Hello Carsten,

as time goes by...

I have not forgotten about this project and have actually build something 
useful...

Could you please take a look at it and provide me with some feedback.

As drop.io has been suspended I have tried another file sharing alternative. 
You can download my files from

http://ge.tt/#5ljmAV

(If you have another sharing method as convenient and reliable as drop.io 
let me know about it.)

What you can find in the ZIP file is:

a) A folder 'lib3ds' which contains the CMaked lib3ds project. I did make 
some minor changes with respect to endianess. Iff this project is going to 
be part of OpenSG I would recommend to provide the lib3ds files with the 
OpenSG distribution.

b) Changes in OpenSG to access this new suppport library. I'm not sure about 
the correctness of this part, however.

c) Little modifications to SceneFileHandler. This is necessary, as the 
current implementation does allows to install multiple file type handlers 
for the same suffix, but it does not provide any means(?) to actually use 
another one than the first one in the mapping list. I did some shortcut in 
allowing to subtract scene file type handlers the user is not interested in. 
I did provide an example 'lib3dsloading.cpp' for that. I think that we 
should provide some means for the user to write its own file type handlers 
for already handled file types. Maybe he has an in house handler for the 
same file type or he must handle files of a different type but using the 
same suffix.

d) A scene file type handler for 3ds which uses the lib3ds library as its 
backend. I have named it 'A3DSLibSceneFileType' and you can found it in 
'opensg\Source\System\FileIO\3DSLib'. I would appreciate if this could be 
part of OpenSG. Maybe it could be placeed in the contrib section. However, 
the handler works already pretty fine (but could be finer, see below for 
that).

e) Some sample models:
        Models\HondaCBR.3DS  ->  now handled correctly. The remaining 
problems are intrinsic to the model and (imho) can't be solved from a file 
type handler.
        Models\107ford-oldcar.3DS  ->  same problems as with standard file 
type handler. What should we do with these cases?
        Models\transformer-bumblebee.3DS  ->  handled correctly
        Models\creature-rig.3DS  ->  this one crashes in the lib3d library. 
I suspect that the model is corrupt. I'm looking for a method to avoid the 
crash but have not found a solution so far.
        Models\jet\HORNET_L.3DS  ->  this one is interesting as it provides 
a bunch of special textures for bump mapping and reflection mapping. I would 
like to handle these cases but need help at this end. See below.

Ok, as already said, I need some help for handling models containing special 
textures. The lib3ds library does provide information about the following 
texture types:

texture1_map
texture2_map
opacity_map
bump_map
specular_map
shininess_map
self_illum_map
reflection_map

I do not know about the semanic of some of them but would like to provide 
support for the as much as I can. Additionally, there are mask textures for 
each of these maps but I do not know what these are used for.
I have already implemented the framework for handling these texture types 
and started with the bump_map. I would like to write a shader for bump 
mapping on behalf of this texture. Unfortunately, this is my very first 
shader. Naively I did look at

http://gpwiki.org/index.php/OpenGL:Tutorials:GLSL_Bump_Mapping

but I could not find a way to make use of the following vertex shader types:

attribute vec3 tangent;
attribute vec3 binormal;

So my first question goes as follows:
How do I implement this case in OpenSG?
As you can see in the implementation file 
'opensg\Source\System\FileIO\3DSLib\OSG3DSLibLoader.cpp', I have already set 
up a simple shader in function 'handle_bump_map'.
Could you provide me with some details about how to setup the case of 
attribute variables?
I did read the archive but could not make much sense about what I found 
there, sorry.

The next question I have is with regard to the semantics of the different 
texture types.
 Do you have semantic explanations for some of them?
Additionally, do you have knowlege about how these should be handled in 
OpenSG?

Ok, thats it for the moment. Thanks for your patient.

Best,
Johannes




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