Cycles DDS oversaturation when alpha is in use #101850

New Issue

tamooz br · 2022-10-16T02:50:30+02:00

tamooz br commented

2022-10-16 02:50:30 +02:00

System Information
Operating system: Arch Linux, Mesa 22.1.7-1
Graphics card: Intel HD Graphics 530

Blender Version
Broken: (2.80.74 (release candidate), 06312c6d2d, master, 2019-07-11), possibly earlier commit.
Worked: none, as 2.8 added alpha support for DDS in cycles.

Short description of error
When using the alpha channel of a DDS, for pixels in which the alpha isn't equal to 0 or 1, artifacts occur.
Exact steps for others to reproduce the error
Bugreport.blend
Test-Tex.dds

Load any model, add a material of any kind and an image texture, and load a DDS with alpha.
connect the alpha of the texture to any node. make sure the alpha or any node that makes use of it is connected to the material output.
now when you use the color, you'd see oddities, in older versions those pixels are completely white (1,1,1) and in newer, ones the value is increased to values above 1.

**System Information** Operating system: Arch Linux, Mesa 22.1.7-1 Graphics card: Intel HD Graphics 530 **Blender Version** Broken: (2.80.74 (release candidate), 06312c6d2db8, master, 2019-07-11), possibly earlier commit. Worked: none, as 2.8 added alpha support for DDS in cycles. **Short description of error** When using the alpha channel of a DDS, for pixels in which the alpha isn't equal to 0 or 1, artifacts occur. **Exact steps for others to reproduce the error** [Bugreport.blend](https://archive.blender.org/developer/F13694290/Bugreport.blend) [Test-Tex.dds](https://archive.blender.org/developer/F13694293/Test-Tex.dds) Load any model, add a material of any kind and an image texture, and load a DDS with alpha. connect the alpha of the texture to any node. make sure the alpha or any node that makes use of it is connected to the material output. now when you use the color, you'd see oddities, in older versions those pixels are completely white (1,1,1) and in newer, ones the value is increased to values above 1. ![Screenshot 2022-10-17 at 20.18.47.png](https://archive.blender.org/developer/F13699956/Screenshot_2022-10-17_at_20.18.47.png)

tamooz br commented

2022-10-16 02:50:30 +02:00

Added subscriber: @Koopa512

Richard Antalik commented

2022-10-16 20:06:27 +02:00

Added subscriber: @iss

Richard Antalik commented

2022-10-16 20:06:27 +02:00

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

Richard Antalik commented

2022-10-16 20:06:27 +02:00

I wasn't able to reproduce the issue, but my data may not suit the scenario. Can you upload simple .blend file with texture?

Aras Pranckevicius commented

2022-10-16 21:00:33 +02:00

Added subscriber: @aras_p

tamooz br commented

2022-10-16 21:57:48 +02:00

Bugreport.blend

Test-Tex.dds

[Bugreport.blend](https://archive.blender.org/developer/F13694290/Bugreport.blend) [Test-Tex.dds](https://archive.blender.org/developer/F13694293/Test-Tex.dds)

tamooz br commented

2022-10-16 21:58:39 +02:00

change to rendered view, and you'll see.
after packing or saving the image as a different format (and reloading it), the white line disappears. it also doesn't appear in EEVEE or Workbench, Doesn't happen on OSL, can't test GPU compute right now.

change to rendered view, and you'll see. after packing or saving the image as a different format (and reloading it), the white line disappears. it also doesn't appear in EEVEE or Workbench, Doesn't happen on OSL, can't test GPU compute right now.

tamooz br commented

2022-10-16 22:30:35 +02:00

Found my Windows laptop, it also happens there, and on CPU compute (GTX 960M, both CUDA and OptiX)