andygeiss/ecs

package ecs

// defaultEngine is simple a composition of an defaultEntityManager and a defaultSystemManager.
type defaultEngine struct {
    entityManager EntityManager
    systemManager SystemManager
}

// Run calls the Process() method for each System
// until ShouldEngineStop is set to true.
func (e *defaultEngine) Run() {
    shouldStop := false
    for !shouldStop {
        for _, system := range e.systemManager.Systems() {
            state := system.Process(e.entityManager)
            if state == StateEngineStop {
                shouldStop = true
                break
            }
        }
    }
}

// Tick calls the Process() method for each System exactly once
func (e *defaultEngine) Tick() {
    for _, system := range e.systemManager.Systems() {
        if state := system.Process(e.entityManager); state == StateEngineStop {
            break
        }
    }
}

// Setup calls the Setup() method for each System
// and initializes ShouldEngineStop and ShouldEnginePause with false.
func (e *defaultEngine) Setup() {
    for _, sys := range e.systemManager.Systems() {
        sys.Setup()
    }
}

// Teardown calls the Teardown() method for each System.
func (e *defaultEngine) Teardown() {
    for _, sys := range e.systemManager.Systems() {
        sys.Teardown()
    }
}

// NewDefaultEngine creates a new Engine and returns its address.
func NewDefaultEngine(entityManager EntityManager, systemManager SystemManager) Engine {
    return &defaultEngine{
        entityManager: entityManager,
        systemManager: systemManager,
    }
}