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Simple particle motion
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import 'dart:math'; | |
import 'package:flutter/foundation.dart'; | |
import 'package:flutter/widgets.dart'; | |
import 'package:flutter/animation.dart'; | |
import 'package:flutter/material.dart'; | |
import 'package:flutter/scheduler.dart' show timeDilation; | |
class DemoPage extends StatefulWidget { | |
@override | |
_DemoPageState createState() => new _DemoPageState(); | |
DemoPage() { | |
timeDilation = 1.0; | |
} | |
} | |
class _DemoPageState extends State<DemoPage> { | |
@override | |
Widget build(BuildContext context) { | |
return new Scaffold( | |
body: new DemoBody(screenSize: MediaQuery.of(context).size), | |
); | |
} | |
} | |
class DemoBody extends StatefulWidget { | |
final Size screenSize; | |
DemoBody({Key key, @required this.screenSize}) : super(key: key); | |
@override | |
State<StatefulWidget> createState() { | |
return new _DemoBodyState(); | |
} | |
} | |
class _DemoBodyState extends State<DemoBody> with TickerProviderStateMixin { | |
AnimationController animationController; | |
final nodeList = <Node>[]; | |
final numNodes = 20; | |
@override | |
void initState() { | |
super.initState(); | |
// Generate list of node | |
new List.generate(numNodes, (i) { | |
nodeList.add(new Node(id: i, screenSize: widget.screenSize)); | |
}); | |
animationController = | |
new AnimationController(vsync: this, duration: new Duration(seconds: 20)) | |
..addListener(() { | |
for (int i = 0; i < nodeList.length; i++) { | |
nodeList[i].move(animationController.value); | |
for (int j = i + 1; j < nodeList.length; j++) { | |
nodeList[i].connect(nodeList[j]); | |
} | |
} | |
}) | |
..repeat(); | |
} | |
@override | |
void dispose() { | |
animationController.dispose(); | |
super.dispose(); | |
} | |
@override | |
Widget build(BuildContext context) { | |
return new Container( | |
child: new AnimatedBuilder( | |
animation: new CurvedAnimation( | |
parent: animationController, curve: Curves.easeInOut), | |
builder: (context, child) => new CustomPaint( | |
size: widget.screenSize, | |
painter: new _DemoPainter(widget.screenSize, nodeList), | |
), | |
), | |
); | |
} | |
} | |
class _DemoPainter extends CustomPainter { | |
final List<Node> nodeList; | |
final Size screenSize; | |
_DemoPainter(this.screenSize, this.nodeList); | |
@override | |
void paint(Canvas canvas, Size size) { | |
for (var node in nodeList) { | |
node.display(canvas); | |
} | |
} | |
@override | |
bool shouldRepaint(_DemoPainter oldDelegate) => true; | |
} | |
enum Direction { | |
LEFT, | |
RIGHT, | |
TOP, | |
BOTTOM, | |
TOP_LEFT, | |
TOP_RIGHT, | |
BOTTOM_LEFT, | |
BOTTOM_RIGHT | |
} | |
class Node { | |
int id; | |
Size screenSize; | |
double radius; | |
double size; | |
Offset position; | |
Direction direction; | |
Random random; | |
Paint notePaint, linePaint; | |
Map<int, Node> connected; | |
Node( | |
{@required this.id, | |
this.size = 5.0, | |
this.radius = 200.0, | |
@required this.screenSize}) { | |
random = new Random(); | |
connected = new Map(); | |
position = screenSize.center(Offset.zero); | |
direction = Direction.values[random.nextInt(Direction.values.length)]; | |
notePaint = new Paint() | |
..color = Colors.orange | |
..strokeWidth = 1.0 | |
..style = PaintingStyle.fill; | |
linePaint = new Paint() | |
..color = Colors.orange | |
..strokeWidth = 0.5 | |
..style = PaintingStyle.stroke; | |
} | |
void move(double seed) { | |
switch (direction) { | |
case Direction.LEFT: | |
position -= new Offset(1.0 + seed, 0.0); | |
if (position.dx <= 5.0) { | |
List<Direction> dirAvailableList = [ | |
Direction.RIGHT, | |
Direction.BOTTOM_RIGHT, | |
Direction.TOP_RIGHT | |
]; | |
direction = dirAvailableList[random.nextInt(dirAvailableList.length)]; | |
} | |
break; | |
case Direction.RIGHT: | |
position += new Offset(1.0 + seed, 0.0); | |
if (position.dx >= screenSize.width - 5.0) { | |
List<Direction> dirAvailableList = [ | |
Direction.LEFT, | |
Direction.BOTTOM_LEFT, | |
Direction.TOP_LEFT | |
]; | |
direction = dirAvailableList[random.nextInt(dirAvailableList.length)]; | |
} | |
break; | |
case Direction.TOP: | |
position -= new Offset(0.0, 1.0 + seed); | |
if (position.dy <= 5.0) { | |
List<Direction> dirAvailableList = [ | |
Direction.BOTTOM, | |
Direction.BOTTOM_LEFT, | |
Direction.BOTTOM_RIGHT | |
]; | |
direction = dirAvailableList[random.nextInt(dirAvailableList.length)]; | |
} | |
break; | |
case Direction.BOTTOM: | |
position += new Offset(0.0, 1.0 + seed); | |
if (position.dy >= screenSize.height - 5.0) { | |
List<Direction> dirAvailableList = [ | |
Direction.TOP, | |
Direction.TOP_LEFT, | |
Direction.TOP_RIGHT, | |
]; | |
direction = dirAvailableList[random.nextInt(dirAvailableList.length)]; | |
} | |
break; | |
case Direction.TOP_LEFT: | |
position -= new Offset(1.0 + seed, 1.0 + seed); | |
if (position.dx <= 5.0 || position.dy <= 5.0) { | |
List<Direction> dirAvailableList = [ | |
Direction.BOTTOM_RIGHT, | |
]; | |
//if y invalid and x valid | |
if (position.dy <= 5.0 && position.dx > 5.0) { | |
dirAvailableList.add(Direction.LEFT); | |
dirAvailableList.add(Direction.RIGHT); | |
dirAvailableList.add(Direction.BOTTOM); | |
dirAvailableList.add(Direction.BOTTOM_LEFT); | |
} | |
//if x invalid and y valid | |
if (position.dx <= 5.0 && position.dy > 5.0) { | |
dirAvailableList.add(Direction.TOP); | |
dirAvailableList.add(Direction.RIGHT); | |
dirAvailableList.add(Direction.BOTTOM); | |
dirAvailableList.add(Direction.TOP_RIGHT); | |
} | |
direction = dirAvailableList[random.nextInt(dirAvailableList.length)]; | |
} | |
break; | |
case Direction.TOP_RIGHT: | |
position -= new Offset(-1.0 - seed, 1.0 + seed); | |
if (position.dx >= screenSize.width - 5.0 || position.dy <= 5.0) { | |
List<Direction> dirAvailableList = [ | |
Direction.BOTTOM_LEFT, | |
]; | |
//if y invalid and x valid | |
if (position.dy <= 5.0 && position.dx < screenSize.width - 5.0) { | |
dirAvailableList.add(Direction.LEFT); | |
dirAvailableList.add(Direction.RIGHT); | |
dirAvailableList.add(Direction.BOTTOM); | |
dirAvailableList.add(Direction.BOTTOM_RIGHT); | |
} | |
//if x invalid and y valid | |
if (position.dx >= screenSize.width - 5.0 && position.dy > 5.0) { | |
dirAvailableList.add(Direction.TOP); | |
dirAvailableList.add(Direction.BOTTOM); | |
dirAvailableList.add(Direction.LEFT); | |
dirAvailableList.add(Direction.TOP_LEFT); | |
} | |
direction = dirAvailableList[random.nextInt(dirAvailableList.length)]; | |
} | |
break; | |
case Direction.BOTTOM_LEFT: | |
position -= new Offset(1.0 + seed, -1.0 + seed); | |
if (position.dx <= 5.0 || position.dy >= screenSize.height - 5.0) { | |
List<Direction> dirAvailableList = [ | |
Direction.TOP_RIGHT, | |
]; | |
//if y invalid and x valid | |
if (position.dy >= screenSize.height - 5.0 && position.dx > 5.0) { | |
dirAvailableList.add(Direction.LEFT); | |
dirAvailableList.add(Direction.RIGHT); | |
dirAvailableList.add(Direction.TOP); | |
dirAvailableList.add(Direction.TOP_LEFT); | |
} | |
//if x invalid and y valid | |
if (position.dx <= 5.0 && position.dy < screenSize.height - 5.0) { | |
dirAvailableList.add(Direction.TOP); | |
dirAvailableList.add(Direction.BOTTOM); | |
dirAvailableList.add(Direction.RIGHT); | |
dirAvailableList.add(Direction.BOTTOM_RIGHT); | |
} | |
direction = dirAvailableList[random.nextInt(dirAvailableList.length)]; | |
} | |
break; | |
case Direction.BOTTOM_RIGHT: | |
position += new Offset(1.0 + seed, 1.0 + seed); | |
if (position.dx >= screenSize.width - 5.0 || | |
position.dy >= screenSize.height - 5.0) { | |
List<Direction> dirAvailableList = [ | |
Direction.TOP_LEFT, | |
]; | |
//if y invalid and x valid | |
if (position.dy >= screenSize.height - 5.0 && | |
position.dx < screenSize.width - 5.0) { | |
dirAvailableList.add(Direction.LEFT); | |
dirAvailableList.add(Direction.RIGHT); | |
dirAvailableList.add(Direction.TOP); | |
dirAvailableList.add(Direction.TOP_RIGHT); | |
} | |
//if x invalid and y valid | |
if (position.dx >= screenSize.width - 5.0 && | |
position.dy < screenSize.height - 5.0) { | |
dirAvailableList.add(Direction.TOP); | |
dirAvailableList.add(Direction.BOTTOM); | |
dirAvailableList.add(Direction.LEFT); | |
dirAvailableList.add(Direction.BOTTOM_LEFT); | |
} | |
direction = dirAvailableList[random.nextInt(dirAvailableList.length)]; | |
} | |
break; | |
} | |
} | |
bool canConnect(Node node) { | |
double x = node.position.dx - position.dx; | |
double y = node.position.dy - position.dy; | |
double d = x * x + y * y; | |
return d <= radius * radius; | |
} | |
void connect(Node node) { | |
if (canConnect(node)) { | |
if (!node.connected.containsKey(id)) { | |
connected.putIfAbsent(node.id, () => node); | |
} | |
} else if (connected.containsKey(node.id)) { | |
connected.remove(node.id); | |
} | |
} | |
void display(Canvas canvas) { | |
canvas.drawCircle(position, size, notePaint); | |
connected.forEach((id, node) { | |
canvas.drawLine(position, node.position, linePaint); | |
}); | |
} | |
bool operator ==(o) => o is Node && o.id == id; | |
int get hashCode => id; | |
} |
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