[x3d-public] Updation of PTM (draft notes)

[Joe D Williams]

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
>