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.
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!)