System Manager - README

This code demonstrates the System Manager, which manages systems in an Entity-Component-System (ECS) architecture. The code handles the dependencies between systems and provides a sorted execution order based on those dependencies.

Purpose

The System Manager was created to simplify the handling of dependencies between systems in an ECS system. By automatically sorting the execution order based on dependencies, it eliminates the need for manually adjusting system indices when adding or removing systems.

Algorithm Overview

1. The System Manager maintains a Data map to store system instances, a Need map to store system dependencies, and Sequence and Done queues for managing the execution order.
2. When a system is created using Create(), it is added to the Data map along with an empty dependency list in the Need map.
3. Dependencies are set using SetDependency(), where the dependent system's name is added to the dependency list of the main system.
4. To determine the execution order, the Sort() function is called. It uses a topological sorting algorithm.
5. The Sort() function initializes a DepCount map to keep track of the number of dependencies for each system.
6. It then iterates through the Need map and increments the dependency count for each system based on its dependencies.
7. Systems with no dependencies (count = 0) are pushed into the Sequence queue and marked as processed by decrementing their dependency count.
8. The function continues this process until all systems are processed and added to the Sequence queue.
9. Finally, the Frame() function executes the systems in the sorted Sequence queue, and the executed systems are moved to the Done queue.
10. The Frame() function repeats this process until all systems have been executed.

Usage

1. Create instances of systems using the Create() function in the SystemManager class.
2. Set dependencies between systems using the SetDependency() function.
3. Call Sort() to sort the systems based on their dependencies.
4. Execute the systems in the sorted order using the Frame() function.
5. Clean up the systems using Destroy().

Example

#include <iostream>
#include <vector>
#include <queue>
#include <string>
#include <set>
#include <map>
#include <cstdarg>
#include <windows.h>

// Define ISystem struct

// Define SystemManager class

int main()
{
    // Create system instances
    ISystem* Render = SystemManager::GetHandle().Create("RenderSystem");
    ISystem* Move = SystemManager::GetHandle().Create("MovementSystem");
    ISystem* Collision = SystemManager::GetHandle().Create("CollisionSystem");
    ISystem* Light = SystemManager::GetHandle().Create("LightSystem");
    ISystem* Physics = SystemManager::GetHandle().Create("PhysicsSystem");
    ISystem* Camera = SystemManager::GetHandle().Create("CameraSystem");

    // Set system dependencies
    SystemManager::GetHandle().SetDependency(Move, Collision);
    SystemManager::GetHandle().SetDependency(Render, Move);
    SystemManager::GetHandle().SetDependency(Render, Light);
    SystemManager::GetHandle().SetDependency(Collision, Physics);
    SystemManager::GetHandle().SetDependency(Light, Physics);

    // Circlic Dependency
    SystemManager::GetHandle().SetDependency(Camera, Render);
    SystemManager::GetHandle().SetDependency(Render, Camera);

    // Sort systems based on dependencies
    SystemManager::GetHandle().Sort();

    // Execute systems in the sorted order
    SystemManager::GetHandle().Frame();

    // Clean up systems
    SystemManager::GetHandle().Destroy();

    return 0;
}