mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
170 lines
4.3 KiB
HTML
170 lines
4.3 KiB
HTML
<!DOCTYPE html>
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<!--
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Copyright 2013 The Ebiten Authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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<link rel="shortcut icon" href="../favicon.png" type="image/png" >
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<link rel="icon" href="../favicon.png" type="image/png" >
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<title>Ebiten example - masking</title>
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<style>
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body {
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font-family: sans-serif;
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}
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iframe {
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border-color: #999;
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border-style: solid;
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border-width: 1px;
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overflow: hidden;
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}
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pre {
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background: #eee;
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padding: 1em;
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}
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</style>
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<nav><a href="..">Ebiten</a></nav>
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<h1>Ebiten example - masking</h1>
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<iframe src="masking.content.html" width="640" height="480"></iframe>
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<pre><code>package main
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import (
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"image"
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"image/color"
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_ "image/jpeg"
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"log"
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"math"
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"github.com/hajimehoshi/ebiten"
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"github.com/hajimehoshi/ebiten/examples/common"
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)
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const (
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screenWidth = 320
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screenHeight = 240
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)
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var (
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gophersImage *ebiten.Image
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fiveyearsImage *ebiten.Image
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maskImage *ebiten.Image
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spotLightImage *ebiten.Image
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spotLightX = 0
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spotLightY = 0
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spotLightVX = 1
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spotLightVY = 1
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)
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func update(screen *ebiten.Image) error {
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spotLightX += spotLightVX
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spotLightY += spotLightVY
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if spotLightX < 0 {
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spotLightX = -spotLightX
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spotLightVX = -spotLightVX
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}
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if spotLightY < 0 {
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spotLightY = -spotLightY
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spotLightVY = -spotLightVY
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}
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w, h := spotLightImage.Size()
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maxX, maxY := screenWidth-w, screenHeight-h
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if maxX < spotLightX {
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spotLightX = -spotLightX + 2*maxX
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spotLightVX = -spotLightVX
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}
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if maxY < spotLightY {
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spotLightY = -spotLightY + 2*maxY
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spotLightVY = -spotLightVY
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}
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if err := maskImage.Clear(); err != nil {
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return err
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}
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op := &ebiten.DrawImageOptions{}
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op.GeoM.Translate(float64(spotLightX), float64(spotLightY))
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if err := maskImage.DrawImage(spotLightImage, op); err != nil {
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return err
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}
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op = &ebiten.DrawImageOptions{}
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op.CompositeMode = ebiten.CompositeModeSourceOut
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if err := maskImage.DrawImage(fiveyearsImage, op); err != nil {
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return err
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}
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if err := screen.Fill(color.RGBA{0x00, 0x00, 0x80, 0xff}); err != nil {
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return err
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}
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if err := screen.DrawImage(gophersImage, &ebiten.DrawImageOptions{}); err != nil {
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return err
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}
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if err := screen.DrawImage(maskImage, &ebiten.DrawImageOptions{}); err != nil {
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return err
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}
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return nil
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}
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func max(a, b int) int {
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if a < b {
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return b
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}
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return a
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}
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func min(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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func main() {
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var err error
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gophersImage, _, err = common.AssetImage("gophers.jpg", ebiten.FilterNearest)
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if err != nil {
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log.Fatal(err)
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}
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fiveyearsImage, _, err = common.AssetImage("fiveyears.jpg", ebiten.FilterNearest)
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if err != nil {
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log.Fatal(err)
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}
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maskImage, err = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterNearest)
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if err != nil {
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log.Fatal(err)
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}
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as := image.Point{128, 128}
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a := image.NewAlpha(image.Rectangle{image.ZP, as})
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for j := 0; j < as.Y; j++ {
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for i := 0; i < as.X; i++ {
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r := as.X / 2
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d := math.Sqrt(float64((i-r)*(i-r) + (j-r)*(j-r)))
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b := uint8(max(0, min(0xff, 3*0xff-int(d*3*0xff)/r)))
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a.SetAlpha(i, j, color.Alpha{b})
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}
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}
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spotLightImage, err = ebiten.NewImageFromImage(a, ebiten.FilterNearest)
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if err != nil {
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log.Fatal(err)
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}
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if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Masking (Ebiten Demo)"); err != nil {
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log.Fatal(err)
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}
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}
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</code></pre>
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<footer>© 2013 Hajime Hoshi</footer>
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