# The Tetris game in wxPython

The Tetris game is one of the most popular computer games ever created. The original game was designed and programmed by a Russian programmer Alexey Pajitnov in 1985. Since then, Tetris is available on almost every computer platform in lots of variations.

Tetris is called a falling block puzzle game. In this game, we have seven different shapes called tetrominoes: S-shape, Z-shape, T-shape, L-shape, Line-shape, MirroredL-shape, and a Square-shape. Each of these shapes is formed with four squares. The shapes are falling down the board. The object of the Tetris game is to move and rotate the shapes so that they fit as much as possible. If we manage to form a row, the row is destroyed and we score. We play the Tetris game until we top out.

wxPython is a toolkit designed to create applications. There are other libraries which are targeted at creating computer games. Nevertheless, wxPython and other application toolkits can be used to create games.

## The development

We do not have images for our Tetris game, we draw the tetrominoes using the drawing API available in wxPython. Behind every computer game, there is a mathematical model. So it is in Tetris.

Some ideas behind the game:

• We use `wx.Timer` to create a game cycle
• The tetrominoes are drawn
• The shapes move on a square by square basis (not pixel by pixel)
• Mathematically a board is a simple list of numbers
tetris.py
```#!/usr/bin/env python

"""
ZetCode wxPython tutorial

This is Tetris game clone in wxPython.

author: Jan Bodnar
website: www.zetcode.com
"""

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):

self.statusbar = self.CreateStatusBar()
self.statusbar.SetStatusText('0')
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]

def y(self, index):

return self.coords[index]

def setX(self, index, x):

self.coords[index] = x

def setY(self, index, y):

self.coords[index] = y

def minX(self):

m = self.coords
for i in range(4):
m = min(m, self.coords[i])

return m

def maxX(self):

m = self.coords
for i in range(4):
m = max(m, self.coords[i])

return m

def minY(self):

m = self.coords
for i in range(4):
m = min(m, self.coords[i])

return m

def maxY(self):

m = self.coords

for i in range(4):
m = max(m, self.coords[i])

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()
```

The game is simplified a bit so that it is easier to understand. It starts immediately after the application is launched. We can pause the game by pressing the p key. The Space key drops the falling Tetris piece immediately to the bottom. The d key drops the piece one line down. (It can be used to speed up the falling.) The game goes at constant speed, no acceleration is implemented. The score is the number of lines that we have removed.

```def __init__(self, *args, **kw):

super(Board, self).__init__(*args, **kw)
```

A note for Windows users. If you cannot use the arrow keys, add `style=wx.WANTS_CHARS` to the board constructor.

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

Before we start the game cycle, we initialize some important variables. The `self.board` variable is a list of numbers from 0 ... 7. It represents the position of various shapes and remains of the shapes on the board.

```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 painting of the game is divided into two steps. In the first step, we draw all the shapes, or remains of the shapes that have been dropped to the bottom of the board. All the squares are rememberd in the `self.board` list variable. We access it using the `shapeAt()` method.

```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 drawing of the actual piece that is falling down.

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

In the `OnKeyDown()` method we check for pressed keys. If we press the left arrow key, we try to move the piece to the left. We say try because the piece might not be able to move.

```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
```

In the `tryMove()` method we try to move our shapes. If the shape is at the edge of the board or is adjacent to some other piece, we return `False`; otherwise we place the current falling piece to a new position and return `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()
```

In the `OnTimer()` method we either create a new piece, after the previous one was dropped to the bottom, or we move a falling piece one line down.

```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 piece hits the bottom, we call the `removeFullLines()` method. First we find out all full lines and remove them. We do it by moving all lines above the current full line to be removed one line down. Notice that we reverse the order of the lines to be removed. Otherwise, it would not work correctly. In our case we use a naive gravity. This means that the pieces may be floating above empty gaps.

```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')
```

The `newPiece()` method creates randomly a new tetris piece. If the piece cannot go into its initial position, the game is over.

The `Shape` class saves information about the tetris piece.

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

Upon creation we create an empty coordinates list. The list will save the coordinates of the Tetris piece. For example, the tuples (0, -1), (0, 0), (-1, 0), (-1, -1) represent a rotated S-shape. The following diagram illustrates the shape.

When we draw the current falling piece, we draw it at `self.curX` and `self.curY position`. Then we look at the coordinates table and draw all the four squares.