Writing to an attribute that is also a vertexgroup results in black when used in a shader #95610

New Issue

rob · 2022-02-08T13:02:39+01:00

rob commented

2022-02-08 13:02:39 +01:00

System Information
Operating system: Windows-10-10.0.19042-SP0 64 Bits
Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71

Blender Version
Broken: version: 3.1.0 Beta, branch: master, commit date: 2022-02-07 22:08, hash: 229d0ace02
Worked: (newest version of Blender that worked as expected)

Caused by b8a634cb1d

Short description of error
When adding a color in the output of the Geometry nodes group and i add this color in the attribute node in the shader editor, it does not appear.

When opening the included Blender file, switch to material view and the plane shows black. This should be a black and white plane because i added a setup to apply this black and white color in geo nodes. When opening the Blend file in Blender 3.0, it works.

path_3.1.blend

**System Information** Operating system: Windows-10-10.0.19042-SP0 64 Bits Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71 **Blender Version** Broken: version: 3.1.0 Beta, branch: master, commit date: 2022-02-07 22:08, hash: `229d0ace02` Worked: (newest version of Blender that worked as expected) Caused by b8a634cb1d **Short description of error** When adding a color in the output of the Geometry nodes group and i add this color in the attribute node in the shader editor, it does not appear. When opening the included Blender file, switch to material view and the plane shows black. This should be a black and white plane because i added a setup to apply this black and white color in geo nodes. When opening the Blend file in Blender 3.0, it works. [path_3.1.blend](https://archive.blender.org/developer/F12855626/path_3.1.blend)

rob commented

2022-02-08 13:02:39 +01:00

Added subscriber: @RobTuytel

Philipp Oeser commented

2022-02-08 15:15:51 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2022-02-08 15:15:51 +01:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Philipp Oeser commented

2022-02-08 15:15:51 +01:00

Seems like the .blend file is missing?

rob commented

2022-02-08 19:04:12 +01:00

path_3.1.blend

the file is now included

[path_3.1.blend](https://archive.blender.org/developer/F12855626/path_3.1.blend) the file is now included

Philipp Oeser commented

2022-02-08 19:40:04 +01:00

Changed status from 'Needs User Info' to: 'Needs Triage'

Pratik Borhade commented

2022-02-09 05:38:20 +01:00

Added subscriber: @PratikPB2123

Pratik Borhade commented

2022-02-09 05:38:20 +01:00

I can confirm. Broke between 5920de9247f2 - 48fbf0baea88
@lichtwerk , can you check?
I suspect issue came with e7912dfa19 or b8a634cb1d

(I get an assert when opening this file on debug build)

I can confirm. Broke between `5920de9247f2 - 48fbf0baea88` @lichtwerk , can you check? I suspect issue came with e7912dfa1959 or b8a634cb1dff (I get an assert when opening this file on debug build)

Philipp Oeser commented

2022-02-09 10:34:43 +01:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Philipp Oeser commented

2022-02-09 10:34:43 +01:00

Added subscriber: @JacquesLucke

Philipp Oeser commented

2022-02-09 10:34:43 +01:00

Yep, caused by b8a634cb1d

Since that commit enabled writing to vertex colors again, the situation is a bit hairy though.
The example file writes a color to an attribute that is also a vertexgroup.
This never ends up in the vertexgroup (only if you change the type to float).
And vertexgroups themselves were never really readable in a shader tree I think?
So it seems at one point we could write a color to an attribute (that was also a vertexgroup, and this was somehow ignored and only seen as an attribute in the shader tree)

Also this example file does not really use the vertexgroup anyways, so when removing it, the attribute works again in the shader tree.

Not really sure what the best solution here would be? Have vertexgroups be readable in the shadertree also?
CC @JacquesLucke

Yep, caused by b8a634cb1d Since that commit enabled writing to vertex colors again, the situation is a bit hairy though. The example file writes a **color** to an attribute that is also a vertexgroup. This never ends up in the vertexgroup (only if you change the type to float). And vertexgroups themselves were never really readable in a shader tree I think? So it seems at one point we could write a color to an attribute (that was also a vertexgroup, and this was somehow ignored and only seen as an attribute in the shader tree) Also this example file does not really use the vertexgroup anyways, so when removing it, the attribute works again in the shader tree. Not really sure what the best solution here would be? Have vertexgroups be readable in the shadertree also? CC @JacquesLucke

Philipp Oeser changed title from ~~Attribute color does not appear on mesh~~ to Writing to an attribute that is also a vertexgroup results in black when used in a shader

2022-02-09 10:36:25 +01:00

Jacques Lucke commented

2022-02-09 10:37:47 +01:00

Haven't checked in detail right now, but it's probably related to D14051.

Haven't checked in detail right now, but it's probably related to [D14051](https://archive.blender.org/developer/D14051).

blender-admin commented

2022-02-09 15:50:03 +01:00

This issue was referenced by 7313a84c5a

This issue was referenced by 7313a84c5acb401817f1c44cfd8bf22428f34424

Jacques Lucke commented

2022-02-09 15:54:12 +01:00

Changed status from 'Needs Developer To Reproduce' to: 'Resolved'

Jacques Lucke closed this issue

2022-02-09 15:54:12 +01:00

Jacques Lucke self-assigned this 2022-02-09 15:54:12 +01:00

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Writing to an attribute that is also a vertexgroup results in black when used in a shader #95610