Tested versions

• Reproducible in 4.6.dev3 (9d84f3d)
• Not reproducible in 4.6.dev2 (7864ac8)
• Regression from Overhaul and optimize Glow in the mobile renderer #110077

System information

Fedora Linux 42 (KDE Plasma Desktop Edition) on Wayland - X11 display driver, Multi-window, 1 monitor - Vulkan (Forward+) - integrated AMD Radeon 780M Graphics (RADV PHOENIX) - AMD Ryzen 7 8845HS w/ Radeon 780M Graphics (16 threads) - 60.60 GiB memory

Issue description

#110077 changed the default value for Environment.glow_hdr_threshold from 1.0 to 0.0, and this changes drastically how glow looks like. So this breaks compat and existing projects, such as Kenney starter kits: https://github.com/KenneyNL/Starter-Kit-3D-Platformer

4.6-dev2:

4.6-dev3:

4.6-dev3 with Environment.glow_hdr_threshold set back to 1.0 in the WorldEnvironment:

I'm not sure that default value change was intentional in #110077, or if it was a debug change that slipped through. The documentation hasn't been adjusted for it either, inferring that good defaults are 1.0 for Forward+ and 0.9 for Mobile:

The lower threshold of the HDR glow. When using the Mobile rendering method (which only supports a lower dynamic range up to [code]2.0[/code]), this may need to be below [code]1.0[/code] for glow to be visible. A value of [code]0.9[/code] works well in this case. This value also needs to be decreased below [code]1.0[/code] when using glow in 2D, as 2D rendering is performed in SDR.

The issue is reproducible with all 3 rendering methods in the Kenney 3D Platformer.

Steps to reproduce

• Run https://github.com/KenneyNL/Starter-Kit-3D-Platformer

Minimal reproduction project (MRP)

https://github.com/KenneyNL/Starter-Kit-3D-Platformer is not minimal but should be simple enough to debug.