Texture Paint colour sampling is broken on some image formats #73682

New Issue

Vas · 2020-02-08T22:02:23+01:00

Vas commented

2020-02-08 22:02:23 +01:00

System Information
Operating system: Windows-10-10.0.17763-SP0 64 Bits
Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.66

Blender Version
Broken: version: 2.82 (sub 6), branch: master, commit date: 2020-02-06 20:44, hash: 763f117c48
Worked: (optional)

Short description of error

Basically, if your image texture is saved in one of these broken formats, you lose the capability of colour sampling correct colour, instead it'll always sample merged (affecting in that way the desired colour, since model could be in shadow/affected by environment colours)

Broken formats: DPX 16bit, HDR 32bit, EXR 32bit
(ignore PNG 32Bit in the image below, its actually mislabaled EXR 32bit)

Exact steps for others to reproduce the error

Open the file
It has two cubes that have respective formats with broken eyedropper sampling
try to texture paint on either of those
notice that when you sample color "S" it wont pick the correct color, instead it'll pick merged color as seen on viewport

(optional)

create a new cube
assign it a new texture
save texture as a PNG (8bit, 16bit)
go into texture paint
sample and notice that there is no problem!

Edit v1: fixed some mistakes in the description (removed PNG 32bit)
FORMAT PROBLEM.blend

**System Information** Operating system: Windows-10-10.0.17763-SP0 64 Bits Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.66 **Blender Version** Broken: version: 2.82 (sub 6), branch: master, commit date: 2020-02-06 20:44, hash: `763f117c48` Worked: (optional) **Short description of error** Basically, if your image texture is saved in one of these broken formats, you lose the capability of colour sampling correct colour, instead it'll always sample merged (affecting in that way the desired colour, since model could be in shadow/affected by environment colours) Broken formats: DPX 16bit, HDR 32bit, EXR 32bit *(ignore PNG 32Bit in the image below, its actually mislabaled EXR 32bit)* ![image.png](https://archive.blender.org/developer/F8329970/image.png) **Exact steps for others to reproduce the error** - Open the file - It has two cubes that have respective formats with broken eyedropper sampling - try to texture paint on either of those - notice that when you sample color "S" it wont pick the correct color, instead it'll pick merged color as seen on viewport (optional) - create a new cube - assign it a new texture - save texture as a PNG (8bit, 16bit) - go into texture paint - sample and notice that there is no problem! *Edit v1: fixed some mistakes in the description (removed PNG 32bit)* [FORMAT PROBLEM.blend](https://archive.blender.org/developer/F8330031/FORMAT_PROBLEM.blend)

Vas commented

2020-02-08 22:02:23 +01:00

Added subscriber: @Alumx

Evan Wilson commented

2020-02-09 07:02:19 +01:00

Added subscribers: @fclem, @Jeroen-Bakker, @EAW

Evan Wilson commented

2020-02-09 07:02:19 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Evan Wilson commented

2020-02-09 07:02:19 +01:00

I can confirm. It seems that for some textures saved as higher bit depth formats, the color picker in texture paint mode treats the "Sampled Merged" check box as if it was always checked. For all 8-bit and some 16-bit textures, the color picker respects the check box. Perhaps the difference is whether the formats are saved as Linear or sRGB?

Other similar issues with vertex paint have been noted as needing improvements, and closed as invalid. See #72530, #63586, However, those appear to deal with the color picker picking the output display color in general, not differing between texture and display color per image format.

@Jeroen-Bakker @fclem I am not sure if this particular issue is already on the color management improvement radar. I did see https://developer.blender.org/T69562#864859, but not this specific issue.

@Alumx what did you mean when you wrote PNG 32bit? Blender refers to the per channel bit depth in the UI, so only 8-bit and 16-bit are available. See https://docs.blender.org/manual/en/latest/files/media/image_formats.html#image-formats

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 470/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 388.13

Blender Version
Broken: version: 2.83 (sub 2), branch: master, commit date: 2020-02-07 22:49, hash: a010d97204

I can confirm. It seems that for some textures saved as higher bit depth formats, the color picker in texture paint mode treats the "Sampled Merged" check box as if it was always checked. For all 8-bit and some 16-bit textures, the color picker respects the check box. Perhaps the difference is whether the formats are saved as Linear or sRGB? ![samples_merged.png](https://archive.blender.org/developer/F8330688/samples_merged.png) Other similar issues with vertex paint have been noted as needing improvements, and closed as invalid. See #72530, #63586, However, those appear to deal with the color picker picking the output display color in general, not differing between texture and display color per image format. @Jeroen-Bakker @fclem I am not sure if this particular issue is already on the color management improvement radar. I did see https://developer.blender.org/T69562#864859, but not this specific issue. @Alumx what did you mean when you wrote `PNG 32bit`? Blender refers to the per channel bit depth in the UI, so only 8-bit and 16-bit are available. See https://docs.blender.org/manual/en/latest/files/media/image_formats.html#image-formats --- **System Information** Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: GeForce GTX 470/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 388.13 **Blender Version** Broken: version: 2.83 (sub 2), branch: master, commit date: 2020-02-07 22:49, hash: `a010d97204`

Vas commented

2020-02-09 14:10:48 +01:00

Ah! You're right @EAW it was my mistake, apparently I saved it as EXR 32bit/channel , idk why I wrote PNG 32bit (might've gotten confused while checking extensions of all the textures)

Ah! You're right @EAW it was my mistake, apparently I saved it as EXR 32bit/channel , idk why I wrote PNG 32bit (might've gotten confused while checking extensions of all the textures) ![image.png](https://archive.blender.org/developer/F8331059/image.png)

blender-admin commented

2020-02-11 07:13:33 +01:00

This issue was referenced by 3a1af7444c

This issue was referenced by 3a1af7444c36df7a3bd0ffcd8566c52136b14629

Campbell Barton commented

2020-02-11 07:15:07 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Campbell Barton closed this issue

2020-02-11 07:15:07 +01:00

Campbell Barton self-assigned this 2020-02-11 07:15:07 +01:00

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Texture Paint colour sampling is broken on some image formats #73682