Add pure-Dart engine core: RNG, grid, placement, line clear, scoring, piece generator

PCG32 seeded RNG; immutable 8x8 GridState with occupancy bitmask;
placement legality + anyPlacementExists; simultaneous row/col clears
with single-count gem credit; combo scoring with one-move grace;
weighted-bag generator with pity bias and depth-3 solvability nudge.
All TDD, 51 tests green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
2026-06-11 13:05:55 +09:00
parent 40528238b2
commit 0210c14858
19 changed files with 1408 additions and 0 deletions
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import 'package:block_seasons/game/engine/line_clear.dart';
import 'package:block_seasons/game/models/cell.dart';
import 'package:block_seasons/game/models/grid.dart';
import 'package:flutter_test/flutter_test.dart';
GridState _fillRow(GridState grid, int y, {Set<int>? skip}) {
for (var x = 0; x < GridState.size; x++) {
if (skip?.contains(x) ?? false) continue;
grid = grid.withCell(x, y, const Cell(CellType.filled, colorId: 0));
}
return grid;
}
GridState _fillCol(GridState grid, int x, {Set<int>? skip}) {
for (var y = 0; y < GridState.size; y++) {
if (skip?.contains(y) ?? false) continue;
grid = grid.withCell(x, y, const Cell(CellType.filled, colorId: 0));
}
return grid;
}
void main() {
group('detectAndClear', () {
test('no full lines leaves the grid untouched', () {
final grid = _fillRow(GridState.empty(), 3, skip: {5});
final result = detectAndClear(grid);
expect(result.clearedRows, isEmpty);
expect(result.clearedCols, isEmpty);
expect(result.linesCleared, 0);
expect(result.gemsCleared, 0);
expect(result.grid.occupiedCount, grid.occupiedCount);
});
test('clears a single full row', () {
final grid = _fillRow(GridState.empty(), 2);
final result = detectAndClear(grid);
expect(result.clearedRows, [2]);
expect(result.clearedCols, isEmpty);
expect(result.linesCleared, 1);
expect(result.grid.occupiedCount, 0);
});
test('clears a single full column', () {
final grid = _fillCol(GridState.empty(), 6);
final result = detectAndClear(grid);
expect(result.clearedRows, isEmpty);
expect(result.clearedCols, [6]);
expect(result.grid.occupiedCount, 0);
});
test('clears two rows at once', () {
var grid = _fillRow(GridState.empty(), 0);
grid = _fillRow(grid, 7);
final result = detectAndClear(grid);
expect(result.clearedRows, [0, 7]);
expect(result.linesCleared, 2);
expect(result.grid.occupiedCount, 0);
});
test('row and column sharing a corner clear together', () {
var grid = _fillRow(GridState.empty(), 4);
grid = _fillCol(grid, 4);
final result = detectAndClear(grid);
expect(result.clearedRows, [4]);
expect(result.clearedCols, [4]);
expect(result.linesCleared, 2);
// 8 + 8 - 1 shared cell were occupied; all gone now.
expect(result.grid.occupiedCount, 0);
});
test('counts gems in cleared lines, intersection gem only once', () {
var grid = GridState.empty();
grid = grid.withCell(4, 4, const Cell(CellType.gem));
grid = grid.withCell(0, 4, const Cell(CellType.gem));
grid = grid.withCell(4, 0, const Cell(CellType.gem));
grid = _fillRow(grid, 4, skip: {0, 4});
grid = _fillCol(grid, 4, skip: {0, 4});
final result = detectAndClear(grid);
expect(result.clearedRows, [4]);
expect(result.clearedCols, [4]);
// Gems at (0,4), (4,0), and the shared (4,4) -> exactly 3.
expect(result.gemsCleared, 3);
});
test('cells outside cleared lines survive', () {
var grid = _fillRow(GridState.empty(), 1);
grid = grid.withCell(3, 5, const Cell(CellType.filled, colorId: 2));
final result = detectAndClear(grid);
expect(result.grid.occupiedCount, 1);
expect(result.grid.cellAt(3, 5).colorId, 2);
});
});
}
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import 'package:block_seasons/core/rng.dart';
import 'package:block_seasons/game/engine/piece_generator.dart';
import 'package:block_seasons/game/models/cell.dart';
import 'package:block_seasons/game/models/grid.dart';
import 'package:block_seasons/game/models/piece_library.dart';
import 'package:flutter_test/flutter_test.dart';
/// Checkerboard: no line can ever be completed, big shapes never fit.
GridState _checkerboard() {
var grid = GridState.empty();
for (var y = 0; y < GridState.size; y++) {
for (var x = 0; x < GridState.size; x++) {
if ((x + y).isEven) {
grid = grid.withCell(x, y, const Cell(CellType.filled, colorId: 0));
}
}
}
return grid;
}
/// Rows 1..7 filled except column 0; row 0 filled except (0,0).
/// Only column 0 is free -> tight but recoverable via line clears.
GridState _tightBoard() {
var grid = GridState.empty();
for (var y = 0; y < GridState.size; y++) {
for (var x = 1; x < GridState.size; x++) {
grid = grid.withCell(x, y, const Cell(CellType.filled, colorId: 0));
}
}
return grid;
}
void main() {
group('isTrayPlayable', () {
test('any tray plays out on an empty grid', () {
final tray = [
PieceLibrary.byId('square3'),
PieceLibrary.byId('line5_h'),
PieceLibrary.byId('rect3x2'),
];
expect(isTrayPlayable(GridState.empty(), tray), isTrue);
});
test('recognizes trays that need intermediate line clears', () {
// Column 0 free (8 cells); tray sums to 9 cells, so it only plays out
// if placements trigger clears that open space.
final tray = [
PieceLibrary.byId('line4_v'),
PieceLibrary.byId('line4_v'),
PieceLibrary.byId('mono'),
];
expect(isTrayPlayable(_tightBoard(), tray), isTrue);
});
test('returns false when no ordering can play all pieces', () {
final tray = [
PieceLibrary.byId('square3'),
PieceLibrary.byId('square3'),
PieceLibrary.byId('line5_h'),
];
expect(isTrayPlayable(_checkerboard(), tray), isFalse);
});
});
group('PieceGenerator', () {
test('same seed produces identical tray sequences', () {
final a = PieceGenerator(SeededRng(42));
final b = PieceGenerator(SeededRng(42));
final grid = GridState.empty();
for (var i = 0; i < 100; i++) {
final trayA = a.nextTray(grid).map((p) => p.id).toList();
final trayB = b.nextTray(grid).map((p) => p.id).toList();
expect(trayA, trayB);
}
});
test('trays always contain exactly 3 pieces with distinct ids', () {
final gen = PieceGenerator(SeededRng(7));
final grids = [GridState.empty(), _checkerboard(), _tightBoard()];
for (final grid in grids) {
for (var i = 0; i < 200; i++) {
final tray = gen.nextTray(grid);
expect(tray.length, 3);
expect(tray.map((p) => p.id).toSet().length, 3);
}
}
});
test('pity bias: tighter boards get smaller pieces on average', () {
final emptyGen = PieceGenerator(SeededRng(123));
final tightGen = PieceGenerator(SeededRng(123));
final empty = GridState.empty();
final tight = _checkerboard(); // 50% fill, no clears possible
double meanSize(PieceGenerator gen, GridState grid) {
var total = 0;
for (var i = 0; i < 400; i++) {
for (final p in gen.nextTray(grid)) {
total += p.size;
}
}
return total / (400 * 3);
}
final emptyMean = meanSize(emptyGen, empty);
final tightMean = meanSize(tightGen, tight);
expect(tightMean, lessThan(emptyMean));
});
test('nudge: tight-but-recoverable boards always get playable trays',
() {
final gen = PieceGenerator(SeededRng(2026));
final grid = _tightBoard();
for (var i = 0; i < 100; i++) {
final tray = gen.nextTray(grid);
expect(isTrayPlayable(grid, tray), isTrue,
reason: 'deal #$i: ${tray.map((p) => p.id).join(", ")}');
}
});
test('on a dead board the tray still contains the smallest pieces', () {
// Fully occupied: nothing fits; engine handles game over, but the
// generator must not loop forever and should fall back to small pieces.
var grid = GridState.empty();
for (var y = 0; y < GridState.size; y++) {
for (var x = 0; x < GridState.size; x++) {
grid = grid.withCell(x, y, const Cell(CellType.filled, colorId: 0));
}
}
final tray = PieceGenerator(SeededRng(5)).nextTray(grid);
expect(tray.length, 3);
expect(tray.every((p) => p.size <= 2), isTrue);
});
});
}
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import 'package:block_seasons/game/engine/placement.dart';
import 'package:block_seasons/game/models/cell.dart';
import 'package:block_seasons/game/models/grid.dart';
import 'package:block_seasons/game/models/piece.dart';
import 'package:flutter_test/flutter_test.dart';
const mono = Piece(id: 'mono', colorId: 0, offsets: [(0, 0)]);
const dominoH = Piece(id: 'domino_h', colorId: 1, offsets: [(0, 0), (1, 0)]);
const square2 = Piece(
id: 'square2',
colorId: 2,
offsets: [(0, 0), (1, 0), (0, 1), (1, 1)],
);
void main() {
group('canPlace', () {
test('any piece fits anywhere legal on an empty grid', () {
final grid = GridState.empty();
expect(canPlace(grid, mono, 0, 0), isTrue);
expect(canPlace(grid, mono, 7, 7), isTrue);
expect(canPlace(grid, square2, 6, 6), isTrue);
});
test('rejects out-of-bounds placements', () {
final grid = GridState.empty();
expect(canPlace(grid, square2, 7, 7), isFalse);
expect(canPlace(grid, dominoH, 7, 0), isFalse);
expect(canPlace(grid, mono, -1, 0), isFalse);
expect(canPlace(grid, mono, 0, 8), isFalse);
});
test('rejects overlap with occupied cells', () {
final grid = GridState.empty()
.withCell(1, 0, const Cell(CellType.filled, colorId: 0));
expect(canPlace(grid, dominoH, 0, 0), isFalse);
expect(canPlace(grid, dominoH, 2, 0), isTrue);
});
});
group('place', () {
test('fills cells with the piece color and keeps original grid', () {
final grid = GridState.empty();
final next = place(grid, square2, 3, 3);
expect(grid.occupiedCount, 0);
expect(next.occupiedCount, 4);
for (final (dx, dy) in square2.offsets) {
expect(next.cellAt(3 + dx, 3 + dy).type, CellType.filled);
expect(next.cellAt(3 + dx, 3 + dy).colorId, square2.colorId);
}
});
});
group('anyPlacementExists', () {
test('true on an empty grid', () {
expect(anyPlacementExists(GridState.empty(), [square2]), isTrue);
});
test('detects when only a small piece fits', () {
// Fill everything except (7, 7).
var grid = GridState.empty();
for (var y = 0; y < GridState.size; y++) {
for (var x = 0; x < GridState.size; x++) {
if (x == 7 && y == 7) continue;
grid = grid.withCell(x, y, const Cell(CellType.filled, colorId: 0));
}
}
expect(anyPlacementExists(grid, [mono]), isTrue);
expect(anyPlacementExists(grid, [dominoH]), isFalse);
expect(anyPlacementExists(grid, [dominoH, mono]), isTrue);
});
test('false when the grid is completely full', () {
var grid = GridState.empty();
for (var y = 0; y < GridState.size; y++) {
for (var x = 0; x < GridState.size; x++) {
grid = grid.withCell(x, y, const Cell(CellType.filled, colorId: 0));
}
}
expect(anyPlacementExists(grid, [mono]), isFalse);
});
});
}
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import 'package:block_seasons/game/engine/scoring.dart';
import 'package:flutter_test/flutter_test.dart';
void main() {
group('lineClearBase', () {
test('escalates with simultaneous lines', () {
expect(lineClearBase(1), 100);
expect(lineClearBase(2), 300);
expect(lineClearBase(3), 600);
expect(lineClearBase(4), 1000);
});
});
group('comboMultiplier', () {
test('grows by 0.5 per streak step and caps at 8', () {
expect(comboMultiplier(1), 1.5);
expect(comboMultiplier(2), 2.0);
expect(comboMultiplier(8), 5.0);
expect(comboMultiplier(12), 5.0);
});
});
group('ComboState', () {
test('clearing placements grow the streak', () {
var combo = ComboState.initial;
combo = combo.advance(cleared: true);
expect(combo.streak, 1);
combo = combo.advance(cleared: true);
expect(combo.streak, 2);
});
test('one dry move is grace, streak survives', () {
var combo = ComboState.initial;
combo = combo.advance(cleared: true);
combo = combo.advance(cleared: false);
expect(combo.streak, 1);
combo = combo.advance(cleared: true);
expect(combo.streak, 2);
});
test('two consecutive dry moves reset the streak', () {
var combo = ComboState.initial;
combo = combo.advance(cleared: true);
combo = combo.advance(cleared: false);
combo = combo.advance(cleared: false);
expect(combo.streak, 0);
combo = combo.advance(cleared: true);
expect(combo.streak, 1);
});
});
group('scorePlacement', () {
test('placement without clear scores cell count only', () {
final delta = scorePlacement(
cellsPlaced: 4,
linesCleared: 0,
combo: ComboState.initial,
);
expect(delta.points, 4);
expect(delta.combo.streak, 0);
});
test('first clear applies x1.5 multiplier', () {
final delta = scorePlacement(
cellsPlaced: 5,
linesCleared: 1,
combo: ComboState.initial,
);
// 5 + round(100 * 1.5) = 155
expect(delta.points, 155);
expect(delta.combo.streak, 1);
});
test('streak compounds across placements', () {
var combo = ComboState.initial;
final first = scorePlacement(
cellsPlaced: 3,
linesCleared: 1,
combo: combo,
);
combo = first.combo;
final second = scorePlacement(
cellsPlaced: 3,
linesCleared: 2,
combo: combo,
);
// 3 + round(300 * 2.0) = 603
expect(second.points, 603);
expect(second.combo.streak, 2);
});
});
}