Arche Model

Arche Model provides a wrapper around the Arche Entity Component System (ECS), and some common systems and resources. It's purpose is to get started with prototyping and developing simulation models immediately, focussing on the model logic.

Features

• Scheduler for running logic and UI systems with independent update rates.
• Interfaces for ECS systems and observers.
• Ready-to-use systems for common tasks like writing CSV files or terminating a simulation.
• Common ECS resources, like central PRNG source or the current model tick.

Installation

go get github.com/mlange-42/arche-model

Usage

See the API docs for more details and examples.

package main

import (
	"github.com/mlange-42/arche-model/model"
	"github.com/mlange-42/arche-model/system"
	"github.com/mlange-42/arche/ecs"
	"github.com/mlange-42/arche/generic"
)

// Position component
type Position struct {
	X float64
	Y float64
}

// Velocity component
type Velocity struct {
	X float64
	Y float64
}

func main() {
	// Create a new, seeded model.
	m := model.New().Seed(123)
	// Limit simulation speed
	m.TPS = 30

	// Add systems to the model.
	m.AddSystem(&VelocitySystem{EntityCount: 1000})
	// Add a termination system that ends the simulation.
	m.AddSystem(&system.FixedTermination{Steps: 100})

	// Run the model.
	m.Run()
}

// VelocitySystem is an example system adding velocity to position.
// For simplicity, it also creates entities during initialization.
type VelocitySystem struct {
	EntityCount int
	filter      generic.Filter2[Position, Velocity]
}

// Initialize the system
func (s *VelocitySystem) Initialize(w *ecs.World) {
	s.filter = *generic.NewFilter2[Position, Velocity]()

	mapper := generic.NewMap2[Position, Velocity](w)
	mapper.NewBatch(s.EntityCount)
}

// Update the system
func (s *VelocitySystem) Update(w *ecs.World) {
	query := s.filter.Query(w)

	for query.Next() {
		pos, vel := query.Get()
		pos.X += vel.X
		pos.Y += vel.Y
	}
}

// Finalize the system
func (s *VelocitySystem) Finalize(w *ecs.World) {}

License

This project is distributed under the MIT licence.