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213 lines
7.2 KiB
HTML
213 lines
7.2 KiB
HTML
<!DOCTYPE html>
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<meta charset="utf-8">
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<meta property="og:image" itemprop="image primaryImageOfPage" content="https://hajimehoshi.github.io/ebiten/images/examples/sprites.png">
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<meta name="description" content="Ebiten example - sprites">
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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 - sprites</title>
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<link rel="stylesheet" href="../stylesheets/bootstrap.min.css">
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<link rel="stylesheet" href="../stylesheets/highlight-github.css">
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<link rel="stylesheet" href="../stylesheets/ebiten.css">
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<script src="../scripts/googleanalytics.js"></script>
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<nav class="navbar"><div class="container">
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<nav class="d-flex flex-row" style="width: 100%;">
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<div class="nav mr-auto"><a class="navbar-brand" href="../"><img src="../images/logo_white.svg" alt="EBITEN"></a></div>
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<ul class="nav">
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<li class="nav-item"><a class="nav-link" href="https://github.com/hajimehoshi/ebiten">GitHub</a></li>
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<li class="nav-item"><a class="nav-link" href="https://godoc.org/github.com/hajimehoshi/ebiten">GoDoc</a></li>
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<li class="nav-item"><a class="nav-link" href="https://github.com/hajimehoshi/ebiten/wiki">Wiki</a>
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<li class="nav-item"><a class="nav-link" href="https://ebiten-playground.github.io/">Playground</a>
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</ul>
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</nav>
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</div></nav>
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<main><div class="container">
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<h2>Ebiten example - sprites</h2>
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<iframe src="sprites.content.html" width="640" height="480"></iframe>
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<div class="card"><pre class="card-body"><code class="language-go">// +build example jsgo
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package main
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import (
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"bytes"
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"fmt"
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"image"
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_ "image/png"
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"log"
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"math"
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"math/rand"
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"github.com/hajimehoshi/ebiten"
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"github.com/hajimehoshi/ebiten/ebitenutil"
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"github.com/hajimehoshi/ebiten/examples/resources/images"
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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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maxAngle = 256
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)
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var (
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ebitenImage *ebiten.Image
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)
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type Sprite struct {
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imageWidth int
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imageHeight int
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x int
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y int
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vx int
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vy int
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angle int
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}
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func (s *Sprite) Update() {
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s.x += s.vx
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s.y += s.vy
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if s.x < 0 {
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s.x = -s.x
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s.vx = -s.vx
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} else if screenWidth <= s.x+s.imageWidth {
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s.x = 2*(screenWidth-s.imageWidth) - s.x
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s.vx = -s.vx
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}
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if s.y < 0 {
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s.y = -s.y
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s.vy = -s.vy
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} else if screenHeight <= s.y+s.imageHeight {
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s.y = 2*(screenHeight-s.imageHeight) - s.y
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s.vy = -s.vy
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}
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s.angle++
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s.angle %= maxAngle
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}
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type Sprites struct {
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sprites []*Sprite
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num int
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}
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func (s *Sprites) Update() {
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for _, sprite := range s.sprites {
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sprite.Update()
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}
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}
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const (
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MinSprites = 0
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MaxSprites = 50000
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)
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var (
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sprites = &Sprites{make([]*Sprite, MaxSprites), 500}
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op = &ebiten.DrawImageOptions{}
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)
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func init() {
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// Decode image from a byte slice instead of a file so that
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// this example works in any working directory.
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// If you want to use a file, there are some options:
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// 1) Use os.Open and pass the file to the image decoder.
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// This is a very regular way, but doesn't work on browsers.
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// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
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// This works even on browsers.
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// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
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// This also works on browsers.
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img, _, err := image.Decode(bytes.NewReader(images.Ebiten_png))
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if err != nil {
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log.Fatal(err)
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}
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origEbitenImage, _ := ebiten.NewImageFromImage(img, ebiten.FilterDefault)
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w, h := origEbitenImage.Size()
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ebitenImage, _ = ebiten.NewImage(w, h, ebiten.FilterNearest)
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op := &ebiten.DrawImageOptions{}
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op.ColorM.Scale(1, 1, 1, 0.5)
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ebitenImage.DrawImage(origEbitenImage, op)
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for i := range sprites.sprites {
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w, h := ebitenImage.Size()
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x, y := rand.Intn(screenWidth-w), rand.Intn(screenHeight-h)
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vx, vy := 2*rand.Intn(2)-1, 2*rand.Intn(2)-1
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a := rand.Intn(maxAngle)
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sprites.sprites[i] = &Sprite{
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imageWidth: w,
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imageHeight: h,
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x: x,
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y: y,
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vx: vx,
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vy: vy,
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angle: a,
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}
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}
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}
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func update(screen *ebiten.Image) error {
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// Decrease the nubmer of the sprites.
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if ebiten.IsKeyPressed(ebiten.KeyLeft) {
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sprites.num -= 20
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if sprites.num < MinSprites {
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sprites.num = MinSprites
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}
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}
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// Increase the nubmer of the sprites.
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if ebiten.IsKeyPressed(ebiten.KeyRight) {
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sprites.num += 20
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if MaxSprites < sprites.num {
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sprites.num = MaxSprites
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}
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}
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sprites.Update()
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if ebiten.IsRunningSlowly() {
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return nil
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}
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// Draw each sprite.
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// DrawImage can be called many many times, but in the implementation,
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// the actual draw call to GPU is very few since these calls satisfy
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// some conditions e.g. all the rendering sources and targets are same.
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// For more detail, see:
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// https://godoc.org/github.com/hajimehoshi/ebiten#Image.DrawImage
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w, h := ebitenImage.Size()
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for i := 0; i < sprites.num; i++ {
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s := sprites.sprites[i]
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op.GeoM.Reset()
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op.GeoM.Translate(-float64(w)/2, -float64(h)/2)
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op.GeoM.Rotate(2 * math.Pi * float64(s.angle) / maxAngle)
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op.GeoM.Translate(float64(w)/2, float64(h)/2)
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op.GeoM.Translate(float64(s.x), float64(s.y))
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screen.DrawImage(ebitenImage, op)
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}
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msg := fmt.Sprintf(`FPS: %0.2f
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Num of sprites: %d
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Press <- or -> to change the number of sprites`, ebiten.CurrentFPS(), sprites.num)
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ebitenutil.DebugPrint(screen, msg)
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return nil
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}
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func main() {
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if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Sprites (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></div>
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</div></main>
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<footer><div class="container">
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<p>© 2013 Hajime Hoshi</p>
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<p>Code is licensed under <a href="https://github.com/hajimehoshi/ebiten/blob/master/LICENSE">the Apache License 2.0</a>.</p>
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<p>The content of this page is licensed under <a href="https://creativecommons.org/licenses/by/4.0/">the Creative Commons Attribution 4.0 License</a>.</p>
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</div></footer>
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<script src="../scripts/highlight.pack.js"></script>
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<script>hljs.initHighlightingOnLoad();</script>
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