ebiten/examples/life/main.go
2018-03-15 01:26:21 +09:00

193 lines
4.3 KiB
Go

// The MIT License (MIT)
//
// Copyright (c) 2015-2016 Martin Lindhe
// Copyright (c) 2016 Hajime Hoshi
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
// +build example jsgo
package main
import (
"log"
"math/rand"
"time"
"github.com/hajimehoshi/ebiten"
)
// World represents the game state.
type World struct {
area [][]bool
}
func newArea(width, height int) [][]bool {
a := make([][]bool, height)
for i := 0; i < height; i++ {
a[i] = make([]bool, width)
}
return a
}
// NewWorld creates a new world.
func NewWorld(width, height int, maxInitLiveCells int) *World {
w := &World{
area: newArea(width, height),
}
w.init(maxInitLiveCells)
return w
}
func init() {
rand.Seed(time.Now().UnixNano())
}
// init inits world with a random state.
func (w *World) init(maxLiveCells int) {
height := len(w.area)
width := len(w.area[0])
for i := 0; i < maxLiveCells; i++ {
x := rand.Intn(width)
y := rand.Intn(height)
w.area[y][x] = true
}
}
// Update game state by one tick.
func (w *World) Update() {
height := len(w.area)
width := len(w.area[0])
next := newArea(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
}
// Draw paints current game state.
func (w *World) Draw(pix []byte) {
height := len(w.area)
width := len(w.area[0])
for y := 0; y < height; y++ {
for x := 0; x < width; x++ {
idx := 4*y*width + 4*x
if w.area[y][x] {
pix[idx] = 0xff
pix[idx+1] = 0xff
pix[idx+2] = 0xff
pix[idx+3] = 0xff
} else {
pix[idx] = 0
pix[idx+1] = 0
pix[idx+2] = 0
pix[idx+3] = 0
}
}
}
}
func max(a, b int) int {
if a < b {
return b
}
return a
}
func min(a, b int) int {
if a < b {
return a
}
return b
}
// neighbourCount calculates the Moore neighborhood of (x, y).
func neighbourCount(a [][]bool, x, y int) int {
w := len(a[0])
h := len(a)
minI := max(x-1, 0)
minJ := max(y-1, 0)
maxI := min(x+1, w-1)
maxJ := min(y+1, h-1)
c := 0
for j := minJ; j <= maxJ; j++ {
for i := minI; i <= maxI; i++ {
if i == x && j == y {
continue
}
if a[j][i] {
c++
}
}
}
return c
}
const (
screenWidth = 320
screenHeight = 240
)
var (
world = NewWorld(screenWidth, screenHeight, int((screenWidth*screenHeight)/10))
pixels = make([]byte, screenWidth*screenHeight*4)
)
func update(screen *ebiten.Image) error {
world.Update()
if ebiten.IsRunningSlowly() {
return nil
}
world.Draw(pixels)
screen.ReplacePixels(pixels)
return nil
}
func main() {
if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Game of Life (Ebiten Demo)"); err != nil {
log.Fatal(err)
}
}