Entitas-Go

Entitas-GO is a fast Entity Component System Framework (ECS) Go 1.17 port of Entitas v1.13.0 for C# and Unity.

Code Generator

1. Install the library in your project

go get github.com/Falldot/Entitas-Go

2. Create context file, with components.

//Important! The file should contain this line
//go:generate go run github.com/Falldot/Entitas-Go

Game.go

package main

//go:generate go run github.com/Falldot/Entitas-Go

type Position struct {
	X, Y float64
}

type Direction struct {
	X, Y float64
}

type Speed int

type Health int

type Sprite struct {
	tag  string
	W, H int
}

3. Use

go generate

4. A folder 'Entitas' will be created in your project, please do not edit it

5. Edit the context file, add methods and components, and then use again go generate

Examples

Entity

// main.go file
package main

import (
	ecs "myProject/Entitas"
)

func main() {
	contexts := ecs.CreateContexts()
    game := contexts.Game()

    // System registration
    systems := ecs.CreateSystemPool()
    systems.Add(&Translate{})
    systems.Add(&ReactiveTranslate{})

    // Create entity
    player := game.CreateEntity()

    // Add component
	player.AddPosition(10, 30)
	player.AddDirection(0, 0)
	player.AddSpeed(5)

    // Remove component
    player.RemoveSpeed()

    // Replace component
    player.ReplacePosition(30, 10)

    // On or Off component
    player.OffDirection()
    player.OnDirection()

    // Destroy entity
    player.Destroy()

    // GameLoop
    systems.Init(contexts)
    for true {
        systems.Execute()
        systems.Clean()
    }
    systems.Exit(contexts)
}

System

type Translate struct {
    group ecs.Group
}

func (s *Translate) Initer(contexts ecs.Contexts) {
	game := contexts.Game()
    s.group = game.Group(ecs.NewMatcher().AllOf(ecs.Position))
}

func (s *Translate) Executer() {
	for _, e := range s.group.GetEntities() {
        pos := e.GetPosition()
		e.ReplacePosition(pos.X + 10, pos.X + 10)
	}
}

Reactive system

type ReactiveTranslate struct {
}

func (s *ReactiveTranslate) Trigger(contexts ecs.Contexts) ecs.Collector {
	game := contexts.Game()
	return game.Collector(ecs.NewMatcher().AllOf(ecs.Position)).OnUpdate().OnAdd()
}

func (s *ReactiveTranslate) Filter(entity *ecs.Entity) bool {
	return entity.Has(ecs.Position)
}

func (s *ReactiveTranslate) Executer(entities []*ecs.Entity) {
	for _, e := range entities {
		pos := e.GetPosition()
		e.ReplacePosition(pos.X+10, pos.X+10)
	}
}

The MIT License (MIT)

Copyright © 2021 Vladislav Fedotov (Falldot)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.