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Re: [css-shaders] subdivision for transparency

From: Alan Gresley <alan@css-class.com>
Date: Wed, 05 Oct 2011 21:45:10 +1100
Message-ID: <4E8C3536.50705@css-class.com>
To: "Gregg Tavares (wrk)" <gman@google.com>
CC: www-style list <www-style@w3.org>
On 5/10/2011 3:52 AM, Gregg Tavares (wrk) wrote:

Hello Gregg. It good to reply to the same message thread instead of 
creating a new topic.

> Note that that isn't just a "display" problem.
>
> If you look at the 2 screenshots
>
> http://greggman.com/downloads/examples/correct-3d-css-polygon-sorting-subdivisions-safari.png
> http://greggman.com/downloads/examples/incorrect-3d-css-polygon-sorting-subdivisions-chrome.png
>
>
> You'll notice that in the chrome screenshot Element #2 (green) has been
> drawn in front of the other 2 elements (red, blue). Based on what is
> displayed the user would expect to be able to click on anything in Element
> #2. But, being based on WebKit the clicking code acts as though the scene
> was subdivided meaning if you click on areas that overlap you'll get
> unexpected results.
>
> This will only get much worse with CSS shaders where without proper sorting
> it will be very hard to figure out to which elements mouse events should go.

I don't see how this is related to CSS shaders. I don't see how you can 
even suggest that it could cause problems with clicking. You are jumping 
to fast and what is needed are simpler test cases.

Anyway, it's a Chrome painting bug and it's wrong. Here a test case 
(with two examples).

http://css-class.com/test/bugs/transforms/painting-order-intersecting-transforms1.htm

The div with a blue background paints in front of parts of the div with 
a lime background and parts of the #frame with a red border. Changing 
the order of the source does nothing to change the bug.

Note for implementers. I was going to report it on WebKit Bugzilla but 
Chrome is not available for selection. Where can I report this bug?




-- 
Alan Gresley
http://css-3d.org/
http://css-class.com/
Received on Wednesday, 5 October 2011 10:45:54 GMT

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