Collada Export: texcoord set="N" no longer starts at 0 #108053

New Issue

Scurest · 2023-05-18T19:09:56+02:00

Scurest commented

2023-05-18 19:09:56 +02:00

System Information
Operating system: Linux

Blender Version
Broken: blender-3.5.0-beta+v35.f23e3c7f04f3-linux.x86_64-release

Short description of error
In Collada exports, texcoord attributes are ordered by a "set" number, eg <input semantic="TEXCOORD" source="#Cube-mesh-map-0" offset="2" set="0"/>. The set used to start at zero for the first UVMap and go up, set="0", then set="1", etc.

It no longer does this. I think it changed because of the UVMap -> generic attribute conversion: non-UV attributes affect the layer index.

AFAICT, this isn't actually wrong according to spec, but I don't think it was an intentional change and it's been noticed: https://www.vg-resource.com/thread-41711.html

I believe the relevant code is 406cfd214a/source/blender/io/collada/GeometryExporter.cpp (L373-L382). Note that when the "UV|Only Selected Map" option is on, it does default to set="0", which reinforces that the code was intended to start from 0.

Exact steps for others to reproduce the error

Create default cube.
Export to Collada with default options.
Search .dae for <input semantic="TEXCOORD" and observe that set="1".
Add some Face Corner color attributes.
Export to Collada again.
Observe the set has gone up by the number of attributes you added.

**System Information** Operating system: Linux **Blender Version** Broken: blender-3.5.0-beta+v35.f23e3c7f04f3-linux.x86_64-release **Short description of error** In Collada exports, texcoord attributes are ordered by a "set" number, eg `<input semantic="TEXCOORD" source="#Cube-mesh-map-0" offset="2" set="0"/>`. The set used to start at zero for the first UVMap and go up, `set="0"`, then `set="1"`, etc. It no longer does this. I think it changed because of the UVMap -> generic attribute conversion: non-UV attributes affect the layer index. AFAICT, this isn't actually wrong according to spec, but I don't think it was an intentional change and it's been noticed: https://www.vg-resource.com/thread-41711.html I believe the relevant code is https://projects.blender.org/blender/blender/src/commit/406cfd214aaad9c90b62ce48eda6d72d2eacb6fe/source/blender/io/collada/GeometryExporter.cpp#L373-L382. Note that when the "UV|Only Selected Map" option is on, it does default to set="0", which reinforces that the code was intended to start from 0. **Exact steps for others to reproduce the error** 1. Create default cube. 2. Export to Collada with default options. 3. Search .dae for `<input semantic="TEXCOORD"` and observe that `set="1"`. 4. Add some Face Corner color attributes. 5. Export to Collada again. 6. Observe the set has gone up by the number of attributes you added.

Scurest added the

labels 2023-05-18 19:09:57 +02:00

Pratik Borhade commented

2023-05-22 19:23:16 +02:00

Thanks for the report. Can confirm.
I also think this is affected by 6c774feba2
@Baardaap ^

Thanks for the report. Can confirm. I also think this is affected by 6c774feba2c9a1eb5834646f597a0f2c63177914 @Baardaap ^