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from __future__ import division
from math import sqrt, ceil
import random, pygame, sys
import os
import json
from pygame.locals import *
pygame.init()
GRAY = ( 182, 182, 182)
VIOLET = (150, 100, 190)
RED = (150, 0, 0)
GREEN = (0, 150, 0)
BLUE = (30, 30, 180)
VERYLIGHT = (210, 210, 210)
BLACK = (0,0,0)
WHITE = (255, 255, 255)
TIME_STEP = 0.01
K = 10000
X_SCREEN_BORDER = 1200
Y_SCREEN_BORDER = 800
INITIAL_SPEED_X = 50
INITIAL_SPEED_Y = 0
INITIAL_Y = 400
DEFAULT_OLD_X = 2 - INITIAL_SPEED_X*TIME_STEP
DEFAULT_OLD_Y = INITIAL_Y - INITIAL_SPEED_Y*TIME_STEP
def main():
#create the screen
window = pygame.display.set_mode((1200, 800))
colors = [GRAY, VIOLET, RED, GREEN, BLUE, VERYLIGHT, BLACK]
global INITIAL_SPEED_X
global INITIAL_SPEED_Y
global INITIAL_Y
#Initialize universe with some atoms
atom1 = Particle(1000, Vector2(500,500), Vector2(500,500), 20, BLUE)
atom2 = Particle(1, Vector2(2,400), Vector2(2-TIME_STEP*INITIAL_SPEED_X, INITIAL_Y- TIME_STEP*INITIAL_SPEED_Y), 1, RED)
universe = Universe([atom1, atom2])
screen = Screen(window, colors, universe)
screen.draw_surface()
keep_running = True
while keep_running:
screen.draw_surface()
universe.update_positions()
for event in pygame.event.get():
if event.type == pygame.QUIT:
keep_running = False
elif event.type == pygame.KEYUP:
if event.key == K_UP :
INITIAL_Y -= 10
elif event.key == K_DOWN:
INITIAL_Y += 10
elif event.key == K_RIGHT:
INITIAL_SPEED_X += 20
elif event.key == K_LEFT:
INITIAL_SPEED_X -= 20
if(INITIAL_SPEED_X < 0):
INITIAL_SPEED_X = 0
elif event.key == K_SPACE:
universe.add_particle(Particle(1, Vector2(2,INITIAL_Y),
Vector2(2-TIME_STEP*INITIAL_SPEED_X, INITIAL_Y- TIME_STEP*INITIAL_SPEED_Y),
1, random.choice(colors)))
print "Pygame thread exited."
class Screen:
def __init__(self, window, colors, universe):
self.communicates = []
self.communicates.append("Rutherford scattering")
self.window = window
self.universe = universe
self.colors = colors
self.color = WHITE
def change_color(self):
self.color = random.choice(self.colors)
def draw_universe(self):
self.draw_guide()
for particle in self.universe.particles:
self.draw_particle(particle)
def draw_particle(self, particle):
position = (int(ceil(particle.position.x)), int(ceil(particle.position.y)))
pygame.draw.circle(self.window, particle.color, position, 6+ int(particle.mass/100) )
def draw_guide(self):
pygame.draw.line(self.window, BLACK, (0, INITIAL_Y), (X_SCREEN_BORDER,INITIAL_Y), 2)
def draw_surface(self):
self.window.fill(self.color)
self.draw_universe()
for i, text in enumerate(self.communicates):
self.print_text(text, 20, 20 + i*20, (0, 0, 0), 30, self.window)
pygame.display.flip()
def print_text(self, text,xx,yy,color,text_size, screen):
font = pygame.font.SysFont(None,text_size)
ren = font.render(text,1,color)
screen.blit(ren, (xx,yy))
class Vector2:
def __init__(self, x, y):
self.x = x
self.y = y
class Particle:
def __init__(self, mass, position, old_position, charge, color):
self.mass = mass
self.position = position
self.old_position = old_position
self.acc = Vector2(0,0)
self.color = color
self.charge = charge
class Universe:
def __init__(self, particles):
self.particles = particles
print("Universe has just been created!")
def update_accelerations(self):
for particle in self.particles:
particle.acc = Vector2(0,0)
for x in range(1, len(self.particles)):
accelerations = self.compute_acc(self.particles[x], self.particles[0])
self.particles[x].acc = accelerations[0]
def update_positions(self):
self.update_accelerations()
for particle in self.particles:
temporary_x = particle.position.x
temporary_y = particle.position.y
particle.position.x = 2 * particle.position.x - particle.old_position.x
particle.position.x += particle.acc.x * TIME_STEP * TIME_STEP
particle.position.y = 2 * particle.position.y - particle.old_position.y
particle.position.y += particle.acc.y * TIME_STEP * TIME_STEP
particle.old_position.x = temporary_x
particle.old_position.y = temporary_y
particle = self.limit_position(particle)
def limit_position(self, particle):
if(particle.position.x > X_SCREEN_BORDER or particle.position.y > Y_SCREEN_BORDER or
particle.position.x < 0 or particle.position.y < 0):
random_offset = random.randrange(-20, 20)
particle.position.x = 2
particle.old_position.x = 2 - INITIAL_SPEED_X*TIME_STEP
particle.position.y = INITIAL_Y + random_offset
particle.old_position.y = INITIAL_Y - INITIAL_SPEED_Y*TIME_STEP + random_offset
return particle
def compute_acc(self, particle1, particle2):
vertical_distance = particle1.position.y - particle2.position.y
horizontal_distance = particle1.position.x - particle2.position.x
distance = sqrt((vertical_distance)**2 + (horizontal_distance)**2)
force = particle1.charge * particle2.charge *K/distance**2
acc1x = force/particle1.mass*horizontal_distance/distance
acc1y = force/particle1.mass*vertical_distance/distance
acc2x = -force/particle2.mass*horizontal_distance/distance
acc2y = -force/particle2.mass*vertical_distance/distance
return [Vector2(acc1x, acc1y), Vector2(acc2x, acc2y)]
def add_particle(self, particle):
self.particles.append(particle)
if __name__ == '__main__':
main()
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