pobounty/flame.go

package main

import (
	"bytes"
	_ "embed"
	"image"
	_ "image/png"

	"github.com/hajimehoshi/ebiten/v2"
)

const (
	FLAME_ANIMATION_CYCLES = 8
	FLAME_WIDTH            = 24
	FLAME_HEIGHT           = 32
)

var (
	//go:embed resources/images/hot.png
	flameAssets_png []byte
	assetsFlame     *ebiten.Image
)

type Flame struct {
	Sprite *ebiten.Image //our principle sprite representing the flame
	cycle  int           //current animation cycle for the character
}

func NewFlame() *Flame {
	return &Flame{
		cycle:  0,
		Sprite: ebiten.NewImage(FLAME_WIDTH, FLAME_HEIGHT),
	}
}

func (f *Flame) CycleUpdate() {
	f.cycle = (f.cycle + 1) % CHARACTER_ANIMATION_CYCLES
}

func (f *Flame) Animate() {

	//compute start and end location of asset to use for animation frame cycle
	sx := FLAME_WIDTH * f.cycle
	sy := 0
	ex := FLAME_WIDTH * (f.cycle + 1)
	ey := FLAME_HEIGHT

	f.Sprite.Clear()
	f.Sprite.DrawImage(assetsFlame.SubImage(image.Rect(sx, sy, ex, ey)).(*ebiten.Image), nil)

	f.CycleUpdate()
}

func (f *Flame) GetWidth() int {
	return f.Sprite.Bounds().Dx()
}

func (f *Flame) GetHeight() int {
	return f.Sprite.Bounds().Dy()
}

func init() {
	img, _, err := image.Decode(bytes.NewReader(flameAssets_png))
	if err != nil {
		DashLogger.Fatal(err)
	}
	assetsFlame = ebiten.NewImageFromImage(img)
}