[x3d-public] Problem with inverted polygons/normals: actually texture transparency

Sun Nov 12 15:09:11 PST 2017

Hi Doug and list,

please find below Doug's response to the request for spec. comments.

I agree with Michalis that modulating by multiplying the multiple sources
of transparency instead of defining priorities is really a separate concern.

-Andreas

On Nov 12, 2017 9:40 AM, "doug sanden" <highaspirations at hotmail.com> wrote:

> Andreas,
> (please forward to x3d-public - I'm not subscribed)
> Spec change?
> There was that specification complaint by a few (Michalis and Doug):
> replace vs modulation in lighting model:
> currently replace:
> texture > CPV > material
> modulate:
> texture x CPV x material
> Modulate would in theory give us more permutations to play with, but would
> break old scenes.
> http://x3dgraphics.com/examples/X3dForWebAuthors/
> KelpForestExhibit/SharkLefty.x3d
> - has material, CPV and texture
>
> Same with transparency - it could be modulated with spec change, breaking
> old scenes.
> For example if you have a texture with transparency, and on top of that
> you want to apply an overall material transparency, it doesn't work because
> image.transparancy > material.transparency
> http://dug9.users.sourceforge.net/web3d/tests/DebateModulateAlpha/
> - 2 scenes with image transparency.  _05 has material transparency set to
> .5
> - I have this scene working in freewrl right now with an internal
> half-modulation setting, at the expense of some other scenarios not
> rendering as per specs.
> - the _10 (material transparency 1.0) scenes: freewrl and view3dscene show
> no sphere (invisible)
> -- Octaga, Instant, H3D show sphere with texture transparency pattern
> -- Vivaty white-screens
>
> -Doug
>
>
> ________________________________________
> From: Andreas Plesch <andreasplesch at gmail.com>
> Sent: November 11, 2017 4:06 PM
> To: Don Brutzman
> Cc: Roy Walmsley; support at okino.com; Michalis Kamburelis; Patrick Dähne;
> Holger Seelig; Johannes Behr; Max Limper; X3D Graphics public mailing list;
> doug sanden
> Subject: Re: [x3d-public] Problem with inverted polygons/normals: actually
> texture transparency
>
> Well, my remark was an attempt to lower expectations for specification
> comments. But perhaps there is an ambiguity which can be addressed.
>
> So I would say x_cite is wrong but with the major qualifier that it may be
> unreasonable to expect transparency to be rendered perfectly for any
> situation especially in the presence of a misleading alpha channel.
>
> Andreas
>
> On Nov 11, 2017 1:08 PM, "Don Brutzman" <brutzman at nps.edu<mailto:brutz
> man at nps.edu>> wrote:
> Sorry Andreas, am looking but still not understanding whether inconsistent
> rendering (for image textures that contain alpha channel information) is a
> specification issue or not.  Patrick indicated (below) that the
> specification is ambiguous, i.e. "none of the browsers is wrong or right."
>
> Either the specification needs to be more precise, or else some browser
> implementations are erroneous.
>
>
> Opinions by X3D browser implementers please, which is it?
>
> 17.2.2 Lighting model
> http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/
> components/lighting.html#Lightingmodel
>
> 18.2.1 Texture map formats
> http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/
> components/texturing.html#TextureMapFormats
>
> 18.2.2 Texture map image formats
> http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/
> components/texturing.html#TextureMapImageFormats
>
>
>
>
> On 11/9/2017 7:06 AM, Andreas Plesch wrote:
> Date: Wed, 8 Nov 2017 08:04:52 -0800
> From: Don Brutzman <brutzman at nps.edu<mailto:brutzman at nps.edu>>
> To: 'Patrick D?hne' <pdaehne at gmail.com<mailto:pdaehne at gmail.com>>,
> Michalis Kamburelis
>          <michalis.kambi at gmail.com<mailto:michalis.kambi at gmail.com>>, Roy
> Walmsley <roy.walmsley at ntlworld.com<mailto:roy.walmsley at ntlworld.com>>
> Cc: 'X3D Graphics public mailing list' <x3d-public at web3d.org<mailto:x
> 3d-public at web3d.org>>, Mario
>          Nagamura <mnagamur at lsi.usp.br<mailto:mnagamur at lsi.usp.br>>,
> Marcello Zuffo <mkzuffo at usp.br<mailto:mkzuffo at usp.br>>, Barb
>          Helfer <blhelfer at gmail.com<mailto:blhelfer at gmail.com>>, <
> support at okino.com<mailto:support at okino.com>>
> Subject: Re: [x3d-public] Problem with inverted polygons/normals:
>          actually texture transparency
>
> Patrick: really great.  Thank you.
>
> Your replacement version is uploaded and checked in (25% smaller), Shay D
> Pixel has become less shy and is fully with us now.  8)
>
> http://x3dGraphics.com/examples/X3dForAdvancedModeling/
> ShayDPixel/pixelModel_BaseColor.png
>
> The first .png version was converted from original .tga Targa image using
> latest GIMP.  If further image scrutiny is desired by anyone, all original
> .tga images now available at
> http://x3dgraphics.com/examples/X3dForAdvancedModeling/
> ShayDPixel/images/originals/
>
> (No good deed goes unpunished!) Request: who is writing up the
> specification feedback issue?
>
>          Web3D Standards Comment Form
>          http://www.web3d.org/content/web3d-standards-comment-form
>
>
> To me the issue does not seem to impact the standard. Each browser
> does its best to render transparency.
>
> It is an implementation and authoring issue. Perhaps it is a case for
> adding guidance in the ImageTexture tooltip: "If the texture is
> opaque, omitting the alpha channel in the image file can help avoid
> rendering artefacts related to transparency and reduce file size."
>
> -Andreas
>
> Excellent, thank you, now added to ImageTexture and (slightly edited) to
> PixelTexture.  Also improved hints for TextureProperties node.
>
> http://www.web3d.org/x3d/tooltips/X3dTooltips.html#ImageTexture
> http://www.web3d.org/x3d/tooltips/X3dTooltips.html#PixelTexture
> http://www.web3d.org/x3d/tooltips/X3dTooltips.html#TextureProperties
>
> On 11/8/2017 7:51 AM, Roy Walmsley wrote:
> Patrick,
>
> Great spot. Thank you.
>
> That also explains the behaviour of my Coin3D viewer. It saves transparent
> objects to render after opaque objects, and I had it set to sort
> transparent objects by distance.
>
> All the best,
>
> Roy
>
> On 11/8/2017 7:45 AM, Michalis Kamburelis wrote:
> 2017-11-08 16:27 GMT+01:00 Patrick D?hne <pdaehne at gmail.com<mailto:pdae
> hne at gmail.com>>:
> As soon as the texture file contains an alpha channel, X3D browsers
> classify shapes with that texture as transparent shapes. Rendering
> transparent shapes is difficult. Browsers handle transparent shapes
> differently. Instant Player and X3DOM write transparent objects to the
> depth buffer. Most other browser don?t. In this special case, the result of
> Instant Player and X3DOM looks better than result of other browsers, but
> that is pure coincidence. None of the browsers is wrong or right.
>
> And view3dscene looks at the texture contents to decide whether to use
> alpha testing (which doesn't have problems with ordering) or alpha
> blending (which is indeed tricky, but can represent partial
> transparency). It can be overridden by "alphaChannel" field,
> https://castle-engine.sourceforge.io/x3d_implementation_texturing_
> extensions.php#section_ext_alpha_channel_detection
> .
>
> Regards,
> Michalis
>
> -----Original Message-----
> From: x3d-public [mailto:x3d-public-bounces at web3d.org<mailto:x3d-public-
> bounces at web3d.org>] On Behalf Of Patrick D?hne
> Sent: 08 November 2017 15:27
> To: X3D Graphics public mailing list <x3d-public at web3d.org<mailto:x
> 3d-public at web3d.org>>
> Subject: Re: [x3d-public] Problem with inverted polygons/normals
>
> Am 07.11.2017 um 16:17 schrieb Don Brutzman <brutzman at nps.edu<mailto:brutz
> man at nps.edu>>:
>
> Initial draft version of an interesting new model is available at
>
>       Shay D Pixel Version 2
>       http://x3dgraphics.com/examples/X3dForAdvancedModeling/ShayDPixel/
> ShayDPixelVersion2Index.html
>
> This version was exported from an .fbx version using Okino Nugraf.
> Original at
>
>       http://x3dgraphics.com/examples/X3dForAdvancedModeling/
> ShayDPixel/pixel_v2.fbx
>
> It looks OK in several players (such as Instant Reality and X3DOM) but
> polygon ordering appears reversed in X_ITE.  Adjusting the solid field
> hasn't helped.  Perhaps a normal issue?
>
> Wondering if anyone else can figure out what is going on here, screenshot
> attached for clarity.  TIA for all help.
>
>
> The texture of the model contains an alpha channel. Remove the alpha
> channel from the texture, and everything looks right.
>
> As soon as the texture file contains an alpha channel, X3D browsers
> classify shapes with that texture as transparent shapes. Rendering
> transparent shapes is difficult. Browsers handle transparent shapes
> differently. Instant Player and X3DOM write transparent objects to the
> depth buffer. Most other browser don?t. In this special case, the result of
> Instant Player and X3DOM looks better than result of other browsers, but
> that is pure coincidence. None of the browsers is wrong or right.
>
> Bye,
>
> Patrick
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 8 Nov 2017 11:15:52 -0500
> From: Russ Kinter <pyth7 at verizon.net<mailto:pyth7 at verizon.net>>
> To: x3d-public at web3d.org<mailto:x3d-public at web3d.org>
> Subject: [x3d-public] Instant Player Sound Issue on Windows 10
> Message-ID: <15f9c6a8c9c-c09-144bc at webjas-vad212.srv.aolmail.net<mailto:
> 15f9c6a8c9c-c09-144bc at webjas-vad212.srv.aolmail.net>>
> Content-Type: text/plain; charset="utf-8"
>
> Hi All,
> Instant Player 64 bit will not play this simple test file on a new laptop
> with Windows 10:
> http://www.deepmatrix.org/Sound_test/Sound_test.wrl
>
> All other VRML browsers, including FreeWRL will play the file on the same
> laptop.
> My wife's laptop with Windows 10 won't play the file either using Instant
> Player 64 bit.
>
> However, an older version of Instant Player WILL play the file on my XP
> midtower.
>
> Does anyone else with Windows 10 have sound issues with Instant Player 64
> bit?
>
> Thanks!
> Russ Kinter
>
> all the best, Don
> --
> Don Brutzman  Naval Postgraduate School, Code USW/Br
> brutzman at nps.edu<mailto:brutzman at nps.edu>
> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA
> +1.831.656.2149<tel:%2B1.831.656.2149>
> X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/
> brutzman
>
>
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