导读：本文我们要制作一个俄罗斯方块游戏。

01 俄罗斯方块 Tetris

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

制作电脑游戏也是提高自己编程能力的一种很好的方式。

02 开发

没有图片，所以就自己用绘画画出来几个图形。每个游戏里都有数学模型的，这个也是。

开工之前：

• 用QtCore.QBasicTimer()QtCore.QBasicTimer()创建一个游戏循环
• 模型是一直下落的
• 模型的运动是以小块为基础单位的，不是按像素
• 从数学意义上来说，模型就是就是一串数字而已

代码由四个类组成：Tetris, Board, Tetrominoe和Shape。Tetris类创建游戏，Board是游戏主要逻辑。Tetrominoe包含了所有的砖块，Shape是所有砖块的代码。

  1#!/usr/bin/python3
  2# -*- coding: utf-8 -*-
  3
  4"""
  5ZetCode PyQt5 tutorial
  6This is a Tetris game clone.
  7
  8Author: Jan Bodnar
  9Website: zetcode.com
 10Last edited: August 2017
 11"""
 12
 13from PyQt5.QtWidgets import QMainWindow, QFrame, QDesktopWidget, QApplication
 14from PyQt5.QtCore import Qt, QBasicTimer, pyqtSignal
 15from PyQt5.QtGui import QPainter, QColor
 16import sys, random
 17
 18class Tetris(QMainWindow):
 19
 20   def __init__(self):
 21       super().__init__()
 22
 23       self.initUI()
 24
 25
 26   def initUI(self):
 27       '''initiates application UI'''
 28
 29       self.tboard = Board(self)
 30       self.setCentralWidget(self.tboard)
 31
 32       self.statusbar = self.statusBar()
 33       self.tboard.msg2Statusbar[str].connect(self.statusbar.showMessage)
 34
 35       self.tboard.start()
 36
 37       self.resize(180, 380)
 38       self.center()
 39       self.setWindowTitle('Tetris')
 40       self.show()
 41
 42
 43   def center(self):
 44       '''centers the window on the screen'''
 45
 46       screen = QDesktopWidget().screenGeometry()
 47       size = self.geometry()
 48       self.move((screen.width()-size.width())/2,
 49           (screen.height()-size.height())/2)
 50
 51
 52class Board(QFrame):
 53
 54   msg2Statusbar = pyqtSignal(str)
 55
 56   BoardWidth = 10
 57   BoardHeight = 22
 58   Speed = 300
 59
 60   def __init__(self, parent):
 61       super().__init__(parent)
 62
 63       self.initBoard()
 64
 65
 66   def initBoard(self):
 67       '''initiates board'''
 68
 69       self.timer = QBasicTimer()
 70       self.isWaitingAfterLine = False
 71
 72       self.curX = 0
 73       self.curY = 0
 74       self.numLinesRemoved = 0
 75       self.board = []
 76
 77       self.setFocusPolicy(Qt.StrongFocus)
 78       self.isStarted = False
 79       self.isPaused = False
 80       self.clearBoard()
 81
 82
 83   def shapeAt(self, x, y):
 84       '''determines shape at the board position'''
 85
 86       return self.board[(y * Board.BoardWidth) + x]
 87
 88
 89   def setShapeAt(self, x, y, shape):
 90       '''sets a shape at the board'''
 91
 92       self.board[(y * Board.BoardWidth) + x] = shape
 93
 94
 95   def squareWidth(self):
 96       '''returns the width of one square'''
 97
 98       return self.contentsRect().width() // Board.BoardWidth
 99
100
101   def squareHeight(self):
102       '''returns the height of one square'''
103
104       return self.contentsRect().height() // Board.BoardHeight
105
106
107   def start(self):
108       '''starts game'''
109
110       if self.isPaused:
111           return
112
113       self.isStarted = True
114       self.isWaitingAfterLine = False
115       self.numLinesRemoved = 0
116       self.clearBoard()
117
118       self.msg2Statusbar.emit(str(self.numLinesRemoved))
119
120       self.newPiece()
121       self.timer.start(Board.Speed, self)
122
123
124   def pause(self):
125       '''pauses game'''
126
127       if not self.isStarted:
128           return
129
130       self.isPaused = not self.isPaused
131
132       if self.isPaused:
133           self.timer.stop()
134           self.msg2Statusbar.emit("paused")
135
136       else:
137           self.timer.start(Board.Speed, self)
138           self.msg2Statusbar.emit(str(self.numLinesRemoved))
139
140       self.update()
141
142
143   def paintEvent(self, event):
144       '''paints all shapes of the game'''
145
146       painter = QPainter(self)
147       rect = self.contentsRect()
148
149       boardTop = rect.bottom() - Board.BoardHeight * self.squareHeight()
150
151       for i in range(Board.BoardHeight):
152           for j in range(Board.BoardWidth):
153               shape = self.shapeAt(j, Board.BoardHeight - i - 1)
154
155               if shape != Tetrominoe.NoShape:
156                   self.drawSquare(painter,
157                       rect.left() + j * self.squareWidth(),
158                       boardTop + i * self.squareHeight(), shape)
159
160       if self.curPiece.shape() != Tetrominoe.NoShape:
161
162           for i in range(4):
163
164               x = self.curX + self.curPiece.x(i)
165               y = self.curY - self.curPiece.y(i)
166               self.drawSquare(painter, rect.left() + x * self.squareWidth(),
167                   boardTop + (Board.BoardHeight - y - 1) * self.squareHeight(),
168                   self.curPiece.shape())
169
170
171   def keyPressEvent(self, event):
172       '''processes key press events'''
173
174       if not self.isStarted or self.curPiece.shape() == Tetrominoe.NoShape:
175           super(Board, self).keyPressEvent(event)
176           return
177
178       key = event.key()
179
180       if key == Qt.Key_P:
181           self.pause()
182           return
183
184       if self.isPaused:
185           return
186
187       elif key == Qt.Key_Left:
188           self.tryMove(self.curPiece, self.curX - 1, self.curY)
189
190       elif key == Qt.Key_Right:
191           self.tryMove(self.curPiece, self.curX + 1, self.curY)
192
193       elif key == Qt.Key_Down:
194           self.tryMove(self.curPiece.rotateRight(), self.curX, self.curY)
195
196       elif key == Qt.Key_Up:
197           self.tryMove(self.curPiece.rotateLeft(), self.curX, self.curY)
198
199       elif key == Qt.Key_Space:
200           self.dropDown()
201
202       elif key == Qt.Key_D:
203           self.oneLineDown()
204
205       else:
206           super(Board, self).keyPressEvent(event)
207
208
209   def timerEvent(self, event):
210       '''handles timer event'''
211
212       if event.timerId() == self.timer.timerId():
213
214           if self.isWaitingAfterLine:
215               self.isWaitingAfterLine = False
216               self.newPiece()
217           else:
218               self.oneLineDown()
219
220       else:
221           super(Board, self).timerEvent(event)
222
223
224   def clearBoard(self):
225       '''clears shapes from the board'''
226
227       for i in range(Board.BoardHeight * Board.BoardWidth):
228           self.board.append(Tetrominoe.NoShape)
229
230
231   def dropDown(self):
232       '''drops down a shape'''
233
234       newY = self.curY
235
236       while newY > 0:
237
238           if not self.tryMove(self.curPiece, self.curX, newY - 1):
239               break
240
241           newY -= 1
242
243       self.pieceDropped()
244
245
246   def oneLineDown(self):
247       '''goes one line down with a shape'''
248
249       if not self.tryMove(self.curPiece, self.curX, self.curY - 1):
250           self.pieceDropped()
251
252
253   def pieceDropped(self):
254       '''after dropping shape, remove full lines and create new shape'''
255
256       for i in range(4):
257
258           x = self.curX + self.curPiece.x(i)
259           y = self.curY - self.curPiece.y(i)
260           self.setShapeAt(x, y, self.curPiece.shape())
261
262       self.removeFullLines()
263
264       if not self.isWaitingAfterLine:
265           self.newPiece()
266
267
268   def removeFullLines(self):
269       '''removes all full lines from the board'''
270
271       numFullLines = 0
272       rowsToRemove = []
273
274       for i in range(Board.BoardHeight):
275
276           n = 0
277           for j in range(Board.BoardWidth):
278               if not self.shapeAt(j, i) == Tetrominoe.NoShape:
279                   n = n + 1
280
281           if n == 10:
282               rowsToRemove.append(i)
283
284       rowsToRemove.reverse()
285
286
287       for m in rowsToRemove:
288
289           for k in range(m, Board.BoardHeight):
290               for l in range(Board.BoardWidth):
291                       self.setShapeAt(l, k, self.shapeAt(l, k + 1))
292
293       numFullLines = numFullLines + len(rowsToRemove)
294
295       if numFullLines > 0:
296
297           self.numLinesRemoved = self.numLinesRemoved + numFullLines
298           self.msg2Statusbar.emit(str(self.numLinesRemoved))
299
300           self.isWaitingAfterLine = True
301           self.curPiece.setShape(Tetrominoe.NoShape)
302           self.update()
303
304
305   def newPiece(self):
306       '''creates a new shape'''
307
308       self.curPiece = Shape()
309       self.curPiece.setRandomShape()
310       self.curX = Board.BoardWidth // 2 + 1
311       self.curY = Board.BoardHeight - 1 + self.curPiece.minY()
312
313       if not self.tryMove(self.curPiece, self.curX, self.curY):
314
315           self.curPiece.setShape(Tetrominoe.NoShape)
316           self.timer.stop()
317           self.isStarted = False
318           self.msg2Statusbar.emit("Game over")
319
320
321
322   def tryMove(self, newPiece, newX, newY):
323       '''tries to move a shape'''
324
325       for i in range(4):
326
327           x = newX + newPiece.x(i)
328           y = newY - newPiece.y(i)
329
330           if x < 0 or x >= Board.BoardWidth or y < 0 or y >= Board.BoardHeight:
331               return False
332
333           if self.shapeAt(x, y) != Tetrominoe.NoShape:
334               return False
335
336       self.curPiece = newPiece
337       self.curX = newX
338       self.curY = newY
339       self.update()
340
341       return True
342
343
344   def drawSquare(self, painter, x, y, shape):
345       '''draws a square of a shape'''
346
347       colorTable = [0x000000, 0xCC6666, 0x66CC66, 0x6666CC,
348                     0xCCCC66, 0xCC66CC, 0x66CCCC, 0xDAAA00]
349
350       color = QColor(colorTable[shape])
351       painter.fillRect(x + 1, y + 1, self.squareWidth() - 2,
352           self.squareHeight() - 2, color)
353
354       painter.setPen(color.lighter())
355       painter.drawLine(x, y + self.squareHeight() - 1, x, y)
356       painter.drawLine(x, y, x + self.squareWidth() - 1, y)
357
358       painter.setPen(color.darker())
359       painter.drawLine(x + 1, y + self.squareHeight() - 1,
360           x + self.squareWidth() - 1, y + self.squareHeight() - 1)
361       painter.drawLine(x + self.squareWidth() - 1,
362           y + self.squareHeight() - 1, x + self.squareWidth() - 1, y + 1)
363
364
365class Tetrominoe(object):
366
367   NoShape = 0
368   ZShape = 1
369   SShape = 2
370   LineShape = 3
371   TShape = 4
372   SquareShape = 5
373   LShape = 6
374   MirroredLShape = 7
375
376
377class Shape(object):
378
379   coordsTable = (
380       ((0, 0),     (0, 0),     (0, 0),     (0, 0)),
381       ((0, -1),    (0, 0),     (-1, 0),    (-1, 1)),
382       ((0, -1),    (0, 0),     (1, 0),     (1, 1)),
383       ((0, -1),    (0, 0),     (0, 1),     (0, 2)),
384       ((-1, 0),    (0, 0),     (1, 0),     (0, 1)),
385       ((0, 0),     (1, 0),     (0, 1),     (1, 1)),
386       ((-1, -1),   (0, -1),    (0, 0),     (0, 1)),
387       ((1, -1),    (0, -1),    (0, 0),     (0, 1))
388   )
389
390   def __init__(self):
391
392       self.coords = [[0,0] for i in range(4)]
393       self.pieceShape = Tetrominoe.NoShape
394
395       self.setShape(Tetrominoe.NoShape)
396
397
398   def shape(self):
399       '''returns shape'''
400
401       return self.pieceShape
402
403
404   def setShape(self, shape):
405       '''sets a shape'''
406
407       table = Shape.coordsTable[shape]
408
409       for i in range(4):
410           for j in range(2):
411               self.coords[i][j] = table[i][j]
412
413       self.pieceShape = shape
414
415
416   def setRandomShape(self):
417       '''chooses a random shape'''
418
419       self.setShape(random.randint(1, 7))
420
421
422   def x(self, index):
423       '''returns x coordinate'''
424
425       return self.coords[index][0]
426
427
428   def y(self, index):
429       '''returns y coordinate'''
430
431       return self.coords[index][1]
432
433
434   def setX(self, index, x):
435       '''sets x coordinate'''
436
437       self.coords[index][0] = x
438
439
440   def setY(self, index, y):
441       '''sets y coordinate'''
442
443       self.coords[index][1] = y
444
445
446   def minX(self):
447       '''returns min x value'''
448
449       m = self.coords[0][0]
450       for i in range(4):
451           m = min(m, self.coords[i][0])
452
453       return m
454
455
456   def maxX(self):
457       '''returns max x value'''
458
459       m = self.coords[0][0]
460       for i in range(4):
461           m = max(m, self.coords[i][0])
462
463       return m
464
465
466   def minY(self):
467       '''returns min y value'''
468
469       m = self.coords[0][1]
470       for i in range(4):
471           m = min(m, self.coords[i][1])
472
473       return m
474
475
476   def maxY(self):
477       '''returns max y value'''
478
479       m = self.coords[0][1]
480       for i in range(4):
481           m = max(m, self.coords[i][1])
482
483       return m
484
485
486   def rotateLeft(self):
487       '''rotates shape to the left'''
488
489       if self.pieceShape == Tetrominoe.SquareShape:
490           return self
491
492       result = Shape()
493       result.pieceShape = self.pieceShape
494
495       for i in range(4):
496
497           result.setX(i, self.y(i))
498           result.setY(i, -self.x(i))
499
500       return result
501
502
503   def rotateRight(self):
504       '''rotates shape to the right'''
505
506       if self.pieceShape == Tetrominoe.SquareShape:
507           return self
508
509       result = Shape()
510       result.pieceShape = self.pieceShape
511
512       for i in range(4):
513
514           result.setX(i, -self.y(i))
515           result.setY(i, self.x(i))
516
517       return result
518
519
520if __name__ == '__main__':
521
522   app = QApplication([])
523   tetris = Tetris()
524   sys.exit(app.exec_())

(代码可以左右滑动)

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()方法里发生的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。如果按下的是右方向键，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:
   self.tryMove(self.curPiece.rotateLeft(), self.curX, self.curY)

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):

   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

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

def timerEvent(self, 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):

   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)
...

如果方块碰到了底部，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):

   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)),
       ...
   )
...    

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

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

上面创建了一个新的空坐标数组，这个数组将用来保存方块的坐标。

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):

   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：