[x3d-public] extra NavigationInfo modes, ptm
Andreas Plesch
andreasplesch at gmail.com
Thu Jan 30 05:51:01 PST 2020
I agree, just dealing with generating texture coordinates (on the fly, in
the shader) and plugging into the texCoord field feels much more seamless.
Would that work for typical use cases ? Are those limited to reconstruction
of obliquely acquired images (from the air or inside a body) ?
Applying oblique imagery to a surface is really more of an image processing
step, and less of a visualization step.
Since a projector really acts as a light source, could it be modeled as an
image based light ?
I did not understand what the advantage of direction+upVector over
orientation as rotation is? Perhaps it is easier to animate direction
separately since upVector typically is constant ?
---on the phone---
On Thu, Jan 30, 2020, 7:59 AM Michalis Kamburelis <michalis.kambi at gmail.com>
wrote:
> 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
> > > >> x3d-public at web3d.org
> > > >>
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> > > >> or, via email, send a message with subject or body 'help' to
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> > > >>
> > > >> When replying, please edit your Subject line so it is more specific
> > > >> 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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> > > > _______________________________________________
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> >
> >
> > --
> > Andreas Plesch
> > Waltham, MA 02453
>
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