Procedural Terrain Generation

Generate realistic, infinite terrain using noise functions, erosion simulation, and biome systems that create believable natural landscapes.

Heightmap-Based Terrain

The most common approach to terrain generation uses a heightmap — a 2D grid where each cell stores an elevation value. Multiple layers of noise at different frequencies (octaves) are combined to create natural-looking terrain.

Noise Layering

Erosion Simulation

Raw noise terrain looks alien and unrealistic. Erosion simulation transforms it into natural-looking landscapes by simulating water and thermal processes.

• Hydraulic erosion: Simulate water droplets flowing downhill, picking up sediment and depositing it. Creates river valleys, deltas, and realistic drainage patterns.
• Thermal erosion: Material falls from steep slopes to shallow ones, creating talus slopes and softening sharp features.
• Wind erosion: Simulate wind carrying particles, creating dunes and wearing down exposed surfaces.

def erode(heightmap, iterations=50000):
    for _ in range(iterations):
        # Random droplet starting position
        x = random.uniform(0, heightmap.shape[1] - 1)
        y = random.uniform(0, heightmap.shape[0] - 1)
        sediment = 0.0
        speed = 1.0
        water = 1.0

        for step in range(64):
            # Calculate gradient at current position
            gx, gy = compute_gradient(heightmap, x, y)

            # Move droplet downhill
            x -= gx
            y -= gy

            if out_of_bounds(heightmap, x, y):
                break

            # Calculate height difference
            h_new = sample(heightmap, x, y)
            h_diff = h_new - h_old

            # Deposit or erode
            if h_diff > 0:  # Going uphill
                deposit(heightmap, x, y, sediment)
            else:  # Going downhill
                erode_point(heightmap, x, y, -h_diff)

            water *= 0.99  # Evaporation
    return heightmap

Biome Distribution

Biomes are assigned based on elevation and moisture. Use a Whittaker diagram to map temperature/moisture combinations to biome types:

• Low elevation + high moisture = Tropical rainforest
• Low elevation + low moisture = Desert
• High elevation + high moisture = Taiga/Snow
• Medium elevation + medium moisture = Temperate forest

Infinite Terrain (Chunked Generation)

For open-world games, terrain is generated in chunks around the player. Since noise functions are deterministic and position-based, each chunk generates identically regardless of when it is created.

• Load ring: Generate chunks within a radius around the player.
• LOD levels: Nearby chunks get full resolution; distant chunks use lower resolution meshes.
• Seamless borders: Because noise is continuous, chunk borders are automatically seamless.
• Async generation: Generate chunks on background threads to avoid frame stutters.