ebiten/example/rotate/main.go

77 lines
1.9 KiB
Go

// Copyright 2014 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"github.com/hajimehoshi/ebiten"
"github.com/hajimehoshi/ebiten/ebitenutil"
_ "image/jpeg"
"log"
"math"
)
const (
screenWidth = 320
screenHeight = 240
)
var (
count int
horizontalCount int
verticalCount int
gophersImage *ebiten.Image
)
func update(screen *ebiten.Image) error {
count++
if ebiten.IsKeyPressed(ebiten.KeyLeft) {
horizontalCount--
}
if ebiten.IsKeyPressed(ebiten.KeyRight) {
horizontalCount++
}
if ebiten.IsKeyPressed(ebiten.KeyDown) {
verticalCount--
}
if ebiten.IsKeyPressed(ebiten.KeyUp) {
verticalCount++
}
w, h := gophersImage.Size()
geo := ebiten.TranslateGeometry(-float64(w)/2, -float64(h)/2)
scaleX := math.Pow(1.05, float64(horizontalCount))
scaleY := math.Pow(1.05, float64(verticalCount))
geo.Concat(ebiten.ScaleGeometry(scaleX, scaleY))
geo.Concat(ebiten.RotateGeometry(float64(count%720) * 2 * math.Pi / 720))
geo.Concat(ebiten.TranslateGeometry(screenWidth/2, screenHeight/2))
if err := screen.DrawImage(gophersImage, &ebiten.DrawImageOptions{
GeometryMatrix: geo,
}); err != nil {
return err
}
return nil
}
func main() {
var err error
gophersImage, _, err = ebitenutil.NewImageFromFile("images/gophers.jpg", ebiten.FilterNearest)
if err != nil {
log.Fatal(err)
}
if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Image (Ebiten Demo)"); err != nil {
log.Fatal(err)
}
}