[x3d-public] Updation of PTM (draft notes)
Joe D Williams
joedwil at earthlink.net
Sat Feb 7 11:20:14 PST 2015
Cameras define near and far
clipping planes to create a viewing volume outside of which
no objects are visible.
Projectors define near and far
projection limits to create a
projection volume outside of which
no objects are lit by projector.
Perspective projection volume is conic section
with characteristics of a SpotLight.
Parallel projection is size of texture
with characteristics of a DirectionalLight.
Thanks and Best,
Joe
----- Original Message -----
From: "Don Brutzman" <brutzman at nps.edu>
To: <khyoo at chungbuk.ac.kr>
Cc: "Joe D Williams" <joedwil at earthlink.net>; "X3D Graphics public
mailing list" <x3d-public at web3d.org>
Sent: Wednesday, February 04, 2015 6:46 PM
Subject: Re: Updation of PTM (draft notes)
> Kwan Hee Yoo, thank you for the in-depth discussion call today with
> Joe and I.
>
> Your slides are attached. The proposed nodes that treat a texture
> like a light source are really interesting!
>
> List of comments:
>
> a. slide 10, X3DProjetiveTextureNode
>
> spelling: X3DProjectiveTextureNode
>
> maybe better name to match other nodes:
>
> X3DTextureProjectorNode
>
> b. Slide 11 and 12, Consistent names, re-sorted:
>
> TextureProjectorPerspective
> TextureProjectorParallel
>
> c. Slide 11, Get rid of aspectRatio since it is already defined by
> the ImageTexturee
>
> d. Slides 10, 11 and 12, add PixelTexture to ImageTexture and
> MovieTexture
>
> e. Split out nearFar into two separate fields
>
> Potential names nearDistance farDistance
>
> Note that farDistance is the same as "radius" field for
> DirectionalLight and SpotLight
>
> (Incidentally nearDistance is somewhat similar to the first value of
> NavigationInfo avatarSize field.)
>
> f. Missing: attenuation field for TextureProjectorPerspective, same
> as SpotLight
>
> g. Slide 11, fieldOfView value should be radians
>
> h. Slide 12, TextureProjectParallel needs to define what is actual
> width and height for given aspectRatio pixel dimensions
>
> i. Slide 12, I still don't understand "volume" is - perhaps that is
> intended to be similar to width and height in previous point?
>
> j. Consider whether to include TextureTransform
>
> k. A few simple hand diagrams of geometry might help
>
> l. Add slides for DirectionalLight, PointLight, SpotLight - helpful
> for comparisons.
>
> You might also find that these tooltips are interesting:
>
> http://www.web3d.org/x3d/content/X3dTooltips.html#DirectionalLight
> http://www.web3d.org/x3d/content/X3dTooltips.html#PointLight
> http://www.web3d.org/x3d/content/X3dTooltips.html#SpotLight
>
> m. Looks like we have some bad characters in the Korean Tooltips:
> http://www.web3d.org/x3d/content/X3dTooltipsKorean.html#SpotLight
> http://www.web3d.org/x3d/content/X3dTooltipsKorean.html#PointLight
> http://www.web3d.org/x3d/content/X3dTooltipsKorean.html#SpotLight
>
> n. Slide 14. I don't yet understand what this other node is adding
> that is different from the other nodes. Please add more description
> so that we understand.
>
> We will meet again in 3 weeks, same time (5 pm California on 25th,
> 10 am Korea on 26th). Web3D Calendar entry added.
>
> Thank you!!
>
> On 2/2/2015 11:44 PM, Kwan-Hee Yoo wrote:
>> Dear Don,
>>
>> Did you come back to home well?
>> After discussing on PTM, I update PTM material.
>> The material includes PTM abstract node and real PTM nodes.
>>
>> The material will be used with you to discuss PTM at Feb.
>> 5(Thursday) 10:00 AM (Korean Time).
>> After fixing out NODEs for PTM, we will re-implement PTM into
>> FreeWRL.
>>
>> Thanks.
>> Kwan-Hee Yoo
>
> 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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