俄罗斯方块游戏
本章实现一个俄罗斯方块游戏。
简介
俄罗斯方块游戏是有史以来最受欢迎的电脑游戏之一。最初的游戏是由俄罗斯程序员 Alexey Pajitnov 在1985年设计并编写的。从那时起，《俄罗斯方块》便以多种形式出现在几乎所有平台上。
俄罗斯方块被称为掉落方块拼图游戏。在这款游戏中，我们有 7 种不同的形状，叫做砖块 (tetrminoes)：S 形、Z 形、T 形、L 形、线形、反向 L 形和方形。每个形状都是由四个正方形组成的。这些形状从顶部掉落。《俄罗斯方块》游戏的目标是移动和旋转形状，尽可能的拼到一起，如果拼成一行，这一行会消失，这样就能得分，直到方块堆叠到顶部，游戏结束。
图示：Tetrominoes
PyQt6 目标是创建应用程序，有些其他的库的目标是创造电脑游戏。尽管如此，PyQt6 和其他库也可以用于创建简单的游戏。
制作一个电脑游戏是提高编程技能的好方法。
开发
因为没有游戏砖块的图片，所以这里使用 PyQt6 编程工具包中的绘图 API 来绘制砖块。每一款电脑游戏的背后都有一个数学模型，俄罗斯方块也是如此。
一些思路：
- 使用
QtCore.QBasicTimer创建游戏循环 - 画出砖块
- 砖块整体旋转或移动 (不是分开操作)
- 数学意义上，游戏面板是个简单的数字列表
代码包含四个类：Tetris，Board，Tetrominoe 和 Shape。Tetris 类设置了游戏。Board 是编写游戏逻辑的地方。Tetrominoe 类包含所有俄罗斯方块的名称，Shape 类包含俄罗斯方块的代码。
python
#!/usr/bin/python
# files: tetris.py
"""
ZetCode PyQt6 tutorial
This is a Tetris game clone.
Author: Jan Bodnar
Website: zetcode.com
"""
import random
import sys
from PyQt6.QtCore import Qt, QBasicTimer, pyqtSignal
from PyQt6.QtGui import QPainter, QColor
from PyQt6.QtWidgets import QMainWindow, QFrame, QApplication
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(180, 380)
self.center()
self.setWindowTitle('Tetris')
self.show()
def center(self):
"""centers the window on the screen"""
qr = self.frameGeometry()
cp = self.screen().availableGeometry().center()
qr.moveCenter(cp)
self.move(qr.topLeft())
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.FocusPolicy.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.Key_P:
self.pause()
return
if self.isPaused:
return
elif key == Qt.Key.Key_Left.value:
self.tryMove(self.curPiece, self.curX - 1, self.curY)
elif key == Qt.Key.Key_Right.value:
self.tryMove(self.curPiece, self.curX + 1, self.curY)
elif key == Qt.Key.Key_Down.value:
self.tryMove(self.curPiece.rotateRight(), self.curX, self.curY)
elif key == Qt.Key.Key_Up.value:
self.tryMove(self.curPiece.rotateLeft(), self.curX, self.curY)
elif key == Qt.Key.Key_Space.value:
self.dropDown()
elif key == Qt.Key.Key_D.value:
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:
NoShape = 0
ZShape = 1
SShape = 2
LineShape = 3
TShape = 4
SquareShape = 5
LShape = 6
MirroredLShape = 7
class Shape:
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
def main():
app = QApplication([])
tetris = Tetris()
sys.exit(app.exec())
if __name__ == '__main__':
main()游戏被简化了一点，这样更容易理解。游戏启动后立即开始。我们可以按 P 键暂停游戏。按空格键，方块会立即掉落到底部。游戏以固定的速度运行，没有任加速度。分数是消除的行数。
python
self.tboard = Board(self)
self.setCentralWidget(self.tboard)实例化 Board 类，并将其设置为应用程序的中心部件。
python
self.statusbar = self.statusBar()
self.tboard.msg2Statusbar[str].connect(self.statusbar.showMessage)这里创建一个状态栏，用于显示消息。我们将显示三种可能的消息：已经删除的行数，暂停消息，或游戏结束消息。msg2Statusbar 是在 Board 类中实现的自定义信号。showMessage 是一个内置方法，用于在状态栏上显示消息。
python
self.tboard.start()初始化游戏。
python
class Board(QFrame):
msg2Statusbar = pyqtSignal(str)
...pyqtSignal 创建了一个自定义信号。想在状态栏上展示信息或者分数，触发 msg2Statusbar 信号即可。
python
BoardWidth = 10
BoardHeight = 22
Speed = 300这些是 Board 的参数。BoardWidth 和 BoardHeight 定义画板的宽高。Speed 是游戏的速度，每 300 毫秒游戏循环进行一次。
python
...
self.curX = 0
self.curY = 0
self.numLinesRemoved = 0
self.board = []
...在 initBoard 方法中，我们初始化一些变量。self.board 是一个从 0 到 7 的数字列表，代表了砖块的各种形状和位置信息。
python
def shapeAt(self, x, y):
"""determines shape at the board position"""
return self.board[(y * Board.BoardWidth) + x]shapeAt 方法决定了形状的位置。
python
def squareWidth(self):
"""returns the width of one square"""
return self.contentsRect().width() // Board.BoardWidth画板可以动态调整大小。squareWidth 计算并返回单个形状的像素宽度。Board.BoardWidth 是画板的大小。
python
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 方法暂停游戏，停止计时并在状态栏上显示一个信息。
python
def paintEvent(self, event):
"""paints all shapes of the game"""
painter = QPainter(self)
rect = self.contentsRect()
...paintEvent 方法内绘制游戏。QPainter 是 PyQt6 里执行底层绘制的方法。
python
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)游戏绘制分为两个步骤。在第一步中，我们画出所有的形状，或者已经落在画板底部的形状。所有的方格都记录在 self.board 的变量列表。可以使用 shapeAt 方法访问该变量。
python
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())第二步画出正在下落的砖块。
python
elif key == Qt.Key.Key_Right.value:
self.tryMove(self.curPiece, self.curX + 1, self.curY)在 keyPressEvent 方法中，我们检查按下的键。如果按下右箭头键，将尝试部件向右移动。说 “尝试” 是因为它可能无法移动。
python
elif key == Qt.Key.Key_Up.value:
self.tryMove(self.curPiece.rotateLeft(), self.curX, self.curY)Up 键向左旋转砖块。
python
elif key == Qt.Key.Key_Space.value:
self.dropDown()Space 键会让砖块直接落到底部。
python
elif key == Qt.Key.Key_D.value:
self.oneLineDown()按下 D 键，则会让砖块加速下落一会。
python
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)在计时器事件中，要么在前一个砖块到底部之后创建一个新的，要么将一个砖块向下移动一行。
python
def clearBoard(self):
"""clears shapes from the board"""
for i in range(Board.BoardHeight * Board.BoardWidth):
self.board.append(Tetrominoe.NoShape)clearBoard 方法用设置 Tetrominoe.NoShape 的方式做到清空画板上的全部砖块。
python
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)
...如果砖块落在底部，就调用 removeFullLines 方法，找出所有完整的一行并删除。将所有行移动到当前整行的位置上，做到删除的效果。注意，我们颠倒了要删除的行的顺序，不然会出现 BUG，在我们的例子中，我们使用了 naive gravity，这意味着不是整行的砖块可能漂浮在空白的间隙之上。
python
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 方法创建随机的砖块，如果创建的砖块不能到达初始位置，游戏结束。
python
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 TruetryMove 方法尝试移动一个砖块，如果砖块在画板或者另外一个砖块的边缘，返回 False。否则就执行移动。
python
class Tetrominoe:
NoShape = 0
ZShape = 1
SShape = 2
LineShape = 3
TShape = 4
SquareShape = 5
LShape = 6
MirroredLShape = 7Tetrominoe 类包含了所有形状的名称，这里也有一个叫 NoShape 的空形状。
Shape 类保存了砖块的信息。
python
class Shape(object):
coordsTable = (
((0, 0), (0, 0), (0, 0), (0, 0)),
((0, -1), (0, 0), (-1, 0), (-1, 1)),
...
)
...coordsTable 元组里包括了所有砖块的组合坐标，可以从这个模板里拼出需要的砖块。
python
self.coords = [[0,0] for i in range(4)]初始化时，创建一个空的坐标列表，用来存储砖块的坐标。
图示：坐标
上面的图能帮助我们更好的理解坐标值的意义。比如，(0, -1), (0, 0), (-1, 0), (-1, -1) 代表了 Z 字形的砖块，图示里就是这个形状。
python
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 resultrotateLeft 方法向左旋转砖块。方形没必要旋转，所以就直接返回当前的对象。当砖块发生旋转时，会产生一个新的对象代表这个旋转后的砖块。
图示：俄罗斯方块