CandyTetris

Tetris built on the SugarCraft stack. SugarCraft runtime, CandySprinkles for the rounded borders and per-piece colours, deterministic 7-bag RNG, ghost piece, hard drop, hold, level-driven gravity ramp, line-clear scoring.

Run it

composer install
./bin/tetris         # Single player mode
./bin/tetris -v      # VS Computer mode
./bin/tetris --vs    # VS Computer mode (long form)

VS Computer Mode

Compete against an AI opponent in split-screen mode. When you clear lines, garbage rows are sent to the computer. When the computer clears lines, garbage rows are sent to you. Last player standing wins!

VS Mode Controls

Key	Action
← / →	Move left / right
↑ / x	Rotate clockwise
z	Rotate counter-cw
↓	Soft drop
Space	Hard drop
p	Pause / resume
q	Quit

The computer opponent uses weighted heuristics (board height, holes, gaps, lines) to make optimal moves.

Controls

Key	Action
← / →	Move left / right
↑ / x	Rotate clockwise
z	Rotate counter-cw
↓	Soft drop
Space	Hard drop
p	Pause / resume
q	Quit

Scoring

Line-clear scoring

Lines cleared	Base points × (level + 1)
1	40
2	100
3	300
4 (Tetris)	1200

Level rises every 10 lines. Gravity speeds up at every level — by level 9 pieces fall every 6 frames, by level 29+ they fall every frame. The frame-rate-agnostic Score::framesPerRow() is what the gravity tick consults.

T-Spin scoring

When a T piece is rotated into a position where two or more of its four diagonal corner cells are already filled (walls count as filled), it scores as a T-Spin:

Type	Base points
T-Spin	400 × (level + 1)
T-Spin Mini	100 × (level + 1)

T-Spin Mini is detected when exactly two front corners are filled (the side the piece entered from).

3-corner rule: A T-Spin is active when the locked T piece's final position differs in rotation from its pre-lock rotation, AND at least two of the four diagonal corner cells around the T are occupied (wall/out-of-bounds = occupied). See Scoring\TSpin::detect().

Back-to-Back (B2B) bonus

Consecutive Tetris clears or full T-Spins (non-mini) carry a 1.5× multiplier on the line-clear base points:

• 4-line Tetris after a prior Tetris → 1200 × 1.5 × (level + 1)
• Full T-Spin after a prior full T-Spin → 400 × 1.5 × (level + 1)

B2B resets when a 1–3 line clear or a T-Spin Mini breaks the streak.

Combo bonus

Consecutive line clears (regardless of type) build a combo counter — each combo step adds combo × 10 × (level + 1) bonus points. The counter resets to 0 on any clean (zero-line) piece placement.

Perfect clear bonus

When all lines are cleared at once and the board becomes completely empty, an additional +5000 × (level + 1) bonus is awarded.

DAS / ARR keyboard timing

Horizontal movement uses Delayed Auto Shift (DAS) and Auto Repeat Rate (ARR) for precise key repeat:

Parameter	Default	Description
DAS delay	167 ms	Time a direction key must be held before auto-repeat begins
ARR interval	50 ms	Interval between repeated actions once DAS threshold is passed

This gives precise single-tap control (release before DAS) and smooth continuous movement (hold past DAS threshold). Defaults can be overridden via Das::create($dasMicroseconds, $arrMicroseconds). See Input\Das.

Architecture

Nine pure-state classes, each individually testable without booting the runtime:

Tetromino    enum   ─►  shape data + colour for each of the 7 pieces
Piece        VO     ─►  Tetromino + rotation + (x, y), with immutable transforms
Board        VO     ─►  10×24 grid (4 hidden rows above), fits/place/clearLines/dropPiece
Bag          ──►    7-bag RNG with peek(); injectable RNG closure for deterministic tests
Score        VO     ─►  points / lines / level + level-driven gravity interval
Game         Model  ─►  SugarCraft Model orchestrating the above + key handling
Computer     ──►    AI opponent with board-evaluation heuristics
VsGame       Model  ─►  VS mode combining two Games with garbage row passing
Renderer     ──►    pure view function from Game to frame string
VsRenderer   ──►    split-screen view for VS mode

Why so split? Because each piece is testable in isolation — line-clear correctness has nothing to do with rotation correctness has nothing to do with score arithmetic. The full test suite is 82 tests, 1669 assertions and runs in ~300 ms; the deterministic RNG injection means even the Game integration tests are reproducible across runs.

Super Rotation System

candy-tetris implements the official Tetris Association Super Rotation System (SRS) — the same system used in modern Tetris games. When a piece rotation would collide with a wall or occupied cell, SRS tries a series of offset candidates before giving up:

Piece type	Offsets tried per rotation
J / L / S / T / Z	5 candidates per transition
I	5 candidates (larger offsets)
O	No kicks (always valid)

The tables are from the official SRS specification. Piece::rotationsWithKicks() returns all candidates in order; the Game loop tests each for board validity and uses the first fit.

// All valid rotated positions (naive + wall-kick offsets)
$candidates = $piece->rotationsWithKicks(+1); // clockwise
foreach ($candidates as $candidate) {
    if ($board->fits($candidate)) {
        $piece = $candidate;
        break;
    }
}

Architecture

Nine pure-state classes + one rotation table, each individually testable without booting the runtime:

Tetromino    enum   ─►  shape data + colour for each of the 7 pieces
Piece        VO     ─►  Tetromino + rotation + (x, y), with immutable transforms
Board        VO     ─►  10×24 grid (4 hidden rows above), fits/place/clearLines/dropPiece
Bag          ──►    7-bag RNG with peek(); injectable RNG closure for deterministic tests
Score        VO     ─►  points / lines / level + level-driven gravity interval
Game         Model  ─►  SugarCraft Model orchestrating the above + key handling
Computer     ──►    AI opponent with board-evaluation heuristics
VsGame       Model  ─►  VS mode combining two Games with garbage row passing
Renderer     ──►    pure view function from Game to frame string
VsRenderer   ──►    split-screen view for VS mode
Rotation/
  SrsKickTable  ──►  official SRS kick-offset tables (J/L/S/T/Z + I piece)