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import 'dart:math';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:flutter/src/scheduler/ticker.dart';
import 'package:flutter/widgets.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) => MaterialApp(
title: 'Game of Life',
theme: ThemeData(primarySwatch: Colors.amber),
home: MyHomePage());
}
class MyHomePage extends StatefulWidget {
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
@override
Widget build(BuildContext context) => Scaffold(
appBar: AppBar(title: Text('Game Of Life')),
body: Center(child: GameOfLifeWidget(width: 100, height: 100)));
}
void updateGameOfLife(
int width, int height, Uint8List inputCells, Uint8List outputCells) {
assert(width * height == inputCells.length);
assert(width * height == outputCells.length);
for (var y = width; y < (width - 1) * height; y += width) {
for (var x = 1; x < width - 1; x++) {
var neighbors = 0;
var index = x + y;
for (var ny = -width; ny <= width; ny += width) {
for (var nx = -1; nx <= 1; nx++) {
if (ny == 0 && nx == 0) continue;
neighbors += inputCells[index + nx + ny];
}
}
if (inputCells[index] == 0) {
outputCells[index] = (neighbors == 3) ? 1 : 0;
} else {
outputCells[index] = (neighbors == 2 || neighbors == 3) ? 1 : 0;
}
}
}
}
class GameOfLifePainter extends CustomPainter {
final _GameOfLifeWidgetState state;
@override
void paint(Canvas canvas, Size size) {
Paint p = Paint();
p.color = Colors.red;
canvas.drawLine(Offset(0, 0), Offset(size.width, size.height), p);
var cellWidth = size.width / state.cellsByX;
var cellHeight = size.height / state.cellsByY;
for (var y = 0; y < state.cellsByY; y++) {
for (var x = 0; x < state.cellsByX; x++) {
var ry = y * cellHeight;
var rx = x * cellWidth;
var r = Rect.fromLTWH(rx, ry, cellWidth, cellHeight);
p.color = state.cells[y * state.cellsByX + x] == 0
? Colors.green
: Colors.red;
canvas.drawRect(r, p);
}
}
}
@override
bool shouldRepaint(GameOfLifePainter oldDelegate) =>
oldDelegate.state != state;
GameOfLifePainter({this.state});
}
class GameOfLifeWidget extends StatefulWidget {
final int width;
final int height;
@override
_GameOfLifeWidgetState createState() => _GameOfLifeWidgetState();
GameOfLifeWidget({@required this.width, @required this.height});
}
class _GameOfLifeWidgetState extends State<GameOfLifeWidget>
with SingleTickerProviderStateMixin {
Ticker _ticker;
Uint8List _cellsA;
Uint8List _cellsB;
Uint8List _cells;
get cells => _cells;
get cellsByX => widget.width;
get cellsByY => widget.height;
void init() {
_cellsA.fillRange(0, _cellsA.length - 1, 0);
_cellsB.fillRange(0, _cellsB.length - 1, 0);
_cells = _cellsA;
var random = Random();
for (var y = 1; y < widget.height - 1; y++)
for (var x = 1; x < widget.width - 1; x++)
_cellsA[y * widget.width + x] = random.nextInt(5) == 0 ? 1 : 0;
}
void update() {
updateGameOfLife(
widget.width,
widget.height,
_cells == _cellsA ? _cellsA : _cellsB,
_cells == _cellsA ? _cellsB : _cellsA);
_cells = (_cells == _cellsA) ? _cellsB : _cellsA;
}
void initState() {
super.initState();
_ticker = createTicker((Duration elapsed) => setState(() => update()));
var size = widget.width * widget.height;
_cellsA = Uint8List(size);
_cellsB = Uint8List(size);
_cells = _cellsA;
init();
}
@override
void dispose() {
_ticker.dispose();
_ticker = null;
super.dispose();
}
@override
Widget build(BuildContext context) => LayoutBuilder(
builder: (BuildContext context, BoxConstraints constraints) =>
Column(mainAxisAlignment: MainAxisAlignment.spaceAround, children: [
Flexible(
child: Container(
width: min(constraints.maxHeight, constraints.maxWidth),
height: min(constraints.maxHeight, constraints.maxWidth),
child: CustomPaint(painter: GameOfLifePainter(state: this))),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
mainAxisSize: MainAxisSize.min,
children: [
if (_ticker != null)
FlatButton(
child: Text('Play'),
onPressed: _ticker.isActive
? null
: () => setState(() => _ticker.start()),
),
if (_ticker != null)
FlatButton(
child: Text('Stop'),
onPressed: _ticker.isActive
? () => setState(() => _ticker.stop())
: null),
if (_ticker != null)
FlatButton(
child: Text('Step'),
onPressed: _ticker.isActive
? null
: () => setState(() => update())),
FlatButton(
child: Text('Random'),
onPressed: () => setState(() => init()),
),
])
]));
}
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