Aurora

Aurora is Atlas's terrain system. It creates renderable terrain from image heightmaps or procedural generators and can assign biomes using height, moisture, and temperature ranges.

Choose a terrain source

Use a heightmap when an artist or external terrain tool defines the shape. Use a generator when the terrain should be reproducible from parameters or created at runtime.

import { Terrain, MountainGenerator } from "aurora";

const generator = new MountainGenerator(0.02, 24, 6, 0.5);
const terrain = Terrain.fromGenerator(generator);

The mountain constructor takes scale, amplitude, octave count, and persistence. A lower scale spreads features over a larger area; amplitude controls their height; octaves add detail; persistence controls how strongly later octaves contribute.

Other built-in generators are HillGenerator, PlainGenerator, and IslandGenerator. CompoundGenerator layers several generators:

import {
    CompoundGenerator,
    HillGenerator,
    IslandGenerator,
    Terrain,
} from "aurora";

const generator = new CompoundGenerator();
generator.addGenerator(new IslandGenerator(18, 0.015));
generator.addGenerator(new HillGenerator(0.05, 3));

const terrain = Terrain.fromGenerator(generator);

Load a heightmap

import { Resource, ResourceType } from "atlas";
import { Terrain } from "aurora";

const heightmap = Resource.fromAssetPath(
    "terrain/island-height.png",
    ResourceType.Texture,
    "Island Heightmap",
);

const terrain = Terrain.fromHeightmap(heightmap);

Terrain is a GameObject, so it uses the familiar transform and visibility methods: setPosition, move, setRotation, setScale, show, and hide. Its width, length, height, maxPeak, and seaLevel values control the generated result.

Add biomes

A biome combines a texture or fallback color with selection ranges. Add narrower biomes before broad fallback regions so their intent remains easy to understand.

import { Biome } from "aurora";
import { Color } from "atlas/units";
import { Texture, TextureType } from "atlas/graphics";

const snowColor = new Color(0.92, 0.95, 1, 1);
const snowTexture = Texture.createColor(
    snowColor,
    TextureType.Color,
    1,
    1,
);
const snow = new Biome("Snow", snowTexture, snowColor, false);

snow.minHeight = 0.72;
snow.maxHeight = 1;
snow.minMoisture = 0;
snow.maxMoisture = 1;
snow.minTemperature = 0;
snow.maxTemperature = 0.4;

terrain.addBiome(snow);

Set useTexture to true and call attachTexture() when the biome should use an actual surface texture. Moisture and temperature textures allow the same height band to produce different regions.

Sample noise directly

Aurora also exposes PerlinNoise, SimplexNoise, WorleyNoise, FractalNoise, and the Noise convenience class. These return scalar samples and are useful for placement, masks, weather maps, or custom generation logic.

import { PerlinNoise } from "aurora";

const noise = new PerlinNoise(42);
const density = noise.noise(worldX * 0.01, worldZ * 0.01);

Keep the seed stable when the same project must reproduce the same terrain. Terrain generation creates geometry, so avoid rebuilding it every frame.