Operating system: Mageia 8 x86_64 (Linux)
Graphics card: Intel HD Graphics 630, Mesa 20.1.0
Broken: 2.83.0, 2.90.0-aed11c673efe
Worked: 2.82a, 2.83-ce76e17584ee
Short description of error
In Blender 2.82a, when using a reference image with opacity between 0.0 and 1.0, the image is properly blended using the opacity value, provided that "Use Alpha" is enabled. (I.e. an image with opacity 0.20 will be less visible than an image with opacity 0.80, though both are transparent - like in most image editors.)
A few weeks back I used 2.83-ce76e17584ee, and there the "Use Alpha" setting was renamed to "Transparency", but the behavior stayed the same.
Opacity working in Blender 2.82a:
After updating to 2.83.0 (stable) now, I see that opacity no longer works as intended, it behaves like an on/off switch without any blending.
An image will look the same with opacity 0.0001 or 1.0 (and will be invisible with opacity 0).
Opacity not working in Blender 2.83.0 (same .blend):
Current 2.90 alpha seems to suffer from the same issue.
Exact steps for others to reproduce the error
- Add > Image > Reference
- Pick an image
- In object properties, enable Transparency, and try different values of Opacity. Opacity doesn't impact the blending of the reference image in the viewport (unless it's 0, which makes it disappear).