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< title > Ebiten example - life< / title >
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< a class = "navbar-brand" href = ".." > Ebiten< / a >
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< h2 > Ebiten example - life< / h2 >
< iframe src = "life.content.html" width = "640" height = "480" > < / iframe >
< pre > < code class = "language-go" > // + build example
package main
import (
" log"
" math/rand"
" time"
" github.com/hajimehoshi/ebiten"
)
// World represents the game state
type World struct {
area [][]bool
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rnd *rand.Rand
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}
// NewWorld creates a new world
func NewWorld(width, height int) *World {
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world := World{
area: makeArea(width, height),
rnd: rand.New(rand.NewSource(time.Now().UnixNano())),
}
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return & world
}
// RandomSeed inits world with a random state
func (w *World) RandomSeed(limit int) {
height := len(w.area)
width := len(w.area[0])
for i := 0; i < limit; i+ + {
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x := w.rnd.Intn(width)
y := w.rnd.Intn(height)
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w.area[y][x] = true
}
}
// Progress game state by one tick
func (w *World) Progress() {
height := len(w.area)
width := len(w.area[0])
next := makeArea(width, height)
for y := 0; y < height; y+ + {
for x := 0; x < width; x+ + {
pop := neighbourCount(w.area, x, y)
switch {
case pop < 2:
// rule 1. Any live cell with fewer than two live neighbours
// dies, as if caused by under-population.
next[y][x] = false
case (pop == 2 || pop == 3) & & w.area[y][x]:
// rule 2. Any live cell with two or three live neighbours
// lives on to the next generation.
next[y][x] = true
case pop > 3:
// rule 3. Any live cell with more than three live neighbours
// dies, as if by over-population.
next[y][x] = false
case pop == 3:
// rule 4. Any dead cell with exactly three live neighbours
// becomes a live cell, as if by reproduction.
next[y][x] = true
}
}
}
w.area = next
}
// DrawImage paints current game state
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func (w *World) DrawImage(pix []uint8) {
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height := len(w.area)
width := len(w.area[0])
for y := 0; y < height; y+ + {
for x := 0; x < width; x+ + {
pos := 4*y*width + 4*x
if w.area[y][x] {
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pix[pos] = 0xff
pix[pos+ 1] = 0xff
pix[pos+ 2] = 0xff
pix[pos+ 3] = 0xff
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} else {
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pix[pos] = 0
pix[pos+ 1] = 0
pix[pos+ 2] = 0
pix[pos+ 3] = 0
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}
}
}
}
// neighbourCount calculates the Moore neighborhood of x, y
func neighbourCount(a [][]bool, x, y int) int {
height := len(a)
width := len(a[0])
lowX := 0
if x > 0 {
lowX = x - 1
}
lowY := 0
if y > 0 {
lowY = y - 1
}
highX := width - 1
if x < width-1 {
highX = x + 1
}
highY := height - 1
if y < height-1 {
highY = y + 1
}
near := 0
for pY := lowY; pY < = highY; pY+ + {
for pX := lowX; pX < = highX; pX+ + {
if !(pX == x & & pY == y) & & a[pY][pX] {
near+ +
}
}
}
return near
}
func makeArea(width, height int) [][]bool {
area := make([][]bool, height)
for i := 0; i < height; i+ + {
area[i] = make([]bool, width)
}
return area
}
const (
screenWidth = 320
screenHeight = 240
)
var (
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world = NewWorld(screenWidth, screenHeight)
pixels = make([]uint8, screenWidth*screenHeight*4)
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)
func update(screen *ebiten.Image) error {
world.Progress()
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if ebiten.IsRunningSlowly() {
return nil
}
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world.DrawImage(pixels)
screen.ReplacePixels(pixels)
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return nil
}
func main() {
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world.RandomSeed(int((screenWidth * screenHeight) / 10))
if err := ebiten.Run(update, screenWidth, screenHeight, 2.0, " Game of Life (Ebiten Demo)" ); err != nil {
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log.Fatal(err)
}
}
< / code > < / pre >
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< p > © 2013 Hajime Hoshi< / p >
< 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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