gaoypeng/3dcodeverse/c3d-scene-night

Night light — few sources, believable glow, no tents

The frame gate stops black frames (dark_frame: mean luminance under 0.12 or more than 35 % near-black on an authored camera); this skill is about the opposite failure, a night lit like a fairground. Read c3d-scene-lighting's linear-vs-hex section first — half of "my night scene is black" is an albedo 40x darker than its neighbour.

Emissive windows

Requirement: a lit facade is lit with variation — not every window, not one flat glow — and the street under it agrees with the windows above (emissive illuminates nothing, so a facade with no light beside it floats in the dark). Pair each big lit facade with one dim matching PointLight. references/window-canvas.md describes the canvas version.

Glow without postprocessing

The renderer's post chain blooms emissives on its own (author them at a peak of a few units, not twenty). Where you want more, two layered additive sprites per source — a small bright core plus a large faint halo, both depthWrite: false — read as bloom where one sprite reads as a sticker; the bulb mesh itself is MeshBasicMaterial (a lit bulb does not shade).

Street lamps — fake the pool, few real lights

WebGL forward lighting costs per fragment per light, and thirty real lights is both slow and flat. One option: real PointLights (decay 2) on the foreground lamps only, and for the rest an additive radial-gradient disc on the ground plus a faint gradient cone for the shaft.

Light shafts are barely there

Measured in the reference harness: a NORMAL-blended shaft at 0.3+ opacity renders as a solid white TENT and buries the scene behind it. Additive blending at a few percent opacity, alpha fading along the cone, is the range that reads. If the shaft reads clearly in a thumbnail, it is too strong.

Wet road

A near-black road is one of the dark-ground cases the lighting skill warns about: it passes the band only because it mirrors something. Low roughness, high metalness, and a night environment bake whose LOWER half carries the window and neon colours (see c3d-scene-atmosphere for the bake) — without a coloured bake the wet road has nothing to mirror and just goes black.

Light that agrees with itself

The judge scores the night's light as a whole (lighting_atmosphere: "inconsistent lighting", thin_atmosphere: no falloff): every source in frame has to belong to the place — its lamps, its windows, its signs, its moon or none — and the ground, the air and the reflections agree with those sources. A moon is one cool directional light at low intensity; two suns, or a fill with no source in the scene, is what the judge reads as inconsistent. How many colours the night has is the brief's: a sodium street is one, a market with signs is many.

Verify before you finish

One frame: count the distinct light colours; check one lamp's ground pool exists; check no shaft reads as a solid; check the road mirrors colour, not blackness; read camera_checks for mean_lum and dark_frac on every authored camera.