## WxPython step 11 (Tetris)

Chen Python 2020-11-16 14:40:43
wxpython step tetris

Tetris is a Russian programmer Alexey Pajitnov  stay 1985 Designed and programmed .

In this game , We have seven different shapes ：S shape ,Z shape ,T shape ,L shape , Linear , The mirror L shape , And a square . Each shape is made up of four small squares . These shapes fall off the chessboard . The object of Tetris is to move and rotate these shapes , Make them fit as much as possible . If we succeed in forming a row , This row will be destroyed , We'll score . We play Tetris , Until we reach the top .

<img src="https://mymarkdowm.oss-cn-beijing.aliyuncs.com/markdownimg/tetrominoes.png" alt="Tetrominoes" style="zoom:50%;" />

wxPython Is a toolkit for creating applications . There are other libraries like pygame It's about creating computer games , but wxPython It can also be used to create games .

### The development process

Our Tetris game has no images , We use wxPython Drawing provided in API Drawing Tetris . Behind every computer game , There's a mathematical model . The same is true in Tetris .

Some basic ideas behind the game .

• use wx.Timer To create a game cycle .
• Draw different shapes
• Shapes move in squares （ Not in pixels ）.
• In Mathematics , A chessboard is a simple list of numbers .
```#tetris_game.py
import wx
import random
class Tetris(wx.Frame):
def __init__(self, parent):
wx.Frame.__init__(self, parent, size=(180, 380),
style=wx.DEFAULT_FRAME_STYLE ^ wx.RESIZE_BORDER ^ wx.MAXIMIZE_BOX)
self.initFrame()
def initFrame(self):
```

`# status bar Show scores self.statusbar = self.CreateStatusBar() self.statusbar.SetStatusText('0') # Lord board self.board = Board(self) self.board.SetFocus() self.board.start() self.SetTitle(" tetris ") self.Centre() class Board(wx.Panel): BoardWidth = 10 BoardHeight = 22 Speed = 300 ID_TIMER = 1 def __init__(self, *args, **kw): super(Board, self).__init__(*args, **kw) 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 def main(): app = wx.App() ex = Tetris(None) ex.Show() app.MainLoop() if __name__ == '__main__': main()`

<img src="https://mymarkdowm.oss-cn-beijing.aliyuncs.com/markdownimg/image-20201115192956845.png" alt="image-20201115192956845" style="zoom:50%;" />

After the application starts , Start immediately . We can do this by pressing p Key to pause the game . The space bar will immediately drop the dropped Tetris to the bottom .d The key will make the chess pieces fall faster . The down button will rotate the shape . The game is played at a constant speed , The score is the number of rows we delete .

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

Before starting the game cycle , Let's initialize some important variables first . `self.board`  A variable is a variable from 0 To 7 A list of numbers . It represents the positions of various shapes and traces of shapes on the chessboard .

```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)
```

The drawing of the game is divided into two steps . First step , We draw all the shapes , Or the shape that falls to the bottom of the chessboard . All the squares are saved in `self.board`  List variables . We use `shapeAt()`  Method to access it .

```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())
```

The next step is to draw the actual work that is left behind .

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

stay OnKeyDown() In the method , We check to see if any buttons are pressed . If you press the left arrow key , Will try to move the pieces to the left .tryMove It's because the pieces may not move ( On the border ).

```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
```

stay `tryMove()`  In the method , We try to move our shapes . If the shape is on the edge of the chessboard or adjacent to other pieces , We go back to "False"; Otherwise, we will put the current falling pieces in a new position and return to "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()
```

stay `OnTimer()`  In the method , We're either after the previous piece has fallen to the bottom , Create a new chessman , Or move the falling pieces down one line .

```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))
...
```

If the shape reaches the bottom , Just call removeFullLines() Method . First, let's find out all the full lines , And delete it . Our approach is to move all rows above the current full row down one line .

`de`
```f 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()`  Method randomly create a new Tetris . If the chessman cannot enter its initial position , The game is over .

`Shape`  Class holds information about Tetris .

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

After creation, we create an empty list of coordinates . The list will hold the coordinates of Tetris . for example , Tuples (0,-1),(0,0),(-1,0),(-1,-1) For a spinning S shape . The figure below shows the shape .

<img src="https://mymarkdowm.oss-cn-beijing.aliyuncs.com/markdownimg/coordinates.png" alt="Coordinates" style="zoom:50%;" />

When drawing the currently dropped pieces , We are `self.curX`  and `self.curY Location `  Draw it . Then we look at the table of coordinates , Draw all four squares .