mizu

README

Mizu

Mizu is Entity Component System framework for Ebiten.

Mizu is based on ento, which is made by wfranczyk.

The name is short for Mizutaki, a japenese dish, where chicken pieces and vegetables stewed in a simple stock, and eaten with dipping sauce such as ponzu.

Contents

• Features
• Installation
• Usage
• Examples

Features

• Very low boilerplate in exchange for a certain amount of reflection.
• Scene management.
• Compile defined components and entities.

Examples

To check all examples, visit this page.

Installation

go get github.com/sedyh/mizu

Usage

Import this package

import "github.com/sedyh/mizu/pkg/engine"

Define components, attributes of your game objects.

// Position for any entity, if it needs
type Pos struct {
    X, Y float64 // Just a 2D point
}

// Velocity for any entity, if it needs
type Vel struct {
    L, M float64 // Also, 2D point
}

// Radius for any entity, if it needs
type Rad struct {
    Value float64 // Width value
}

Define entities, your game objects.

// Your game object
type Ball struct {
    Pos // Ball position
    Vel // Ball velocity
    Rad // Ball radius
}

Define systems, your game mechanics that will work for a specific set of components.

// You can go through all entities that have a certain set of 
// components specifying the requirements in the fields of the system
type Velocity struct {
    *Pos // Current entity position
    *Vel // Current entity velocity
}

// Apply velocity for each entity that has Pos and Vel
func (v *Velocity) Update(w engine.World) {
    // If they are registered components, they will not be nil
    v.Pos.X += v.Vel.L
    v.Pos.Y += v.Vel.M
}

// When you need many sets of components
// in one system, you can use the views
type Render struct {}

// Render every entity
func (r *Render) Draw(screen *ebiten.Image) {
    // But choose the ones you need yourself
    view := w.View(Pos{}, Rad{})
    view.Each(func(entity engine.Entity) {
        var pos *Pos
        var rad *Rad
        entity.Get(&pos, &rad)
        
        ebitenutil.DrawRect(
            screen,
            pos.X-rad.Value/2, pos.Y-rad.Value/2,
            rad.Value, rad.Value,
            colornames.Aliceblue,
        )
    })
}

Define scenes, where will all this live.

type Game struct{}

// Main scene, you can use that for settings or main menu
func (g *Game) Setup(w engine.World) {
    w.AddComponents(Pos{}, Vel{}, Rad{})
    w.AddEntities(&Ball{Pos{0, 0}, Vel{4, 4}, Rad{10}})
    w.AddSystems(&Velocity{}, &Render{})
}

Run the game.

// Provides its own ebiten.Game implementation
g := engine.NewGame(&Game{})
if err := ebiten.RunGame(g); err != nil {
	log.Fatal(err)
}