Merge pull request #14 from VGVentures/feat/paths

feat: path component

lib/game/components/components.dart

@@ -2,6 +2,7 @@ export 'anchor.dart';
 export 'ball.dart';
 export 'board_side.dart';
 export 'flipper.dart';
+export 'pathway.dart';
 export 'plunger.dart';
 export 'score_points.dart';
 export 'wall.dart';

lib/game/components/pathway.dart

@@ -0,0 +1,178 @@
+import 'package:flame/extensions.dart';
+import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:flutter/material.dart';
+import 'package:geometry/geometry.dart';
+
+/// {@template pathway}
+/// [Pathway] creates lines of various shapes.
+///
+/// [BodyComponent]s such as a Ball can collide and move along a [Pathway].
+/// {@endtemplate}
+class Pathway extends BodyComponent {
+  Pathway._({
+    // TODO(ruialonso): remove color when assets added.
+    Color? color,
+    required Vector2 position,
+    required List<List<Vector2>> paths,
+  })  : _position = position,
+        _paths = paths {
+    paint = Paint()
+      ..color = color ?? const Color.fromARGB(0, 0, 0, 0)
+      ..style = PaintingStyle.stroke;
+  }
+
+  /// Creates a uniform unidirectional (straight) [Pathway].
+  ///
+  /// Does so with two [ChainShape] separated by a [width]. Placed
+  /// at a [position] between [start] and [end] points. Can
+  /// be rotated by a given [rotation] in radians.
+  ///
+  /// If [singleWall] is true, just one [ChainShape] is created.
+  factory Pathway.straight({
+    Color? color,
+    required Vector2 position,
+    required Vector2 start,
+    required Vector2 end,
+    required double width,
+    double rotation = 0,
+    bool singleWall = false,
+  }) {
+    final paths = <List<Vector2>>[];
+
+    // TODO(ruialonso): Refactor repetitive logic
+    final firstWall = [
+      start.clone(),
+      end.clone(),
+    ].map((vector) => vector..rotate(rotation)).toList();
+    paths.add(firstWall);
+
+    if (!singleWall) {
+      final secondWall = [
+        start + Vector2(width, 0),
+        end + Vector2(width, 0),
+      ].map((vector) => vector..rotate(rotation)).toList();
+      paths.add(secondWall);
+    }
+
+    return Pathway._(
+      color: color,
+      position: position,
+      paths: paths,
+    );
+  }
+
+  /// Creates an arc [Pathway].
+  ///
+  /// The [angle], in radians, specifies the size of the arc. For example, 2*pi
+  /// returns a complete circumference and minor angles a semi circumference.
+  ///
+  /// The center of the arc is placed at [position].
+  ///
+  /// Does so with two [ChainShape] separated by a [width]. Which can be
+  /// rotated by a given [rotation] in radians.
+  ///
+  /// The outer radius is specified by [radius], whilst the inner one is
+  /// equivalent to [radius] - [width].
+  ///
+  /// If [singleWall] is true, just one [ChainShape] is created.
+  factory Pathway.arc({
+    Color? color,
+    required Vector2 position,
+    required double width,
+    required double radius,
+    required double angle,
+    double rotation = 0,
+    bool singleWall = false,
+  }) {
+    final paths = <List<Vector2>>[];
+
+    // TODO(ruialonso): Refactor repetitive logic
+    final outerWall = calculateArc(
+      center: position,
+      radius: radius,
+      angle: angle,
+      offsetAngle: rotation,
+    );
+    paths.add(outerWall);
+
+    if (!singleWall) {
+      final innerWall = calculateArc(
+        center: position,
+        radius: radius - width,
+        angle: angle,
+        offsetAngle: rotation,
+      );
+      paths.add(innerWall);
+    }
+
+    return Pathway._(
+      color: color,
+      position: position,
+      paths: paths,
+    );
+  }
+
+  /// Creates a bezier curve [Pathway].
+  ///
+  /// Does so with two [ChainShape] separated by a [width]. Which can be
+  /// rotated by a given [rotation] in radians.
+  ///
+  /// First and last [controlPoints] set the beginning and end of the curve,
+  /// inner points between them set its final shape.
+  ///
+  /// If [singleWall] is true, just one [ChainShape] is created.
+  factory Pathway.bezierCurve({
+    Color? color,
+    required Vector2 position,
+    required List<Vector2> controlPoints,
+    required double width,
+    double rotation = 0,
+    bool singleWall = false,
+  }) {
+    final paths = <List<Vector2>>[];
+
+    // TODO(ruialonso): Refactor repetitive logic
+    final firstWall = calculateBezierCurve(controlPoints: controlPoints)
+        .map((vector) => vector..rotate(rotation))
+        .toList();
+    paths.add(firstWall);
+
+    if (!singleWall) {
+      final secondWall = calculateBezierCurve(
+        controlPoints: controlPoints
+            .map((vector) => vector + Vector2(width, -width))
+            .toList(),
+      ).map((vector) => vector..rotate(rotation)).toList();
+      paths.add(secondWall);
+    }
+
+    return Pathway._(
+      color: color,
+      position: position,
+      paths: paths,
+    );
+  }
+
+  final Vector2 _position;
+  final List<List<Vector2>> _paths;
+
+  @override
+  Body createBody() {
+    final bodyDef = BodyDef()
+      ..type = BodyType.static
+      ..position = _position;
+
+    final body = world.createBody(bodyDef);
+    for (final path in _paths) {
+      final chain = ChainShape()
+        ..createChain(
+          path.map(gameRef.screenToWorld).toList(),
+        );
+      final fixtureDef = FixtureDef(chain);
+
+      body.createFixture(fixtureDef);
+    }
+
+    return body;
+  }
+}

lib/game/pinball_game.dart

@@ -1,5 +1,4 @@
 import 'dart:async';
-
 import 'package:flame/input.dart';
 import 'package:flame_bloc/flame_bloc.dart';
 import 'package:flame_forge2d/flame_forge2d.dart';

packages/geometry/.gitignore

@@ -0,0 +1,7 @@
+# See https://www.dartlang.org/guides/libraries/private-files
+
+# Files and directories created by pub
+.dart_tool/
+.packages
+build/
+pubspec.lock

packages/geometry/README.md

@@ -0,0 +1,11 @@
+# geometry
+
+[![style: very good analysis][very_good_analysis_badge]][very_good_analysis_link]
+[![License: MIT][license_badge]][license_link]
+
+Helper package to calculate points of lines, arcs and curves for the pathways of the ball.
+
+[license_badge]: https://img.shields.io/badge/license-MIT-blue.svg
+[license_link]: https://opensource.org/licenses/MIT
+[very_good_analysis_badge]: https://img.shields.io/badge/style-very_good_analysis-B22C89.svg
+[very_good_analysis_link]: https://pub.dev/packages/very_good_analysis

packages/geometry/analysis_options.yaml

@@ -0,0 +1 @@
+include: package:very_good_analysis/analysis_options.2.4.0.yaml

packages/geometry/lib/geometry.dart

@@ -0,0 +1,3 @@
+library geometry;
+
+export 'src/geometry.dart';

packages/geometry/lib/src/geometry.dart

@@ -0,0 +1,107 @@
+import 'dart:math' as math;
+import 'package:flame/extensions.dart';
+
+/// Calculates all [Vector2]s of a circumference.
+///
+/// A circumference can be achieved by specifying a [center] and a [radius].
+/// In addition, a semi-circle can be achieved by specifying its [angle] and an
+/// [offsetAngle] (both in radians).
+///
+/// The higher the [precision], the more [Vector2]s will be calculated;
+/// achieving a more rounded arc.
+///
+/// For more information read: https://en.wikipedia.org/wiki/Trigonometric_functions.
+List<Vector2> calculateArc({
+  required Vector2 center,
+  required double radius,
+  required double angle,
+  double offsetAngle = 0,
+  int precision = 100,
+}) {
+  final stepAngle = angle / (precision - 1);
+
+  final points = <Vector2>[];
+  for (var i = 0; i < precision; i++) {
+    final xCoord = center.x + radius * math.cos((stepAngle * i) + offsetAngle);
+    final yCoord = center.y - radius * math.sin((stepAngle * i) + offsetAngle);
+
+    final point = Vector2(xCoord, yCoord);
+    points.add(point);
+  }
+
+  return points;
+}
+
+/// Calculates all [Vector2]s of a bezier curve.
+///
+/// A bezier curve of [controlPoints] that say how to create this curve.
+///
+/// First and last points specify the beginning and the end respectively
+/// of the curve. The inner points specify the shape of the curve and
+/// its turning points.
+///
+/// The [step] must be between zero and one (inclusive), indicating the
+/// precision to calculate the curve.
+///
+/// For more information read: https://en.wikipedia.org/wiki/B%C3%A9zier_curve
+List<Vector2> calculateBezierCurve({
+  required List<Vector2> controlPoints,
+  double step = 0.001,
+}) {
+  assert(
+    0 <= step && step <= 1,
+    'Step ($step) must be in range  0 <= step <= 1',
+  );
+  assert(
+    controlPoints.length >= 2,
+    'At least 2 control points needed to create a bezier curve',
+  );
+
+  var t = 0.0;
+  final n = controlPoints.length - 1;
+  final points = <Vector2>[];
+
+  do {
+    var xCoord = 0.0;
+    var yCoord = 0.0;
+    for (var i = 0; i <= n; i++) {
+      final point = controlPoints[i];
+
+      xCoord +=
+          binomial(n, i) * math.pow(1 - t, n - i) * math.pow(t, i) * point.x;
+      yCoord +=
+          binomial(n, i) * math.pow(1 - t, n - i) * math.pow(t, i) * point.y;
+    }
+    points.add(Vector2(xCoord, yCoord));
+
+    t = t + step;
+  } while (t <= 1);
+
+  return points;
+}
+
+/// Calculates the binomial coefficient of 'n' and 'k'.
+///
+/// For more information read: https://en.wikipedia.org/wiki/Binomial_coefficient
+num binomial(num n, num k) {
+  assert(0 <= k && k <= n, 'k ($k) and n ($n) must be in range 0 <= k <= n');
+
+  if (k == 0 || n == k) {
+    return 1;
+  } else {
+    return factorial(n) / (factorial(k) * factorial(n - k));
+  }
+}
+
+/// Calculate the factorial of 'n'.
+///
+/// For more information read: https://en.wikipedia.org/wiki/Factorial
+num factorial(num n) {
+  assert(n >= 0, 'Factorial is not defined for negative number n ($n)');
+
+  if (n == 0 || n == 1) {
+    return 1;
+  } else {
+    return n * factorial(n - 1);
+  }
+}

packages/geometry/pubspec.yaml

@@ -0,0 +1,19 @@
+name: geometry
+description: Helper package to calculate points of lines, arcs and curves for the pathways of the ball
+version: 1.0.0+1
+publish_to: none
+
+environment:
+  sdk: ">=2.16.0 <3.0.0"
+
+dependencies: 
+  flame: ^1.0.0
+  flutter:
+    sdk: flutter
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+  mocktail: ^0.2.0
+  test: ^1.19.2
+  very_good_analysis: ^2.4.0

packages/geometry/test/src/geometry_test.dart

@@ -0,0 +1,159 @@
+// ignore_for_file: prefer_const_constructors, cascade_invocations
+import 'package:flame/extensions.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:geometry/geometry.dart';
+
+class Binomial {
+  Binomial({required this.n, required this.k});
+
+  final num n;
+  final num k;
+}
+
+void main() {
+  group('calculateArc', () {
+    test('returns by default 100 points as indicated by precision', () {
+      final points = calculateArc(
+        center: Vector2.zero(),
+        radius: 100,
+        angle: 90,
+      );
+      expect(points.length, 100);
+    });
+
+    test('returns as many points as indicated by precision', () {
+      final points = calculateArc(
+        center: Vector2.zero(),
+        radius: 100,
+        angle: 90,
+        precision: 50,
+      );
+      expect(points.length, 50);
+    });
+  });
+
+  group('calculateBezierCurve', () {
+    test('fails if step not in range', () {
+      expect(
+        () => calculateBezierCurve(
+          controlPoints: [
+            Vector2(0, 0),
+            Vector2(10, 10),
+          ],
+          step: 2,
+        ),
+        throwsAssertionError,
+      );
+    });
+
+    test('fails if not enough control points', () {
+      expect(
+        () => calculateBezierCurve(controlPoints: [Vector2.zero()]),
+        throwsAssertionError,
+      );
+      expect(
+        () => calculateBezierCurve(controlPoints: []),
+        throwsAssertionError,
+      );
+    });
+
+    test('returns by default 1000 points as indicated by step', () {
+      final points = calculateBezierCurve(
+        controlPoints: [
+          Vector2(0, 0),
+          Vector2(10, 10),
+        ],
+      );
+      expect(points.length, 1000);
+    });
+
+    test('returns as many points as indicated by step', () {
+      final points = calculateBezierCurve(
+        controlPoints: [
+          Vector2(0, 0),
+          Vector2(10, 10),
+        ],
+        step: 0.01,
+      );
+      expect(points.length, 100);
+    });
+  });
+
+  group('binomial', () {
+    test('fails if k is negative', () {
+      expect(() => binomial(1, -1), throwsAssertionError);
+    });
+
+    test('fails if n is negative', () {
+      expect(() => binomial(-1, 1), throwsAssertionError);
+    });
+
+    test('fails if n < k', () {
+      expect(() => binomial(1, 2), throwsAssertionError);
+    });
+
+    test('for a specific input gives a correct value', () {
+      final binomialInputsToExpected = {
+        Binomial(n: 0, k: 0): 1,
+        Binomial(n: 1, k: 0): 1,
+        Binomial(n: 1, k: 1): 1,
+        Binomial(n: 2, k: 0): 1,
+        Binomial(n: 2, k: 1): 2,
+        Binomial(n: 2, k: 2): 1,
+        Binomial(n: 3, k: 0): 1,
+        Binomial(n: 3, k: 1): 3,
+        Binomial(n: 3, k: 2): 3,
+        Binomial(n: 3, k: 3): 1,
+        Binomial(n: 4, k: 0): 1,
+        Binomial(n: 4, k: 1): 4,
+        Binomial(n: 4, k: 2): 6,
+        Binomial(n: 4, k: 3): 4,
+        Binomial(n: 4, k: 4): 1,
+        Binomial(n: 5, k: 0): 1,
+        Binomial(n: 5, k: 1): 5,
+        Binomial(n: 5, k: 2): 10,
+        Binomial(n: 5, k: 3): 10,
+        Binomial(n: 5, k: 4): 5,
+        Binomial(n: 5, k: 5): 1,
+        Binomial(n: 6, k: 0): 1,
+        Binomial(n: 6, k: 1): 6,
+        Binomial(n: 6, k: 2): 15,
+        Binomial(n: 6, k: 3): 20,
+        Binomial(n: 6, k: 4): 15,
+        Binomial(n: 6, k: 5): 6,
+        Binomial(n: 6, k: 6): 1,
+      };
+      binomialInputsToExpected.forEach((input, value) {
+        expect(binomial(input.n, input.k), value);
+      });
+    });
+  });
+
+  group('factorial', () {
+    test('fails if negative number', () {
+      expect(() => factorial(-1), throwsAssertionError);
+    });
+
+    test('for a specific input gives a correct value', () {
+      final factorialInputsToExpected = {
+        0: 1,
+        1: 1,
+        2: 2,
+        3: 6,
+        4: 24,
+        5: 120,
+        6: 720,
+        7: 5040,
+        8: 40320,
+        9: 362880,
+        10: 3628800,
+        11: 39916800,
+        12: 479001600,
+        13: 6227020800,
+      };
+      factorialInputsToExpected.forEach((input, expected) {
+        expect(factorial(input), expected);
+      });
+    });
+  });
+}

pubspec.lock

@@ -198,6 +198,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.2"
+  geometry:
+    dependency: "direct main"
+    description:
+      path: "packages/geometry"
+      relative: true
+    source: path
+    version: "1.0.0+1"
   glob:
     dependency: transitive
     description:

pubspec.yaml

@@ -17,6 +17,8 @@ dependencies:
   flutter_bloc: ^8.0.1
   flutter_localizations:
     sdk: flutter
+  geometry: 
+    path: packages/geometry
   intl: ^0.17.0
   pinball_theme:
     path: packages/pinball_theme

test/game/components/pathway_test.dart

@@ -0,0 +1,255 @@
+// ignore_for_file: cascade_invocations, prefer_const_constructors
+import 'dart:math' as math;
+import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:flame_test/flame_test.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pinball/game/game.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final flameTester = FlameTester(PinballGame.new);
+
+  group('Pathway', () {
+    const width = 50.0;
+
+    group('straight', () {
+      group('color', () {
+        flameTester.test(
+          'has transparent color by default when no color is specified',
+          (game) async {
+            final pathway = Pathway.straight(
+              position: Vector2.zero(),
+              start: Vector2(10, 10),
+              end: Vector2(20, 20),
+              width: width,
+            );
+            await game.ensureAdd(pathway);
+
+            expect(game.contains(pathway), isTrue);
+            expect(pathway.paint, isNotNull);
+            expect(
+              pathway.paint.color,
+              equals(Color.fromARGB(0, 0, 0, 0)),
+            );
+          },
+        );
+
+        flameTester.test(
+          'has a color when is specified',
+          (game) async {
+            const defaultColor = Colors.blue;
+
+            final pathway = Pathway.straight(
+              color: defaultColor,
+              position: Vector2.zero(),
+              start: Vector2(10, 10),
+              end: Vector2(20, 20),
+              width: width,
+            );
+            await game.ensureAdd(pathway);
+
+            expect(game.contains(pathway), isTrue);
+            expect(pathway.paint, isNotNull);
+            expect(pathway.paint.color.value, equals(defaultColor.value));
+          },
+        );
+      });
+
+      flameTester.test(
+        'loads correctly',
+        (game) async {
+          final pathway = Pathway.straight(
+            position: Vector2.zero(),
+            start: Vector2(10, 10),
+            end: Vector2(20, 20),
+            width: width,
+          );
+          await game.ensureAdd(pathway);
+
+          expect(game.contains(pathway), isTrue);
+        },
+      );
+
+      group('body', () {
+        flameTester.test(
+          'positions correctly',
+          (game) async {
+            final position = Vector2.all(10);
+            final pathway = Pathway.straight(
+              position: position,
+              start: Vector2(10, 10),
+              end: Vector2(20, 20),
+              width: width,
+            );
+            await game.ensureAdd(pathway);
+
+            game.contains(pathway);
+            expect(pathway.body.position, position);
+          },
+        );
+
+        flameTester.test(
+          'is static',
+          (game) async {
+            final pathway = Pathway.straight(
+              position: Vector2.zero(),
+              start: Vector2(10, 10),
+              end: Vector2(20, 20),
+              width: width,
+            );
+            await game.ensureAdd(pathway);
+
+            expect(pathway.body.bodyType, equals(BodyType.static));
+          },
+        );
+      });
+
+      group('fixtures', () {
+        flameTester.test(
+          'has only one ChainShape when singleWall is true',
+          (game) async {
+            final pathway = Pathway.straight(
+              position: Vector2.zero(),
+              start: Vector2(10, 10),
+              end: Vector2(20, 20),
+              width: width,
+              singleWall: true,
+            );
+            await game.ensureAdd(pathway);
+
+            expect(pathway.body.fixtures.length, 1);
+            final fixture = pathway.body.fixtures[0];
+            expect(fixture, isA<Fixture>());
+            expect(fixture.shape.shapeType, equals(ShapeType.chain));
+          },
+        );
+
+        flameTester.test(
+          'has two ChainShape when singleWall is false (default)',
+          (game) async {
+            final pathway = Pathway.straight(
+              position: Vector2.zero(),
+              start: Vector2(10, 10),
+              end: Vector2(20, 20),
+              width: width,
+            );
+            await game.ensureAdd(pathway);
+
+            expect(pathway.body.fixtures.length, 2);
+            for (final fixture in pathway.body.fixtures) {
+              expect(fixture, isA<Fixture>());
+              expect(fixture.shape.shapeType, equals(ShapeType.chain));
+            }
+          },
+        );
+      });
+    });
+
+    group('arc', () {
+      flameTester.test(
+        'loads correctly',
+        (game) async {
+          final pathway = Pathway.arc(
+            position: Vector2.zero(),
+            width: width,
+            radius: 100,
+            angle: math.pi / 2,
+          );
+          await game.ensureAdd(pathway);
+
+          expect(game.contains(pathway), isTrue);
+        },
+      );
+
+      group('body', () {
+        flameTester.test(
+          'positions correctly',
+          (game) async {
+            final position = Vector2.all(10);
+            final pathway = Pathway.arc(
+              position: position,
+              width: width,
+              radius: 100,
+              angle: math.pi / 2,
+            );
+            await game.ensureAdd(pathway);
+
+            game.contains(pathway);
+            expect(pathway.body.position, position);
+          },
+        );
+
+        flameTester.test(
+          'is static',
+          (game) async {
+            final pathway = Pathway.arc(
+              position: Vector2.zero(),
+              width: width,
+              radius: 100,
+              angle: math.pi / 2,
+            );
+            await game.ensureAdd(pathway);
+
+            expect(pathway.body.bodyType, equals(BodyType.static));
+          },
+        );
+      });
+    });
+
+    group('bezier curve', () {
+      final controlPoints = [
+        Vector2(0, 0),
+        Vector2(50, 0),
+        Vector2(0, 50),
+        Vector2(50, 50),
+      ];
+
+      flameTester.test(
+        'loads correctly',
+        (game) async {
+          final pathway = Pathway.bezierCurve(
+            position: Vector2.zero(),
+            controlPoints: controlPoints,
+            width: width,
+          );
+          await game.ensureAdd(pathway);
+
+          expect(game.contains(pathway), isTrue);
+        },
+      );
+
+      group('body', () {
+        flameTester.test(
+          'positions correctly',
+          (game) async {
+            final position = Vector2.all(10);
+            final pathway = Pathway.bezierCurve(
+              position: position,
+              controlPoints: controlPoints,
+              width: width,
+            );
+            await game.ensureAdd(pathway);
+
+            game.contains(pathway);
+            expect(pathway.body.position, position);
+          },
+        );
+
+        flameTester.test(
+          'is static',
+          (game) async {
+            final pathway = Pathway.bezierCurve(
+              position: Vector2.zero(),
+              controlPoints: controlPoints,
+              width: width,
+            );
+            await game.ensureAdd(pathway);
+
+            expect(pathway.body.bodyType, equals(BodyType.static));
+          },
+        );
+      });
+    });
+  });
+}