README
¶
goecs
A simple Go ECS
Info
Entity–component–system (ECS) is an architectural patter that follows the composition over inheritance principle that allows greater flexibility in defining entities where every object in a world.
Every entity consists of one or more components which contains data or state. Therefore, the behavior of an entity can be changed at runtime by systems that add, remove or mutate components.
This eliminates the ambiguity problems of deep and wide inheritance hierarchies that are difficult to understand, maintain and extend.
Common ECS approaches are highly compatible and often combined with data-oriented design techniques.
For a more in deep read on this topic I could recommend this article.
Example
package main
import (
"fmt"
"github.com/juan-medina/goecs"
"reflect"
)
// Simple Usage
func main() {
// creates the world
world := goecs.New()
// add our movement system
world.AddSystem(MovementSystem)
// add a listener
world.AddListener(ChangePostListener)
// add a first entity
world.AddEntity(
Pos{X: 0, Y: 0},
Vel{X: 1, Y: 1},
)
// this entity shouldn't be updated
world.AddEntity(
Pos{X: 2, Y: 2},
)
// add a third entity
world.AddEntity(
Pos{X: 2, Y: 2},
Vel{X: 3, Y: 3},
)
// ask the world to update
if err := world.Update(0.5); err != nil {
fmt.Printf("error on update %v\n", err)
}
// print the world
fmt.Println()
fmt.Println("Pos:")
for it := world.Iterator(PosType); it != nil; it = it.Next() {
fmt.Println(it.Value().Get(PosType))
}
}
// MovementSystem is a simple movement system
func MovementSystem(world *goecs.World, delta float32) error {
// get all the entities that we need to update, only if they have Pos & Vel
for it := world.Iterator(PosType, VelType); it != nil; it = it.Next() {
// get the values
ent := it.Value()
pos := ent.Get(PosType).(Pos)
vel := ent.Get(VelType).(Vel)
// calculate new pos
npos := Pos{
X: pos.X + (vel.X * delta),
Y: pos.Y + vel.Y*delta,
}
// signal the change
if err := world.Signal(PosChangeSignal{From: pos, To: npos}); err != nil {
return err
}
// set the new pos
ent.Set(npos)
}
return nil
}
// ChangePostListener listen to PosChangeSignal
func ChangePostListener(world *goecs.World, signal interface{}, delta float32) error {
switch s := signal.(type) {
case PosChangeSignal:
// print the change
fmt.Printf("pos change from %v to %v\n", s.From, s.To)
}
return nil
}
// Pos represent a 2D position
type Pos struct {
X float32
Y float32
}
// PosType is the reflect.Type of Pos
var PosType = reflect.TypeOf(Pos{})
// Vel represent a 2D velocity
type Vel struct {
X float32
Y float32
}
// VelType is the reflect.Type of Vel
var VelType = reflect.TypeOf(Vel{})
// PosChangeSignal is a signal that a Pos has change
type PosChangeSignal struct {
From Pos
To Pos
}
This will output:
pos change from {0 0} to {0.5 0.5}
pos change from {2 2} to {3.5 3.5}
Pos:
{0.5 0.5}
{2 2}
{3.5 3.5}
Installation
go get -v -u github.com/juan-medina/goecs
License
Copyright (C) 2020 Juan Medina
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
Documentation
¶
Overview ¶
Package goecs provides a Go implementation of an Entity–component–system (ECS)
Entity–component–system (ECS) is an architectural patter that follows the composition over inheritance principle that allows greater flexibility in defining entities where every object in a world.
Every entity consists of one or more components which contains data or state. Therefore, the behavior of an entity can be changed at runtime by systems that add, remove or mutate components.
This eliminates the ambiguity problems of deep and wide inheritance hierarchies that are difficult to understand, maintain and extend.
Common ECS approaches are highly compatible and often combined with data-oriented design techniques.
See: World, Entity
Example ¶
Simple Usage
/*
* Copyright (c) 2020 Juan Medina.
*
* 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.
*/
package main
import (
"fmt"
"github.com/juan-medina/goecs"
"reflect"
)
// Simple Usage
func main() {
// creates the world
world := goecs.New()
// add our movement system
world.AddSystem(MovementSystem)
// add a listener
world.AddListener(ChangePostListener)
// add a first entity
world.AddEntity(
Pos{X: 0, Y: 0},
Vel{X: 1, Y: 1},
)
// this entity shouldn't be updated
world.AddEntity(
Pos{X: 2, Y: 2},
)
// add a third entity
world.AddEntity(
Pos{X: 2, Y: 2},
Vel{X: 3, Y: 3},
)
// ask the world to update
if err := world.Update(0.5); err != nil {
fmt.Printf("error on update %v\n", err)
}
// print the world
fmt.Println()
fmt.Println("Pos:")
for it := world.Iterator(PosType); it != nil; it = it.Next() {
fmt.Println(it.Value().Get(PosType))
}
}
// MovementSystem is a simple movement system
func MovementSystem(world *goecs.World, delta float32) error {
// get all the entities that we need to update, only if they have Pos & Vel
for it := world.Iterator(PosType, VelType); it != nil; it = it.Next() {
// get the values
ent := it.Value()
pos := ent.Get(PosType).(Pos)
vel := ent.Get(VelType).(Vel)
// calculate new pos
npos := Pos{
X: pos.X + (vel.X * delta),
Y: pos.Y + vel.Y*delta,
}
// signal the change
if err := world.Signal(PosChangeSignal{From: pos, To: npos}); err != nil {
return err
}
// set the new pos
ent.Set(npos)
}
return nil
}
// ChangePostListener listen to PosChangeSignal
func ChangePostListener(world *goecs.World, signal interface{}, delta float32) error {
switch s := signal.(type) {
case PosChangeSignal:
// print the change
fmt.Printf("pos change from %v to %v\n", s.From, s.To)
}
return nil
}
// Pos represent a 2D position
type Pos struct {
X float32
Y float32
}
// PosType is the reflect.Type of Pos
var PosType = reflect.TypeOf(Pos{})
// Vel represent a 2D velocity
type Vel struct {
X float32
Y float32
}
// VelType is the reflect.Type of Vel
var VelType = reflect.TypeOf(Vel{})
// PosChangeSignal is a signal that a Pos has change
type PosChangeSignal struct {
From Pos
To Pos
}
Output: pos change from {0 0} to {0.5 0.5} pos change from {2 2} to {3.5 3.5} Pos: {0.5 0.5} {2 2} {3.5 3.5}
Index ¶
- type Entity
- func (ent *Entity) Add(component interface{}) *Entity
- func (ent Entity) Contains(rtypes ...reflect.Type) bool
- func (ent Entity) Get(rtype reflect.Type) interface{}
- func (ent Entity) ID() int64
- func (ent Entity) NotContains(rtypes ...reflect.Type) bool
- func (ent *Entity) Remove(typ reflect.Type)
- func (ent *Entity) Set(component interface{}) *Entity
- func (ent Entity) String() string
- type Iterator
- type Listener
- type System
- type View
- type World
- func (world *World) AddListener(lis Listener)
- func (world *World) AddListenerWithPriority(lis Listener, priority int32)
- func (world *World) AddSystem(sys System)
- func (world *World) AddSystemWithPriority(sys System, priority int32)
- func (world *World) Clear()
- func (world *World) Signal(signal interface{}) error
- func (world World) String() string
- func (world *World) Update(delta float32) error
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Entity ¶
type Entity struct {
// contains filtered or unexported fields
}
Entity represents a instance of an object in a ECS
func NewEntity ¶
func NewEntity(components ...interface{}) *Entity
NewEntity creates a new Entity giving a set of varg components
func (Entity) NotContains ¶
NotContains check that the Entity has not the given varg reflect.Type
type Iterator ¶
type Iterator interface {
// Next returns next element
Next() Iterator
// Value returns the current item value
Value() *Entity
}
Iterator for view
type View ¶
type View struct {
// contains filtered or unexported fields
}
View represent a set of Entity objects
type World ¶
type World struct {
*View
// contains filtered or unexported fields
}
World is a view.View that contains the Entity and System of our ECS
func (*World) AddListener ¶
AddListener adds the given Listener to the world
func (*World) AddListenerWithPriority ¶
AddListenerWithPriority adds the given Listener to the world with a priority
func (*World) AddSystemWithPriority ¶
AddSystemWithPriority adds the given System to the world with a priority
func (*World) Clear ¶
func (world *World) Clear()
Clear removes all System, Listener, Signals and Entity from the World
Source Files
Directories