俄罗斯方块游戏

本章我们要制作⼀个俄罗斯方块游戏。

Tetris

 译注：称呼：方块是由四个小方格组成的

俄罗斯方块游戏是世界上最流行的游戏之⼀。是由⼀名叫Alexey Pajitnov的俄罗斯程序员在1985年制作的，从那时起，这个游戏就风靡了各个游戏平台。 俄罗斯⽅块归类为下落块迷宫游戏。游戏有7个基本形状：S、Z、T、L、反向L、 直线、⽅块，每个形状都由4个方块组成，方块最终都会落到屏幕底部。所以玩家 通过控制形状的左右位置和旋转，让每个形状都以合适的位置落下，如果有⼀行全部被方块填充，这行就会消失，并且得分。游戏结束的条件是有形状接触到了屏幕 顶部。

方块展示：

PyQt5是专为创建图形界面产⽣的，⾥⾯⼀些专⻔为制作游戏⽽开发的组件，所 以PyQt5是能制作小游戏的。

from PyQt5.QtWidgets import QMainWindow, QFrame, QDesktopWidget, QApplication
from PyQt5.QtCore import Qt, QBasicTimer, pyqtSignal
from PyQt5.QtGui import QPainter, QColor
import sys, random

class Tetris(QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()
    def initUI(self):
# '''initiates application UI'''
        self.tboard = Board(self)
        self.setCentralWidget(self.tboard)
        self.statusbar = self.statusBar()
        self.tboard.msg2Statusbar[str].connect(self.statusbar.showMessage)
        self.tboard.start()
        self.resize(300, 500)
        self.center()
        self.setWindowTitle('Tetris')
        self.show()
    def center(self):
# '''centers the window on the screen'''
        screen = QDesktopWidget().screenGeometry()
        size = self.geometry()
        self.move((screen.width()-size.width())/2, (screen.height()-size.height())/2)
class Board(QFrame):
    msg2Statusbar = pyqtSignal(str)
    BoardWidth = 10
    BoardHeight = 22
    Speed = 300
    def __init__(self, parent):
        super().__init__(parent)
        self.initBoard()
    def initBoard(self):
#  '''initiates board'''
        self.timer = QBasicTimer()
        self.isWaitingAfterLine = False
        self.curX = 0
        self.curY = 0
        self.numLinesRemoved = 0
        self.board = []
        self.setFocusPolicy(Qt.StrongFocus)
        self.isStarted = False
        self.isPaused = False
        self.clearBoard()
    def shapeAt(self, x, y):
# '''determines shape at the board position'''
        return self.board[(y * Board.BoardWidth) + x]
    def setShapeAt(self, x, y, shape):
# '''sets a shape at the board'''
        self.board[(y * Board.BoardWidth) + x] = shape
    def squareWidth(self):
#  '''returns the width of one square'''
        return self.contentsRect().width() // Board.BoardWidth
    def squareHeight(self):
#  '''returns the height of one square'''
        return self.contentsRect().height() // Board.BoardHeight
    def start(self):
# '''starts game'''
        if self.isPaused:
            return
        self.isStarted = True
        self.isWaitingAfterLine = False
        self.numLinesRemoved = 0
        self.clearBoard()
        self.msg2Statusbar.emit(str(self.numLinesRemoved))
        self.newPiece()
        self.timer.start(Board.Speed, self)
    def pause(self):
# '''pauses game'''
        if not self.isStarted:
            return
        self.isPaused = not self.isPaused
        if self.isPaused:
            self.timer.stop()
            self.msg2Statusbar.emit("paused")
        else:
            self.timer.start(Board.Speed, self)
            self.msg2Statusbar.emit(str(self.numLinesRemoved))
        self.update()
    def paintEvent(self, event):
# '''paints all shapes of the game'''
        painter = QPainter(self)
        rect = self.contentsRect()
        boardTop = rect.bottom() - Board.BoardHeight * self.squareHeight()
        for i in range(Board.BoardHeight):
            for j in range(Board.BoardWidth):
                shape = self.shapeAt(j, Board.BoardHeight - i - 1)
                if shape != Tetrominoe.NoShape:
                    self.drawSquare(painter,
                    rect.left() + j * self.squareWidth(),
                    boardTop + i * self.squareHeight(), shape)
        if self.curPiece.shape() != Tetrominoe.NoShape:
            for i in range(4):
                x = self.curX + self.curPiece.x(i)
                y = self.curY - self.curPiece.y(i)
                self.drawSquare(painter, rect.left() + x * self.squareWidth(),
                boardTop + (Board.BoardHeight - y - 1) * self.squareHeight(),
                self.curPiece.shape())
    def keyPressEvent(self, event):
# '''processes key press events'''
        if not self.isStarted or self.curPiece.shape() == Tetrominoe.NoShape:
            super(Board, self).keyPressEvent(event)
            return
        key = event.key()
        if key == Qt.Key_P:
            self.pause()
            return
        if self.isPaused:
            return
        elif key == Qt.Key_Left:
            self.tryMove(self.curPiece, self.curX - 1, self.curY)
        elif key == Qt.Key_Right:
            self.tryMove(self.curPiece, self.curX + 1, self.curY)
        elif key == Qt.Key_Down:
            self.tryMove(self.curPiece.rotateRight(), self.curX, self.curY)
        elif key == Qt.Key_Up:
            self.tryMove(self.curPiece.rotateLeft(), self.curX, self.curY)
        elif key == Qt.Key_Space:
            self.dropDown()
        elif key == Qt.Key_D:
            self.oneLineDown()
        else:
            super(Board, self).keyPressEvent(event)
    def timerEvent(self, event):
# '''handles timer event'''
        if event.timerId() == self.timer.timerId():
            if self.isWaitingAfterLine:
                self.isWaitingAfterLine = False
                self.newPiece()
            else:
                self.oneLineDown()
        else:
            super(Board, self).timerEvent(event)
    def clearBoard(self):
# '''clears shapes from the board'''
        for i in range(Board.BoardHeight * Board.BoardWidth):
            self.board.append(Tetrominoe.NoShape)
    def dropDown(self):
# '''drops down a shape'''
        newY = self.curY
        while newY > 0:
            if not self.tryMove(self.curPiece, self.curX, newY - 1):
                break
        newY -= 1
        self.pieceDropped()
    def oneLineDown(self):
# '''goes one line down with a shape'''
        if not self.tryMove(self.curPiece, self.curX, self.curY - 1):
            self.pieceDropped()
    def pieceDropped(self):
# '''after dropping shape, remove full lines and create new shape'''
        for i in range(4):
            x = self.curX + self.curPiece.x(i)
            y = self.curY - self.curPiece.y(i)
            self.setShapeAt(x, y, self.curPiece.shape())
            self.removeFullLines()
        if not self.isWaitingAfterLine:
            self.newPiece()
    def removeFullLines(self):
# '''removes all full lines from the board'''
        numFullLines = 0
        rowsToRemove = []
        for i in range(Board.BoardHeight):
            n = 0
            for j in range(Board.BoardWidth):
                if not self.shapeAt(j, i) == Tetrominoe.NoShape:
                    n = n + 1
                    if n == 10:
                        rowsToRemove.append(i)
                        rowsToRemove.reverse()
        for m in rowsToRemove:
            for k in range(m, Board.BoardHeight):
                for l in range(Board.BoardWidth):
                    self.setShapeAt(l, k, self.shapeAt(l, k + 1))
        numFullLines = numFullLines + len(rowsToRemove)
        if numFullLines > 0:
            self.numLinesRemoved = self.numLinesRemoved + numFullLines
            self.msg2Statusbar.emit(str(self.numLinesRemoved))
            self.isWaitingAfterLine = True
            self.curPiece.setShape(Tetrominoe.NoShape)
            self.update()
    def newPiece(self):
# '''creates a new shape'''
        self.curPiece = Shape()
        self.curPiece.setRandomShape()
        self.curX = Board.BoardWidth // 2 + 1
        self.curY = Board.BoardHeight - 1 + self.curPiece.minY()
        if not self.tryMove(self.curPiece, self.curX, self.curY):
            self.curPiece.setShape(Tetrominoe.NoShape)
            self.timer.stop()
            self.isStarted = False
            self.msg2Statusbar.emit("Game over")
    def tryMove(self, newPiece, newX, newY):
# '''tries to move a shape'''
        for i in range(4):
            x = newX + newPiece.x(i)
            y = newY - newPiece.y(i)
            if x < 0 or x >= Board.BoardWidth or y < 0 or y >= Board.BoardHeight:
                return False
            if self.shapeAt(x, y) != Tetrominoe.NoShape:
                return False
        self.curPiece = newPiece
        self.curX = newX
        self.curY = newY
        self.update()
        return True
    def drawSquare(self, painter, x, y, shape):
# '''draws a square of a shape'''
        colorTable = [0x000000, 0xCC6666, 0x66CC66, 0x6666CC,
                            0xCCCC66, 0xCC66CC, 0x66CCCC, 0xDAAA00]
        color = QColor(colorTable[shape])
        painter.fillRect(x + 1, y + 1, self.squareWidth() - 2, self.squareHeight() - 2, color)
        painter.setPen(color.lighter())
        painter.drawLine(x, y + self.squareHeight() - 1, x, y)
        painter.drawLine(x, y, x + self.squareWidth() - 1, y)
        painter.setPen(color.darker())
        painter.drawLine(x + 1, y + self.squareHeight() - 1,
            x + self.squareWidth() - 1, y + self.squareHeight() -1)

        painter.drawLine(x + self.squareWidth() - 1,
            y + self.squareHeight() - 1, x + self.squareWidth() - 1, y +1)
class Tetrominoe(object):
    NoShape = 0
    ZShape = 1
    SShape = 2
    LineShape = 3
    TShape = 4
    SquareShape = 5
    LShape = 6
    MirroredLShape = 7
class Shape(object):
    coordsTable = (
 ((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 i in range(4)]
        self.pieceShape = Tetrominoe.NoShape
        self.setShape(Tetrominoe.NoShape)
    def shape(self):
# '''returns shape'''
        return self.pieceShape
    def setShape(self, shape):
# '''sets a shape'''
        table = Shape.coordsTable[shape]
        for i in range(4):
            for j in range(2):
                self.coords[i][j] = table[i][j]
                self.pieceShape = shape
    def setRandomShape(self):
# '''chooses a random shape'''
        self.setShape(random.randint(1, 7))
    def x(self, index):
# '''returns x coordinate'''
        return self.coords[index][0]
    def y(self, index):
# '''returns y coordinate'''
        return self.coords[index][1]
    def setX(self, index, x):
# '''sets x coordinate'''
        self.coords[index][0] = x
    def setY(self, index, y):
# '''sets y coordinate'''
        self.coords[index][1] = y
    def minX(self):
# '''returns min x value'''
        m = self.coords[0][0]
        for i in range(4):
            m = min(m, self.coords[i][0])
        return m
    def maxX(self):
# '''returns max x value'''
        m = self.coords[0][0]
        for i in range(4):
            m = max(m, self.coords[i][0])
        return m
    def minY(self):
# '''returns min y value'''
        m = self.coords[0][1]
        for i in range(4):
            m = min(m, self.coords[i][1])
        return m
    def maxY(self):
# '''returns max y value'''
        m = self.coords[0][1]
        for i in range(4):
            m = max(m, self.coords[i][1])
        return m
    def rotateLeft(self):
# '''rotates shape to the left'''
        if self.pieceShape == Tetrominoe.SquareShape:
            return self
        result = Shape()
        result.pieceShape = self.pieceShape
        for i in range(4):
            result.setX(i, self.y(i))
            result.setY(i, -self.x(i))
        return result
    def rotateRight(self):
# '''rotates shape to the right'''
        if self.pieceShape == Tetrominoe.SquareShape:
            return self
        result = Shape()
        result.pieceShape = self.pieceShape
        for i in range(4):
            result.setX(i, -self.y(i))
            result.setY(i, self.x(i))

        return result
if __name__ == '__main__':
    app = QApplication([])
    tetris = Tetris()
    sys.exit(app.exec_())

游戏很简单，所以也就很好理解。程序加载之后游戏也就直接开始了，可以用P键暂停游戏，空格键让方块直接落到最下面。游戏的速度是固定的，并没有实现加速的功能。分数就是游戏中消除的行数。

        self.tboard = Board(self)

        self.setCentralWidget(self.tboard)

创建了⼀个Board类的实例，并设置为应用的中心组件。

        self.statusbar = self.statusBar()         self.tboard.msg2Statusbar[str].connect(self.statusbar.showMessage

创建⼀个 statusbar 来显示三种信息：消除的行数，游戏暂停状态或者游戏结束状态。 msg2Statusbar 是⼀个自定义的信号，用在（和）Board类（交 互）， showMessage() 方法是⼀个内建的，用来在statusbar上显示信息的方法。

        self.tboard.start()

初始化游戏：

class Board(QFrame):

        msg2Statusbar = pyqtSignal(str)

        ...

创建了⼀个自定义信号 msg2Statusbar ，当我们想往 statusbar 里显示信息的时 候，发出这个信号就行了。

        BoardWidth = 10

        BoardHeight = 22

        Speed = 300

这些是 Board 类的变量。 BoardWidth 和 BoardHeight 分别是board的宽度和高度。 Speed 是游戏的速度，每300ms出现⼀个新的方块。

...

self.curX = 0

self.curY = 0

self.numLinesRemoved = 0

self.board = []

...

在 initBoard()里初始化了⼀些重要的变量。 self.board 定义了方块的形状和位 置，取值范围是0-7。

def shapeAt(self, x, y):

        return self.board[(y * Board.BoardWidth) + x]

shapeAt() 决定了board里方块的的种类。

        def squareWidth(self):

                return self.contentsRect().width() // Board.BoardWidth

board的大小可以动态的改变。所以方格的大小也应该随之变化。 squareWidth() 计算并返回每个块应该占用多少像素--也即 Board.BoardWidth 。

def pause(self):
# '''pauses game'''
        if not self.isStarted:
            return
        self.isPaused = not self.isPaused
        if self.isPaused:
            self.timer.stop()
            self.msg2Statusbar.emit("paused")
        else:
            self.timer.start(Board.Speed, self)
            self.msg2Statusbar.emit(str(self.numLinesRemoved))
        self.update()

pause() 方法⽤来暂停游戏，停止计时并在 statusbar 上显示⼀条信息。

'''

    def paintEvent(self, event):
# '''paints all shapes of the game'''
        painter = QPainter(self)
        rect = self.contentsRect()

'''

渲染是在paintEvent()f 法里发生的 QPainter 负责PyQt5里所有低级绘画操作。 

for i in range(Board.BoardHeight):
    for j in range(Board.BoardWidth):
        shape = self.shapeAt(j, Board.BoardHeight - i - 1)
        if shape != Tetrominoe.NoShape:
            self.drawSquare(painter,
            rect.left() + j * self.squareWidth(),
            boardTop + i * self.squareHeight(), shape)

渲染游戏分为两步。第⼀步是先画出所有已经落在最下面的的图，这些保存 在 self.board ⾥。可以使用 shapeAt() 查看这个这个变量。 

if self.curPiece.shape() != Tetrominoe.NoShape:
    for i in range(4):
        x = self.curX + self.curPiece.x(i)
        y = self.curY - self.curPiece.y(i)
        self.drawSquare(painter, rect.left() + x * self.squareWidth(),
        boardTop + (Board.BoardHeight - y - 1) * self.squareHeight(),
        self.curPiece.shape())

第⼆步是画出更在下落的方块。 

elif key == Qt.Key_Right:

        self.tryMove(self.curPiece, self.curX + 1, self.curY)

在 keyPressEvent() 方法获得用户按下的按键。如果按下的是右方键，就尝试把方块向右移动，说尝试是因为有可能到边界不能移动了。

elif key == Qt.Key_Up:
上⽅向键是把⽅块向左旋转⼀下

elif key == Qt.Key_Space:

        self.dropDown()

空格键会直接把方块放到底部

elif key == Qt.Key_D:

        self.oneLineDown()

D键是加速⼀次下落速度。

def tryMove(self, newPiece, newX, newY):
# '''tries to move a shape'''
        for i in range(4):
            x = newX + newPiece.x(i)
            y = newY - newPiece.y(i)
            if x < 0 or x >= Board.BoardWidth or y < 0 or y >= Board.BoardHeight:
                return False
            if self.shapeAt(x, y) != Tetrominoe.NoShape:
                return False
        self.curPiece = newPiece
        self.curX = newX
        self.curY = newY
        self.update()

tryMove() 是尝试移动方块的方法。如果方块已经到达board的边缘或者遇到了其他方块，就返回False。否则就把方块下落到想要位置。

 def timerEvent(self, event):
# '''handles timer event'''
        if event.timerId() == self.timer.timerId():
            if self.isWaitingAfterLine:
                self.isWaitingAfterLine = False
                self.newPiece()
            else:
                self.oneLineDown()
        else:
            super(Board, self).timerEvent(event)

在计时器事件里，要么是等⼀个方块下落完之后创建⼀个新的方块，要么是让⼀个方块直接落到底（move a falling piece one line down）。

def clearBoard(self):

        for i in range(Board.BoardHeight * Board.BoardWidth):

                self.board.append(Tetrominoe.NoShape)

clearBoard( )方法通过 Tetrominoe.NoShape 清空 broad 。

'''

 def removeFullLines(self):
# '''removes all full lines from the board'''
        numFullLines = 0
        rowsToRemove = []
        for i in range(Board.BoardHeight):
            n = 0
            for j in range(Board.BoardWidth):
                if not self.shapeAt(j, i) == Tetrominoe.NoShape:
                    n = n + 1
                    if n == 10:
                        rowsToRemove.append(i)
                        rowsToRemove.reverse()
        for m in rowsToRemove:
            for k in range(m, Board.BoardHeight):
                for l in range(Board.BoardWidth):
                    self.setShapeAt(l, k, self.shapeAt(l, k + 1))
        numFullLines = numFullLines + len(rowsToRemove)

'''

如果f 块碰到了底部，就调用 removeFullLines() 方法，找到所有能消除的行消除它们。消除的具体动作就是把符合条件的行消除掉之后，再把它上面的行下降⼀行。注意移除满行的动作是倒着来的，因为我们是按照重力来表现游戏的，如果不这样就有可能出现有些方块浮在空中的现象。

def newPiece(self):
# '''creates a new shape'''
        self.curPiece = Shape()
        self.curPiece.setRandomShape()
        self.curX = Board.BoardWidth // 2 + 1
        self.curY = Board.BoardHeight - 1 + self.curPiece.minY()
        if not self.tryMove(self.curPiece, self.curX, self.curY):
            self.curPiece.setShape(Tetrominoe.NoShape)
            self.timer.stop()
            self.isStarted = False
            self.msg2Statusbar.emit("Game over")

newPiece() 方法是用来创建形状随机的方块。如果随机的方块不能正确的出现在预设的位置，游戏结束。

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

Tetrominoe 类保存了所有方块的形状。我们还定义了⼀个 NoShape 的空形状。 Shape类保存类方块内部的信息。

'''

class Shape(object):
    coordsTable = (
 ((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))
 )

'''

coordsTable元组保存了所有的f 块形状的组成。是⼀个构成f 块的坐标模版。

        self.coords = [[0,0] for i in range(4)]

上面创建了⼀个新的空坐标数组，这个数组将来用保存方块的坐标。 坐标系示意图：

上面的图片可以帮助我们更好的理解坐标值的意义。比如元组 (0, -1), (0, 0), (-1, 0), (-1, -1) 代表了⼀个Z形状的方块。这个图表就描绘了这个形状。

def rotateLeft(self):
# '''rotates shape to the left'''
        if self.pieceShape == Tetrominoe.SquareShape:
            return self
        result = Shape()
        result.pieceShape = self.pieceShape
        for i in range(4):
            result.setX(i, self.y(i))
            result.setY(i, -self.x(i))
        return result
    def rotateRight(self):
# '''rotates shape to the right'''
        if self.pieceShape == Tetrominoe.SquareShape:
            return self
        result = Shape()
        result.pieceShape = self.pieceShape
        for i in range(4):
            result.setX(i, -self.y(i))
            result.setY(i, self.x(i))

        return result

rotateLeft()方法向右旋转⼀个方块。正方形的方块就没必要旋转，就直接返回 了。其他的是返回⼀个新的，能表示这个形状旋转了的坐标。

程序展示：