Headlights

Headlights

Lights for every car that come on as it gets dark.

What it does

A renderer can light each surface with only a few real lights. So the player's car (real: true) gets two real spot lights that light the road, the trees and the other cars. Every car, the player's too, also gets:

• a beam painted on the road ahead, a fan of light added on top of the tarmac, which is how a headlight looks from above;
• two glowing lenses;
• two red tail lamps that brighten while the car brakes.

Use it in a scene

{
  "Player": {
    "components": {
      "MeshPrimitive": {
        "primitive": "box",
        "width": 1.9,
        "height": 1,
        "depth": 4.2
      },
      "CarDrive": {},
      "Headlights": {
        "real": true,
        "beamStrength": 0.35,
        "forward": 2.0,
        "side": 0.7
      }
    }
  }
}

Put a plain "Headlights": {} on traffic blueprints. Call registerHeadlightsExtension(adapter) at bootstrap. Without it, a real car still gets two spot lights, but no car gets beams, lenses or tail lamps.

Coming on at dusk

The System hears darkness from dayNight.changed and turns it into a light level with a smooth ramp:

export function lightLevel(darkness: number, onAt: number, fullAt: number): number {
  if (fullAt <= onAt) return darkness >= onAt ? 1 : 0;
  const t = Math.max(0, Math.min(1, (darkness - onAt) / (fullAt - onAt)));
  return t * t * (3 - 2 * t);
}

With the defaults, darkness 0.4 gives a level of 0.16. Darkness 0.5 gives 0.5. The lights ease in rather than snap on.

Range falloff

Real light fades with the square of the distance. A headlight bright enough to reach far down the road that way would blind the car's own bonnet. So the plugin gives its spot lights a set range instead: the beam fades out at that distance. The lenses are glossy glass. The beam on the road is light, so it is unlit and added on top.

Light bar

A car with "beacon": true gets a red and blue light bar on its roof. It stays dark until headlights.beacon.set turns it on. Then the two halves take turns, each with a quick double flash:

  const phase = (((t * rate) % 1) + 1) % 1;
  const lit = (a: number) => (phase >= a && phase < a + 0.15) || (phase >= a + 0.25 && phase < a + 0.4);
  return { red: lit(0) ? 1 : 0, blue: lit(0.5) ? 1 : 0 };

At the default beaconRate one cycle takes 0.71 s. Red flashes twice in the first half and blue twice in the second, day or night. Each flash lays a round red or blue glow on the road, washRadius metres in radius. The glow is painted on like the beam. It is not a real light, because the sun, the sky and the player's headlights already use up the few each surface can take.

Pools and ghosts

A pooled car that parks hides its lights, and they come back when the car does. A car tagged as a ghost by CarCollision (riding in a truck, or waiting to respawn) shows no lights.

Settings

Events

Needs

• MeshPrimitive: where each car is.
• CarDrive: the car's heading, and its brake and speed for the brake lamps.
• CarCollision: its ghost tag, which hides the lights.