wxPython 教程（十六） wxPython 俄罗斯方块

转自：http://thisis.yorven.site/blog/index.php/2017/10/12/wxpython-eluosifangkuai/

俄罗斯方块是最受欢迎的电脑游戏之一，它最初是由一个俄罗斯程序员 Alexey Pajitnov 在 1985 年设计编写的。从那以后，各种俄罗斯方块就成了几乎每个电脑必装的游戏。本节讲述 wxPython 俄罗斯方块 游戏的编写。

俄罗斯方块是一种下落方块的拼图游戏。在这个游戏中，我们有 7 个不同的 tetrominoes ：S 形、Z 形、T 形、L 形、线形、反 L 形、正方形。每一个都是由 4 个小方块构成的，它们会从顶端下落，玩家的目标是通过移动和旋转这些形状来使得它们更契合的堆放在最下面。如果有一行被填满，则会消去一行并得到一定分数。直到方块堆积到顶部无法继续下落时，游戏结束。

开发

我们没有需要的图片，因此我们使用 wxPython 提供的绘制 API 来绘制四格拼板。每个电脑游戏背后都有数学模型，这个游戏也不例外。
一些思路：

• 我们使用 wx.Timer 来创建游戏循环
• 绘制四格拼板
• 一个方格一个方格的移动（而非一个像素一个像素）
• 数学上，一个面板即一列数字

下面的例子是一个俄罗斯方块游戏的修改版本，需要安装 PyQt4 相关文件。

#!/usr/bin/python
 
# tetris.py
 
import wx
import random
 
class Tetris(wx.Frame):
     
    def __init__(self, parent, title):
        wx.Frame.__init__(self, parent, title=title, size=(180, 380))
         
        self.initFrame()
     
    def initFrame(self):
 
        self.statusbar = self.CreateStatusBar()
        self.statusbar.SetStatusText('0')
        self.board = Board(self)
        self.board.SetFocus()
        self.board.start()
 
        self.Centre()
        self.Show(True)
        
 
class Board(wx.Panel):
     
    BoardWidth = 10
    BoardHeight = 22
    Speed = 300
    ID_TIMER = 1
 
    def __init__(self, parent):
        wx.Panel.__init__(self, parent)
         
        self.initBoard()
         
    def initBoard(self):    
 
        self.timer = wx.Timer(self, Board.ID_TIMER)
        self.isWaitingAfterLine = False
        self.curPiece = Shape()
        self.nextPiece = Shape()
        self.curX = 0
        self.curY = 0
        self.numLinesRemoved = 0
        self.board = []
 
        self.isStarted = False
        self.isPaused = False
 
        self.Bind(wx.EVT_PAINT, self.OnPaint)
        self.Bind(wx.EVT_KEY_DOWN, self.OnKeyDown)
        self.Bind(wx.EVT_TIMER, self.OnTimer, id=Board.ID_TIMER)
 
        self.clearBoard()
 
    def shapeAt(self, x, y):
         
        return self.board[(y * Board.BoardWidth) + x]
 
    def setShapeAt(self, x, y, shape):
         
        self.board[(y * Board.BoardWidth) + x] = shape
 
    def squareWidth(self):
         
        return self.GetClientSize().GetWidth() / Board.BoardWidth
 
    def squareHeight(self):
         
        return self.GetClientSize().GetHeight() / Board.BoardHeight
 
    def start(self):
         
        if self.isPaused:
            return
 
        self.isStarted = True
        self.isWaitingAfterLine = False
        self.numLinesRemoved = 0
        self.clearBoard()
 
        self.newPiece()
        self.timer.Start(Board.Speed)
 
    def pause(self):
         
        if not self.isStarted:
            return
 
        self.isPaused = not self.isPaused
        statusbar = self.GetParent().statusbar
 
        if self.isPaused:
            self.timer.Stop()
            statusbar.SetStatusText('paused')
        else:
            self.timer.Start(Board.Speed)
            statusbar.SetStatusText(str(self.numLinesRemoved))
 
        self.Refresh()
 
    def clearBoard(self):
         
        for i in range(Board.BoardHeight * Board.BoardWidth):
            self.board.append(Tetrominoes.NoShape)
 
    def OnPaint(self, event):
 
        dc = wx.PaintDC(self)        
 
        size = self.GetClientSize()
        boardTop = size.GetHeight() - 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 != Tetrominoes.NoShape:
                    self.drawSquare(dc,
                        0 + j * self.squareWidth(),
                        boardTop + i * self.squareHeight(), shape)
 
        if self.curPiece.shape() != Tetrominoes.NoShape:
            for i in range(4):
                x = self.curX + self.curPiece.x(i)
                y = self.curY - self.curPiece.y(i)
                self.drawSquare(dc, 0 + x * self.squareWidth(),
                    boardTop + (Board.BoardHeight - y - 1) * self.squareHeight(),
                    self.curPiece.shape())
 
 
    def OnKeyDown(self, event):
         
        if not self.isStarted or self.curPiece.shape() == Tetrominoes.NoShape:
            event.Skip()
            return
 
        keycode = event.GetKeyCode()
 
        if keycode == ord('P') or keycode == ord('p'):
            self.pause()
            return
        if self.isPaused:
            return
        elif keycode == wx.WXK_LEFT:
            self.tryMove(self.curPiece, self.curX - 1, self.curY)
        elif keycode == wx.WXK_RIGHT:
            self.tryMove(self.curPiece, self.curX + 1, self.curY)
        elif keycode == wx.WXK_DOWN:
            self.tryMove(self.curPiece.rotatedRight(), self.curX, self.curY)
        elif keycode == wx.WXK_UP:
            self.tryMove(self.curPiece.rotatedLeft(), self.curX, self.curY)
        elif keycode == wx.WXK_SPACE:
            self.dropDown()
        elif keycode == ord('D') or keycode == ord('d'):
            self.oneLineDown()
        else:
            event.Skip()
 
 
    def OnTimer(self, event):
         
        if event.GetId() == Board.ID_TIMER:
            if self.isWaitingAfterLine:
                self.isWaitingAfterLine = False
                self.newPiece()
            else:
                self.oneLineDown()
        else:
            event.Skip()
 
 
    def dropDown(self):
         
        newY = self.curY
         
        while newY > 0:
            if not self.tryMove(self.curPiece, self.curX, newY - 1):
                break
            newY -= 1
 
        self.pieceDropped()
 
    def oneLineDown(self):
         
        if not self.tryMove(self.curPiece, self.curX, self.curY - 1):
            self.pieceDropped()
             
 
    def pieceDropped(self):
         
        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):
     
        numFullLines = 0
 
        statusbar = self.GetParent().statusbar
 
        rowsToRemove = []
 
        for i in range(Board.BoardHeight):
            n = 0
            for j in range(Board.BoardWidth):
                if not self.shapeAt(j, i) == Tetrominoes.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
                statusbar.SetStatusText(str(self.numLinesRemoved)) 
                self.isWaitingAfterLine = True
                self.curPiece.setShape(Tetrominoes.NoShape)
                self.Refresh()
 
 
    def newPiece(self):
         
        self.curPiece = self.nextPiece
        statusbar = self.GetParent().statusbar
        self.nextPiece.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(Tetrominoes.NoShape)
            self.timer.Stop()
            self.isStarted = False
            statusbar.SetStatusText('Game over')
             
 
    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) != Tetrominoes.NoShape:
                return False
 
        self.curPiece = newPiece
        self.curX = newX
        self.curY = newY
        self.Refresh()
         
        return True
 
 
    def drawSquare(self, dc, x, y, shape):
         
        colors = ['#000000', '#CC6666', '#66CC66', '#6666CC',
                  '#CCCC66', '#CC66CC', '#66CCCC', '#DAAA00']
 
        light = ['#000000', '#F89FAB', '#79FC79', '#7979FC', 
                 '#FCFC79', '#FC79FC', '#79FCFC', '#FCC600']
 
        dark = ['#000000', '#803C3B', '#3B803B', '#3B3B80', 
                 '#80803B', '#803B80', '#3B8080', '#806200']
 
        pen = wx.Pen(light[shape])
        pen.SetCap(wx.CAP_PROJECTING)
        dc.SetPen(pen)
 
        dc.DrawLine(x, y + self.squareHeight() - 1, x, y)
        dc.DrawLine(x, y, x + self.squareWidth() - 1, y)
 
        darkpen = wx.Pen(dark[shape])
        darkpen.SetCap(wx.CAP_PROJECTING)
        dc.SetPen(darkpen)
 
        dc.DrawLine(x + 1, y + self.squareHeight() - 1,
            x + self.squareWidth() - 1, y + self.squareHeight() - 1)
        dc.DrawLine(x + self.squareWidth() - 1, 
        y + self.squareHeight() - 1, x + self.squareWidth() - 1, y + 1)
 
        dc.SetPen(wx.TRANSPARENT_PEN)
        dc.SetBrush(wx.Brush(colors[shape]))
        dc.DrawRectangle(x + 1, y + 1, self.squareWidth() - 2, 
        self.squareHeight() - 2)
 
 
class Tetrominoes(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 = Tetrominoes.NoShape
 
        self.setShape(Tetrominoes.NoShape)
 
    def shape(self):
         
        return self.pieceShape
 
    def setShape(self, 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):
         
        self.setShape(random.randint(1, 7))
 
    def x(self, index):
         
        return self.coords[index][0]
 
    def y(self, index):
         
        return self.coords[index][1]
 
    def setX(self, index, x):
         
        self.coords[index][0] = x
 
    def setY(self, index, y):
         
        self.coords[index][1] = y
 
    def minX(self):
         
        m = self.coords[0][0]
        for i in range(4):
            m = min(m, self.coords[i][0])
 
        return m
 
    def maxX(self):
         
        m = self.coords[0][0]
        for i in range(4):
            m = max(m, self.coords[i][0])
 
        return m
 
    def minY(self):
         
        m = self.coords[0][1]
        for i in range(4):
            m = min(m, self.coords[i][1])
 
        return m
 
    def maxY(self):
         
        m = self.coords[0][1]
         
        for i in range(4):
            m = max(m, self.coords[i][1])
 
        return m
 
    def rotatedLeft(self):
         
        if self.pieceShape == Tetrominoes.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 rotatedRight(self):
         
        if self.pieceShape == Tetrominoes.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
 
 
app = wx.App()
Tetris(None, title='Tetris')
app.MainLoop()

游戏比较简单，所以更好理解。应用启动后便开始游戏，我们可以按 p 键暂停游戏，空格可以让方块理解调入底部，d 键可以多下落一行，可用作加速下落。游戏以恒速运行，未执行加速。分数是消去的行数。

def __init__(self, parent):
    wx.Panel.__init__(self, parent)

对于 Windows 系统的用户，如果无法使用箭头按键，在 panel 构造函数中加入 style=wx.WANTS_CHARS 即可。

...
self.curX = 0
self.curY = 0
self.numLinesRemoved = 0
self.board = []
...

在我们开始游戏循环之前，需要先初始化一些重要的参数。self.bord 参数是一列数字，从 0 到 7。它代表不同的形状的位置以及面板上留有的形状。

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

游戏的绘制分两部分，第一步，我们先绘制所有的形状，或者保留那些掉入底部的形状。所有的方块都被存储在 self.board 的 list 中。我们可以使用 shapeAt() 方法获取。

if self.curPiece.shape() != Tetrominoes.NoShape:
    for i in range(4):
        x = self.curX + self.curPiece.x(i)
        y = self.curY - self.curPiece.y(i)
        self.drawSquare(dc, 0 + x * self.squareWidth(),
            boardTop + (Board.BoardHeight - y - 1) * self.squareHeight(),
            self.curPiece.shape())

下一步是绘制实际下落的部分。

elif keycode == wx.WXK_LEFT:
    self.tryMove(self.curPiece, self.curX - 1, self.curY)

在 OnKeyDown() 方法中我们检查按下的键，如果按的是左键，我们尝试将块想左移动，也有可能无法移动。

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) != Tetrominoes.NoShape:
            return False
 
    self.curPiece = newPiece
    self.curX = newX
    self.curY = newY
    self.Refresh()
     
    return True

在 tryMove() 方法中，我们移动形状。如果形状已经在边缘或者临近有其他形状，则返回 False，否则我们将当前下落的形状移至新的位置，并返回 True。

def OnTimer(self, event):
 
    if event.GetId() == Board.ID_TIMER:
        if self.isWaitingAfterLine:
            self.isWaitingAfterLine = False
            self.newPiece()
        else:
            self.oneLineDown()
    else:
        event.Skip()

在 OnTimer() 函数中，我们或者创建一个新的形状，在之前一个已经落入底部之后，或者我们将下降的形状往下移一格。

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) == Tetrominoes.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))
...

如果形状接触到底部，我们调用 removeFullLines() 方法。首先，我们找到所有的完整行，并去除他们。注意到我们反转了要去除行的顺序，否则将无法正确工作。

def newPiece(self):
 
    self.curPiece = self.nextPiece
    statusbar = self.GetParent().statusbar
    self.nextPiece.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(Tetrominoes.NoShape)
        self.timer.Stop()
        self.isStarted = False
        statusbar.SetStatusText('Game over')

newPiece() 方法可以创建一个随机的块，如果无法进入初始位置，则游戏结束。
Shape 类存储块的信息。

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

我们最开始创建了一个空的坐标列表，这保存了方块的坐标。比如 (0,-1),(0,0),(-1,0),(-1,-1)代表一个旋转的 S 形，下面的图可以解释这一形状。

当我们完成下落方块时，我们将它放置在 self.curX 和 self.curY 的位置，然后我们查看坐标表，并下降 4 个小方块。

以上，即 wxPython 俄罗斯方块 游戏。