AuraLite Shaders

🚀 What's New in v1.2.0 — Physical Clouds

Version 1.2.0 is the first release of the physical cloud line. The cloud deck stops being four painted sheets and becomes a medium with a droplet spectrum; the atmosphere coefficients are re-derived from measured column depths; godrays integrate a filtered transmittance with a fixed step count; the colour stage becomes twelve sliders;

☁️ Volumetric Cloud Engine — Microphysics, Not Constants

• The deck is a medium. CLOUD_DENSITY selects a liquid water content (0.075 / 0.15 / 0.30 g/m³) and CLOUD_MICRO a droplet spectrum (Continental 6 µm / Typical 8 µm / Maritime 12 µm); extinction is derived from them (σ = 3·LWC·Q_ext / 4ρ·r_eff), so "dense" is a physical quantity rather than a number that was tuned by eye.
• Resolution and detail are independent. CLOUD_QUALITY is the raymarch budget (Cheap 14 / Standard 24 / High 36 / Extreme 56 steps) and the new CLOUD_DETAIL is the shape field (2–5 octaves, 1080 → 135 m features). A weak GPU can keep crisp cloud tops and drop the step count instead of the shape; the two multiply, and the cost table is in the release notes.
• Coverage is cloud fraction, not brightness. New CLOUD_COVERAGE (Clear / Scattered / Broken / Broken to overcast / Overcast) moves the threshold the shape field has to cross, and each octave preset carries a bisected offset so "Broken" covers the same ~40 % of the sky on every profile.
• Cirrus is ice, not a small cumulus. New CLOUD_CIRRUS marches a fibrous veil at 6.5–11.2 km with its own extinction (~0.09 g/m³, 25 µm), and it dissolves into the horizon haze instead of ending on a visible edge.
• An independent mid-level deck. New CLOUD_MID_LAYER adds a second, separate layer rather than repeating the cumulus field.
• Real air. Altitudes in metres via CLOUD_HEIGHT (400 m / 1200 m / 2400 m / 3600 m), deck depth as a fraction of the base altitude, reach out to 32 km, wind as a velocity in m/s, per-cloud condensation level (CLOUD_BASE_VARIATION) and vertical development (CLOUD_UPDRAFT), and multiple scattering instead of a single-sample light tap.
• CLOUD_MODE keeps the v1.1.4 layered sheets available (Layered sheets / Volumetric) for hardware that cannot afford the march.

🌤️ Godrays — Filtered, Bounded and Stable in Time

• Shafts sample a filtered shadow term — a smoothstep band expressed in the same space as the depth compare — instead of step() on the blocker depth. Moving the camera by a fraction of a shadow texel no longer flips whole samples between lit and unlit.
• Fixed step count. The path is bounded (40 km) and divided into a constant number of taps, so the optical depth changes continuously as the sun moves instead of jumping whenever the path crosses a multiple of the old 150 m step.
• One cloud-shadow column per frame. The cloud transmittance that gates the shafts is screen-independent, so it is evaluated once per fullscreen-quad vertex in composite.vsh and handed over as a flat varying — 4 evaluations per frame instead of 2 million. That file is generated from composite.fsh by tools/gen_composite_vsh.py, so the duplicated field code cannot drift; CI can verify it with --check.
• Near-horizontal light fades out towards the horizon instead of integrating an effectively infinite path through the deck, which is what made the shafts "breathe" at sunset.

🌇 Atmosphere — Coefficients From Measurements, Twilight From Optics

• Rayleigh, aerosol scattering and absorption, and ozone as a 25 ± 15 km tent (Bruneton/Hillaire) replace the hand-tuned triplet that carried roughly 9× too much aerosol and no ozone at all.
• Twilight is produced by the optical path: civil, nautical and astronomical phases, the Earth's shadow and the Belt of Venus, all in gbuffers_skybasic. The old global on/off ramp over the finished result is gone, so the sky no longer dies by solar −1.4°.
• Airglow is added after the dark-adaptation gain. Multiplying it by the gain (which reaches 28 in deep twilight) used to paint the entire night sky blue at every hour.
• The physical sky (SKY_MODE = 1) now shares its LUT-derived transmittance with the default gradient sky, so terrain fog, water reflection, clouds, godrays and the SSR sky fallback agree in both modes.

🎚️ Colour Grading — Twelve Sliders, One Tone Curve

• The three-stop EXPOSURE / COLOR_SATURATION / CONTRAST buttons are replaced by a dedicated [Colour Grading] tab with continuous sliders: Exposure, Brightness, Contrast, Saturation, Output Gamma, Red/Green/Blue gain, Warmth, Tint, Vibrance and Vignette strength, plus a Tone Curve selector (ACES / ACES soft / ACES punchy / Photographic (AgX-like)).
• These are declared as real Iris sliders — dragging is the point, and every value in between exists. Everything else in the pack stays an enumerated button on purpose.
• COLOR_LUMA_PROTECT keeps average brightness fixed while the channel and warm/tint sliders move, so a white-balance experiment does not also change exposure.

💧 Water, Foliage and Stability

• Water has an ID. minecraft:water / flowing_water map to block ID 10020, so water classification no longer guesses from colour and depth — and the whole rescue ladder that existed for that guess is now a fallback, not the primary path.
• One wind-wave spectrum. Eight components with deep-water dispersion (ω = √(gk)) and wavelength-derived amplitude, evaluated in world space. The three longest displace the mesh (26 / 15.5 / 9.5 blocks — no aliasing on Minecraft's one-vertex-per-block grid), the rest live in the normal. The v1.1.4 surface was driven by three unrelated sine fields, one of them in view space.
• Water no longer writes into the shadow map. A flat receiver standing in its own shadow map with centimetre waves produced self-shadow stripes whose period was constant in pixels; the vertex shader now pushes water out of the shadow pass entirely.
• Vegetation is three classes, not one: tall plants bend from the base, short grass flutters, flower heads nod — and the wave phase is taken from world coordinates, so grass stops "speeding up" when you walk across chunk borders. Mirrored in shadow.vsh.
• Dither is a fixed 4×4 ordered pattern, not two fract(sin(...)) hashes of gl_FragCoord: the hash was uncorrelated between pixels and unstable in float, so it read as grain over the whole frame and shimmered even when the camera was still. The cloud ray start is deterministic as well — every pixel aims at the middle of its shell, and the slicing that the jitter used to dissolve is now handled by CLOUD_QUALITY.

🎚️ Profile Rebalance (v1.2.0)

Camera jitter remains off by default in every profile.