jl-ecs/world.go

package ecs

import (
	"fmt"
	"log"
	"math"
	"time"

	"github.com/yohamta/donburi"
	"github.com/yohamta/donburi/features/events"
)

type WorldState int

type WorldId int

const (
	Init WorldState = iota
	Running
	Pause
	Error
	Closed
)

type (
	World interface {

		// Id returns the unique identifier for the world.
		Id() WorldId
		// Create creates a new entity with the specified components.
		Create(components ...donburi.IComponentType) *Entry
		// CreateMany creates a new entity with the specified components.
		CreateMany(n int, components ...donburi.IComponentType) []*Entry
		// Entry returns an entry for the specified entity.
		Entry(entity Entity) *Entry
		// Remove removes the specified entity.
		Remove(entity Entity)
		// Valid returns true if the specified entity is valid.
		Valid(e Entity) bool
		// Len returns the number of entities in the world.
		Len() int

		StartUp()
		Pause()
		Resume()
		SetSpeed(speed float64) error
		AddSystem(sys ...ISystem)
		// 在世界中执行逻辑(在世界运行线程中)
		Execute(fn ExecuteFunc)
		Close()
		// 世界时间间隔
		Tick() int
		Running() bool
	}
	// 世界执行函数
	ExecuteFunc func()
)

type world struct {
	world   donburi.World
	systems []ISystem
	state   WorldState
	tick    int
	ticker  *time.Ticker
	speed   float64
	// 下一帧需要执行的次数
	times float64

	// 退出信号
	quit chan struct{}
	// 待执行函数
	toBeExecuteds chan ExecuteFunc
}

// 新建一个组件类型
func NewComponentType[T any](opts ...interface{}) *ComponentType[T] {
	ct := donburi.NewComponentType[T](opts...)
	return &ComponentType[T]{ct}
}

// 新建一个标签（注意：新建的标签如果作为全局变量，使用Each，First等方法时必须在World线程中执行，即调用World.Execute执行）
func NewTag() *ComponentType[struct{}] {
	return NewComponentType[struct{}]()
}

// 初始化一个新World
// tick 单位为ms，且必须大于0,(小于15ms的值在Windows系统中会达不到，Windows系统中系统中断好像默认是15.6ms，也就是一秒最多64次)
func NewWorld(tick int) World {
	return &world{
		world:         donburi.NewWorld(),
		systems:       make([]ISystem, 0),
		state:         Init,
		tick:          tick,
		ticker:        time.NewTicker(time.Duration(tick) * time.Millisecond),
		speed:         1,
		times:         1,
		quit:          make(chan struct{}),
		toBeExecuteds: make(chan ExecuteFunc, 1024),
	}
}
func (w *world) Running() bool {
	return w.state == Running
}
func (w *world) Tick() int {
	return w.tick
}
func (w *world) Id() WorldId {
	return WorldId(w.world.Id())
}

func (w *world) Create(components ...donburi.IComponentType) *Entry {
	entity := w.world.Create(components...)
	return &Entry{w.world.Entry(entity)}
}

func (w *world) CreateMany(n int, components ...donburi.IComponentType) []*Entry {
	entitys := w.world.CreateMany(n, components...)
	ets := make([]*Entry, len(entitys))
	for i, e := range entitys {
		ets[i] = &Entry{w.world.Entry(e)}
	}
	return ets
}

func (w *world) Entry(entity Entity) *Entry {
	return &Entry{w.world.Entry(entity.Entity)}
}

func (w *world) Remove(entity Entity) {
	w.world.Remove(entity.Entity)
}

func (w *world) Valid(e Entity) bool {
	return w.world.Valid(e.Entity)
}

func (w *world) Len() int {
	return w.world.Len()
}

// 添加系统
func (w *world) AddSystem(sys ...ISystem) {
	w.systems = append(w.systems, sys...)
}

// 执行所有事件处理
func (w *world) ProcessAllEvents() {
	events.ProcessAllEvents(w.world)
}

// 暂停世界
func (w *world) Pause() {
	if w.state == Running {
		w.state = Pause
	}
}

// 恢复世界运行
func (w *world) Resume() {
	if w.state == Pause {
		w.state = Running
	}
}

const (
	SpeedMin = 0.1
	SpeedMax = 10
)

// 设置世界运行速度
func (w *world) SetSpeed(speed float64) error {
	if speed < SpeedMin || speed > SpeedMax {
		return fmt.Errorf("速度必须在[%f, %d]之间", SpeedMin, SpeedMax)
	}
	w.speed = speed
	return nil
}

// 启动世界,世界逻辑开始执行且世界为运行状态
func (w *world) StartUp() {
	if w.state == Init { // 避免重复运行
		w.state = Running
		go w.run()
	}
}

// 在世界线程执行逻辑
func (w *world) Execute(fn ExecuteFunc) {
	w.toBeExecuteds <- fn
}

// 关闭世界
func (w *world) Close() {
	w.quit <- struct{}{}
}

// 执行待处理方法
func (w *world) executeTodos() {
	manageEventChan := w.toBeExecuteds
	for {
		select {
		case callBack := <-manageEventChan:
			{
				callBack()
			}
		default:
			return
		}
	}
}
func (w *world) run() {
	for {
		select {
		case <-w.quit: // 退出信号
			// 仿真退出,更新状态
			log.Println("仿真退出,id:", w.world.Id())
			w.state = Closed
		default:
		}
		if w.state == Error {
			// 世界错误,关闭世界
			return
		}
		if w.state == Closed {
			// 世界正常关闭
			return
		}
		<-w.ticker.C
		if w.state == Pause { // 暂停不更新
			continue
		}
		if w.times > 1 {
			times := int(math.Floor(w.times))
			for i := 0; i < times; i++ {
				for _, sys := range w.systems {
					sys.Update(w)
				}
				// 处理事件管理相关
				w.executeTodos()
				// 处理所有事件
				processAllEvents(w)
			}
			w.times = w.times - float64(times) + w.speed
		} else {
			w.times += w.speed
		}
	}
}