RoadsideScenery

RoadsideScenery

Woods, farms and towns beside a HighwayRoad, planted the same way on every drive.

What it does

For each 30 m chunk of road, RoadsideScenery.core makes a list of things standing beside it. Pines, oaks and birches clump into woods. Bushes, rocks and farm fences fill the gaps, reeds grow on river banks, and telephone poles and reflector posts line the shoulders. In towns there are houses, the odd barn and street lamps.

The road plan says where nothing may stand: the tarmac, the ditch and the river.

Use it in a scene

{
  "Scenery": {
    "components": {
      "RoadsideScenery": {
        "seed": 7,
        "follow": "Player",
        "treeDensity": 0.7,
        "reach": 78
      }
    }
  }
}

It finds the HighwayRoad on its own. If the world has no road, it plants beside a default one. Call registerRoadsideSceneryExtension(adapter) at bootstrap to see it.

Seeded chunks

Each chunk gets its own random numbers, made from the two seeds and the chunk number:

  const seed = (p.seed | 0) ^ (road.params.seed | 0);
  const rng = makeRng(hash3(seed, index, 0x51ce));

So chunk 4012 is the same wood every time you pass it, and chunks can be built in any order. A new road seed gives new woods too. A few things come at a fixed rhythm instead of by chance:

/** Reflector posts along the shoulders, this far apart. */
export const POST_SPACING = 40;
/** A green highway sign this often. */
export const SIGN_SPACING = 640;
/** A yellow warning sign this far before a bridge. */
export const WARNING_BEFORE_BRIDGE = 110;

Draw calls

Each kind of thing is one low-poly mesh with its colour baked into the vertices. The plugin draws it once and repeats it for every placement (thin instances), with a small tint per copy so no two trees match. A forest of two thousand trees costs about as many draw calls as there are kinds of tree. The trees and houses cast shadows on the road when castShadows is on.

Without the plugin nothing is drawn, but the plan still exists, so cars still hit the trees.

At night

The lamp heads and house windows glow, and each street lamp lays a soft pool of light on the road. The pools are painted on, not real lights. A whole town costs nothing against the light limit the headlights need.

Solid things

Trunks, poles, lamps, signs, rocks and houses are also circles. CarCollision asks for the ones near a car, from its own code:

    const scenery = findScenery(world);
    // ...
    plan.obstaclesIn(b.z - reach - 6, b.z + reach + 6, this.obstacles);

That is how a car that leaves the road hits a tree. Bushes, reeds, fences and reflector posts give way.

Settings

Change any of them while the game runs (LiveTuner does) and the roadside replants around the car.

Events

Needs

• HighwayRoad: the shape of the road to plant beside.
• MeshPrimitive: where the followed car is right now.