Bevy 0.12 Beginner Tutorial Series - Ep 4 - Schedules, System Ordering, SystemSets, and Flush Points

Tutorial: Understanding Schedules, System Ordering, SystemSets, and Flush Points in Bevy 0.12

Introduction:

1. Welcome to Bevy Basics: This tutorial will guide you through understanding schedules, system ordering, system sets, and flush points in Bevy 0.12.
2. Key Concepts: Schedules determine the order of systems execution, system ordering ensures dependencies are met, system sets organize systems into logical groups, and flush points manage changes in the game state.

Understanding Schedules:

1. Main Schedule Overview:

   • The main schedule organizes and executes other schedules.
   • It runs built-in schedules like pre-update, state transition, fixed update loop, update, and post-update.

2. Using Main Schedule:

   • Avoid adding systems directly to the main schedule.
   • Utilize sub-schedules provided by Bevy like update for better organization.
   • Refer to the documentation for a detailed understanding of the main schedule's order of execution.

System Ordering:

1. Fixed Update vs. Update:

   • Fixed update ensures consistent timing for systems that require it, like physics.
   • Use before, after, and chain APIs to establish dependencies between systems.

2. Applying System Ordering:

   • Use before to specify a system to run before another.
   • Use after to ensure a system runs after its dependent system.
   • Use chain to order multiple systems sequentially without repeating before and after statements.

SystemSets and Flush Points:

1. Introduction to SystemSets:

   • SystemSets group systems into logical sets for better organization.
   • Configure SystemSets using configure_set method on the Bevy app.

2. Managing Flush Points:

   • Apply apply_deferred system to create explicit flush points within a schedule.
   • Use SystemSets to order systems across plugins for scalability and clarity.

Best Practices and Recommendations:

1. System Orchestration:

   • Order systems within a plugin using system ordering APIs.
   • Orchestrate systems across plugins using SystemSets for logical grouping and ordering.

2. Handling Complexity:

   • Leverage scheduling tools like before, after, chain, and SystemSets to manage system dependencies and execution order efficiently.

Conclusion:

1. Practice and Implementation:

   • Clone the source code from GitHub for hands-on practice.
   • Experiment with scheduling, system ordering, and SystemSets to gain a deeper understanding.

2. Feedback and Learning:

   • Share your experiences with scheduling and system ordering in the comments.
   • Stay tuned for more tutorials to enhance your Bevy skills.

By following these steps and practicing with the provided source code, you can master the concepts of schedules, system ordering, SystemSets, and flush points in Bevy 0.12. Happy coding!