TITLE = 'Flappy Ball'

WIDTH = 800

HEIGHT = 600

BLUE = 0, 128, 255

GRAVITY = 2000.0 # pixels per second per second

class Ball:

def __init__(self, initial_x, initial_y):

self.x = initial_x

self.y = initial_y

self.vx = 200

self.vy = 0

self.radius = 20

def draw(self):

pos = (self.x, self.y)

screen.draw.filled_circle(pos, self.radius, BLUE)

ball = Ball(50, 100)

def draw():

screen.clear()

ball.draw()

def update(dt):

# Apply constant acceleration formulae

uy = ball.vy

ball.vy += GRAVITY * dt

ball.y += (uy + ball.vy) * 0.5 * dt

# detect and handle bounce

if ball.y > HEIGHT - ball.radius: # we've bounced!

ball.y = HEIGHT - ball.radius # fix the position

ball.vy = -ball.vy * 0.9 # inelastic collision

# X component doesn't have acceleration

ball.x += ball.vx * dt

if ball.x > WIDTH - ball.radius or ball.x < ball.radius:

ball.vx = -ball.vx

def on_key_down(key):

"""Pressing a key will kick the ball upwards."""

if key == keys.SPACE:

ball.vy = -500