{"id":4088,"date":"2019-11-02T08:19:23","date_gmt":"2019-11-02T07:19:23","guid":{"rendered":"https:\/\/pythonprogramming.altervista.org\/?p=4088"},"modified":"2019-11-02T16:46:11","modified_gmt":"2019-11-02T15:46:11","slug":"python-and-classic-arcade-games-pong","status":"publish","type":"post","link":"https:\/\/pythonprogramming.altervista.org\/python-and-classic-arcade-games-pong\/","title":{"rendered":"Python and classic arcade games: Pong"},"content":{"rendered":"

Let’s start<\/h2>\n

In this post you will find the whole code to make a game with Python, finally. You will find also a live coding video here (go check below).<\/p>\n

Let’s examine the different parts of the code.<\/p>\n

But, first, let’s take a look to the screen of the game:<\/p>\n

\"\"<\/a><\/p>\n

Part 1: Import Pygame<\/h2>\n

You need pygame. I suggest you to use python 3.7 at the moment, because pygame does not works for python 3.8 (we’re at november 2019… it will work soon, so if you read this later, try to make it with 3.8, 3.9 or… 4.0!).<\/p>\n

import pygame<\/pre>\n
Part 2: The global variables<\/h2>\n
Nothing fancy here, just variables for colors and for the positions of:<\/p>\n
    \n
  • player 1 (x1, y1)<\/li>\n
  • player 2 (x2, y2)<\/li>\n
  • the ball (xb, yb)<\/li>\n<\/ul>\n
    This are useful for:<\/p>\n
      \n
    • moving the “sprites”<\/li>\n
    • intercept the collision among ball and sprites<\/li>\n
    • intercept when the ball goes out of the screen<\/li>\n
    • intercept when the ‘bar’ toucht the limit of the screen<\/li>\n<\/ul>\n
      So… they are simple variables, but make the game work.<\/p>\n
      P.S.: there are the 2 variables for the score too and the direction of the ball (left or right, up or down… this are useful for bouncing the ball on the walls or on the sprite bars).<\/p>\n
      BLACK = (0, 0, 0)\r\nRED = (255, 0, 0)\r\nGREEN = (0, 255, 0)\r\n# Coordinates p1, p2 and ball\r\nx1 = 490\r\ny1 = 250\r\nx2 = 0\r\ny2 = 250\r\nxb = 300\r\nyb = 300\r\n\r\ndbo = 'left'\r\ndbv = 'down'\r\n\r\nscorep1 = 0\r\nscorep2 = 0<\/pre>\n
      Part 3: Initialization of pygame and screen<\/h2>\n
      This is for the frame rate and the screen size and the title of the screen (that will have score in it).<\/p>\n
      clock = pygame.time.Clock()\r\nscreen = pygame.display.set_mode((500, 500))\r\npygame.display.set_caption(\"My game\" + \"Score player 1: \" + str(scorep1) + \" - Score player 2: \" + str(scorep2))\r\n\r\npygame.init()<\/pre>\n
      Part 4: Draw the ball… it’s a circle<\/h2>\n
      def ball():\r\n\t\"Draw the ball\"\r\n\tglobal xb, yb\r\n\tpygame.draw.ellipse(screen, GREEN, (xb, yb, 10, 10))<\/pre>\n
      The position of the ball uses global variables that we defined above (part 2).<\/p>\n
      Part 5: draw sprite 1 and 2<\/h2>\n
      def sprite1(x,y):\r\n\t\"Draw Player 1\"\r\n\tpygame.draw.rect(screen, RED, (x, y, 10, 50))\r\n\r\ndef sprite2(x,y):\r\n\t\"Draw Player 2\"\r\n\tpygame.draw.rect(screen, GREEN, (x, y, 10, 50))<\/pre>\n
      This are the bars (a couples of rectangles)<\/p>\n
      Move the ball please<\/h2>\n
      The ball start moving from left and right (going up or down) and if finds a wall it bounces.<\/p>\n
      def move_ball(x,y):\r\n\t\"The ball moves\"\r\n\tglobal xb, yb, dbo, dbv\r\n\tif dbo == \"left\":\r\n\t\txb -= 10\r\n\tif dbv == 'down':\r\n\t\tyb += 10\r\n\t\tif yb > 490:\r\n\t\t\tdbv = 'up'\r\n\tif dbv == 'up':\r\n\t\tyb -= 10\r\n\t\tif yb < 10:\r\n\t\t\tdbv = 'down'\r\n\tif dbo == \"right\":\r\n\t\txb += 10<\/pre>\n
      What if… collision?<\/h2>\n
      If the ball meets a bar bounce back, else… it restart and give score to the player.<\/p>\n
      def collision():\r\n\tglobal x1, y1 # the player 1 x and y (on the right)\r\n\tglobal x2, y2 # the player 2 x and y (on the left)\r\n\tglobal xb, yb # the ball x and y\r\n\tglobal dbo\r\n\tglobal scorep1, scorep2\r\n\tif dbo == \"left\":\r\n\t\tif xb < 10:\r\n\t\t\tif yb >= y2 and  yb < y2 + 50:\r\n\t\t\t\tdbo = \"right\"\r\n\t\t\telse:\r\n\t\t\t\tpygame.draw.ellipse(screen, BLACK, (xb, yb, 10, 10))\r\n\t\t\t\tpygame.display.update()\r\n\t\t\t\txb, yb = 300, 300\r\n\t\t\t\tscorep2 += 10\r\n\t\t\t\tpygame.display.set_caption(\"My game\" + \"Score player 1: \" + str(scorep1) + \" - Score player 2: \" + str(scorep2))\r\n\telse:\r\n\t\tif xb > 480:\r\n\t\t\tif yb >= y1 and  yb < y1 + 50:\r\n\t\t\t\tdbo = \"left\"\t\t\r\n\t\t\telse:\r\n\t\t\t\tpygame.draw.ellipse(screen, BLACK, (xb, yb, 10, 10))\r\n\t\t\t\tpygame.display.update()\r\n\t\t\t\txb, yb = 300, 300\r\n\t\t\t\tscorep1 += 10\r\n\t\t\t\tpygame.display.set_caption(\"My game\" + \"Score player 1: \" + str(scorep1) + \" - Score player 2: \" + str(scorep2))<\/pre>\n
      How to move the bars<\/h2>\n
      The bar moves with a and z and k and m for player 1 and 2 respectively.<\/p>\n
      def move1():\r\n\tglobal y2\r\n\tif y2 <= 450:\r\n\t\tif keys[pygame.K_z]:\r\n\t\t\ty2 += 20\r\n\tif y2 > 0:\r\n\t\tif keys[pygame.K_a]:\r\n\t\t\ty2 -= 20\r\n\r\ndef move2():\r\n\tglobal y1\r\n\tif y1 <= 450:\r\n\t\tif keys[pygame.K_m]:\r\n\t\t\ty1 += 20\r\n\tif y1 > 0:\r\n\t\tif keys[pygame.K_k]:\r\n\t\t\ty1 -= 20<\/pre>\n
      Finally: the loop that makes the game and ball go round<\/h2>\n
      This is the infinite loop that moves the objects, update the screen, looks for collision and ends the game when you press the quit button of the window.<\/p>\n
      loop = 1\r\nwhile loop:\r\n\tkeys = pygame.key.get_pressed()\r\n\tfor event in pygame.event.get():\r\n\t\tif event.type == pygame.QUIT:\r\n\t\t\tloop = 0\r\n\tmove1()\r\n\tmove2()\r\n\tmove_ball(xb, yb)\r\n\tball()\r\n\tsprite1(x1,y1)\r\n\tsprite2(x2,y2)\r\n\tcollision()\r\n\tpygame.display.update()\r\n\tscreen.fill((0, 0, 0))\r\n\tclock.tick(30)\r\n\r\n\r\n\r\npygame.quit()<\/pre>\n
      Now, that we examined the parts of the game, go and watch the video with the live coding. At the end you will find the whole code.<\/p>\n
      The full live coding video about Pong with Python<\/h2>\n
      So, this is the full live coding of the video, made… live. You will find some pauses in the video. The first 35 minutes are without audio. The last part is with audio.<\/p>\n