Documentation/content/world/worldgen/zones.en.md

---
title: Zones
type: docs
weight: 6
---

Zones define distinct regions of the world with specific generation rules, biomes, and features.

**Package:** `com.hypixel.hytale.server.worldgen.zone`

## Zone System

Zones partition the world into distinct areas:

```java
public class ZoneManager {
    // Get zone at position
    public Zone getZone(int x, int z);

    // Register zone
    public void registerZone(Zone zone);

    // Get all zones
    public List<Zone> getZones();
}
```

## Zone Definition

```yaml
# zones/emerald_grove.yaml
Type: Zone
Id: emerald_grove
DisplayName: "Emerald Grove"
Shape: Circle
Center: [0, 0]
Radius: 1000
Biomes:
  - forest
  - dense_forest
Climate:
  TemperatureOffset: 0.1
  HumidityOffset: 0.2
Features:
  - giant_trees
  - fairy_circles
Prefabs:
  - elf_village
  - forest_shrine
MobSpawns:
  - Type: deer
    Weight: 20
  - Type: forest_spirit
    Weight: 5
```

## Zone Class

```java
public class Zone {
    private String id;
    private String displayName;
    private ZoneShape shape;
    private List<String> biomes;
    private ClimateModifier climate;
    private List<String> features;
    private List<String> prefabs;
    private List<MobSpawn> mobSpawns;

    // Check if position is in zone
    public boolean contains(int x, int z);

    // Get zone-specific biome
    public Biome getBiome(int x, int z);

    // Modify generation
    public void modifyGeneration(GenerationContainer container);
}
```

## Zone Shapes

```java
public interface ZoneShape {
    boolean contains(int x, int z);
    float getDistanceToEdge(int x, int z);
}

public class CircleZone implements ZoneShape {
    private int centerX, centerZ;
    private int radius;

    public boolean contains(int x, int z) {
        int dx = x - centerX;
        int dz = z - centerZ;
        return dx * dx + dz * dz <= radius * radius;
    }
}

public class RectangleZone implements ZoneShape {
    private int minX, minZ, maxX, maxZ;

    public boolean contains(int x, int z) {
        return x >= minX && x <= maxX && z >= minZ && z <= maxZ;
    }
}

public class PolygonZone implements ZoneShape {
    private List<Vector2i> vertices;

    public boolean contains(int x, int z) {
        // Point-in-polygon algorithm
        return isPointInPolygon(x, z, vertices);
    }
}
```

## Zone Transitions

Smooth transitions between zones:

```java
public class ZoneTransition {
    private int transitionWidth;

    public float getBlendFactor(Zone from, Zone to, int x, int z) {
        float distFrom = from.getShape().getDistanceToEdge(x, z);
        float distTo = to.getShape().getDistanceToEdge(x, z);

        if (distFrom > transitionWidth) {
            return 0.0f;  // Fully in 'from' zone
        }
        if (distTo > transitionWidth) {
            return 1.0f;  // Fully in 'to' zone
        }

        return distFrom / (distFrom + distTo);
    }
}
```

## Zone Layers

Zones can have vertical layers:

```yaml
# zones/underground_kingdom.yaml
Type: Zone
Id: underground_kingdom
Shape: Circle
Center: [5000, 5000]
Radius: 500
VerticalRange:
  MinY: 0
  MaxY: 40
Biomes:
  - crystal_cave
  - mushroom_forest
Features:
  - glowing_crystals
  - underground_lake
```

## Zone Priority

When zones overlap, priority determines which applies:

```java
public class ZonePriority {
    public Zone getActiveZone(int x, int y, int z) {
        List<Zone> containing = zones.stream()
            .filter(z -> z.contains(x, z) && z.containsY(y))
            .sorted(Comparator.comparing(Zone::getPriority).reversed())
            .toList();

        return containing.isEmpty() ? defaultZone : containing.get(0);
    }
}
```

## Dynamic Zones

Zones that can change at runtime:

```java
public class DynamicZone extends Zone {
    public void expand(int amount) {
        if (shape instanceof CircleZone circle) {
            circle.setRadius(circle.getRadius() + amount);
        }
    }

    public void move(int dx, int dz) {
        shape.translate(dx, dz);
    }
}
```

## Configuration

```yaml
# worldgen/zone_config.yaml
Zones:
  Default: wilderness
  TransitionWidth: 32
  List:
    - Id: spawn_area
      Priority: 100
      Shape: Circle
      Center: [0, 0]
      Radius: 200
    - Id: wilderness
      Priority: 0
      Shape: Infinite
```

## Best Practices

{{< callout type="info" >}}
**Zone Guidelines:**
- Use zones for distinct world regions
- Define smooth transitions between zones
- Consider zone priority for overlaps
- Use appropriate shapes for zone boundaries
- Test zone generation thoroughly
{{< /callout >}}