Texture Paint Fill Tool is broken with partial strength on Float/Linear Textures #82518

New Issue

tom k · 2020-11-08T23:59:39+01:00

tom k commented

2020-11-08 23:59:39 +01:00

System Information
Operating system: Linux-4.15.0-55-generic-x86_64-with-debian-stretch-sid 64 Bits
Graphics card: GeForce GTX 750 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 384.130

Blender Version
Broken: version: 2.92.0 Alpha, branch: master, commit date: 2020-11-07 16:22, hash: 7be47dadea
also 2.79, 2.80, 2.81, 2.83.5, 2.90.1
Worked: probably never?

Short description of error
Texture Paint Fill Tool behaves strangely with partial strength (0-1 exclusive) when painting on float/linear textures. It appears as though strength were ignored when filling over a black image, but doing so over a non-black image shows some weird interaction.

Note that the Texture Paint Draw Tool behaves correctly, so I guess the fix is for fill to just do what draw does.

(minor note: working with colour spaces is difficult and I figured there's a chance the problem is just me not understanding it/doing it wrong, but I think the fact that the draw tool does work as expected has me covered.)

Video demonstration:
(I've fast-forwarded unimportant parts)

0:14 - Non-float image. Draw tool with strength=1.0, then 0.1, then fill tool with strength=0.1. Behaves as expected.
0:43 - float image. Same test. Draw behaviour with low strength appears correct. Fill behaviour is incorrect.

BlenderFloatFillBug.mp4

Exact steps for others to reproduce the error
From default startup:

enter texture paint workspace
properties editor -> tool settings, set texture slots mode to single image, make new image with 32 bit float.
set tool to fill, set strength to any value below 1, except 0.
click cube to fill black texture with white paint. Expected: some shade of grey. Result: full-bright white.

Results of tests with various shades/strengths:

all performed in 3d viewport
each test performed on empty black image
input/output are HSV values
0.7354 being middle grey
output value is sampled from viewport with eyedropper
fill 2nd click is result after two clicks of fill

in	strength	draw output	fill output	fill 2nd click
0.01	0.01	0.0001	0.01	0.0199
	0.1	0.001	0.01	0.019
	0.5	0.005	0.01	0.015
0.1	0.01	0.001294	0.099998	0.15143
	0.1	0.012949	0.099998	0.14752
	0.5	0.061102	0.099998	0.128549
0.5	0.01	0.027639	0.49997	0.684261
	0.1	0.157658	0.49997	0.670251
	0.5	0.36078	0.49997	0.602086
0.7354	0.01	0.060985	0.735162	0.998114
	0.1	0.247814	0.735162	0.97771
	0.5	0.537175	0.735162	0.880889
0.99	0.01	0.098344	0.99001	0.999924
	0.1	0.345314	0.99001	0.999924
	0.5	0.727916	0.99001	0.999924
1	0.01	0.099802	0.999924	0.999924
	0.1	0.349084	0.999924	0.999924
	0.5	0.735271	0.999924	0.999924

Notice:

the first click of the fill tool always gives the same result regardless of strength.
the second click makes the image brighter than the colour we're filling with, which doesn't make sense.
the second click gives lower values for higher strengths, when you'd expect the opposite.

Another demonstration:

left: black texture painted with grey values 0.1 .. 1.0.
right: then filled with middle grey 0.7354 with strength 0.5.

Notice:

every shade becomes brighter (or remains ~1.0), even those greater than 0.7354 that should darken (move towards middle grey).

**System Information** Operating system: Linux-4.15.0-55-generic-x86_64-with-debian-stretch-sid 64 Bits Graphics card: GeForce GTX 750 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 384.130 **Blender Version** Broken: version: 2.92.0 Alpha, branch: master, commit date: 2020-11-07 16:22, hash: `7be47dadea` also 2.79, 2.80, 2.81, 2.83.5, 2.90.1 Worked: probably never? **Short description of error** Texture Paint Fill Tool behaves strangely with partial strength (0-1 exclusive) when painting on float/linear textures. It appears as though strength were ignored when filling over a black image, but doing so over a non-black image shows some weird interaction. Note that the Texture Paint Draw Tool behaves correctly, so I guess the fix is for fill to just do what draw does. (minor note: working with colour spaces is difficult and I figured there's a chance the problem is just me not understanding it/doing it wrong, but I think the fact that the draw tool does work as expected has me covered.) **Video demonstration:** (I've fast-forwarded unimportant parts) 0:14 - Non-float image. Draw tool with strength=1.0, then 0.1, then fill tool with strength=0.1. Behaves as expected. 0:43 - float image. Same test. Draw behaviour with low strength appears correct. Fill behaviour is incorrect. [BlenderFloatFillBug.mp4](https://archive.blender.org/developer/F9240465/BlenderFloatFillBug.mp4) **Exact steps for others to reproduce the error** From default startup: 1. enter texture paint workspace 2. properties editor -> tool settings, set texture slots mode to single image, make new image with 32 bit float. 3. set tool to fill, set strength to any value below 1, except 0. 4. click cube to fill black texture with white paint. Expected: some shade of grey. Result: full-bright white. **Results of tests with various shades/strengths**: - all performed in 3d viewport - each test performed on empty black image - input/output are HSV values - 0.7354 being middle grey - output value is sampled from viewport with eyedropper - fill 2nd click is result after two clicks of fill | in | strength | draw output | fill output | fill 2nd click | -- | -- | -- | -- | -- | | 0.01 | 0.01 | 0.0001 | 0.01 | 0.0199 | || 0.1 | 0.001 | 0.01 | 0.019 | || 0.5 | 0.005 | 0.01 | 0.015 | | 0.1 | 0.01 | 0.001294 | 0.099998 | 0.15143 | || 0.1 | 0.012949 | 0.099998 | 0.14752 | || 0.5 | 0.061102 | 0.099998 | 0.128549 | | 0.5 | 0.01 | 0.027639 | 0.49997 | 0.684261 | || 0.1 | 0.157658 | 0.49997 | 0.670251 | || 0.5 | 0.36078 | 0.49997 | 0.602086 | | 0.7354 | 0.01 | 0.060985 | 0.735162 | 0.998114 | || 0.1 | 0.247814 | 0.735162 | 0.97771 | || 0.5 | 0.537175 | 0.735162 | 0.880889 | | 0.99 | 0.01 | 0.098344 | 0.99001 | 0.999924 | || 0.1 | 0.345314 | 0.99001 | 0.999924 | || 0.5 | 0.727916 | 0.99001 | 0.999924 | | 1 | 0.01 | 0.099802 | 0.999924 | 0.999924 | || 0.1 | 0.349084 | 0.999924 | 0.999924 | || 0.5 | 0.735271 | 0.999924 | 0.999924 | Notice: - the first click of the fill tool always gives the same result regardless of strength. - the second click makes the image brighter than the colour we're filling with, which doesn't make sense. - the second click gives lower values for higher strengths, when you'd expect the opposite. **Another demonstration:** - left: black texture painted with grey values 0.1 .. 1.0. - right: then filled with middle grey 0.7354 with strength 0.5. ![blenderFloatFillBug.png](https://archive.blender.org/developer/F9241241/blenderFloatFillBug.png) Notice: - every shade becomes brighter (or remains ~1.0), even those greater than 0.7354 that should darken (move towards middle grey).

tom k commented

2020-11-08 23:59:39 +01:00

Added subscriber: @tomjk

Philipp Oeser commented

2020-11-09 12:25:20 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2020-11-09 12:25:20 +01:00

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

Philipp Oeser self-assigned this 2020-11-09 12:25:20 +01:00

Philipp Oeser commented

2020-11-09 12:25:20 +01:00

This indeed looks wrong, will check

Philipp Oeser removed their assignment 2020-11-17 14:13:08 +01:00

Philipp Oeser removed the

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Texture Paint Fill Tool is broken with partial strength on Float/Linear Textures #82518