Received on Monday, 1 July 2019 19:56:34 UTC

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