pong.py

'''
The MIT License (MIT)
Copyright (c) 2016 Antal Janos Monori.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
'''

###########
# Imports #
###########

try:
    import simplegui
except ImportError:
    import SimpleGUICS2Pygame.simpleguics2pygame as simplegui
import simpleplot
import random

#############
# Variables #
#############

# 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

####################
# Helper functions #
####################

# helper function that spawns a ball, returns a position vector and a velocity vector
# if right is True, spawn to the right, else spawn to the left
def ball_init(right):
    """Initializes tha ball"""
    global ball_pos, ball_vel # these are vectors stored as lists
    ball_pos = [WIDTH / 2, HEIGHT / 2]
    if right: ball_vel = [random.randrange(4, 8), -5]
    else: ball_vel = [-random.randrange(3, 6), -5]

def paddle_init():
    """Initializes the paddles"""
    global paddle1_pos, paddle2_pos, paddle1_vel, paddle2_vel
    paddle1_pos = [[PAD_WIDTH, HEIGHT / 2 - HALF_PAD_HEIGHT], [PAD_WIDTH, HEIGHT / 2 + HALF_PAD_HEIGHT]]
    paddle2_pos = [[WIDTH - PAD_WIDTH, HEIGHT / 2 - HALF_PAD_HEIGHT], [WIDTH - PAD_WIDTH, HEIGHT / 2 + HALF_PAD_HEIGHT]]
    paddle1_vel = 0
    paddle2_vel = 0

def calculateMid(paddle):
    """Calculates midpoint for each paddle, much easier to move the paddle this way"""
    midpoint = int(paddle[0][1] + paddle[1][1]) / 2
    return midpoint

def midpointToCoord(midpoint, paddle):
    """Converts the midpoint back to line coordinates."""
    paddle[0][1] = midpoint - HALF_PAD_HEIGHT
    paddle[1][1] = midpoint + HALF_PAD_HEIGHT
    return paddle[0][1], paddle[1][1]

def checkSides():
    """Checks for the north and south wall and changes the velocity."""
    global ball_pos, ball_vel
    if (ball_pos[1] >= (HEIGHT - BALL_RADIUS) ): ball_vel[1] = - ball_vel[1]
    if (ball_pos[1] <= (BALL_RADIUS) ): ball_vel[1] = - ball_vel[1]

def checkGutters():
    """Checks for the gutters and moves the ball."""
    global ball_pos, ball_vel
    global score1, score2
    if (ball_pos[0] >= (WIDTH)):
        ball_init(False)
        score1 += 1
#        print str(score1)+" : "+str(score2)
    if (ball_pos[0] <= (BALL_RADIUS)):
        ball_init(True)
        score2 += 1
#        print str(score1)+" : "+str(score2)

def checkPaddles():
    """Checks for the Paddles and moves the ball."""
    global ball_pos, ball_vel, paddle1, paddle2
    if (ball_pos[1] in range(paddle1 - HALF_PAD_HEIGHT, paddle1 + HALF_PAD_HEIGHT)) and (ball_pos[0] <= PAD_WIDTH + BALL_RADIUS):
        ball_vel[0] = - ball_vel[0]
    elif (ball_pos[1] in range(paddle2 - HALF_PAD_HEIGHT, paddle2 + HALF_PAD_HEIGHT)) and (ball_pos[0] >= WIDTH - (PAD_WIDTH + BALL_RADIUS)):
        ball_vel[0] = - ball_vel[0]

def movePaddles():
    """Moves the paddles according to the current paddle velocity."""
    global paddle1, paddle2, paddle1_pos, paddle2_pos, paddle1_vel, paddle2_vel
    paddle1 = calculateMid(paddle1_pos)
    if (paddle1_pos[0][1] > 0) and (paddle1_pos[1][1] < HEIGHT):
        paddle1 = paddle1 + paddle1_vel
    else: paddle1 = paddle1 - (2 * paddle1_vel)
    paddle1_pos[0][1] = midpointToCoord(paddle1, paddle1_pos)[0]
    paddle1_pos[1][1] = midpointToCoord(paddle1, paddle1_pos)[1]

    paddle2 = calculateMid(paddle2_pos)
    if (paddle2_pos[0][1] > 0) and (paddle2_pos[1][1] < HEIGHT):
        paddle2 = paddle2 + paddle2_vel
    else: paddle2 = paddle2 - (2 * paddle2_vel)
    paddle2_pos[0][1] = midpointToCoord(paddle2, paddle2_pos)[0]
    paddle2_pos[1][1] = midpointToCoord(paddle2, paddle2_pos)[1]

def moveBall():
    """Moves the ball."""
    global ball_pos, ball_vel
    ball_pos[0] += ball_vel[0]
    ball_pos[1] += ball_vel[1]

############
# Handlers #
############

# define event handlers
def init():
    """Restart button uses this function"""
    global score1, score2  # these are ints
    ball_init(True)
    paddle_init()
    score1 = 0
    score2 = 0

def draw(c):
    """Draw handler"""
    global paddle1_pos, paddle2_pos, ball_pos, ball_vel, paddle1_vel, paddle2_vel

    # update paddle's vertical position, keep paddle on the screen
    movePaddles()

    # draw mid line and gutters
    c.draw_line([WIDTH / 2, 0],[WIDTH / 2, HEIGHT], 1, "White")
    c.draw_line([PAD_WIDTH, 0],[PAD_WIDTH, HEIGHT], 1, "White")
    c.draw_line([WIDTH - PAD_WIDTH, 0],[WIDTH - PAD_WIDTH, HEIGHT], 1, "White")

    # draw paddles
    c.draw_line(paddle1_pos[0], paddle1_pos[1], PAD_WIDTH, "White")
    c.draw_line(paddle2_pos[0], paddle2_pos[1], PAD_WIDTH, "White")

    # update ball
    checkSides()
    checkGutters()
    checkPaddles()
    moveBall()

    # draw ball and scores
    c.draw_circle(ball_pos, BALL_RADIUS, 1, "White", "White")
    c.draw_text(str(score1), ((WIDTH / 2) - PAD_HEIGHT, (HEIGHT / 2) - PAD_HEIGHT), 45, "White")
    c.draw_text(str(score2), ((WIDTH / 2) + PAD_HEIGHT, (HEIGHT / 2) - PAD_HEIGHT), 45, "White")

def keydown(key):
    """Changes the velocity according to the key pressed."""
    global paddle1_vel, paddle2_vel
    if key == simplegui.KEY_MAP["w"]:
        paddle1_vel = -2
    if key == simplegui.KEY_MAP["s"]:
        paddle1_vel = 2
    if key == simplegui.KEY_MAP["up"]:
        paddle2_vel = -2
    if key == simplegui.KEY_MAP["down"]:
        paddle2_vel = 2

def keyup(key):
    """Sets the velocity back as soon as the user releases the key."""
    global paddle1_vel, paddle2_vel
    if (key == simplegui.KEY_MAP["w"]) or (key == simplegui.KEY_MAP["s"]):
        paddle1_vel = 0
    if (key == simplegui.KEY_MAP["up"]) or (key == simplegui.KEY_MAP["down"]):
        paddle2_vel = 0

######
# UI #
######

# 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("Restart", init, 100)

########
# Main #
########

# start frame
init()
frame.start()