ebiten/examples/alphablending/main.go
2016-02-16 01:13:04 +09:00

87 lines
2.0 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 (
"image/color"
_ "image/png"
"log"
"github.com/hajimehoshi/ebiten"
"github.com/hajimehoshi/ebiten/ebitenutil"
)
const (
screenWidth = 320
screenHeight = 240
)
var (
count int
tmpRenderTarget *ebiten.Image
ebitenImage *ebiten.Image
saved bool
)
func update(screen *ebiten.Image) error {
count++
count %= 600
diff := float64(count) * 0.2
switch {
case 480 < count:
diff = 0
case 240 < count:
diff = float64(480-count) * 0.2
}
if err := tmpRenderTarget.Clear(); err != nil {
return err
}
for i := 0; i < 10; i++ {
op := &ebiten.DrawImageOptions{}
op.GeoM.Translate(15+float64(i)*diff, 20)
op.ColorM.Scale(1.0, 1.0, 1.0, 0.5)
if err := tmpRenderTarget.DrawImage(ebitenImage, op); err != nil {
return err
}
}
screen.Fill(color.NRGBA{0x00, 0x00, 0x80, 0xff})
for i := 0; i < 10; i++ {
op := &ebiten.DrawImageOptions{}
op.GeoM.Translate(0, float64(i)*diff)
if err := screen.DrawImage(tmpRenderTarget, op); err != nil {
return err
}
}
return nil
}
func main() {
var err error
ebitenImage, _, err = ebitenutil.NewImageFromFile("images/ebiten.png", ebiten.FilterNearest)
if err != nil {
log.Fatal(err)
}
tmpRenderTarget, err = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterNearest)
if err != nil {
log.Fatal(err)
}
if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Alpha Blending (Ebiten Demo)"); err != nil {
log.Fatal(err)
}
}