Alpine daylight normalization — 15 September 2026

The actual Windows photographs in QA/20260915-142737-campaign show an excessively dark sky. This is a rejected intermediate render.

The unmodified CC0 kloofendal_43d_clear_puresky RGBE panorama was decoded numerically. Rec.709 luminance percentiles in the upper hemisphere are 0.1195 (10%), 0.2226 (median), 0.9716 (90%), 1.9734 (99%) and 4.4641 (99.9%). Its brightest solar pixel is 110947.328. The cosine-weighted upper-hemisphere integral is 5.45773304185; the integral excluding source luminance above 10 is 1.24896336095. This bounded threshold excludes the solar disk and its brightest immediate surround; it is an explicit normalization method, not a separate measured sky illuminance.

Previously HDRP's Lux mode scaled the total integral to 18000 lux. With this very bright disk, the remaining diffuse sky was consequently only about 4120 lux. In the pinned HDRP SkySettings.GetIntensityFromSettings(), Lux mode is precisely desiredLuxValue / upperHemisphereLuxValue; changing the panorama without considering its disk changed the ratio between direct sunlight and visible sky.

The Alps now use a target total of 78654.18 lux, approximately the original panorama multiplied by 18000 / 1.24896336095. Camera exposure stays EV13 and the HDR bytes, colour space and compression stay unchanged. The intended diffuse level is approximately 18000 lux. This is an art-lighting normalization; the solar image and directional light have not been separately radiometrically calibrated. Other regions and the garage are unchanged.

RAMPAGE_SKY reports the actual loaded cubemap, face resolution, intensity multiplier, target lux and fixed camera exposure in the next native player log. The source includes a relatively clear sky; a cloud-filled photograph is not promised for every direction. New native photographs are required before accepting brightness, cloud detail, material response or sun alignment.