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Michalis,<br>
<br>
A quick read of this, sounds like it was written by someone really
in the trenches with this, good job!<br>
<br>
Notes:<br>
<br>
Item 5, in your proposal:<br>
<i>Proposed clarification:</i> <tt>function="COMPLEMENT"</tt> works
only on RGB, does not touch alpha channel. This seems more suitable
for usual cases, and follows the majority of implementations. <br>
<br>
I can think of times I would simply want to invert the A channel. Is
there a preferred way to do that? I like your earlier proposal of
using a slash / to specify Alpha behavior, thus "/COMPLEMENT" would
just invert the alpha channel. Sometimes alpha is 'transparent' and
sometimes 'opacity'<br>
<br>
I would love it if there were a clear and/or simple way to specify:
Diffuse, Specular, Diffuse+Specular, Diffuse+Bump, Specular+Bump,
Diffuse+Specular+Bump, etc. And easy ways to specify
Self-Illuminated, Lightmap (shadows), Parallax, etc. Note Bump being
Normals or Displacement (Height). These are all just combinations of
RGB(A) textures, right?<br>
<br>
If the spec will allow for all of this, then clear examples for such
common uses should be there. If the spec does not allow for this,
but would require custom shaders, fine, but I would lobby for a
public library of such shaders as they are so very common and
necessary these days.<br>
<br>
I can imagine a common shader which has input channel options for
diffuse, normal, specular, self-illuminated, shadow, transparency,
etc, each with a parameter or so for 'amount' and/or 'invert' and/or
'channels involved'. Then you could cobble together much (most?
all?) of these behaviors. Custom shaders would then be needed for
the 2% of the time you need something really fancy.<br>
<br>
Dave A<br>
<br>
<br>
<br>
<div class="moz-cite-prefix">On 8/3/2013 10:01 AM, Michalis
Kamburelis wrote:<br>
</div>
<blockquote cite="mid:51FD3777.9030601@gmail.com" type="cite">Hi,
<br>
<br>
While I'm on the roll, I thought that I remind about our page with
multi-texturing tests, problems and proposed solutions on:
<br>
<br>
<a class="moz-txt-link-freetext" href="http://castle-engine.sourceforge.net/x3d_multi_texturing.php">http://castle-engine.sourceforge.net/x3d_multi_texturing.php</a>
<br>
<br>
I propose to start applying the proposed fixes to the
specification. :) Let's not let this effort go in vain. I'm very
willing to prepare the exact prose to the spec (actually, the
above page already contains a sensible prose for some fixes). All
I need is someone to actually modify the spec to include it.
<br>
<br>
Since there were no objections on the list, I assume that people
are fine with all the proposed fixes? (And if not, please speak up
:).
<br>
<br>
Let's at least start with easy fixes, things that have easy (local
wording fixes) solutions:
<br>
<br>
- problem 2 ("REPLACE" mode is specified as "Arg2", which makes no
sense)
<br>
- problem 3 (The meaning of ADDSIGNED and ADDSIGNED2X modes is not
clear)
<br>
- problem 5 (It's not specified what channels are inverted by the
function="COMPLEMENT" value)
<br>
- problem 6 (two paragraphs should be swapped in spec)
<br>
<br>
Regards,
<br>
Michalis
<br>
<br>
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<br>
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