gohan/examples/twinstick/game/game.go

//go:build example
// +build example

package game

import (
	"image/color"
	"os"
	"sync"

	"code.rocketnine.space/tslocum/gohan/examples/twinstick/world"

	"code.rocketnine.space/tslocum/gohan"
	"code.rocketnine.space/tslocum/gohan/examples/twinstick/asset"
	"code.rocketnine.space/tslocum/gohan/examples/twinstick/component"
	"code.rocketnine.space/tslocum/gohan/examples/twinstick/entity"
	"code.rocketnine.space/tslocum/gohan/examples/twinstick/system"
	"github.com/hajimehoshi/ebiten/v2"
)

// game is an isometric demo game.
type game struct {
	w, h int

	player gohan.Entity

	op *ebiten.DrawImageOptions

	disableEsc bool

	debugMode  bool
	cpuProfile *os.File

	movementSystem *system.MovementSystem

	sync.Mutex
}

// NewGame returns a new isometric demo game.
func NewGame() (*game, error) {
	g := &game{
		op: &ebiten.DrawImageOptions{},
	}

	g.player = entity.NewPlayer()

	g.addSystems()

	err := g.loadAssets()
	if err != nil {
		return nil, err
	}

	asset.ImgWhiteSquare.Fill(color.White)

	return g, nil
}

// Layout is called when the game's layout changes.
func (g *game) Layout(outsideWidth, outsideHeight int) (int, int) {
	s := ebiten.DeviceScaleFactor()
	w, h := int(s*float64(outsideWidth)), int(s*float64(outsideHeight))
	if w != g.w || h != g.h {
		if g.w == 0 || g.h == 0 {
			position := world.World.Component(g.player, component.PositionComponentID).(*component.PositionComponent)
			position.X, position.Y = float64(w)/2-16, float64(h)/2-16
		}

		g.w, g.h = w, h
		g.movementSystem.ScreenW, g.movementSystem.ScreenH = float64(w), float64(h)
	}
	return g.w, g.h
}

func (g *game) Update() error {
	if ebiten.IsWindowBeingClosed() {
		g.Exit()
		return nil
	}

	return world.World.Update()
}

func (g *game) Draw(screen *ebiten.Image) {
	err := world.World.Draw(screen)
	if err != nil {
		panic(err)
	}
}

func (g *game) addSystems() {
	w := world.World

	w.AddSystem(system.NewMovementInputSystem(g.player))

	g.movementSystem = &system.MovementSystem{
		Player: g.player,
	}
	w.AddSystem(g.movementSystem)

	w.AddSystem(system.NewFireInputSystem(g.player))

	renderBullet := system.NewDrawBulletsSystem()
	w.AddSystem(renderBullet)

	renderPlayer := system.NewDrawPlayerSystem(g.player)
	w.AddSystem(renderPlayer)

	printInfo := system.NewPrintInfoSystem(g.player)
	w.AddSystem(printInfo)

	w.AddSystem(system.NewProfileSystem(g.player))
}

func (g *game) loadAssets() error {
	return nil
}

func (g *game) Exit() {
	os.Exit(0)
}