ebiten/example/game/rotating_image.go
2013-06-22 02:42:14 +09:00

63 lines
1.4 KiB
Go

package game
import (
"github.com/hajimehoshi/go.ebiten/graphics"
"github.com/hajimehoshi/go.ebiten/graphics/matrix"
"image"
"image/color"
_ "image/png"
"os"
)
type RotatingImage struct {
ebitenTexture graphics.Texture
x int
}
func NewRotatingImage() *RotatingImage {
return &RotatingImage{}
}
func (game *RotatingImage) ScreenWidth() int {
return 256
}
func (game *RotatingImage) ScreenHeight() int {
return 240
}
func (game *RotatingImage) Init(tf graphics.TextureFactory) {
file, err := os.Open("ebiten.png")
if err != nil {
panic(err)
}
defer file.Close()
img, _, err := image.Decode(file)
if err != nil {
panic(err)
}
game.ebitenTexture = tf.NewTextureFromImage(img)
}
func (game *RotatingImage) Update() {
game.x++
}
func (game *RotatingImage) Draw(g graphics.GraphicsContext, offscreen graphics.Texture) {
g.Fill(&color.RGBA{R: 128, G: 128, B: 255, A: 255})
geometryMatrix := matrix.IdentityGeometry()
tx, ty := float64(game.ebitenTexture.Width), float64(game.ebitenTexture.Height)
geometryMatrix.Translate(-tx/2, -ty/2)
geometryMatrix.Rotate(float64(game.x) / 60)
geometryMatrix.Translate(tx/2, ty/2)
centerX := float64(game.ScreenWidth()) / 2
centerY := float64(game.ScreenHeight()) / 2
geometryMatrix.Translate(centerX-tx/2, centerY-ty/2)
g.DrawTexture(game.ebitenTexture,
geometryMatrix,
matrix.IdentityColor())
}