155 provide example for the material mapping

[ClemensLinnhoff]

Describe your changes

• [x] Add example glTF file showcasing both mesh-based and texture-based material assignment
• [x] Adjust material examples, mapping table, asset file etc. to fit to this example
• [x] Add Readme to explain the examples

Issue ticket number and link

Fixes #155

Checklist before requesting a review

• [x] I have performed a self-review of my code/documentation.
• [x] My changes generate no new warnings during the documentation generation.

[ClemensLinnhoff]

@MatthiasThDs @ipg-jsc @ipg-sig @lyndyRott please also feel free to review this.

[lyndyRott]

looks like a good example to me. From the checker_xom.png (referring to red and blue material definitions) and the color-channels provided in the mapping table (referring to black and white texture names with red and blue rgb-values) it could be confusing to understand the mapping, if the chosen color values are mixed channel. Nevertheless, I can understand that these are the chosen IDs for the material mapping.

[ClemensLinnhoff]

looks like a good example to me. From the checker_xom.png (referring to red and blue material definitions) and the color-channels provided in the mapping table (referring to black and white texture names with red and blue rgb-values) it could be confusing to understand the mapping, if the chosen color values are mixed channel. Nevertheless, I can understand that these are the chosen IDs for the material mapping.

Thanks for your review. I can see how this might be confusing. But I actually deliberately chose other colors than black and white for the assignment texture to showcase, that these are just arbitrary mapping IDs and not the actual colors of the visual texture. I think we need to make this very clear in the documentation about the assignment/mapping.

[KimuraDIVP]

I think we'd better add the discription about assigning Matrial Mapping File (example_mapping.xomm) to Asset File (example_asset.xoma).

[ClemensLinnhoff]

I think we'd better add the discription about assigning Matrial Mapping File (example_mapping.xomm) to Asset File (example_asset.xoma).

You are right, thanks for the remark. I somehow missed that. I added it now as "materialMappingUri".