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OmarShehata

Writing an RTI viewer?

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So I'm currently part of a project to build a catalog of our objects that can be viewed and manipulated in a browser. 

 

This is the only web rti viewer we found:

 

http://vcg.isti.cnr.it/rti/webviewer.php

 

But it doesn't support a "specular enhancement" mode. I was wondering how feasible it would be to just build our own. Would it just be a matter of:

 

  • Extract the original image and the normal/bump map from the .rti image
  • Write the shader to render it through WebGL using the correct lighting model(s)

Is there anything else to it? I've written written shaders to simulate lighting of this kind before, but I'm not sure exactly what goes into the .rti format or how I can extract stuff from it. (Any links/info on that would be appreciated!) 

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Dear Omar -

 

First, I want to let you know that the file formats for ptm and rti files are available, and this post has the info:

http://forums.culturalheritageimaging.org/index.php?/topic/389-where-can-i-find-the-file-format-specifications-for-rti-and-ptm/?hl=format

 

It is my understanding that the rendering modes cannot be implemented directly in WebGL.  In addition to the viewer by Gianpaolo Palma from the Visual Computing Lab, there is also an effort at Southampton University to make a web based viewer.  They are adding support for annotations, but also not rendering modes due to the same limitations.  There may be a way to somehow emulate (or fake) the rendering modes in conjunction with some kind of preprocessing.  I know that a couple of folks had contemplated that, but I don't think anyone has coded it.

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Thank you very much for the quick reply Carla! I apologize for having missed the PTM/RTI spec in the FAQ!

 

It does seem like a lot of effort has gone into web RTI viewers. I'm unaware of what limitations prevent specular enhancement but allow regular lighting, but I guess looking into the source of the RTI viewer and the spec should answer that question. 

 

Dear Omar -

 

First, I want to let you know that the file formats for ptm and rti files are available, and this post has the info:

http://forums.culturalheritageimaging.org/index.php?/topic/389-where-can-i-find-the-file-format-specifications-for-rti-and-ptm/?hl=format

 

It is my understanding that the rendering modes cannot be implemented directly in WebGL.  In addition to the viewer by Gianpaolo Palma from the Visual Computing Lab, there is also an effort at Southampton University to make a web based viewer.  They are adding support for annotations, but also not rendering modes due to the same limitations.  There may be a way to somehow emulate (or fake) the rendering modes in conjunction with some kind of preprocessing.  I know that a couple of folks had contemplated that, but I don't think anyone has coded it.

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