[x3d-public] extra NavigationInfo modes, ptm
Holger Seelig
holger.seelig at googlemail.com
Thu Jan 30 00:22:13 PST 2020
I implemented Projective Texture Mapping exactly as described in
http://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-WD1/Part01/components/ProjectiveTextureMapping.html
there is a preview of PTM implementation at
http://media.create3000.de/components/ProjectiveTextureMapping/TextureProjectorPerspective/example.html
I think 'direction' and 'upVector' are a nice feature, because it is an
easy way to get the texture always 'up'. The issue that the texture
projector can be 'global' is more complicated to implement, because it
requires some more sampler2D in the shader, and as everybody knows
sampler are limited in the shader. The worst case is that there are only
8 samplers available, and I need already some samplers for Texture2D and
Texture3D and shadows. Even in the best case I only support 2 global
texture projectors, this means if you need more, than you have to use
'local' texture projectors.
Another point which is not yet mentioned is what is with the backwarding
polygons (where the dot product of the normal with the vector from the
projectors location to the vertex is less than zero). I implemented that
these polygons are not affected by the texture projector because it is
an easy and cheap test, and it makes the projector more realistic.
Holger
On 30.01.20 00:59, GPU Group wrote:
> Andreas - I like your Viewpiont-re-use ideas, if necessary split viewpoint
> Viewpoint :: Camera
> Projector :: Camera
> And yes - same orientation methods as Viewpoint would make sense.
> Holger what did you do?
>
> I think because it's slow/busy shader code you wouldn't want it to
> apply universally - you'd want to pair it explicitly with whatever
> shapes are going to get it.
> Projector maybe implies the wrong thing. It's not like you are
> shooting rays from the projector and seeing what geom it htis. It
> should be the other way I think for sanity and efficiency - when you
> have geometry that's getting PTM then you run a special shader and
> give it the relative pose of the projector and (ortho or perspective)
> and construct a ray from your shape surface pixel back toward the
> projectors image plane - through the perspective center / focal point
> if perspective, or perpendicular to the image plane if ortho.
> The image plane is an infinite plane. And when your ray hits that
> plane you get an xy on the plane, and you see if its inside the image.
> If not, its a miss, else it's a hit, and you do a smapler2D on the
> image and do your modulate or replace or whatever.
> Holger what did you do?
> -Doug
>
>
>
> On Wed, Jan 29, 2020 at 3:57 PM Andreas Plesch
> <andreasplesch at gmail.com <mailto:andreasplesch at gmail.com>> wrote:
>
> 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 <mailto:michalis.kambi at gmail.com>> wrote:
> >
> > Andreas Plesch <andreasplesch at gmail.com
> <mailto: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
> <mailto:x3d-public-request at web3d.org>> wrote:
> > >>
> > >> Send x3d-public mailing list submissions to
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> > >>
> > >>
> > >> 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 <mailto:gpugroup at gmail.com>>
> > >> To: X3D Graphics public mailing list <x3d-public at web3d.org
> <mailto: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
> <mailto: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 <mailto: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 <mailto: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>
> <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 <mailto: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
>
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--
Holger Seelig
Digital Media Designer
Scheffelstraße 31a
04277 Leipzig
Germany
Cellular: +49 176 420 479 37
E-Mail: holger.seelig at create3000.de
Web: http://create3000.de
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