Getting Started with the Job System in Unity 2019

Introduction

This tutorial will guide you through getting started with the Job System in Unity 2019. The Unity Job System allows you to write high-performance code by utilizing multithreading, which can significantly improve the efficiency of your game development process. Whether you're a beginner or looking to optimize your existing projects, this guide will provide clear steps to implement the Job System in your Unity projects.

Step 1: Setting Up Your Project

• Open Unity Hub and create a new 3D project.
• Ensure you are using Unity 2019 or later.
• Once the project is created, go to the Package Manager:
  • Navigate to Window > Package Manager.
  • Search for the Jobs package and install it if it is not already added.

Step 2: Understanding the Job System Basics

• Familiarize yourself with the concept of jobs:
  • Jobs are units of work that can run concurrently.
  • They help in offloading tasks to multiple CPU cores, improving performance.
• Understand the key components:
  • IJob: An interface for creating jobs.
  • JobHandle: A struct that manages the execution of jobs.

Step 3: Creating Your First Job

• Create a new C# script called MyFirstJob.
• Implement the IJob interface:

  using Unity.Jobs;
  
  public struct MyFirstJob : IJob
  {
      public void Execute()
      {
          // Your job code here
      }
  }
  

• In the Execute method, write the code for the task you want the job to perform.

Step 4: Scheduling the Job

• In your main script (e.g., JobSystemExample), schedule the job:

  MyFirstJob job = new MyFirstJob();
  JobHandle jobHandle = job.Schedule();
  jobHandle.Complete(); // Wait for the job to complete
  

• This schedules your job to run and ensures your main thread waits for its completion.

Step 5: Passing Data to Jobs

• Use Native containers to manage data safely between the main thread and jobs.
• Create a NativeArray to pass data:

  using Unity.Collections;
  
  NativeArray<float> results = new NativeArray<float>(1, Allocator.TempJob);
  MyFirstJob job = new MyFirstJob { /* initialize data */ };
  JobHandle jobHandle = job.Schedule();
  jobHandle.Complete();
  
  // Access the results
  float resultValue = results[0];
  results.Dispose(); // Dispose when done
  

Step 6: Optimizing Job Performance

• Use the Burst Compiler for performance optimization:
  • Install the Burst package via Package Manager.
  • Add the [BurstCompile] attribute to your job struct:

  using Unity.Burst;
  
  [BurstCompile]
  public struct MyOptimizedJob : IJob
  {
      public void Execute()
      {
          // Optimized job code
      }
  }
  

• This compiles your job to highly optimized machine code, enhancing performance.

Conclusion

In this tutorial, you learned the basics of the Unity Job System, including how to set up your project, create and schedule jobs, and optimize them using the Burst Compiler. These steps are foundational for improving your game’s performance.

As you move forward, consider exploring advanced topics like job dependencies and more complex data handling to further leverage Unity's capabilities. Happy coding!