kongbong / ecsgo

Cache friendly, Multi threading Entity Component System in Go (with Generic)

ECSGo

ECSGo is an Entity Component System(ECS) in Go. This is made with Generic Go, so it needs Go 1.18 version

• Cache friendly data storage
• Run systems in concurrently with analyzing dependency tree.

Example

package main

import (
	"context"
	"log"
	"time"

	"github.com/kongbong/ecsgo"
)

type Position struct {
	X float32
	Y float32
}

type Velocity struct {
	X float32
	Y float32
}

type HP struct {
	Hp    float32
	MaxHp float32
}

type EnemyTag struct{}

func main() {
	registry := ecsgo.NewRegistry()

	sys1 := registry.AddSystem("VelocitySystem", 0, func(ctx *ecsgo.ExecutionContext) error {
		qr := ctx.GetQueryResult(0)
		log.Println("This system should have not any archtype", qr.GetArcheTypeCount())
		return nil
	})
	q1 := sys1.NewQuery()
	ecsgo.AddReadWriteComponent[Velocity](q1)
	ecsgo.AddExcludeComponent[EnemyTag](q1)

	o := registry.AddObserver("AddVelocityObserver", func(ctx *ecsgo.ObserverContext) error {
		vel := ecsgo.GetComponentObserver[Velocity](ctx)
		log.Println("This is one time called system", ctx.GetEntityId(), vel)
		return nil
	})
	ecsgo.AddComponentToObserver[Velocity](o)

	sys2 := registry.AddSystem("VelocitySystem2", 0, func(ctx *ecsgo.ExecutionContext) error {
		qr := ctx.GetQueryResult(0)
		qr.ForeachEntities(func(accessor *ecsgo.ArcheTypeAccessor) error {
			vel := ecsgo.GetComponentByAccessor[Velocity](accessor)
			log.Println("VelocitySystem2", accessor.GetEntityId(), vel)
			return nil
		})
		return nil
	})
	q2 := sys2.NewQuery()
	ecsgo.AddExcludeComponent[HP](q2)
	ecsgo.AddReadonlyComponent[Velocity](q2)

	sys3 := registry.AddSystem("PositionAndVelocity", 0, func(ctx *ecsgo.ExecutionContext) error {
		qr := ctx.GetQueryResult(0)
		qr.ForeachEntities(func(accessor *ecsgo.ArcheTypeAccessor) error {
			pos := ecsgo.GetComponentByAccessor[Position](accessor)
			vel := ecsgo.GetComponentByAccessor[Velocity](accessor)
			log.Println("Position, Velocity system", accessor.GetEntityId(), pos, vel, ctx.GetDeltaTime())
			pos.X++
			pos.Y++
			vel.X++
			vel.Y++
			return nil
		})
		return nil
	})
	q3 := sys3.NewQuery()
	ecsgo.AddReadWriteComponent[Position](q3)
	ecsgo.AddReadWriteComponent[Velocity](q3)
	ecsgo.AddReadonlyComponent[EnemyTag](q3)

	entity := registry.CreateEntity()
	ecsgo.AddComponent(registry, entity, Position{10, 10})
	ecsgo.AddComponent(registry, entity, Velocity{20, 20})
	ecsgo.AddComponent(registry, entity, EnemyTag{})

	ctx := context.Background()
	for i := 0; i < 10; i++ {
		registry.Tick(time.Second, ctx)
		time.Sleep(time.Second)
	}
}