-
-
Save soundmasteraj/74097f03e5a7d98f7d4f30aaf8329d65 to your computer and use it in GitHub Desktop.
Simple particle motion
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
import 'dart:ui' as ui; | |
import 'dart:async'; | |
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; | |
List<Node> nodeList; | |
Size screenSize; | |
int numNodes = 20; | |
@override | |
void initState() { | |
super.initState(); | |
screenSize = widget.screenSize; | |
nodeList = new List(); | |
for (int i = 0; i < numNodes; i++) { | |
nodeList.add(new Node(id: i, screenSize: screenSize)); | |
} | |
animationController = new AnimationController( | |
vsync: this, duration: new Duration(seconds: 20)); | |
animationController.addListener(() { | |
for (int i = 0; i < nodeList.length; i++) { | |
nodeList[i].move(); | |
for (int j = 0; j < nodeList.length; j++) { | |
if (i != j) { | |
nodeList[i].connect(nodeList[j]); | |
} | |
} | |
} | |
setState(() {}); | |
}); | |
animationController.addStatusListener((state) { | |
if (state == AnimationStatus.dismissed) { | |
animationController.forward(); | |
} else if (state == AnimationStatus.completed) { | |
animationController.reverse(); | |
} | |
}); | |
animationController.forward(); | |
} | |
@override | |
void dispose() { | |
super.dispose(); | |
} | |
@override | |
Widget build(BuildContext context) { | |
Size screenSize = MediaQuery.of(context).size; | |
return new Container( | |
child: new CustomPaint( | |
size: new Size( | |
screenSize.width, | |
screenSize.height, | |
), | |
painter: new _DemoPainter(screenSize, nodeList), | |
), | |
); | |
} | |
} | |
class _DemoPainter extends CustomPainter { | |
List<Node> nodeList; | |
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() { | |
switch (direction) { | |
case Direction.LEFT: | |
position -= new Offset(1.0, 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, 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); | |
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); | |
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, 1.0); | |
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, 1.0); | |
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, -1.0); | |
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, 1.0); | |
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); | |
}); | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Very nice article!