Adding a timer feature to your game

Another feature we can incorporate into our game is a timer function. Not all games are 'timed', or some even work in 'real time', but in this case we will add a timer feature to add to the requirements of the 'game over' feature. So ....there are multiple ways, just like in life, that you can meet your end. In our game if the player collides with the enemy it is game over...and now we are going to integrate the timer feature so that even if the player does not collide, but runs out of time - the game is sadly lost! You can set your own parameters for how many points need to be scored within a set time - we will set it to a score of 100 to win the game.

Video Demo

Code

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)

#Stores the required winning score
WINNING_SCORE = 100
#The maximum play time for a round in seconds
PLAY_TIME = 30

#Set the max speed the player can move - changing this value can increase/decrease difficulty
PLAYER_SPEED = 5

#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 timer on the screen, showing the amount of time left to the player
def draw_timer(screen, x, y, time_left):
    font = pygame.font.Font(None, 36) #Choose the font for the text
    text = font.render("Time Left = " + str(time_left), 1, WHITE) #Create the text
    screen.blit(text, (x, y)) #Draw the text on the screen


#Draws the game over box on the screen for when we have collided
#With the AI player or the game runs out of time, we have added message_1 and message_2
#paramaters to the function definition so we can set which message to display to the user
def draw_game_over(screen, message_1, message_2):
    pygame.draw.rect(screen, WHITE, (150, 200, 400, 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(message_1, 1, BLACK) #Create the text for "GAME OVER"
    screen.blit(text, (170, 220)) #Draw the text on the screen
    text = font.render(message_2, 1, BLACK) #Create the text for "You hit the other player"
    screen.blit(text, (170, 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 exit 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

#A boolean variable that stores whether the game has ended due to time running out
game_ended = 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

#Stores the start time of the game in milliseconds
start_time = pygame.time.get_ticks() 
 
# -------- 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 or the game_ended 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 or game_ended):
                #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
                    game_ended = False

                    start_time = pygame.time.get_ticks() #reset the start time
                #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

    #Check if Games time is up (it has been more than 30 seconds from when we started the game)
    if (start_time + (PLAY_TIME * 1000) <= pygame.time.get_ticks()):
        #If the time is up, set the boolean game_ended to True 
        #so we can display the correct game over screen
        game_ended = True 
 
    # 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 and not game_ended:
        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) 
        
        #Calculate how much time is left by subtracting the current time
        #from the start time, and then this value from the maximum allowed time (30 seconds).
        #As these times are stored in milliseconds, we then
        #divide by 1000 to convert to seconds, and convert the result to an integer
        #value so that only whole seconds are shown.
        time_left = pygame.time.get_ticks() - start_time #find out how much time has passed since the start of the game
        time_left = time_left / 1000 #Convert this time from milliseconds to seconds
        time_left = PLAY_TIME - time_left #Find out how much time is remaining by subtracting total time from time thats passed
        time_left = int(time_left) #Convert this value to an integer
        draw_timer(screen, 50, 450, time_left) #Once we have calculated how much time is left, draw the timer

    #Else if the game is over (i.e. because we collided with the ai player)
    #We print the game over screen
    elif game_over:
        draw_game_over(screen, "YOU LOSE, SORRY TRY AGAIN", "You hit the other player!") #draw the game over screen
    #Else if the game has ended because the player has run out of time, we print a different game over
    #screen
    elif game_ended:
        #If the score is >= 100, the player has one the game
        if score >= WINNING_SCORE:
            draw_game_over(screen, "YOU WIN THE GAME!", "Final Score: " + str(score))
        #Otherwise they didn't win, so we draw a you lose screen
        else:
            draw_game_over(screen, "YOU LOSE, SORRY TRY AGAIN", "You didn't score enough points")
    # 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()