astercal/main.go

// main.go
package main

import (
	"image"
	_ "image/png"
	"os"
	"time"

	"github.com/faiface/pixel"
	"github.com/faiface/pixel/pixelgl"
	"golang.org/x/image/colornames"
)

func loadSprite(path string) (pixel.Picture, error) {
	file, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	defer file.Close()
	img, _, err := image.Decode(file)
	if err != nil {
		return nil, err
	}
	return pixel.PictureDataFromImage(img), nil
}

func createSpriteSheet(SpriteSheetImg pixel.Picture, spriteSizeX, spriteSizeY float64) []pixel.Rect {
	var frames []pixel.Rect

	for x := SpriteSheetImg.Bounds().Min.X; x < SpriteSheetImg.Bounds().Max.X; x += spriteSizeX {
		for y := SpriteSheetImg.Bounds().Min.Y; y < SpriteSheetImg.Bounds().Max.Y; y += spriteSizeY {
			frames = append(frames, pixel.R(x, y, x+256, y+256))
		}
	}
	return frames
}

func run() {

	cfgMain := pixelgl.WindowConfig{
		Title:  "AsterCal",
		Bounds: pixel.R(0, 0, 1024, 768),
		VSync:  true,
	}

	win, err := pixelgl.NewWindow(cfgMain)
	if err != nil {
		panic(err)
	}

	spritesheet, err := loadSprite("assets/ship_sprite_sheet.png")

	if err != nil {
		panic(err)
	}
	shipFrames := createSpriteSheet(spritesheet, 256, 256)

	player := pixel.NewSprite(spritesheet, shipFrames[0])

	angle := 0.0

	last := time.Now()
	for !win.Closed() {
		dt := time.Since(last).Seconds()
		last = time.Now()

		win.Clear(colornames.Whitesmoke)

		mat := pixel.IM
		mat = mat.Rotated(pixel.ZV, angle)
		mat = mat.Scaled(pixel.ZV, 0.25).Moved(win.Bounds().Center())

		player.Draw(win, mat)

		if win.Pressed(pixelgl.KeyLeft) {
			angle += 3 * dt
		}
		if win.Pressed(pixelgl.KeyRight) {
			angle -= 3 * dt

		}

		win.Update()
	}

}

func main() {
	pixelgl.Run(run)
}