[x3d-public] extra NavigationInfo modes, ptm

Thu Jan 30 09:56:10 PST 2020

As for

> Hypothesis:weeb3d needs a general node(s) for creating a texture once to be used repeatedly later
> (GeneratedCubeMapTexture I think it re-generates every frame)

GeneratedCubeMapTexture already has a field "update" to control this.
In fact by default it is "NEVER", and you need to manually set it to
"ALWAYS" or "NEXT_FRAME_ONLY".

See example usage on
https://castle-engine.io/x3d_implementation_cubemaptexturing.php .

The extensions that generate other textures follow this:

- RenderedTexture (common extension) has also field "update"
https://castle-engine.io/x3d_implementation_texturing_extensions.php#section_ext_rendered_texture

- GeneratedShadowMap (only CGE) has also such field:
https://castle-engine.io/x3d_extensions_shadow_maps.php#section_generated_shadow_map

Regards,
Michalis

czw., 30 sty 2020 o 18:51 Michalis Kamburelis
<michalis.kambi at gmail.com> napisał(a):
>
> In case of CGE  approach, indeed "ProjectedTextureCoordinate" is
> implemented similar to "TextureCoordinateGenerator". A matrix
> (corresponding to the viewpoint projection) is prepared on CPU, passed
> to the GPU shaders as a uniform, and the necessary calculation is done
> in the vertex shader.
>
> ( It even worked with OpenGL fixed-function pipeline, glTexGen, by
> passing proper vectors as GL_EYE_PLANE vectors. Some time ago, even
> whole shadow maps worked in CGE in the fixed-function pipeline. )
>
> The "ProjectedTextureCoordinate.projector" can be a viewpoint or a
> light source (in case of shadow maps, the light source projects a
> special GeneratedShadowMap texture).
>
> As for changing the spec of PTM: I rely on others opinion here :) I'm
> not objective, since I made my own implementation of projective
> texture mapping long time ago (it was presented at the Web3d 2010
> conference). I don't feel objective enough to now almost remake the
> existing PTM component in X3D v4 to essentially match my own
> implementation. I'm happy to hear that my approach seems reasonable.
>
> Regards,
> Michalis
>
> czw., 30 sty 2020 o 17:53 GPU Group <gpugroup at gmail.com> napisał(a):
> >
> > https://webglfundamentals.org/webgl/lessons/webgl-render-to-texture.html
> > - shows rendering to a texture in webgl, so a GenerateOnceTexture or GeneratedTexture with some frequency / start/stop / once fields could work.in webgl
> > -Doug
> >
> >
> > On Thu, Jan 30, 2020 at 9:40 AM GPU Group <gpugroup at gmail.com> wrote:
> >>
> >> Upvector Hypotheses:
> >> H0: orientation,translation vs upvector - they do the same thing, its a matter of convenience, and given one, internally can convert to the other.
> >> If so then if its more convenient during scene authoring to follow viewpoint syntax, and more convenient in shaders to use upvector, then a few lines of code in the implementation can convert.
> >>
> >> Processing vs visualization
> >> Hypothesis:weeb3d needs a general node(s) for creating a texture once to be used repeatedly later
> >> (GeneratedCubeMapTexture I think it re-generates every frame)
> >> <GenerateOnceTexture>
> >> - uses backbuffer or fbo for target
> >> - <scenegraph with viewpoint, shaders etc listed here to render to backbuffer (or USE from Switch case)>
> >> - scrapes backbuffer into a texture
> >> - maybe a fall-back texture in case fbo capabilities aren't available (are they in GL 2.1/webgl?)
> >> </GenerateOnceTexture>
> >>
> >> -Doug
> >>
> >>
> >> On Thu, Jan 30, 2020 at 8:56 AM Andreas Plesch <andreasplesch at gmail.com> wrote:
> >>>
> >>> 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
> >>>> > > >>
> >>>> > > >> To subscribe or unsubscribe via the World Wide Web, visit
> >>>> > > >>         http://web3d.org/mailman/listinfo/x3d-public_web3d.org
> >>>> > > >> or, via email, send a message with subject or body 'help' to
> >>>> > > >>         x3d-public-request at web3d.org
> >>>> > > >>
> >>>> > > >> You can reach the person managing the list at
> >>>> > > >>         x3d-public-owner at web3d.org
> >>>> > > >>
> >>>> > > >> 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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