Spatial Broadcasting

Spatial broadcasting is a technique that helps efficiently distribute data and events in a world divided into spatial partitions. It's particularly useful in large multiplayer games, virtual worlds, or simulations where only relevant data needs to be sent to nearby clients. This reduces network bandwidth and ensures clients only receive the necessary information.

This is implemented by dividing the game world into partitions, allowing broadcasting to occur based on proximity to specific areas, ensuring that clients only receive updates relevant to their location.

Core Concepts

  • World Partitioning: The game world is divided into smaller areas called partitions. Each partition holds game objects and players, and each partition has a defined region within the world.
  • Spatial Indexing: The world is indexed using a grid system where each position corresponds to a partition. This indexing allows the framework to quickly find nearby objects and clients when broadcasting information.
  • GameWorldCoordinator: This class manages multiple game worlds and coordinates access to the partitions within each world.
  • GameWorldManager: Manages individual game worlds and the partitions within them, enabling spatial indexing and object management.

How Spatial Broadcasting Works

Spatial broadcasting allows you to send packets to nearby clients based on their location. The SpatialBroadcast method utilizes world partitioning to determine which clients are within the broadcast range. The main idea is to calculate which world partitions intersect with a specific area and then send the broadcast to the clients in those partitions.

Basic Spatial Broadcasting

Here's an example of how you can use spatial broadcasting to send packets to clients in nearby partitions:

_ = SpatialBroadcast(senderClientId, x, y, packet);

World Partitioning and Spatial Indexing

Each game world is divided into smaller partitions that help manage objects and players. The GameWorldManager class handles this division and provides functionality to update object positions based on their location.

  • Partition Calculation: Partitions are calculated using a partitioner. Each partition holds objects, and when an object moves, it is assigned to a new partition based on its new position.

  • Finding Nearby Objects: To find nearby clients or objects, the framework uses spatial indexing to determine which partitions intersect with a specified area. Once the relevant partitions are identified, the system can efficiently retrieve and send data to the clients within that area.

Optimized Broadcast: Smart Spatial Broadcasting

The framework also supports "smart" spatial broadcasting. This technique is used when the number of players in a room exceeds a specified threshold. Instead of broadcasting to all clients in the room, it calculates which nearby partitions should receive the broadcast.

_ = SmartSpatialBroadcast(senderClientId, x, y, packet);

Key Benefits

  • Reduced Bandwidth: By sending data only to clients that are nearby, the system avoids unnecessary network traffic, reducing bandwidth usage.

  • Efficient Event Distribution: Events like chat bubbles, emotes, or area-based effects are broadcast only to relevant players, improving performance and user experience.

  • Scalability: The partitioning system scales well with large numbers of players, ensuring that as worlds and areas grow, broadcasts remain efficient.