Coursera——Mini-project description - Pong

Coursera——Mini-project description - Pong

链接这里：https://www.coursera.org/learn/interactive-python-1/supplement/wiv24/mini-project-description

# Implementation of classic arcade game Pong

import simplegui
import random

# initialize globals - pos and vel encode vertical info for paddles
WIDTH = 600
HEIGHT = 400       
BALL_RADIUS = 20
PAD_WIDTH = 8
PAD_HEIGHT = 80
HALF_PAD_WIDTH = PAD_WIDTH / 2
HALF_PAD_HEIGHT = PAD_HEIGHT / 2
LEFT = False
RIGHT = True

# initialize ball_pos and ball_vel for new bal in middle of table
# if direction is RIGHT, the ball's velocity is upper right, else upper left
def spawn_ball(direction):
    global ball_pos, ball_vel # these are vectors stored as lists
    ball_pos = [WIDTH/2,HEIGHT/2]
    ball_vel = [random.randrange(2,4),random.randrange(1,3)]
    if direction == RIGHT:
        ball_vel[1] = - ball_vel[1]
    if direction == LEFT:
        ball_vel[0] = - ball_vel[0]
        ball_vel[1] = - ball_vel[1]
        

# define event handlers
def new_game():
    global paddle1_pos, paddle2_pos, paddle1_vel, paddle2_vel  # these are numbers
    global score1, score2  # these are ints
    paddle1_pos = HEIGHT / 2
    paddle2_pos = HEIGHT / 2
    paddle1_vel = 0
    paddle2_vel = 0
    score1 = 0
    score2 = 0
    spawn_ball(RIGHT) #spawn_ball(LEFT) 也可以
    
def draw(canvas):
    global score1, score2, paddle1_pos, paddle2_pos, ball_pos, ball_vel
 
        
    # draw mid line and gutters
    canvas.draw_line([WIDTH / 2, 0],[WIDTH / 2, HEIGHT], 1, "White")
    canvas.draw_line([PAD_WIDTH, 0],[PAD_WIDTH, HEIGHT], 1, "White")
    canvas.draw_line([WIDTH - PAD_WIDTH, 0],[WIDTH - PAD_WIDTH, HEIGHT], 1, "White")
        
    # update ball
    ball_pos[0] += ball_vel[0]
    ball_pos[1] += ball_vel[1]
    #check the top and down  bound
    if ball_pos[1] <=  BALL_RADIUS or  ball_pos[1] >= HEIGHT - BALL_RADIUS:
        ball_vel[1] = -ball_vel[1]
        
   
    # draw ball
    canvas.draw_circle(ball_pos,BALL_RADIUS,4,'Blue','White')
    # update paddle's vertical position, keep paddle on the screen
    if HALF_PAD_HEIGHT <= paddle1_pos + paddle1_vel <= HEIGHT - HALF_PAD_HEIGHT:
        paddle1_pos += paddle1_vel
    if HALF_PAD_HEIGHT <= paddle2_pos + paddle2_vel <= HEIGHT - HALF_PAD_HEIGHT:
        paddle2_pos += paddle2_vel
    
    # draw paddles
    canvas.draw_line((HALF_PAD_WIDTH,paddle1_pos - HALF_PAD_HEIGHT),
                     (HALF_PAD_WIDTH,paddle1_pos + HALF_PAD_HEIGHT),8,'White')
    canvas.draw_line((WIDTH - HALF_PAD_WIDTH,paddle2_pos - HALF_PAD_HEIGHT),
                     (WIDTH - HALF_PAD_WIDTH,paddle2_pos + HALF_PAD_HEIGHT),8,'White')
    # determine whether paddle and ball collide 
    if ball_pos[0] <= PAD_WIDTH + BALL_RADIUS:
        if paddle1_pos - HALF_PAD_HEIGHT <= ball_pos[1] <= paddle1_pos + HALF_PAD_HEIGHT:
            ball_vel[0] = - ball_vel[0]
            ball_vel[0] = ball_vel[0] * 1.1
            ball_vel[1] = ball_vel[1] * 1.1
        else:
            score2 += 1
            spawn_ball(LEFT)
    if ball_pos[0] >= WIDTH - PAD_WIDTH - BALL_RADIUS:
        if paddle2_pos - HALF_PAD_HEIGHT <= ball_pos[1] <= paddle2_pos + HALF_PAD_HEIGHT:
            ball_vel[0] = -ball_vel[0]
            ball_vel[0] = ball_vel[0] * 1.1
            ball_vel[1] = ball_vel[1] * 1.1
        else:
            score1 += 1
            spawn_ball(RIGHT)
   
    # draw scores
    text = str(score1) + ":" + str(score2)
    text_width = frame.get_canvas_textwidth(text,25,"sans-serif")
    pos = [(WIDTH - text_width)/2,text_width+8]
    canvas.draw_text(text,pos,25,'Green',"sans-serif")
def keydown(key):
    global paddle1_vel, paddle2_vel
    vel = 8
    if key == simplegui.KEY_MAP['w']:
        paddle1_vel -= vel
    elif key == simplegui.KEY_MAP['s']:
        paddle1_vel += vel
    elif key == simplegui.KEY_MAP['up']:
        paddle2_vel -= vel
    elif key == simplegui.KEY_MAP['down']:
        paddle2_vel += vel
        
def keyup(key):
    global paddle1_vel, paddle2_vel
    if key == simplegui.KEY_MAP['w']:
        paddle1_vel = 0
    elif key == simplegui.KEY_MAP['s']:
        paddle1_vel = 0
    elif key == simplegui.KEY_MAP['up']:
        paddle2_vel = 0
    elif key == simplegui.KEY_MAP['down']:
        paddle2_vel = 0


# create frame
frame = simplegui.create_frame("Pong", WIDTH, HEIGHT)
frame.set_draw_handler(draw)
frame.set_keydown_handler(keydown)
frame.set_keyup_handler(keyup)
frame.add_button("Reset",new_game)

# start frame
new_game()
frame.start()