monovania/game/game.go

package game

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

	"code.rocketnine.space/tslocum/monovania/world"

	"code.rocketnine.space/tslocum/monovania/component"

	"code.rocketnine.space/tslocum/monovania/entity"

	"code.rocketnine.space/tslocum/monovania/asset"

	"code.rocketnine.space/tslocum/gohan"
	"code.rocketnine.space/tslocum/monovania/system"
	"github.com/hajimehoshi/ebiten/v2"
	"github.com/hajimehoshi/ebiten/v2/audio"
	"golang.org/x/text/language"
	"golang.org/x/text/message"
)

var numberPrinter = message.NewPrinter(language.English)

var startButtons = []ebiten.StandardGamepadButton{
	ebiten.StandardGamepadButtonRightBottom,
	ebiten.StandardGamepadButtonRightRight,
	ebiten.StandardGamepadButtonRightLeft,
	ebiten.StandardGamepadButtonRightTop,
	ebiten.StandardGamepadButtonFrontTopLeft,
	ebiten.StandardGamepadButtonFrontTopRight,
	ebiten.StandardGamepadButtonFrontBottomLeft,
	ebiten.StandardGamepadButtonFrontBottomRight,
	ebiten.StandardGamepadButtonCenterLeft,
	ebiten.StandardGamepadButtonCenterRight,
	ebiten.StandardGamepadButtonLeftStick,
	ebiten.StandardGamepadButtonRightStick,
	ebiten.StandardGamepadButtonLeftBottom,
	ebiten.StandardGamepadButtonLeftRight,
	ebiten.StandardGamepadButtonLeftLeft,
	ebiten.StandardGamepadButtonLeftTop,
	ebiten.StandardGamepadButtonCenterCenter,
}

const sampleRate = 44100

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

	player gohan.Entity

	audioContext *audio.Context

	op *ebiten.DrawImageOptions

	disableEsc bool

	debugMode  bool
	cpuProfile *os.File

	movementSystem *system.MovementSystem
	renderSystem   *system.RenderSystem

	sync.Mutex
	camScale float64

	playerX, playerY float64
}

// NewGame returns a new isometric demo game.
func NewGame() (*game, error) {
	g := &game{
		camScale: 4,
		playerX:  7,
		playerY:  14,
		op:       &ebiten.DrawImageOptions{},
	}

	g.audioContext = audio.NewContext(sampleRate)

	// TODO replace with fs embed
	g.changeMap("/home/trevor/programming/monovania/asset/map/m1.tmx")

	spawnX, spawnY := -math.MaxFloat64, -math.MaxFloat64
	for _, grp := range world.World.ObjectGroups {
		if grp.Name == "PLAYERSPAWN" {
			for _, obj := range grp.Objects {
				spawnX, spawnY = obj.X, obj.Y-1
			}
			break
		}
	}
	if spawnX == -math.MaxFloat64 || spawnY == -math.MaxFloat64 {
		panic("world does not contain a player spawn object")
	}

	g.player = entity.NewPlayer(spawnX, spawnY)

	g.addSystems()

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

	asset.ImgWhiteSquare.Fill(color.White)

	return g, nil
}

func (g *game) tileToGameCoords(x, y int) (float64, float64) {
	return float64(x) * 16, float64(y) * 16
}

func (g *game) changeMap(filePath string) {
	world.LoadMap(filePath)
}

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

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

	err := gohan.Update()
	if err != nil {
		return err
	}

	// Update camera position.
	position := component.Position(g.player)
	system.CamX, system.CamY = position.X, position.Y
	return nil
}

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

func (g *game) addSystems() {
	g.movementSystem = system.NewMovementSystem() // TODO move into component

	gohan.AddSystem(system.NewPlayerMoveSystem(g.player, g.movementSystem))

	gohan.AddSystem(g.movementSystem)

	gohan.AddSystem(system.NewFireWeaponSystem(g.player))

	g.renderSystem = system.NewRenderSystem()
	gohan.AddSystem(g.renderSystem)

	gohan.AddSystem(system.NewRenderDebugTextSystem(g.player))
}

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

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

func angle(x1, y1, x2, y2 float64) float64 {
	return math.Atan2(y1-y2, x1-x2)
}

func deltaXY(x1, y1, x2, y2 float64) (dx float64, dy float64) {
	dx, dy = x1-x2, y1-y2
	if dx < 0 {
		dx *= -1
	}
	if dy < 0 {
		dy *= -1
	}
	return dx, dy
}