gohan/examples/twinstick/system/input_move.go

//go:build example
// +build example

package system

import (
	"code.rocketnine.space/tslocum/gohan"
	"code.rocketnine.space/tslocum/gohan/examples/twinstick/component"
	"github.com/hajimehoshi/ebiten/v2"
)

type movementInputSystem struct {
	player gohan.Entity
}

func NewMovementInputSystem(player gohan.Entity) *movementInputSystem {
	return &movementInputSystem{
		player: player,
	}
}

func (s *movementInputSystem) Components() []gohan.ComponentID {
	return []gohan.ComponentID{
		component.VelocityComponentID,
		component.WeaponComponentID,
	}
}

func (s *movementInputSystem) Update(ctx *gohan.Context) error {
	velocity := component.Velocity(ctx)
	if ebiten.IsKeyPressed(ebiten.KeyA) {
		velocity.X -= 0.5
		if velocity.X < -5 {
			velocity.X = -5
		}
	}
	if ebiten.IsKeyPressed(ebiten.KeyD) {
		velocity.X += 0.5
		if velocity.X > 5 {
			velocity.X = 5
		}
	}
	if ebiten.IsKeyPressed(ebiten.KeyW) {
		velocity.Y -= 0.5
		if velocity.Y < -5 {
			velocity.Y = -5
		}
	}
	if ebiten.IsKeyPressed(ebiten.KeyS) {
		velocity.Y += 0.5
		if velocity.Y > 5 {
			velocity.Y = 5
		}
	}
	return nil
}

func (s *movementInputSystem) Draw(ctx *gohan.Context, _ *ebiten.Image) error {
	return gohan.ErrSystemWithoutDraw
}