gistfile1.txt

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const Scaffold(
        body: Center(
          child: SpaceshipBeaming(),
        ),
      ),
    );
  }
}

class SpaceshipBeaming extends StatefulWidget {
  const SpaceshipBeaming({super.key});

  @override
  SpaceshipBeamingState createState() => SpaceshipBeamingState();
}

class SpaceshipBeamingState extends State<SpaceshipBeaming>
    with SingleTickerProviderStateMixin {
  late AnimationController _animation;

  @override
  void initState() {
    super.initState();
    _animation = AnimationController(
      duration: const Duration(seconds: 5),
      vsync: this,
    )..repeat();
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      alignment: AlignmentDirectional.center,
      children: <Widget>[
        const Positioned(
          child: ColoredBox(
            color: Colors.black,
          ),
        ),
        AnimatedBuilder(
          animation: _animation,
          builder: (_, __) {
            return ClipPath(
              clipper: const BeamClipper(),
              child: Container(
                height: 1000,
                decoration: BoxDecoration(
                  gradient: RadialGradient(
                    radius: 1.5,
                    colors: const [
                      Colors.yellow,
                      Colors.transparent,
                    ],
                    stops: [0, _animation.value],
                  ),
                ),
              ),
            );
          },
        ),
        const FlutterLogo(size: 50),
      ],
    );
  }

  @override
  void dispose() {
    _animation.dispose();
    super.dispose();
  }
}

class BeamClipper extends CustomClipper<Path> {
  const BeamClipper();

  @override
  getClip(Size size) {
    return Path()
      ..lineTo(size.width / 2, size.height / 2)
      ..lineTo(size.width, size.height)
      ..lineTo(0, size.height)
      ..lineTo(size.width / 2, size.height / 2)
      ..close();
  }

  /// Return false always because we always clip the same area.
  @override
  bool shouldReclip(CustomClipper oldClipper) => false;
}