Add example alphablending

example/alphablending/main.go

@@ -0,0 +1,78 @@
+/*
+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/color"
+	_ "image/png"
+	"log"
+)
+
+const (
+	screenWidth  = 320
+	screenHeight = 240
+)
+
+type Game struct {
+	count           int
+	tmpRenderTarget *ebiten.RenderTarget
+	ebitenTexture   *ebiten.Texture
+}
+
+func (g *Game) Update(gr ebiten.GraphicsContext) error {
+	g.count++
+	g.count %= 120
+	diff := float64(g.count) * 0.5
+	if 60 < g.count {
+		diff = float64(120-g.count) * 0.5
+	}
+
+	gr.PushRenderTarget(g.tmpRenderTarget)
+	gr.Clear()
+	for i := 0; i < 10; i++ {
+		geo := ebiten.TranslateGeometry(15+float64(i)*(20+diff), 20)
+		clr := ebiten.ScaleColor(color.RGBA{0xff, 0xff, 0xff, 0x80})
+		ebiten.DrawWholeTexture(gr, g.ebitenTexture, geo, clr)
+	}
+	gr.PopRenderTarget()
+
+	gr.Fill(color.RGBA{0x00, 0x00, 0x80, 0xff})
+	for i := 0; i < 10; i++ {
+		geo := ebiten.TranslateGeometry(0, float64(i)*(10+diff))
+		clr := ebiten.ColorMatrixI()
+		ebiten.DrawWholeTexture(gr, g.tmpRenderTarget.Texture(), geo, clr)
+	}
+	return nil
+}
+
+func main() {
+	g := new(Game)
+	var err error
+	g.ebitenTexture, _, err = ebitenutil.NewTextureFromFile("images/ebiten.png", ebiten.FilterNearest)
+	if err != nil {
+		log.Fatal(err)
+	}
+	g.tmpRenderTarget, err = ebiten.NewRenderTarget(screenWidth, screenHeight, ebiten.FilterNearest)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := ebiten.Run(g.Update, screenWidth, screenHeight, 2, "Perspective (Ebiten Demo)"); err != nil {
+		log.Fatal(err)
+	}
+}