Add Sun Brightness and Ambient Brightness sliders

[kiss-spicoli]

I'd like to point out two LL values visible in DEBUG:

• RenderHDRSkySunlightScale for sunlight brightness, range 0-100, default 1, increment 0.1
• RenderSkyAmbientScale for ambient brightness, range 0-100, default 1, increment 0.1

Note that there are a variety of factors that play into the final results; dependencies could be reverse engineered?

I've gotten some awesome (and very desirable) results by wiring these into sliders in Quick Preferences - I use them all the time.

Must be proper place for them in your snazzy XUI!

[williamweaver]

Hi @kiss-spicoli,

Thanks for taking the time to suggest this, and for pointing out RenderHDRSkySunlightScale and RenderSkyAmbientScale.

I’ve just published a short write-up from earlier development that looks at how these settings behave in legacy versus PBR-enabled skies:

https://github.com/ApertureViewer/Aperture-Viewer/wiki/HDR-Rendering-&-Legacy-Sky-Adjustments

From what I’ve seen, these debug controls mostly affect older, non-PBR environments where ReflectionProbeAmbiance is zero. Aperture is built around the modern PBR/EEP pipeline, and I’m not planning to add UI for legacy behavior—that path adds complexity and tends to produce inconsistent results.

In most cases, setting Probe Ambiance to 1.0 and using the APS atmosphere controls should provide the same lighting effects with more reliable results.

However, I'll keep this issue open for now. If you’re seeing something different, or can provide examples (e.g., images or side-by-side comparisons) demonstrating unique visual benefits these settings offer specifically within a PBR-enabled scene (i.e., where ReflectionProbeAmbiance is > 0) that aren't achievable with existing APS controls, I'd be very interested in reviewing them.

Appreciate you reaching out.

—William

[kiss-spicoli]

Thanks https://github.com/williamweaver,

Thanks for HDR-Rendering-&-Legacy-Sky-Adjustments, I'll have a close look.

And I'll do the same with the mentioned controls and let you know what I find.

Loving Aperture :)

[kiss-spicoli]

Deep dive into https://github.com/ApertureViewer/Aperture-Viewer/wiki/HDR-Rendering-&-Legacy-Sky-Adjustments#4-general-compatibility--tuning-scales

Purpose: To test the effects of RenderHDRSkySunlightScale and RenderSkyAmbientScale
These are effectively global brightness tuners for sky-derived light. Adjust based on artistic preference for overall scene brightness and direct sun/moon intensity.
They likely exist to help tune the perceived brightness of the sun to better match legacy viewer behavior or allow artistic preference under both SDR and HDR rendering modes.
These act as overall multipliers for the calculated sun/moon?light intensity(ies?) passed to the shaders via the SKY_SUNLIGHT_SCALE uniform.

For the following, open Quick Preferences panel and click wrench icon (lower right):

• add "Sun/Moon Intensity" slider bound to RenderHDRSkySunlightScale, range 0-100, increment 0.1 (set to default = 1)
• add "Ambient Intensity" slider bound to RenderSkyAmbientScale, range 0-100, increment 0.1 (set to default = 1)
  Open APS (Alt-P) and:
• Set Gen / Graphics Presets to Eye Candy - without Mirrors (verify Post / Enable HDR set, Evn / Atmosphere / Refl Probe = 1.0)
• Click all APS [D] buttons on all tabs, then Graphics Presets / Save as "Eye Candy - Defaults" for future use
• Set Shd / Loc Lights = 0.

ALL changes below are made in APS/Evn* tab EXCEPT as marked "Sun/Moon Intensity" or "Ambient Intensity" (sliders added to Quick Preferences above).

Strategy for observation of live changes to the above arguments: observe effects of "Sun/Moon Intensity" and/or "Ambient Intensity" in these scenarios:

• in typical exterior scene with Eye Candy APS and without lights; (interior setting with lights later)
  • TP to exterior setting (I tested here: http://maps.secondlife.com/secondlife/Moose%20Beach/104/57/23)
• test with APS EEP presets
• test changes to:
  • RenderSkyAmbientScale: Used when HDR is disabled (RenderHDREnabled = false).
    Per https://github.com/ApertureViewer/Aperture-Viewer/wiki/HDR-Rendering-&-Legacy-Sky-Adjustments:
    It applies regardless of whether legacy auto-adjustment is active, although the base ambient value it multiplies might have already
    been affected by RenderSkyAutoAdjustAmbientScale if a legacy sky is active and auto-adjust is on. Affects the intensity of global
    ambient light from the sky. Values > 1.0 increase ambient brightness (filling shadows more); < 1.0 decrease it.
    A general multiplier for the ambient light contribution from the sky, passed to shaders via the SKY_AMBIENT_SCALE uniform.
  • RenderHDRSkySunlightScale: Used when HDR is enabled (RenderHDREnabled = true).
    Per https://github.com/ApertureViewer/Aperture-Viewer/wiki/HDR-Rendering-&-Legacy-Sky-Adjustments:
    Directly affects the perceived brightness/intensity of the sun/moon and the direct lighting derived from it.
    Values > 1.0 make the sun brighter; < 1.0 make it dimmer than the base sky calculation.

Testing Procedures for the impact on lighting:

Scene #1 - Sunrise

• Click Sunrise (TWICE, see issue Ensure that actions on the the APS Evn / Quick PBR Environment presets properly update Detailed Environment Editing Sub-Tabs #55). Allow time for autoexposure.
• Manipulate the Quick Preferences / Sun/Moon Intensity slider. Observe the results:
  • upon AVs, land, objects, and shadows:
    • 0 no shadows are cast, attached shading remains.
    • 0.1 very dim cast shadows, no apparent change to attached shadows.
    • 1.0 (default) very natural look
    • 10.0 land and objects are brighter and shadows darker
    • 100.0 land and objects are much brighter and shadows much darker. May be useful for edge lighting.
  • on the sky, clouds, water: None-Minor across range.
• Manipulate the Quick Preferences / Ambient Intensity slider. Observe the results: none.

Scene #2, #3, #4, #5 - Noon, Sunset, Midnight, any EEP preset.

• Repeat with other presets: same results as above, EXCEPT:
  • Noon: elevation 61.52, elevation 5-90 shadows appear
  • Midnight: sun -5; moon: elevation 20-80 shadows appear
    More on these to follow.

Findings:

• The Ambient Intensity slider (RenderSkyAmbientScale):
  • has no effect when APS/Env/Atmosphere Settings/Refl Probe <= 1.0
  • has maximum effect when Refl Probe = 0, HDR is not a factor REGARDLESS of Post/Enable HDR
  • has a partial effect when Refl Probe = 0.5, HDR is a factor if Post/Enable HDR is on
  • Presumably this is https://wiki.secondlife.com/wiki/PBR_Materials#When_is_it_Recommended_to_Create_a_Reflection_Probe?:~:text=Probe%20Ambiance%20behavior
  • The question of whether RenderSkyAmbientScale can achieve unique, desirable results using Refl Probe < 1.0 is TBD
• RenderHDRSkySunlightScale offers control over light intensity on AVs, land, objects, and cast shadows with minor or no affects on the sky or water.
  • Ranges from removing shadows (0) through very high contrast lights and shadows (100)
  • Useful to balance atmospheric and non-atmospheric lighting and to manage shadow contrast.
  • This is what sunrise looks like with the above defaults and RenderHDRSkySunlightScale = 1.0:
    https://gyazo.com/813ad98e75ad408ba2772ed7bf21659a
  • This is what sunrise looks like with only change being RenderHDRSkySunlightScale = 100:
    https://gyazo.com/9efc42b2feeb22895475bf5c8a6ad6d7
  • This seems a very desirable result (perhaps better at values < 100)
  • Unclear whether these are results can be achieved without using RenderHDRSkySunlightScale.
    Test vs changes in Atmosphere: Sun color, Refl Probe, Brightness

[Next]

[kiss-spicoli]

I fed the above two pictures to ChatGPT:

RenderHDRSkySunlightScale = 1.0
RenderHDRSkySunlightScale = 100.0

I preloaded query "As a 3D lighting expert, describe these images and their differences." ChatGPT gave an admirable response, describing commonalities (such as location and set) and performing look comparisons between the images, where the only change made was from

Quick Preferences / Sun/Moon Intensity slider = 1.0 to
Quick Preferences / Sun/Moon Intensity slider = 100.0.

Then I entered my goal query: "Compare Sun Intensity on Quick Preferences Panel."

You'll also note that IT DID NOT DETECT the change in that slider -- until I mentioned it!.

Here is its full reply:

---

Sun Intensity in the Quick Preferences panel:

• In Image 1, the Sun Intensity is set to 1.000
• In Image 2, the Sun Intensity is set to 100.000

What this means:

• In Image 1, the lighting is very soft and subdued. Surfaces like the dock and the character don’t catch much direct sunlight, so the whole scene looks low contrast and neutral.
• In Image 2, the lighting is much more dramatic. The strong sunlight brightens surfaces with warm tones, especially the dock, and creates deeper shadows. This makes the image feel more vivid and realistic, like it’s during golden hour.

Summary:
The huge increase in Sun Intensity—from 1.000 to 100.000—is the main reason Image 2 looks warmer, brighter, and more dynamic compared to the flatter look of Image 1.

---

Don't know that I could have said it much better. Except perhaps to add:

The HSL space is highly dimensional, as is how that is affected by the many controls throughout the APS. I'm ready to invite you, or the community as you prefer, to see if you can find paths in those controls to a result as good or better than image #2, and as easily as one slider - OK maybe two.

I am loving Aperture and I look forward to exploring more ways to express imagination through virtualization. I'll be exploring Aperture and will support you as best I can

KIss :)

[kiss-spicoli]

Hey @williamweaver :)

I've passed along a floater_ap_phototools.xml for your review.

As mentioned, I've added an Evn/Legacy tab as a test harness for other sliders we discussed.
I also moved Refl Probe (HDR) and Brightness there for easy testing in relation to the other sliders.
I've done some more research and I consider this a good test harness for other sliders such as the SkyAutoAdjust set that you mentioned.
I've been using it and its stable.

• I also have developed some further opinions:
• I am convinced that Sun/Moon Intensity (RenderHDRSkySunlightScale) ought to be added, as it operates on HDR/PBR envs as well as Legacy.
• I also think Ambient Intensity (RenderSkyAmbientScale) is very useful and ought to be included, though I have yet to full understand its dependencies.
• The interrelationships of many controls is as yet unclear .. they keep surprising me:
  -- For example, Brightness is hard to understand - it sometimes seems inverted.
  -- Other sliders seem sometimes to stop having an effect, but its unclear it that is just unexpected or if it is a bug. Clicking Local Environment twice seems a blunt recovery.
• While I want not to spend more time on Legacy Sky Auto Adjust, I think those who want to support windlight could find its controls very useful.

My plan is to continue my testing of APS controls, especially on Evn (esp. Atmos, Sun&Moon, and Legacy), Shd, Refl, and Post.

[kiss-spicoli]

Get a chance to try the Legacy Panel, @williamweaver ?

[kiss-spicoli]

@williamweaver ... everything OK? Seems mighty quiet lately...