Skip to content

Instantly share code, notes, and snippets.

@aakash-pamnani

aakash-pamnani/ball.dart

Created April 28, 2024 19:04
Show Gist options
  • Save aakash-pamnani/99461f4302740ef084e77390e9f66dc3 to your computer and use it in GitHub Desktop.
Save aakash-pamnani/99461f4302740ef084e77390e9f66dc3 to your computer and use it in GitHub Desktop.
Download ZIP
Raw
ball.dart
import 'dart:math';
import 'dart:ui';
class ForcePoint {
ForcePoint(this.x, this.y);
double computed = 0;
double force = 0;
num x, y;
num get magnitude => x * x + y * y;
ForcePoint add(ForcePoint point) => ForcePoint(point.x + x, point.y + y);
ForcePoint copyWith({num? x, num? y}) => ForcePoint(x ?? this.x, y ?? this.y);
}
class Ball {
Ball(Size size) {
double vel({double ratio = 1}) =>
(Random().nextDouble() > .5 ? 1 : -1) *
(.2 + .25 * Random().nextDouble());
velocity = ForcePoint(vel(ratio: 0.25), vel());
var i = .1;
var h = 1.5;
double calculatePosition(double fullSize) =>
Random().nextDouble() * fullSize;
pos = ForcePoint(
calculatePosition(size.width), calculatePosition(size.height));
this.size = size.shortestSide / 15 +
(Random().nextDouble() * (h - i) + i) * (size.shortestSide / 15);
}
late ForcePoint pos;
late double size;
late ForcePoint velocity;
moveIn(Size size) {
if (pos.x >= size.width - this.size) {
if (pos.x > 0) velocity.x = -velocity.x;
pos = pos.copyWith(x: size.width - this.size);
} else if (pos.x <= this.size) {
if (velocity.x < 0) velocity.x = -velocity.x;
pos.x = this.size;
}
if (pos.y >= size.height - this.size) {
if (velocity.y > 0) velocity.y = -velocity.y;
pos.y = size.height - this.size;
} else if (pos.y <= this.size) {
if (velocity.y < 0) velocity.y = -velocity.y;
pos.y = this.size;
}
pos = pos.add(velocity);
}
}
Raw
lava.dart
import 'package:flutter/material.dart';
/// Lava clock.
/// Copied from https://github.com/RetroMusicPlayer/Paisa/
class LavaAnimation extends StatefulWidget {
const LavaAnimation({
super.key,
required this.child,
this.color,
});
final Widget child;
final Color? color;
@override
LavaAnimationState createState() => LavaAnimationState();
}
class LavaAnimationState extends State<LavaAnimation>
with TickerProviderStateMixin {
final Lava lava = Lava(10);
late final AnimationController _animation =
AnimationController(duration: const Duration(minutes: 10), vsync: this)
..repeat();
@override
void dispose() {
_animation.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return LayoutBuilder(
builder: (context, constraints) => AnimatedBuilder(
animation: _animation,
builder: (BuildContext context, _) => CustomPaint(
size: const Size(100, 100),
painter: LavaPainter(
lava,
color: widget.color ?? context.primary,
),
child: widget.child,
),
),
);
}
}
Raw
lava_painter.dart
import 'dart:math';
import 'package:flutter/material.dart';
import 'ball.dart';
class LavaPainter extends CustomPainter {
LavaPainter(this.lava, {required this.color});
final Color color;
final Lava lava;
@override
void paint(Canvas canvas, Size size) {
if (lava.size != size) lava.updateSize(size);
lava.draw(canvas, size, color, debug: false);
}
@override
bool shouldRepaint(LavaPainter oldDelegate) {
return true;
}
}
class Lava {
Lava(this.ballsLength);
late List<Ball> balls;
int ballsLength;
double iter = 0;
final ix = [1, 0, -1, 0, 0, 1, 0, -1, -1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1];
late Map<int, Map<int, ForcePoint>> matrix;
final List<int> mscases = [0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 0, 2, 1, 1, 0];
bool paint = false;
final List<int> plx = [0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0];
final List<int> ply = [0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1];
late Rect sRect;
int sign = 1;
Size? size;
num step = 5;
double get width => size?.width ?? 10;
double get height => size?.height ?? 10;
double get sx => (width ~/ step).floor().toDouble();
double get sy => (height ~/ step).floor().toDouble();
updateSize(Size size) {
this.size = size;
sRect = Rect.fromCenter(
center: Offset.zero, width: sx.toDouble(), height: sy.toDouble());
matrix = {};
for (int i = (sRect.left - step).toInt(); i < sRect.right + step; i++) {
matrix[i] = {};
for (int j = (sRect.top - step).toInt(); j < sRect.bottom + step; j++) {
matrix[i]![j] = ForcePoint(
(i + sx ~/ 2).toDouble() * step, (j + sy ~/ 2).toDouble() * step);
}
}
balls = List.filled(ballsLength, Ball(const Size(0, 0)));
for (var index = 0; ballsLength > index; index++) {
balls[index] = Ball(size);
}
}
double computeForce(int sx, int sy) {
double force;
if (!sRect.contains(Offset(sx.toDouble(), sy.toDouble()))) {
force = .6 * sign;
} else {
force = 0;
final ForcePoint? point = matrix[sx]![sy];
for (final ball in balls) {
force += ball.size *
ball.size /
(-2 * point!.x * ball.pos.x -
2 * point.y * ball.pos.y +
ball.pos.magnitude +
point.magnitude);
}
force *= sign;
}
matrix[sx]![sy]!.force = force;
return force;
}
List? marchingSquares(List? pathParameters, Path path) {
int sx = pathParameters?[0] ?? 0;
int sy = pathParameters?[1] ?? 0;
int pdir = pathParameters?[2] ?? 0;
if (matrix[sx]![sy]!.computed == iter) return null;
int dir;
int mscase = 0;
for (var a = 0; 4 > a; a++) {
final dx = ix[a + 12];
final dy = ix[a + 16];
double force = matrix[sx + dx]![sy + dy]!.force;
if (force > 0 && sign < 0 || force < 0 && sign > 0 || force == 0) {
force = computeForce(sx + dx, sy + dy);
}
if (force.abs() > 1) mscase += pow(2, a).toInt();
}
if (15 == mscase) {
return [sx, sy - 1, null];
} else if (5 == mscase) {
dir = 2 == pdir ? 3 : 1;
} else if (10 == mscase) {
dir = 3 == pdir ? 0 : 2;
} else {
dir = mscases[mscase];
matrix[sx]![sy]!.computed = iter;
}
final dx1 = plx[4 * dir + 2];
final dy1 = ply[4 * dir + 2];
final pForce1 = matrix[sx + dx1]![sy + dy1]!.force;
final dx2 = plx[4 * dir + 3];
final dy2 = ply[4 * dir + 3];
final pForce2 = matrix[sx + dx2]![sy + dy2]!.force;
final p =
step / ((pForce1.abs() - 1).abs() / (pForce2.abs() - 1).abs() + 1.0);
final dxX = plx[4 * dir];
final dyX = ply[4 * dir];
final dxY = plx[4 * dir + 1];
final dyY = ply[4 * dir + 1];
final lineX = matrix[sx + dxX]![sy + dyX]!.x + ix[dir] * p;
final lineY = matrix[sx + dxY]![sy + dyY]!.y + ix[dir + 4] * p;
if (paint == false) {
path.moveTo(lineX, lineY);
} else {
path.lineTo(lineX, lineY);
}
paint = true;
return [sx + ix[dir + 4], sy + ix[dir + 8], dir];
}
draw(Canvas canvas, Size size, Color color, {bool debug = false}) {
for (Ball ball in balls) {
ball.moveIn(size);
}
try {
iter++;
sign = -sign;
paint = false;
for (Ball ball in balls) {
Path path = Path();
List? pathParameters = [
(ball.pos.x / step - sx / 2).round(),
(ball.pos.y / step - sy / 2).round(),
null
];
do {
pathParameters = marchingSquares(pathParameters, path);
} while (pathParameters != null);
if (paint) {
path.close();
Paint paint = Paint()..color = color;
canvas.drawPath(path, paint);
this.paint = false;
}
}
} catch (_) {}
if (debug) {
for (final ball in balls) {
canvas.drawCircle(Offset(ball.pos.x.toDouble(), ball.pos.y.toDouble()),
ball.size, Paint()..color = Colors.black.withOpacity(0.5));
}
matrix.forEach(
(_, item) => item.forEach(
(_, point) => canvas.drawCircle(
Offset(point.x.toDouble(), point.y.toDouble()),
max(1, min(point.force.abs(), 5)),
Paint()..color = point.force > 0 ? Colors.blue : Colors.red,
),
),
);
}
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment