graphx_triangles.dart

import 'dart:async';
import 'dart:ui' as ui;

import 'package:flutter/material.dart';
import 'package:graphx/graphx.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const Home(),
    );
  }
}

class Home extends StatelessWidget {
  const Home({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: SceneBuilderWidget(
          builder: () => SceneController(
            back: SimpleShapes(MediaQuery.of(context).size),
          ),
          autoSize: true,
          child: const SizedBox.expand(),
        ),
      ),
    );
  }
}

const _colorLevels = [
  50,
  100,
  200,
  300,
  400,
  500,
  600,
  700,
  // 800,
  // 900,
];

class Triangle {
  final Path path;

  Triangle(this.path);
}

class TriangleShape {
  final Triangle triangle;
  final GShape shape;

  TriangleShape(this.triangle, this.shape);

  void setup({required MaterialColor color}) {
    final level = [..._colorLevels]..shuffle();
    shape.graphics.beginFill((color[level.first] ?? color).withOpacity(0.87));
    shape.graphics.drawPath(triangle.path);
    shape.graphics.endFill();
  }
}

Future<ui.Image> getImage(String path) async {
  final byteData = await rootBundle.load(path);
  return await decodeImageFromList(byteData.buffer.asUint8List());
}

const windowOffset = 30.0;
const shapeSize = 60.0;

class SimpleShapes extends GSprite {
  final Size size;

  final points = <GShape>[];
  final triangles = <TriangleShape>[];

  SimpleShapes(this.size);

  @override
  void addedToStage() {
    super.addedToStage();

    double currentX = -windowOffset;
    double currentY = -windowOffset;
    bool useOffset = false;

    for (; currentY < size.height + windowOffset; currentY += shapeSize) {
      final offset = useOffset ? shapeSize / 2 : 0;
      useOffset = !useOffset;
      for (currentX = -windowOffset;
          currentX < size.width + windowOffset;
          currentX += shapeSize) {
        final underTriangle = Triangle(Path()
          ..moveTo(currentX + offset, currentY)
          ..relativeLineTo(shapeSize, 0)
          ..relativeLineTo(-shapeSize / 2, shapeSize)
          ..close());
        final underTriangleShape = TriangleShape(underTriangle, GShape())
          ..setup(color: Colors.amber);
        triangles.add(underTriangleShape);
        addChild(underTriangleShape.shape);

        final overTriangle = Triangle(Path()
          ..moveTo(currentX + offset, currentY)
          ..relativeLineTo(shapeSize / 2, shapeSize)
          ..relativeLineTo(-shapeSize, 0)
          ..close());
        final overTriangleShape = TriangleShape(overTriangle, GShape())
          ..setup(color: Colors.yellow);
        triangles.add(overTriangleShape);
        addChild(overTriangleShape.shape);
      }
    }
  }

  @override
  void update(double delta) {
    final mx = (mouseX / size.width - 0.5) * 50;
    pivotX = mx;
    final my = (mouseY / size.height - 0.5) * 50;
    pivotY = my;

    super.update(delta);
  }
}