I suppose it is possible to have a game that goes on ...and on...and on ...and on, but usually most games end, and therefore must have some sort of parameters set up for the player to "lose" or "die" and the game to be over. With that in mind, this code shows you how to add a "Game Over" feature, which is linked to certain requirements being met -in this case collision with the blue (enemy) stickman will result in certain death!
import pygame import random import sys # Define some colors BLACK = (0, 0, 0) WHITE = (255, 255, 255) GREEN = (0, 255, 0) RED = (255, 0, 0) BLUE = (0, 0, 255) #Set the max speed the player can move - changing this value can increase/decrease difficulty PLAYER_SPEED = 15 #set the max speed the AI can move - changing this value can increase/decrease difficulty AI_SPEED = 5 #set the max speed the ball can move - changing this value can increase/decrease difficulty BALL_SPEED = 7 #set the size of the ball - changing this value can increase/decrease difficulty BALL_SIZE = 10 #Draws the game over box on the screen for when we have collided #With the AI player def draw_game_over(screen): pygame.draw.rect(screen, WHITE, (200, 200, 300, 100), 0) #Draw a white box for the text to sit in font = pygame.font.Font(None, 36) #Choose the font for the text text = font.render("Game Over!", 1, BLACK) #Create the text for "GAME OVER" screen.blit(text, (280, 220)) #Draw the text on the screen text = font.render("You hit the other player!", 1, BLACK) #Create the text for "You hit the other player" screen.blit(text, (210, 260)) #Draw the text on the screen font = pygame.font.Font(None, 28) #Make the font a bit smaller for this bit text = font.render("Press P to play again. Press E to quit the game.", 1, WHITE) #Create text for instructions on what to do now screen.blit(text, (100, 350)) #Draw the text on the screen #Create the text used to display the score and draw it on the screen def draw_score(screen, x, y, score): font = pygame.font.Font(None, 36) #Choose the font for the text text = font.render("Score = " + str(score), 1, WHITE) #Create the text screen.blit(text, (x, y)) #Draw the text on the screen #This function draws the ball def draw_ball(screen, x, y): pygame.draw.circle(screen, GREEN, [x, y], BALL_SIZE, 0) background_image = 'background.jpg' #file name of the background image #This function draws the background on the screen #max_x and max_y are the maximum x and y values of the screen def draw_background(screen, file_name): myimage = pygame.image.load(file_name) imagerect = myimage.get_rect() screen.blit(myimage, imagerect) #This function draws the smaller user-controllable stick figure on the screen #Colour and scale paramaters have been added to the stick figure so that different varieties of stick figure #Can be produced whilst using the same function, with the scale being used #to adjust the size of the stick figure, and the colour being used to set the colour of the stick figures body. def draw_stick_figure(screen, x, y, colour, scale): # Draw the Head #Each value is adjusted by the scale paramater to adjust the size of the stick figure #We have to convert this value to an int as scale may be a float, a type that is not #accepted by pygame.draw.ellipse pygame.draw.ellipse(screen, BLACK, [int(1 * scale) + x, y, int(10 * scale), int(10 * scale)], 0) # Legs #Right leg (colour, length of leg....) pygame.draw.line(screen, BLACK, [int(5 * scale) + x, int(17 * scale) + y], [int(10 * scale) + x, int(27 * scale) + y], int(2 * scale)) #Left Leg pygame.draw.line(screen, BLACK, [int(5 * scale) + x, int(17 * scale) + y], [x, int(27 * scale) + y], int(2 * scale)) # Body pygame.draw.line(screen, colour, [int(5 * scale) + x, int(17 * scale) + y], [int(5 * scale) + x, int(7 * scale) + y], int(2 * scale)) # Arms pygame.draw.line(screen, colour, [int(5 * scale) + x, int(7 * scale) + y], [int(9 * scale) + x, int(17 * scale) + y], int(2 * scale)) pygame.draw.line(screen, colour, [int(5 * scale) + x, int(7 * scale) + y], [int(1 * scale) + x, int(17 * scale) + y], int(2 * scale)) #This function ensures that the number entered is between the range of the min and max values (inclusive). #If the number is outside of this range, we return the closest allowed value. I.e. if the max was 10 and the number #entered was 12, 10 would be returned as this is the maximum value allowed def keep_in_range(number, min_no, max_no): if (number < min_no): return min_no elif (number > max_no): return max_no else: return number # Setup pygame.init() # Set the width and height of the screen [width,height] screen_size = [700, 500] screen = pygame.display.set_mode(screen_size) pygame.display.set_caption("My Game") #A boolean variable that stores whever the game is over #Starts off set to False game_over = False # Loop until the user clicks the close button. done = False # Used to manage how fast the screen updates clock = pygame.time.Clock() #Counts the number of times the screen has been redrawn, incremented for every pygame.display.flip() step = 0 #Stores the score of the player score = 0 #Stores the step at which the last score was made #Starts with a value of -100 so we can score on the first step of the game last_score_step = -100 # Hide the mouse cursor pygame.mouse.set_visible(0) # Speed in pixels per frame x_speed = 0 y_speed = 0 # Current position x_coord = 300 y_coord = 1 #AI Players current position ai_x_coord = 300 ai_y_coord = 300 #The AI players last position old_ai_x_coord = 300 old_ai_y_coord = 300 ai_moves = (-AI_SPEED, 0, AI_SPEED) #A list of moves that the ai player can make each turn #stores the current direction the ai character is moving ai_x_direction = 0 ai_y_direction = 0 #Balls current position ball_x_coord = 300 ball_y_coord = 300 old_ball_x_coord = 300 old_ball_y_coord = 300 #Controls the different moves the ball can make, change these values #To change the ball speed ball_moves = (-BALL_SPEED, BALL_SPEED) ball_x_directon = 0 ball_y_direction = 0 # -------- Main Program Loop ----------- while not done: # --- Event Processing for event in pygame.event.get(): if event.type == pygame.QUIT: done = True # User pressed down on a key elif event.type == pygame.KEYDOWN: # Figure out if it was an arrow key. If so # adjust speed. if event.key == pygame.K_LEFT: x_speed = -PLAYER_SPEED elif event.key == pygame.K_RIGHT: x_speed = PLAYER_SPEED elif event.key == pygame.K_UP: y_speed = -PLAYER_SPEED elif event.key == pygame.K_DOWN: y_speed = PLAYER_SPEED #If the game over boolean is true, then we are on the game over screen #Players therefore have multiple options for what to do on these screens if (game_over): #If they press p, they have decided to play again, therefore we reset all the variables #and set game_over to False so the player can try again if event.key == pygame.K_p: score = 0 step = 0 last_score_step = 0 x_coord = 300 y_coord = 1 ai_x_coord = 300 ai_y_coord = 300 game_over = False #If they press e, they have decided to quit, so we exit the game elif event.key == pygame.K_e: sys.exit() #call sys.exit() to close the window and exit the game # User let up on a key elif event.type == pygame.KEYUP: # If it is an arrow key, reset vector back to zero if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT: x_speed = 0 elif event.key == pygame.K_UP or event.key == pygame.K_DOWN: y_speed = 0 # --- Game Logic # Move the object according to the speed vector. x_coord = x_coord + x_speed y_coord = y_coord + y_speed if (x_coord < 0): x_coord = 0 if (y_coord < 0): y_coord = 0 #Adjust the x and y co-ordinates to ensure that the stick figure is kept on the screen and can't #travel off of it x_coord = keep_in_range(x_coord, 0, screen_size[0] - 10) #We adjust the upper limit of our allowed range to match the stick figures width y_coord = keep_in_range(y_coord, 0, screen_size[1] - 27) #We adjust the upper limit of our allowed range to match the stick figures height #MOVE THE AI PLAYER #Every 30 steps (screen draws) we change the direction the ai player is moving in #This makes the movement of the ai player look more realistic. This works because #step % 30 is gives the remained when the value step is divided by 30, which will only #occur every 30 steps. You can experiment with changing this value and seeing how the ai #character moves if (step % 30 == 0): ai_x_direction = random.choice(ai_moves) ai_y_direction = random.choice(ai_moves) #Update the old ai co-ordinate values old_ai_x_coord = ai_x_coord old_ai_y_coord = ai_y_coord #move the ai player in the chosen direction ai_x_coord = ai_x_coord + ai_x_direction ai_y_coord = ai_y_coord + ai_y_direction #Limit the ai character to ensure it stays on the screen ai_x_coord = keep_in_range(ai_x_coord, 0, screen_size[0] - 20) ai_y_coord = keep_in_range(ai_y_coord, 0, screen_size[1] - 54) #If our x co-ordinate has not changed, then we could have collided with a screen edge so we reverse the direction #This helps to keep the movement looking natural by preventing the ai player from repeatedly #moving along the edge of the screen if (ai_x_coord == old_ai_x_coord): ai_x_direction *= -1; #the same is true for the y co-ordinate if (ai_y_coord == old_ai_y_coord): ai_y_direction *= -1; #MOVE THE BALL #Randomly move the ball basically in the same way as the ai player #Every 50 steps update the ball direction with a new random one if (step % 50 == 0): ball_x_direction = random.choice(ball_moves) ball_y_direction = random.choice(ball_moves) #update the old ball coord old_ball_x_coord = ball_x_coord old_ball_y_coord = ball_y_coord #Move the ball in the chosen direction ball_x_coord += ball_x_direction ball_y_coord += ball_y_direction ball_x_coord = keep_in_range(ball_x_coord, 0, screen_size[0]) ball_y_coord = keep_in_range(ball_y_coord, 0, screen_size[1]) #If our x co-ordinate has not changed, then we could have collided with a screen edge so we reverse the direction #This helps to keep the movement looking natural by preventing the ai player from repeatedly #moving along the edge of the screen if (ball_x_coord == old_ball_x_coord): ball_x_direction *= -1; #the same is true for the y co-ordinate if (ball_y_coord == old_ball_y_coord): ball_y_direction *= -1; #Tests if the ball has collided with the player if (ball_x_coord - BALL_SIZE <= x_coord + 5) and (ball_x_coord + BALL_SIZE >= x_coord - 5) and (ball_y_coord - BALL_SIZE <= y_coord + 27) and (ball_y_coord + BALL_SIZE >= y_coord): #Register the score if it is more than 10 steps after the last score #This is necessary as the ball has a habit of double bouncing against the player #Meaning that we register multiple hits with only one true collision if (last_score_step + 10 < step): score += 10; #increment the score #reverse the ball direction ball_x_directon *= -1 ball_y_direction *= -1 last_score_step = step #record the step at which this score is made print(score) #Test if the player has collided with the ai if (x_coord - 5 <= ai_x_coord + 10) and (x_coord + 5 >= ai_x_coord) and (y_coord - 3 <= ai_y_coord + 54) and (y_coord + 27 >= ai_y_coord): print("COLLIDED WITH AI") game_over = True #set the game over boolean to True so we can trigger the end of the game # --- Drawing Code # First, clear the screen to WHITE. Don't put other drawing commands # above this, or they will be erased with this command. screen.fill(WHITE) #erase the previous screen draw_background(screen, background_image) #draw the background #If the game isn't over. we draw the game if not game_over: draw_stick_figure(screen, x_coord, y_coord, RED, 1) #draw the user controlled stick figure on the screen draw_stick_figure(screen, ai_x_coord, ai_y_coord, BLUE, 2) #draw the ai controlled stick figure on the screen draw_ball(screen, ball_x_coord, ball_y_coord) #Draw the score on the screen draw_score(screen, 550, 450, score) #Else if the game is over (i.e. because we collided with the ai player) #We print the game over screen else: draw_game_over(screen) #draw the game over screen # Go ahead and update the screen with what we've drawn. pygame.display.flip() step += 1#increment step # Limit frames per second clock.tick(60) # Close the window and quit. pygame.quit()