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Re: SVG Compositing + 3D Transform

From: Robert O'Callahan <robert@ocallahan.org>
Date: Tue, 17 May 2011 00:45:17 +1200
Message-ID: <BANLkTik3=UqGM-iEm2Xb+aREa_OWB2ZunQ@mail.gmail.com>
To: Alex Danilo <alex@abbra.com>
Cc: Dirk Schulze <vbs85@gmx.de>, www-svg List <www-svg@w3.org>
On Mon, May 16, 2011 at 11:06 PM, Alex Danilo <alex@abbra.com> wrote:

> Rob, I'm not sure what you mean by preserve-3d?
>

http://www.w3.org/TR/css3-3d-transforms/#transform-style-property

Unfortunately it's currently under-specified so I can't tell you exactly
what it means :-).

The comp-op is applied when the object is rendered to the canvas. So if a
> depth
> buffer is used then it will perform the composite in z-order for the Z
> position
> of the object.
>

I'm not sure what you mean by that. If depth-buffering is used, then we
might have to draw some pixels of an object before we've drawn the object
that should be visible behind those pixels. Not knowing what the background
pixels are, we can't implement the compositing operation correctly.

We could evaluate the compositing operation using the color values currently
in the buffer, ignoring the depth value, but that would produce strange
results.

>
Rob
-- 
"Now the Bereans were of more noble character than the Thessalonians, for
they received the message with great eagerness and examined the Scriptures
every day to see if what Paul said was true." [Acts 17:11]
Received on Monday, 16 May 2011 12:45:44 GMT

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