[x3d-public] extra NavigationInfo modes, ptm

Thu Jan 30 04:59:10 PST 2020

 I think the alternative approach to Projective Texture Mapping,
described by Andreas, is almost exactly what I proposed and
implemented long time ago :)

CGE approach to projective texture mapping (unrelated to PTM in X3Dv4)
is on https://castle-engine.io/x3d_extensions_shadow_maps.php . It's
part of shadow maps specs, but it's useful without shadow maps as
well.

Basically you can just use """ProjectedTextureCoordinate { projector
USE MyViewport }""" as a texture coordinate (in a "texCoord" field).
This generates texture coordinates, nothing more. You set up the
appropriate textures using existing texturing methods.

In the same spirit, I did mirrors on flat objects:
https://castle-engine.io/x3d_extensions_mirror_plane.php , where you
can use """TextureCoordinateGenerator { mode "MIRROR-PLANE" }""".

I admit I like my approach a bit. It cooperates with existing texture
specification without anything additional -- because it just generates
texture coordinates, and doesn't try to do more. But I'm no longer
subjective :)

Regards,
Michalis

śr., 29 sty 2020 o 23:57 Andreas Plesch <andreasplesch at gmail.com> napisał(a):
>
> Hi Michalis,
>
> I took the opportunity to look at
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-WD1/Part01/components/ProjectiveTextureMapping.html
> and some of the history.
>
> My main thought was why not reuse the existing, abstract viewpoint
> nodes to define the projector characteristics. The projector node
> fields just reiterate the viewpoint node fields, for the most part.
> But probably there are enough differences since viewpoint mixes camera
> and navigation options.
>
> Why not follow viewpoint and use orientation as a rotation instead of
> direction and upVector ? Seems more consistent and simpler.
>
> The definition of the coordinate system for location/direction seems
> to be missing. It is probably implied that it is the local coordinate
> system.
>
> Overall, it feels strange to have a global projector to affect all
> appearances by default but perhaps that is the most common scenario.
> The term Texture Mapping rather implies that it is a way to compute
> texture coordinates for a given texture, similar to
> TextureCoordinateGenerator, and on a similar level:
> ProjectiveTextureGenerator. DEF/USE would allow applying it to
> multiple Appearances easily.
>
> -Andreas
>
> On Mon, Jan 27, 2020 at 6:18 PM Michalis Kamburelis
> <michalis.kambi at gmail.com> wrote:
> >
> > Andreas Plesch <andreasplesch at gmail.com> wrote:
> > >
> > > x3dom has an extra explorationMode field which restricts mouse function in examine/turntable mode.
> > > zoom, pan, rotate values restrict to only these.
> > > -zoom, -pan, -rotate disable these.
> > > The field tends to be quite useful.
> > >
> > > I think x-ite implemented Projective Texture Mapping.
> >
> > Good news we have an implementation of PTM.
> >
> > I had some questions about how the Projective Texture Mapping in X3D
> > v4 applies the texture -- what happens if the shape already has a
> > ImageTexture, what happens if shape already has MultiTexture etc. I
> > listed them on "TODO: Address how the projective texturing in spec
> > affects existing textures" in
> > https://github.com/michaliskambi/x3d-tests/wiki/Clarify-%22Projective-texturing%22-component#todo-address-how-the-projective-texturing-in-spec-affects-existing-textures
> > . I'll test how X_ITE answered these questions.
> >
> > Regards,
> > Michalis
> >
> > >
> > > ---on the phone---
> > >
> > > On Mon, Jan 27, 2020, 3:00 PM <x3d-public-request at web3d.org> wrote:
> > >>
> > >> Send x3d-public mailing list submissions to
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> > >> than "Re: Contents of x3d-public digest..."
> > >>
> > >>
> > >> Today's Topics:
> > >>
> > >>    1. Re: x3d v4 proposed changes > 2 opensource criteria > any
> > >>       that are short (GPU Group)
> > >>
> > >>
> > >> ----------------------------------------------------------------------
> > >>
> > >> Message: 1
> > >> Date: Mon, 27 Jan 2020 12:18:39 -0700
> > >> From: GPU Group <gpugroup at gmail.com>
> > >> To: X3D Graphics public mailing list <x3d-public at web3d.org>
> > >> Subject: Re: [x3d-public] x3d v4 proposed changes > 2 opensource
> > >>         criteria > any that are short
> > >> Message-ID:
> > >>         <CAM2ogRfqXoH1duy9iGvX9BEmLFCpiLbYYO_HwMuR7HbYXkRvmg at mail.gmail.com>
> > >> Content-Type: text/plain; charset="utf-8"
> > >>
> > >> INVENTORY
> > >> FREEWRL
> > >> * X3Dv4 Implementations
> > >>    https://www.web3d.org/x3dv4-implementations
> > >> 1) 43 Projective Texture Mapping
> > >> x freewrl does not implement, document is mistaken
> > >> 2) 23.4.4 NavigationInfo > TURNTABLE
> > >> * freewrl implemented
> > >> (other freewrl navmodes and related not in v3.3:
> > >> DIST - explicit control over distance to pivot point for examine, turntable
> > >> - touchpads don't need RMB
> > >> SHIFT - turns off sensors
> > >> HOVER - isOver mode (useful for touch pad - allows triggering of isOver
> > >> only)
> > >> PEDAL - can drag 'floating cursor' in steps
> > >> SPHERICAL - like FLY: YAWPITCH except rotations constrained to viewpoint
> > >> local axes)
> > >> subsets of FLY: YAWZ, XY, YAWPTICH,ROLL)
> > >> 3) GeoSpatial > GeoOrigin - freewrl still allows in v3.3, never deprecated
> > >> in freewrl
> > >> 4) The rest freewrl has not implemented
> > >> /FREEWRL
> > >> Does this table miss anything?
> > >> /INVENTORY
> > >> -Doug Sanden
> > >> PS who's doing projective texture mapping? Should start with that?
> > >>
> > >>
> > >> On Mon, Jan 27, 2020 at 11:59 AM GPU Group <gpugroup at gmail.com> wrote:
> > >>
> > >> > INVENTORY
> > >> > FREEWRL
> > >> > * X3Dv4 Implementations
> > >> >    https://www.web3d.org/x3dv4-implementations
> > >> > 1) 43 Projective Texture Mapping
> > >> > x freewrl does not implement, document is mistaken
> > >> > 2) 23.4.4 NavigationInfo > TURNTABLE
> > >> > * freewrl implemented
> > >> > (other freewrl navmodes and related not in v3.3:
> > >> > DIST - explicit control over distance to pivot point for examine,
> > >> > turntable - touchpads don't need RMB
> > >> > SHIFT - turns off sensors
> > >> > HOVER - isOver mode (useful for touch pad - allows triggering of isOver
> > >> > only)
> > >> > PEDAL - can drag 'floating cursor' in steps
> > >> > SPHERICAL - like FLY: YAWPITCH except rotations constrained to viewpoint
> > >> > local axes)
> > >> > subsets of FLY: YAWZ, XY, YAWPTICH,ROLL)
> > >> > 3) GeoSpatial > GeoOrigin - freewrl still allows in v3.3, never deprecated
> > >> > in freewrl
> > >> > 4) The rest freewrl has not implemented
> > >> > /FREEWRL
> > >> > Does this table miss anything?
> > >> > /INVENTORY
> > >> >
> > >> >
> > >> > On Mon, Jan 27, 2020 at 11:14 AM Don Brutzman <brutzman at nps.edu> wrote:
> > >> >
> > >> >> Thanks for writing Doug.
> > >> >>
> > >> >> On 1/27/2020 6:01 AM, GPU Group wrote:
> > >> >> > A rule of web3d.org <http://web3d.org> is that changes to the spec
> > >> >> need a least 2 opensource implementations.
> > >> >>
> > >> >> * Web3D Standards Adoption Process
> > >> >>    https://www.web3d.org/standards/adoption-process
> > >> >>
> > >> >> 5.c. "Identify at least two independent and interoperable implementations
> > >> >> (at least one should be open source)"
> > >> >>
> > >> >> > Q. are there any proposed changes that do not yet have 2 opensource
> > >> >> implementations?
> > >> >>
> > >> >> Yes, plenty.  We have not taken a recent inventory of features yet, but
> > >> >> will be tracking that at
> > >> >>
> > >> >> * X3Dv4 Implementations
> > >> >>    https://www.web3d.org/x3dv4-implementations
> > >> >>
> > >> >> Our prominent open-source implementations for X3Dv3.3 include FreeWrl,
> > >> >> X_ITE, X3DOM, Castle Game Engine.  Soon Xj3D will be back on the table as
> > >> >> well.  There are also non-rendering X3Dv4 implementations for Java,
> > >> >> JavaScript, Python, conversions and validation.  Not sure about Titania but
> > >> >> presumably yes.  X3D-Editv4 is on the horizon. Interestingly everything on
> > >> >> this list is open source.
> > >> >>
> > >> >> Hoping that FreeWrl developers are keen to keep their record-setting X3D
> > >> >> support accomplishments continuing!  8)
> > >> >>
> > >> >> All feedback welcome, appreciate your many efforts.
> > >> >>
> > >> >> > Thanks,
> > >> >> > Doug Sanden
> > >> >> > -freewrl
> > >> >>
> > >> >> all the best, Don
> > >> >> --
> > >> >> Don Brutzman  Naval Postgraduate School, Code USW/Br
> > >> >> brutzman at nps.edu
> > >> >> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA
> > >> >>  +1.831.656.2149
> > >> >> X3D graphics, virtual worlds, navy robotics
> > >> >> http://faculty.nps.edu/brutzman
> > >> >>
> > >> >
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>
>
> --
> Andreas Plesch
> Waltham, MA 02453