Systems Dev - Network Multiplayer Upgrade System

Purpose

• Develop a light-weight, flexible and iterable upgrade system that works within the framework of Photon’s Fusion Network Multiplayer solution for Unity.

• Decoupled classes with clear separation of concerns between interface, logic, and data.

• Support pre-production design exploration with modular code that supports significant changes to the purchasing mechanics.

• Implement the current state of the design (see requirements).

Requirements

• Upgrade mechanical design requires:

  • Upgrades acquired through interacting with vending machine

  • Players must purchase credits at any given vending machine using their individual funds

  • Purchased credits allows any player to roll a set of 3 upgrade offers

  • The upgrade offers are purchasable until a visible timer reaches 0

  • Players may purchase any or all of the upgrade offers they can afford with their funds

  • While players are interacting with a vending machine, they cannot move or shoot

• Potential future rules:

  • Only one player may interact with a vending machine at a time

  • The cost of tokens increase based on the number of tokens purchased previously at that machine

  • The cost of tokens decreases as time goes on

  • The cost of upgrades increases for every upgrade a player’s avatar has

Constraints

• The project supports 2 player cooperative play over HOST-CLIENT topology.

• Photon Fusion considers Remote Procedural Calls (RPCs) to be relatively less reliable than object spawning.

• Fusion does not permit a native method to support state synchronization of collections => upgrades as pure data require additional bandwidth to upkeep.

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Solution

• Upgrades are genericized prefabs that are instantiated using Fusion’s NetworkSpawn() function to permit for state synchronization and lifecycle management without bandwidth consuming upkeep.

• The upgrade prefab self initializes based on network events so performant data-only model of upgrades per avatar can be used to calculate changes in avatar stats and behaviors.

• The upgrade prefab also permits for HOST simulated behaviors for future upgrades’ mechanical expansion.

• VENDING MACHINE UI code is decoupled from UPGRADE CONTROLLER by use of a simple interface.

• UPGRADE CONTROLLER is decoupled from INPUT STATE CONTROLLER by use of an EVENT and EVENT MANAGER system.

• Data required for the View and Controller codes are stored externally and is readable through Service Locator pattern.