Hi Davide, Certainly the obj loader supports bump maps, but let me be clear about what it actually does. Apologies if this comes over as patronising; I have no idea of your level of expertise.
In OSG/OpenGL land, textures (diffuse, bump map, specular map, etc.) are all attached to a particular geometry via a texture ID - this is an integer index ranging from 0 upwards. Shaders are then applied to this geometry that will colour the pixel based on a particular understanding of what each texture ID actually is. So for example, I can write a shader that assumes that texture unit 0 is the diffuse colour, texture unit 1 is some sort of specularity map, texture unit 2 is a bump map, etc. Or I can assume (for example as osgShadow tends to) that texture unit 0 is the diffuser colour, texture unit 1 is the shadow map. However - and this is the key - there is nothing that enforces this mapping between texture unit and "meaning". 3DS, and the obj format, both explicitly include entries in the model for "diffuse texture" and "specular map" and "bump map" and so on. However the 3DS or obj format loader doesn't know what shader you are going to apply to this model, so has no idea which texture ID/unit to assign a loaded "bump map" texture to. Should it be 1? 2? etc. Some formats (e.g. .osg) allow you to save an objects shader within the object definition itself, thereby guaranteeing that the textures that the object loads are assigned to the right texture unit, and used in the right way. 3DS and .obj don't. AFAIK, there is currently no OSG-wide method for enforcing any consistency. All that being said, the OBJ loader allows you to specify what texture units you want which maps to go to when you load the model, via an options string. The options are all listed in the first few lines of ReaderWriterOBJ.cpp. The mapping between the flags in the .obj file and the name of the texture is in lines 434 onwards of obj.cpp. (It's useful to have a look at that, because the OBJ spec is not rigourously followed by all modelling tools - e.g. you see map_opacity in some obj files, even though it should be map_d according to the spec). I'm not amazingly familiar with osgFX, but reading the source for the BumpMapping technique, I notice that a) you can define which texture units should be used for diffuse and normal (note : not bump) textures, and b) by default these are 0=normal, 1=diffuse. I also don't know what Blender exports in terms of maps. When you say that the blender export isn't exporting the bump map, have you looked in the OBJ file to actually see whether there is a "map_bump" (or "map_Bump", or just "bump") in it? Has it been called something else by the exporter? Hope that helps, David
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