Tetrix

The Tetrix example is a Qt version of the classic Tetrix game.

Tetrix main window

The object of the game is to stack pieces dropped from the top of the playing area so that they fill entire rows at the bottom of the playing area.

When a row is filled, all the blocks on that row are removed, the player earns a number of points, and the pieces above are moved down to occupy that row. If more than one row is filled, the blocks on each row are removed, and the player earns extra points.

The Left cursor key moves the current piece one space to the left, the Right cursor key moves it one space to the right, the Up cursor key rotates the piece counter-clockwise by 90 degrees, and the Down cursor key rotates the piece clockwise by 90 degrees.

To avoid waiting for a piece to fall to the bottom of the board, press D to immediately move the piece down by one row, or press the Space key to drop it as close to the bottom of the board as possible.

This example shows how a simple game can be created using only three classes:

  • The TetrixWindow class is used to display the player’s score, number of lives, and information about the next piece to appear.

  • The TetrixBoard class contains the game logic, handles keyboard input, and displays the pieces on the playing area.

  • The TetrixPiece class contains information about each piece.

In this approach, the TetrixBoard class is the most complex class, since it handles the game logic and rendering. One benefit of this is that the TetrixWindow and TetrixPiece classes are very simple and contain only a minimum of code.

"""PySide6 port of the widgets/widgets/tetrix example from Qt v5.x"""

from enum import IntEnum
import random
import sys

from PySide6.QtCore import QBasicTimer, QSize, Qt, Signal, Slot
from PySide6.QtGui import QColor, QPainter
from PySide6.QtWidgets import (QApplication, QFrame, QGridLayout, QLabel,
                               QLCDNumber, QPushButton, QWidget)


class Piece(IntEnum):
    NoShape = 0
    ZShape = 1
    SShape = 2
    LineShape = 3
    TShape = 4
    SquareShape = 5
    LShape = 6
    MirroredLShape = 7


class TetrixWindow(QWidget):
    def __init__(self):
        super().__init__()

        self.board = TetrixBoard()

        next_piece_label = QLabel()
        next_piece_label.setFrameStyle(QFrame.Box | QFrame.Raised)
        next_piece_label.setAlignment(Qt.AlignCenter)
        self.board.set_next_piece_label(next_piece_label)

        score_lcd = QLCDNumber(5)
        score_lcd.setSegmentStyle(QLCDNumber.Filled)
        level_lcd = QLCDNumber(2)
        level_lcd.setSegmentStyle(QLCDNumber.Filled)
        lines_lcd = QLCDNumber(5)
        lines_lcd.setSegmentStyle(QLCDNumber.Filled)

        start_button = QPushButton("&Start")
        start_button.setFocusPolicy(Qt.NoFocus)
        quit_button = QPushButton("&Quit")
        quit_button.setFocusPolicy(Qt.NoFocus)
        pause_button = QPushButton("&Pause")
        pause_button.setFocusPolicy(Qt.NoFocus)

        start_button.clicked.connect(self.board.start)
        pause_button.clicked.connect(self.board.pause)
        quit_button.clicked.connect(qApp.quit)
        self.board.score_changed.connect(score_lcd.display)
        self.board.level_changed.connect(level_lcd.display)
        self.board.lines_removed_changed.connect(lines_lcd.display)

        layout = QGridLayout(self)
        layout.addWidget(self.create_label("NEXT"), 0, 0)
        layout.addWidget(next_piece_label, 1, 0)
        layout.addWidget(self.create_label("LEVEL"), 2, 0)
        layout.addWidget(level_lcd, 3, 0)
        layout.addWidget(start_button, 4, 0)
        layout.addWidget(self.board, 0, 1, 6, 1)
        layout.addWidget(self.create_label("SCORE"), 0, 2)
        layout.addWidget(score_lcd, 1, 2)
        layout.addWidget(self.create_label("LINES REMOVED"), 2, 2)
        layout.addWidget(lines_lcd, 3, 2)
        layout.addWidget(quit_button, 4, 2)
        layout.addWidget(pause_button, 5, 2)

        self.setWindowTitle("Tetrix")
        self.resize(550, 370)

    def create_label(self, text):
        lbl = QLabel(text)
        lbl.setAlignment(Qt.AlignHCenter | Qt.AlignBottom)
        return lbl


class TetrixBoard(QFrame):
    board_width = 10
    board_height = 22

    score_changed = Signal(int)

    level_changed = Signal(int)

    lines_removed_changed = Signal(int)

    def __init__(self, parent=None):
        super().__init__(parent)

        self.timer = QBasicTimer()
        self.nextPieceLabel = None
        self._is_waiting_after_line = False
        self._cur_piece = TetrixPiece()
        self._next_piece = TetrixPiece()
        self._cur_x = 0
        self._cur_y = 0
        self._num_lines_removed = 0
        self._num_pieces_dropped = 0
        self.score = 0
        self.level = 0
        self.board = None

        self.setFrameStyle(QFrame.Panel | QFrame.Sunken)
        self.setFocusPolicy(Qt.StrongFocus)
        self._is_started = False
        self._is_paused = False
        self.clear_board()

        self._next_piece.set_random_shape()

    def shape_at(self, x, y):
        return self.board[(y * TetrixBoard.board_width) + x]

    def set_shape_at(self, x, y, shape):
        self.board[(y * TetrixBoard.board_width) + x] = shape

    def timeout_time(self):
        return 1000 / (1 + self.level)

    def square_width(self):
        return self.contentsRect().width() / TetrixBoard.board_width

    def square_height(self):
        return self.contentsRect().height() / TetrixBoard.board_height

    def set_next_piece_label(self, label):
        self.nextPieceLabel = label

    def sizeHint(self):
        return QSize(TetrixBoard.board_width * 15 + self.frameWidth() * 2,
                TetrixBoard.board_height * 15 + self.frameWidth() * 2)

    def minimum_size_hint(self):
        return QSize(TetrixBoard.board_width * 5 + self.frameWidth() * 2,
                TetrixBoard.board_height * 5 + self.frameWidth() * 2)

    def start(self):
        if self._is_paused:
            return

        self._is_started = True
        self._is_waiting_after_line = False
        self._num_lines_removed = 0
        self._num_pieces_dropped = 0
        self.score = 0
        self.level = 1
        self.clear_board()

        self.lines_removed_changed.emit(self._num_lines_removed)
        self.score_changed.emit(self.score)
        self.level_changed.emit(self.level)

        self.new_piece()
        self.timer.start(self.timeout_time(), self)

    def pause(self):
        if not self._is_started:
            return

        self._is_paused = not self._is_paused
        if self._is_paused:
            self.timer.stop()
        else:
            self.timer.start(self.timeout_time(), self)

        self.update()

    def paintEvent(self, event):
        super(TetrixBoard, self).paintEvent(event)

        painter = QPainter(self)
        rect = self.contentsRect()

        if self._is_paused:
            painter.drawText(rect, Qt.AlignCenter, "Pause")
            return

        board_top = rect.bottom() - TetrixBoard.board_height * self.square_height()

        for i in range(TetrixBoard.board_height):
            for j in range(TetrixBoard.board_width):
                shape = self.shape_at(j, TetrixBoard.board_height - i - 1)
                if shape != Piece.NoShape:
                    self.draw_square(painter,
                            rect.left() + j * self.square_width(),
                            board_top + i * self.square_height(), shape)

        if self._cur_piece.shape() != Piece.NoShape:
            for i in range(4):
                x = self._cur_x + self._cur_piece.x(i)
                y = self._cur_y - self._cur_piece.y(i)
                self.draw_square(painter, rect.left() + x * self.square_width(),
                        board_top + (TetrixBoard.board_height - y - 1) * self.square_height(),
                        self._cur_piece.shape())

    def keyPressEvent(self, event):
        if not self._is_started or self._is_paused or self._cur_piece.shape() == Piece.NoShape:
            super(TetrixBoard, self).keyPressEvent(event)
            return

        key = event.key()
        if key == Qt.Key_Left:
            self.try_move(self._cur_piece, self._cur_x - 1, self._cur_y)
        elif key == Qt.Key_Right:
            self.try_move(self._cur_piece, self._cur_x + 1, self._cur_y)
        elif key == Qt.Key_Down:
            self.try_move(self._cur_piece.rotated_right(), self._cur_x, self._cur_y)
        elif key == Qt.Key_Up:
            self.try_move(self._cur_piece.rotated_left(), self._cur_x, self._cur_y)
        elif key == Qt.Key_Space:
            self.drop_down()
        elif key == Qt.Key_D:
            self.one_line_down()
        else:
            super(TetrixBoard, self).keyPressEvent(event)

    def timerEvent(self, event):
        if event.timerId() == self.timer.timerId():
            if self._is_waiting_after_line:
                self._is_waiting_after_line = False
                self.new_piece()
                self.timer.start(self.timeout_time(), self)
            else:
                self.one_line_down()
        else:
            super(TetrixBoard, self).timerEvent(event)

    def clear_board(self):
        self.board = [Piece.NoShape for i in range(TetrixBoard.board_height * TetrixBoard.board_width)]

    def drop_down(self):
        drop_height = 0
        new_y = self._cur_y
        while new_y > 0:
            if not self.try_move(self._cur_piece, self._cur_x, new_y - 1):
                break
            new_y -= 1
            drop_height += 1

        self.piece_dropped(drop_height)

    def one_line_down(self):
        if not self.try_move(self._cur_piece, self._cur_x, self._cur_y - 1):
            self.piece_dropped(0)

    def piece_dropped(self, dropHeight):
        for i in range(4):
            x = self._cur_x + self._cur_piece.x(i)
            y = self._cur_y - self._cur_piece.y(i)
            self.set_shape_at(x, y, self._cur_piece.shape())

        self._num_pieces_dropped += 1
        if self._num_pieces_dropped % 25 == 0:
            self.level += 1
            self.timer.start(self.timeout_time(), self)
            self.level_changed.emit(self.level)

        self.score += dropHeight + 7
        self.score_changed.emit(self.score)
        self.remove_full_lines()

        if not self._is_waiting_after_line:
            self.new_piece()

    def remove_full_lines(self):
        num_full_lines = 0

        for i in range(TetrixBoard.board_height - 1, -1, -1):
            line_is_full = True

            for j in range(TetrixBoard.board_width):
                if self.shape_at(j, i) == Piece.NoShape:
                    line_is_full = False
                    break

            if line_is_full:
                num_full_lines += 1
                for k in range(TetrixBoard.board_height - 1):
                    for j in range(TetrixBoard.board_width):
                        self.set_shape_at(j, k, self.shape_at(j, k + 1))

                for j in range(TetrixBoard.board_width):
                    self.set_shape_at(j, TetrixBoard.board_height - 1, Piece.NoShape)

        if num_full_lines > 0:
            self._num_lines_removed += num_full_lines
            self.score += 10 * num_full_lines
            self.lines_removed_changed.emit(self._num_lines_removed)
            self.score_changed.emit(self.score)

            self.timer.start(500, self)
            self._is_waiting_after_line = True
            self._cur_piece.setShape(Piece.NoShape)
            self.update()

    def new_piece(self):
        self._cur_piece = self._next_piece
        self._next_piece.set_random_shape()
        self.show_next_piece()
        self._cur_x = TetrixBoard.board_width // 2 + 1
        self._cur_y = TetrixBoard.board_height - 1 + self._cur_piece.min_y()

        if not self.try_move(self._cur_piece, self._cur_x, self._cur_y):
            self._cur_piece.setShape(Piece.NoShape)
            self.timer.stop()
            self._is_started = False

    def show_next_piece(self):
        if self.nextPieceLabel is not None:
            return

        dx = self._next_piece.max_x() - self._next_piece.min_x() + 1
        dy = self._next_piece.max_y() - self._next_piece.min_y() + 1

        pixmap = QPixmap(dx * self.square_width(), dy * self.square_height())
        painter = QPainter(pixmap)
        painter.fillRect(pixmap.rect(), self.nextPieceLabel.palette().background())

        for int in range(4):
            x = self._next_piece.x(i) - self._next_piece.min_x()
            y = self._next_piece.y(i) - self._next_piece.min_y()
            self.draw_square(painter, x * self.square_width(),
                    y * self.square_height(), self._next_piece.shape())

        self.nextPieceLabel.setPixmap(pixmap)

    def try_move(self, newPiece, newX, newY):
        for i in range(4):
            x = newX + newPiece.x(i)
            y = newY - newPiece.y(i)
            if x < 0 or x >= TetrixBoard.board_width or y < 0 or y >= TetrixBoard.board_height:
                return False
            if self.shape_at(x, y) != Piece.NoShape:
                return False

        self._cur_piece = newPiece
        self._cur_x = newX
        self._cur_y = newY
        self.update()
        return True

    def draw_square(self, painter, x, y, shape):
        color_table = [0x000000, 0xCC6666, 0x66CC66, 0x6666CC,
                      0xCCCC66, 0xCC66CC, 0x66CCCC, 0xDAAA00]

        color = QColor(color_table[shape])
        painter.fillRect(x + 1, y + 1, self.square_width() - 2,
                self.square_height() - 2, color)

        painter.setPen(color.lighter())
        painter.drawLine(x, y + self.square_height() - 1, x, y)
        painter.drawLine(x, y, x + self.square_width() - 1, y)

        painter.setPen(color.darker())
        painter.drawLine(x + 1, y + self.square_height() - 1,
                x + self.square_width() - 1, y + self.square_height() - 1)
        painter.drawLine(x + self.square_width() - 1,
                y + self.square_height() - 1, x + self.square_width() - 1, y + 1)


class TetrixPiece(object):
    coords_table = (
        ((0, 0),     (0, 0),     (0, 0),     (0, 0)),
        ((0, -1),    (0, 0),     (-1, 0),    (-1, 1)),
        ((0, -1),    (0, 0),     (1, 0),     (1, 1)),
        ((0, -1),    (0, 0),     (0, 1),     (0, 2)),
        ((-1, 0),    (0, 0),     (1, 0),     (0, 1)),
        ((0, 0),     (1, 0),     (0, 1),     (1, 1)),
        ((-1, -1),   (0, -1),    (0, 0),     (0, 1)),
        ((1, -1),    (0, -1),    (0, 0),     (0, 1))
    )

    def __init__(self):
        self.coords = [[0,0] for _ in range(4)]
        self._piece_shape = Piece.NoShape

        self.set_shape(Piece.NoShape)

    def shape(self):
        return self._piece_shape

    def set_shape(self, shape):
        table = TetrixPiece.coords_table[shape]
        for i in range(4):
            for j in range(2):
                self.coords[i][j] = table[i][j]

        self._piece_shape = shape

    def set_random_shape(self):
        self.set_shape(random.randint(1, 7))

    def x(self, index):
        return self.coords[index][0]

    def y(self, index):
        return self.coords[index][1]

    def set_x(self, index, x):
        self.coords[index][0] = x

    def set_y(self, index, y):
        self.coords[index][1] = y

    def min_x(self):
        m = self.coords[0][0]
        for i in range(4):
            m = min(m, self.coords[i][0])

        return m

    def max_x(self):
        m = self.coords[0][0]
        for i in range(4):
            m = max(m, self.coords[i][0])

        return m

    def min_y(self):
        m = self.coords[0][1]
        for i in range(4):
            m = min(m, self.coords[i][1])

        return m

    def max_y(self):
        m = self.coords[0][1]
        for i in range(4):
            m = max(m, self.coords[i][1])

        return m

    def rotated_left(self):
        if self._piece_shape == Piece.SquareShape:
            return self

        result = TetrixPiece()
        result._piece_shape = self._piece_shape
        for i in range(4):
            result.set_x(i, self.y(i))
            result.set_y(i, -self.x(i))

        return result

    def rotated_right(self):
        if self._piece_shape == Piece.SquareShape:
            return self

        result = TetrixPiece()
        result._piece_shape = self._piece_shape
        for i in range(4):
            result.set_x(i, -self.y(i))
            result.set_y(i, self.x(i))

        return result


if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = TetrixWindow()
    window.show()
    random.seed(None)
    sys.exit(app.exec())