Ball collision gyroscope flutter

jogo.dart

import 'package:flutter/material.dart';
import 'package:sensors_plus/sensors_plus.dart';
import 'dart:math';

class Jogo extends StatefulWidget {
  const Jogo({Key? key}) : super(key: key);

  @override
  State<Jogo> createState() => JJ();
}

class JJ extends State<Jogo> {
  static const double maxSpeed = 30;

  final testeKey = GlobalKey();
  final playerKey = GlobalKey();

  double playerX = 200;
  double playerY = 100;

  double speed = 10;

  double xVel = 0;
  double yVel = 0;

  int onCollisionWalls(double x, double y) {
    RenderBox? box1 = playerKey.currentContext!.findRenderObject() as RenderBox;
    final size1 = box1.size;
    final position1 = box1.localToGlobal(Offset.zero);

    RenderBox? box2 = testeKey.currentContext!.findRenderObject() as RenderBox;
    final size2 = box2.size;
    final position2 = box2.localToGlobal(Offset.zero);

    final testX = (position1.dx + size1.width > position2.dx && position1.dx < position2.dx + size2.width);
    final testY = (position1.dy + size1.height > position2.dy && position1.dy < position2.dy + size2.height);
    final testXPrev = (position1.dx + size1.width + x > position2.dx && position1.dx + x < position2.dx + size2.width);
    final testYPrev = (position1.dy + size1.height + y > position2.dy && position1.dy + y < position2.dy + size2.height);

    if(testXPrev && testYPrev) {
      if(!testX) return 3;
      else if(!testY) return 2;
      return 1;
    }
    return 0;
  }

  @override
  void initState() {
    super.initState();
    gyroscopeEvents.listen((GyroscopeEvent event) {
      xVel += (-event.z * speed);
      yVel += (event.x * speed);

      double xS = min(maxSpeed, max(-maxSpeed, xVel));
      double yS = min(maxSpeed, max(-maxSpeed, yVel));

      int col = onCollisionWalls(xS, yS);
      if(col == 1) {
        xVel = 0;
        yVel = 0;
      } else if(col == 2) {
        playerX += xS;
        yVel = 0;
      } else if(col == 3) {
        playerY += yS;
        xVel = 0;
      } else {
        playerX += xS;
        playerY += yS;
      }

      setState(() { });
    });
  }

  @override
  Widget build(BuildContext context) {
    var size = MediaQuery.of(context).size;
    return Scaffold(
      body: SafeArea(
        child: Container(
          alignment: Alignment.center,
          padding: const EdgeInsets.all(20),
          child: Stack(
            children: [
              Positioned(
                left: 40,
                top: 100,
                key: testeKey,
                child: Container(
                  width: 100,
                  height: 50,
                  decoration: BoxDecoration(
                    color: Colors.yellow,
                  )
                ),
              ),
              Positioned(
                key: playerKey,
                left: playerX,
                top: playerY,
                child: Container(
                  width: 70,
                  height: 70,
                  decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(80),
                    color: Colors.red
                  )
                ),
              )
            ]
          )
        )
      )
    );
  }
}