ebiten/examples/alphablending/main.go
2022-11-03 12:55:14 +09:00

94 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.
//go:build example
package main
import (
"bytes"
"image"
"image/color"
_ "image/png"
"log"
"github.com/hajimehoshi/ebiten/v2"
"github.com/hajimehoshi/ebiten/v2/examples/resources/images"
)
const (
screenWidth = 320
screenHeight = 240
)
var (
ebitenImage *ebiten.Image
)
type Game struct {
count int
}
func (g *Game) Update() error {
g.count++
g.count %= ebiten.TPS() * 10
return nil
}
func (g *Game) offset() float64 {
v := float64(g.count) * 0.2
switch {
case 480 < g.count:
v = 0
case 240 < g.count:
v = float64(480-g.count) * 0.2
}
return v
}
func (g *Game) Draw(screen *ebiten.Image) {
screen.Fill(color.NRGBA{0x00, 0x00, 0x80, 0xff})
// Draw 100 Ebitens
v := g.offset()
op := &ebiten.DrawImageOptions{}
op.ColorM.Scale(1.0, 1.0, 1.0, 0.5)
for i := 0; i < 10*10; i++ {
op.GeoM.Reset()
x := float64(i%10)*v + 15
y := float64(i/10)*v + 20
op.GeoM.Translate(x, y)
screen.DrawImage(ebitenImage, op)
}
}
func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
return screenWidth, screenHeight
}
func main() {
// Decode an image from the image file's byte slice.
img, _, err := image.Decode(bytes.NewReader(images.Ebiten_png))
if err != nil {
log.Fatal(err)
}
ebitenImage = ebiten.NewImageFromImage(img)
ebiten.SetWindowSize(screenWidth*2, screenHeight*2)
ebiten.SetWindowTitle("Alpha Blending (Ebitengine Demo)")
if err := ebiten.RunGame(&Game{}); err != nil {
log.Fatal(err)
}
}