<!DOCTYPE html> <!-- 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. --> <link rel="shortcut icon" href="../favicon.png" type="image/png" > <link rel="icon" href="../favicon.png" type="image/png" > <title>Ebiten example - sprites</title> <style> body { font-family: sans-serif; } iframe { border-color: #999; border-style: solid; border-width: 1px; overflow: hidden; } pre { background: #eee; padding: 1em; } </style> <nav><a href="..">Ebiten</a></nav> <h1>Ebiten example - sprites</h1> <iframe src="sprites.content.html" width="640" height="480"></iframe> <pre><code>package main import ( "fmt" _ "image/png" "log" "math/rand" "github.com/hajimehoshi/ebiten" "github.com/hajimehoshi/ebiten/ebitenutil" ) const ( screenWidth = 320 screenHeight = 240 ) var ( ebitenImage *ebiten.Image ebitenImageWidth = 0 ebitenImageHeight = 0 ) type Sprite struct { image *ebiten.Image x int y int vx int vy int } func (s *Sprite) Update() { s.x += s.vx s.y += s.vy if s.x < 0 { s.x = -s.x s.vx = -s.vx } if s.y < 0 { s.y = -s.y s.vy = -s.vy } w, h := s.image.Size() if screenWidth <= s.x+w { s.x = 2*(screenWidth-w) - s.x s.vx = -s.vx } if screenHeight <= s.y+h { s.y = 2*(screenHeight-h) - s.y s.vy = -s.vy } } type Sprites struct { sprites []*Sprite num int } func (s Sprites) Update() { for _, sprite := range s.sprites { sprite.Update() } } func (s Sprites) Len() int { return s.num } func (s Sprites) Dst(i int) (x0, y0, x1, y1 int) { if s.num <= i { return 0, 0, 0, 0 } ss := s.sprites[i] return ss.x, ss.y, ss.x + ebitenImageWidth, ss.y + ebitenImageHeight } func (s Sprites) Src(i int) (x0, y0, x1, y1 int) { if s.num <= i { return 0, 0, 0, 0 } return 0, 0, ebitenImageWidth, ebitenImageHeight } const ( MinSprites = 0 MaxSprites = 10000 ) var sprites = &Sprites{make([]*Sprite, MaxSprites), 500} func update(screen *ebiten.Image) error { if ebiten.IsKeyPressed(ebiten.KeyLeft) { sprites.num -= 20 if sprites.num < MinSprites { sprites.num = MinSprites } } if ebiten.IsKeyPressed(ebiten.KeyRight) { sprites.num += 20 if MaxSprites < sprites.num { sprites.num = MaxSprites } } sprites.Update() op := &ebiten.DrawImageOptions{ ImageParts: sprites, } op.ColorM.Scale(1.0, 1.0, 1.0, 0.5) if err := screen.DrawImage(ebitenImage, op); err != nil { return err } msg := fmt.Sprintf(`FPS: %0.2f Num of sprites: %d Press <- or -> to change the number of sprites`, ebiten.CurrentFPS(), sprites.Len()) ebitenutil.DebugPrint(screen, msg) return nil } func main() { var err error ebitenImage, _, err = ebitenutil.NewImageFromFile("_resources/images/ebiten.png", ebiten.FilterNearest) if err != nil { log.Fatal(err) } ebitenImageWidth, ebitenImageHeight = ebitenImage.Size() for i, _ := range sprites.sprites { w, h := ebitenImage.Size() x, y := rand.Intn(screenWidth-w), rand.Intn(screenHeight-h) vx, vy := 2*rand.Intn(2)-1, 2*rand.Intn(2)-1 sprites.sprites[i] = &Sprite{ image: ebitenImage, x: x, y: y, vx: vx, vy: vy, } } if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Sprites (Ebiten Demo)"); err != nil { log.Fatal(err) } } </code></pre> <footer>© 2014 Hajime Hoshi</footer>