The Tetris game in IronPython
Tetris
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. Even my mobile phone has a modified version of the tetris game.
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.
The development
We do not have images for our tetris game, we draw the tetrominoes using the drawing API available in the Winforms library. Behind every computer game, there is a mathematical model. So it is in tetris.
Some ideas behind the game.
- We use 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
The following example is a modified version of the tetris game, available with PyQt4 installation files.
tetris.py#!/usr/bin/ipy import clr clr.AddReference("System.Windows.Forms") clr.AddReference("System.Drawing") clr.AddReference("System") from System.Windows.Forms import Application, Form, FormBorderStyle from System.Windows.Forms import UserControl, Keys, Timer, StatusBar from System.Drawing import Size, Color, SolidBrush, Pen from System.Drawing.Drawing2D import LineCap from System.ComponentModel import Container from System import Random class Tetrominoes(object): NoShape = 0 ZShape = 1 SShape = 2 LineShape = 3 TShape = 4 SquareShape = 5 LShape = 6 MirroredLShape = 7 class Board(UserControl): BoardWidth = 10 BoardHeight = 22 Speed = 200 ID_TIMER = 1 def __init__(self): self.Text = 'Snake' self.components = Container() self.isWaitingAfterLine = False self.curPiece = Shape() self.nextPiece = Shape() self.curX = 0 self.curY = 0 self.numLinesRemoved = 0 self.board = [] self.DoubleBuffered = True self.isStarted = False self.isPaused = False self.timer = Timer(self.components) self.timer.Enabled = True self.timer.Interval = Board.Speed self.timer.Tick += self.OnTick self.Paint += self.OnPaint self.KeyUp += self.OnKeyUp 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.ClientSize.Width / Board.BoardWidth def SquareHeight(self): return self.ClientSize.Height / Board.BoardHeight def Start(self): if self.isPaused: return self.isStarted = True self.isWaitingAfterLine = False self.numLinesRemoved = 0 self.ClearBoard() self.NewPiece() def Pause(self): if not self.isStarted: return self.isPaused = not self.isPaused statusbar = self.Parent.statusbar if self.isPaused: self.timer.Stop() statusbar.Text = 'paused' else: self.timer.Start() statusbar.Text = 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): g = event.Graphics size = self.ClientSize boardTop = size.Height - 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(g, 0 + j * self.SquareWidth(), boardTop + i * self.SquareHeight(), shape) if self.curPiece.GetShape() != Tetrominoes.NoShape: for i in range(4): x = self.curX + self.curPiece.x(i) y = self.curY - self.curPiece.y(i) self.DrawSquare(g, 0 + x * self.SquareWidth(), boardTop + (Board.BoardHeight - y - 1) * self.SquareHeight(), self.curPiece.GetShape()) g.Dispose() def OnKeyUp(self, event): if not self.isStarted or self.curPiece.GetShape() == Tetrominoes.NoShape: return key = event.KeyCode if key == Keys.P: self.Pause() return if self.isPaused: return elif key == Keys.Left: self.TryMove(self.curPiece, self.curX - 1, self.curY) elif key == Keys.Right: self.TryMove(self.curPiece, self.curX + 1, self.curY) elif key == Keys.Down: self.TryMove(self.curPiece.RotatedRight(), self.curX, self.curY) elif key == Keys.Up: self.TryMove(self.curPiece.RotatedLeft(), self.curX, self.curY) elif key == Keys.Space: self.DropDown() elif key == Keys.D: self.OneLineDown() def OnTick(self, sender, event): if self.isWaitingAfterLine: self.isWaitingAfterLine = False self.NewPiece() else: self.OneLineDown() 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.GetShape()) self.RemoveFullLines() if not self.isWaitingAfterLine: self.NewPiece() def RemoveFullLines(self): numFullLines = 0 statusbar = self.Parent.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.Text = str(self.numLinesRemoved) self.isWaitingAfterLine = True self.curPiece.SetShape(Tetrominoes.NoShape) self.Refresh() def NewPiece(self): self.curPiece = self.nextPiece statusbar = self.Parent.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.Text = '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, g, x, y, shape): colors = [ (0, 0, 0), (204, 102, 102), (102, 204, 102), (102, 102, 204), (204, 204, 102), (204, 102, 204), (102, 204, 204), (218, 170, 0) ] light = [ (0, 0, 0), (248, 159, 171), (121, 252, 121), (121, 121, 252), (252, 252, 121), (252, 121, 252), (121, 252, 252), (252, 198, 0) ] dark = [ (0, 0, 0), (128, 59, 59), (59, 128, 59), (59, 59, 128), (128, 128, 59), (128, 59, 128), (59, 128, 128), (128, 98, 0) ] pen = Pen(Color.FromArgb(light[shape][0], light[shape][1], light[shape][2]), 1) pen.StartCap = LineCap.Flat pen.EndCap = LineCap.Flat g.DrawLine(pen, x, y + self.SquareHeight() - 1, x, y) g.DrawLine(pen, x, y, x + self.SquareWidth() - 1, y) darkpen = Pen(Color.FromArgb(dark[shape][0], dark[shape][1], dark[shape][2]), 1) darkpen.StartCap = LineCap.Flat darkpen.EndCap = LineCap.Flat g.DrawLine(darkpen, x + 1, y + self.SquareHeight() - 1, x + self.SquareWidth() - 1, y + self.SquareHeight() - 1) g.DrawLine(darkpen, x + self.SquareWidth() - 1, y + self.SquareHeight() - 1, x + self.SquareWidth() - 1, y + 1) g.FillRectangle(SolidBrush(Color.FromArgb(colors[shape][0], colors[shape][1], colors[shape][2])), x + 1, y + 1, self.SquareWidth() - 1, self.SquareHeight() - 2) pen.Dispose() darkpen.Dispose() 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 GetShape(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): rand = Random() self.SetShape(rand.Next(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 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 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 class IForm(Form): def __init__(self): self.Text = 'Tetris' self.Width = 200 self.Height = 430 self.FormBorderStyle = FormBorderStyle.FixedSingle board = Board() board.Width = 195 board.Height = 380 self.Controls.Add(board) self.statusbar = StatusBar() self.statusbar.Parent = self self.statusbar.Text = 'Ready' board.Start() self.CenterToScreen() Application.Run(IForm())
I have simplified the game a bit, so that it is easier to understand. The game starts immediately, after it is launched. We can pause the game by pressing the p key. The space key will drop the tetris piece immediately to the bottom. The d key will drop the piece one line down. (It can be used to speed up the falling a bit.) The game goes at constant speed, no acceleration is implemented. The score is the number of lines, that we have removed.
class Tetrominoes(object):
NoShape = 0
ZShape = 1
SShape = 2
LineShape = 3
TShape = 4
SquareShape = 5
LShape = 6
MirroredLShape = 7
There are seven different types of tetrominoes.
... 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 Tetrominoes. It represents the position of various shapes and remains of the shapes on the board.
def ClearBoard(self):
for i in range(Board.BoardHeight * Board.BoardWidth):
self.board.append(Tetrominoes.NoShape)
The ClearBoard() method clears the board. It fills the self.board variable with Tetrominoes.NoShape values.
Painting in the tetris game is done in the OnPaint() method.
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(g,
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. 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(g, 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.
In the OnKeyUp() method we check for pressed keys.
elif key == Keys.Left:
self.tryMove(self.curPiece, self.curX - 1, self.curY)
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.
In the TryMove() method we try to move our shapes. If we cannot move the piece, we return False.
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
If the shape is at the edge of the board or is adjacent to some other piece, we return False.
self.curPiece = newPiece self.curX = newX self.curY = newY self.Refresh() return True
Otherwise we place the current falling piece to a new position and return True.
def OnTick(self, sender, event):
if self.isWaitingAfterLine:
self.isWaitingAfterLine = False
self.NewPiece()
else:
self.OneLineDown()
In the OnTick() method we either create a new piece, after the previous one hit the bottom, or we move a falling piece one line down.
If the piece hits the bottom, we call the RemoveFullLines() method. First we find out all full lines.
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)
We cycle throught the board. A row can have ten pieces of shapes. If the row is full, e.g. n is equal to 10, we store the line number for later removal.
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))
These code lines remove the full lines. We reverse the order of the rowsToRemove list so that we begin with the bottom most full line. What we do is remove a full line by placing all lines about it one line down. This happens for all full lines In our case we use a naive gravity. This means, that the pieces may be lef floating above empty gaps.
def NewPiece(self):
self.curPiece = self.nextPiece
statusbar = self.Parent.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.Text = 'Game over'
The NewPiece() method creates randomly a new tetris piece. If the piece cannot go into it's initial position, e.g. the TryMove() method returns False, the game is over.
colors = [ (0, 0, 0), (204, 102, 102),
... ]
light = [ (0, 0, 0), (248, 159, 171),
... ]
dark = [ (0, 0, 0), (128, 59, 59),
... ]
There are three lists of colors. The colors list stores color values for the fills of the squares. Each of seven pieces has its own color. The light and the dark store colors for lines, that will make the square look 3D. These colors are the same, just are lighter and darker. We will draw two lines with light color to the top and left sides of the squares and two lines with darker color to the right and bottom sides.
g.DrawLine(pen, x, y + self.SquareHeight() - 1, x, y) g.DrawLine(pen, x, y, x + self.SquareWidth() - 1, y)
These two lines draw the light lines for a square.
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, these 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, self.curY position. Then we look at the coordinates table and draw all the four squares.
The RotateLeft() method rotates a piece to the left.
if self.pieceShape == Tetrominoes.SquareShape:
return self
If we have the Tetrominoes.SquareShape piece, we do nothing. This shape is always the same.
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
In other cases, we change coordinates of the piece. To understand this code, look at the above figure.
