#(c) Rory Clune 02/11/2011

import sys, pygame
pygame.init()

velocity = [1,1]
position = [100,100]
theta = 0 #rate of spin
radius = 50
cr, fr = 0.9, 0.9

g = 0.002
deltaT = 10 #ms

white = (253,253,253)
# screen width and height
size = width, height = 600, 400
# create a screen
screen = pygame.display.set_mode(size)
# give the screen a title
pygame.display.set_caption('A Bouncing Ball using PyGame')

image = pygame.image.load('ball.jpg').convert()
image = pygame.transform.scale(image, (2*radius,2*radius))
rect = image.get_rect()

clock = pygame.time.Clock()

while 1:
	pygame.time.wait(deltaT)#pause for this long (each loop will, of course, take longer)
	for event in pygame.event.get():
		if event.type == pygame.QUIT: sys.exit()
	velocity[1] += g*deltaT
	
	position[0] += velocity[0]*deltaT
	position[1] += velocity[1]*deltaT + 0.5*g*deltaT*deltaT
	
	rect.center = (round(position[0]), round(position[1]))
	
	if position[0]-radius < 0:
		velocity[0] = -velocity[0]*cr
		velocity[1] *= fr
		position[0] = radius
	elif position[0]+radius > width:
		velocity[0] = -velocity[0]*cr
		velocity[1] *= fr
		position[0] = width - radius		
	if position[1]-radius < 0:
		velocity[1] = -velocity[1]*cr
		velocity[0] *= fr
		position[1] = radius
	elif position[1]+radius > height:
		velocity[1] = -velocity[1]*cr
		velocity[0] *= fr
		position[1] = height - radius
	screen.fill(white)
	screen.blit(image, rect)
	pygame.display.update()