Premultiplied RGBA incorrect rendering in SRGB blending mode #469
Description
Operating System Info
Other
Other OS
macOS 15, Windows 10
OBS Studio Version
Other
OBS Studio Version (Other)
31.0.0, 30.2.3
OBS Studio Log URL
https://obsproject.com/logs/ZJw0Cy9mkJNEyV3i
OBS Studio Crash Log URL
No response
Expected Behavior
The OBS Browser Source should correctly render half transparent colors without darkening colors or introducing artifacts around edges.
Current Behavior
Half transparent pixels render darkened than actual should, and black artifacts are present around text (due anti aliasing, which produce half transparency)
Steps to Reproduce
- Add white color background
- Add this html page like
Browsersource with defaultCSSpreset (transparent body background)
<html lang="en">
<body>
<div style="
margin: 0;
font-size: 2em;
font-weight: 900;
font-family: monospace;
">
<p style="color: #ffffff">#ffffff / 100%</p>
<p style="color: rgb(255 255 255 / 75%)">#ffffff / 75%</p>
<p style="color: rgb(255 255 255 / 25%)">#ffffff / 25%</p>
<p style="color: #1e6ce080">#1e6ce0 / 50%</p>
</div>
</body>
</html>- Switching
Blending MethodbetweenDefaultandSRBG Offand see differences
Anything else we should know?
This artifacts looks like premultiplied RGBA rendering like non premultiplied
I am check rendering mechanism, and it correctly set blending mode for premultiplied renderer
obs-browser/obs-browser-source.cpp
Line 646 in 082a0a2
I try to play with srgb texture binding, and if set gs_enable_framebuffer_srgb(false); and gs_effect_set_texture(image, draw_texture) here:
obs-browser/obs-browser-source.cpp
Line 652 in 082a0a2
All works correctly, but i think, that this code and
linear_sample needed for something
I am interested in fixing this bug and can create a PR, but I need advice on which direction to take next.