#MonthOfCode day 22 - whirlpool

day_22.py

import pygame
from time import sleep
import random
import math
DISP_WIDTH = 640
DISP_HEIGHT = 480
DIST_THRESHOLD = 256

class MovingPix():
    def __init__(self , x,y):
        self.x =  float(x)
        self.y =  float( y)
        self.disp_x ,self.disp_y= x, y
        self.color= tuple( [random.randint(64,255) for i in xrange(3) ]  )
        self.mass =  random.random()*9

    def moveTowardsHole( self, pos_hole ):
        dest_x,dest_y = pos_hole
        if(self.disp_x==dest_x and self.disp_y==dest_y):
            return

        colinear_vect = (dest_x-self.x, dest_y-self.y)
        angle = math.pi/2
        ortho_vect = ( math.cos(angle) * colinear_vect[0] - math.sin(angle)*colinear_vect[1],
            math.cos(angle)*colinear_vect[1] + math.sin(angle)*colinear_vect[0]  )

        grav_factor = 8.0 / self.distance( pos_hole) 
        grav_factor /= self.mass
        turn_factor = 0.5
        turn_factor /= self.mass
        self.x = self.x + (grav_factor)*colinear_vect[0] + turn_factor *ortho_vect[0]
        self.y = self.y + (grav_factor)*colinear_vect[1] + turn_factor *ortho_vect[1]

        self.disp_x , self.disp_y = int(round(self.x)), int(round(self.y))

    def distance(self, targ_pos ):
        return math.sqrt( (self.x - targ_pos[0])**2 + (self.y - targ_pos[1])**2 )


def refreshScreen():
    window.fill(  pygame.Color('black') )
    for pix in l_pix:
        window.set_at( (pix.disp_x, pix.disp_y), pix.color)
        window.set_at( (pix.disp_x-1, pix.disp_y), pix.color)
        window.set_at( (pix.disp_x+1, pix.disp_y), pix.color)
        window.set_at( (pix.disp_x, pix.disp_y-1), pix.color)
        window.set_at( (pix.disp_x, pix.disp_y+1), pix.color)
    pygame.display.flip() 


# init. pygame libr; create the screen and diplays a help message in the console
pygame.init() 
window = pygame.display.set_mode( (DISP_WIDTH, DISP_HEIGHT) )
pygame.display.set_caption('press & hold a mouse button to clean pixels!')
l_pix = list()
for i in xrange( DISP_HEIGHT):
    for j in xrange( DISP_WIDTH):
        if random.choice( range(96) )==0 :
            l_pix.append( MovingPix( j,i))

program_done = False ; sucking = False
refreshScreen()
while not program_done: 
    for event in pygame.event.get(): 
        if event.type == pygame.QUIT: 
            program_done = True
            break 
        if event.type == pygame.MOUSEBUTTONDOWN :
            sucking = True
        if event.type == pygame.MOUSEBUTTONUP :
            sucking = False
    if sucking:
        m_pos = pygame.mouse.get_pos()
        for pix in l_pix:
            if(pix.distance(m_pos)>DIST_THRESHOLD ):
                continue
            pix.moveTowardsHole( m_pos)
        # display
        refreshScreen()
        sleep(0.02)