[ExtraFPS] `RenderSkyAutoAdjustLegacy` does not engage tonemapper

[Viscerous]

Environment

Second Life Release 7.1.11.12363455226 (64bit)
Release Notes

You are at 52.5, 126.3, 91.6 in Cranston located at simhost-04fc9fd708f788a32.agni
SLURL: http://maps.secondlife.com/secondlife/Cranston/52/126/92
(global coordinates 260,404.0, 234,878.0, 91.6)
Second Life Server 2024-11-25.12013542687
Release Notes

CPU: 12th Gen Intel(R) Core(TM) i7-12700K (3609.61 MHz)
Memory: 32510 MB
OS Version: Microsoft Windows 11 64-bit (Build 26100.2605)
Graphics Card Vendor: NVIDIA Corporation
Graphics Card: NVIDIA GeForce RTX 4090/PCIe/SSE2

Windows Graphics Driver Version: 32.0.15.6636
OpenGL Version: 4.6.0 NVIDIA 566.36

Window size: 2560x1417
Font Size Adjustment: 96pt
UI Scaling: 1
Draw distance: 128m
Bandwidth: 3000kbit/s
LOD factor: 1.75
Render quality: 5
Texture memory: 24564MB
Disk cache: Max size 1638.4 MB (91.3% used)

J2C Decoder Version: KDU v7.10.4
Audio Driver Version: OpenAL, version 1.1 ALSOFT 1.23.1 / OpenAL Community / OpenAL Soft: OpenAL Soft
Dullahan: 1.14.0.202408091639
CEF: 118.4.1+g3dd6078+chromium-118.0.5993.54
Chromium: 118.0.5993.54
LibVLC Version: 3.0.21
Voice Server Version: Vivox 4.10.0000.32327.5fc3fe7c.5942f08

Packets Lost: 2/20,852 (0.0%)
December 19 2024 08:37:11

Description

In the ExtraFPS viewer, it is expected that legacy skies are no longer adjusted automatically. However, opting in by using the RenderSkyAutoAdjustLegacy debug setting now only works partially. The exposure slider works, which suggests the sky is correctly being converted to an HDR sky, but the tonemapper doesn't appear to engage automatically. This will also lead to much stronger speculars for example, as it will use HDR lighting without a tonemapper.

It's worth noting that this setting is saved with the graphics preset, so it's possible users from earlier viewers still have this enabled as well.

Reproduction steps

1. Set the Debug Setting RenderSkyAutoAdjustLegacy to TRUE
2. Visit a sim with a legacy sky while using "Shared Environment"
3. Observe how in personal lighting the probe ambiance is auto-adjusted to 0.01 (default RenderSkyAutoAdjustProbeAmbiance)
4. Observe how the tonemapper has not engaged, i.e. adjust the tonemapper mix (default RenderTonemapMix value 0.7) as it does nothing

Optional:

5. Set the probe ambiance manually, i.e. 0.01 or 1.00 and note how the tonemapper engages correctly

[sergiiiproductengine]

Passed QA.

Verified on the Second Life Release 7.1.12.12793544240 on Win10/OSX in the scope of https://github.com/secondlife/iqa/issues/426.