gotris/lib/lib.go

package lib

import (
	"github.com/hajimehoshi/ebiten/v2"
	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
	"github.com/hajimehoshi/ebiten/v2/inpututil"
)

// Scenes: Main Menu
// Game Mode

//Scene - is the highest-level element of state the game can be in.

type GameEvent struct {
	Type int
}

type HandleResult int

const (
	EventNoOp int = iota
	EventKeyRelease
)

const (
	DoNothing HandleResult = iota
	EndProgram
)

type Scene interface {
	HandleEvent(*GameEvent) HandleResult
	Draw(screen *ebiten.Image)
}

// Implements ebiten.Game
type TetrisGame struct {
	activeScene Scene
}

type MainMenuScene struct {
	selections            [1]string
	currentSelectionIndex int
}

func (menu *MainMenuScene) HandleEvent(e *GameEvent) HandleResult {
	if e.Type == 1 {
		if menu.selections[menu.currentSelectionIndex] == "Quit" {
			return EndProgram
		}
	}
	return DoNothing
}

func (menu *MainMenuScene) Draw(screen *ebiten.Image) {
	ebitenutil.DebugPrint(screen, menu.selections[menu.currentSelectionIndex])
}

func NewGame() (*TetrisGame, error) {
	return &TetrisGame{
		activeScene: &MainMenuScene{
			selections:            [1]string{"Quit"},
			currentSelectionIndex: 0,
		},
	}, nil
}

func (g *TetrisGame) Layout(outsideWidth, outsideHeight int) (int, int) {
	//TODO: Make this do whatever it is supposed to do : resizing etc
	return 640, 480
}

func (g *TetrisGame) Update() error {
	//while there are events

	var keys []ebiten.Key
	keys = inpututil.AppendJustReleasedKeys(keys)

	var event GameEvent
	if len(keys) > 0 {
		event = GameEvent{Type: EventKeyRelease}
	} else {
		event = GameEvent{Type: EventNoOp}
	}

	switch g.activeScene.HandleEvent(&event) {
	case EndProgram:
		return ebiten.Termination
	case DoNothing:
		return nil
	default:
		return nil
	}
	return nil
}

func (g *TetrisGame) Draw(screen *ebiten.Image) {
	g.activeScene.Draw(screen)
}