Particles simualtion with Coulomb's Law and cubic gravitational law ( like the normal gravitation law, but with r³ instead of r²). This simulation does not have any phisical meaning, it's just for fun. See some captures at: http://sta.sh/21s1a54ox37m

particledope.py

#! /usr/bin/env python
'''
Controls:

Adding particles (and it's charges):
	left button -> (+)
	right button -> (-)
	middle button -> ( )

SPACE : Play/pause
r : restart game

'''
import pygame, time, random
from pygame import gfxdraw


# Physical Variables
k = 4000000.0
G = 30000000.0
flim = 100000

# Game vars
size = 900
scale = 1
speed = 0.1
bold =0
trans = 1




def uni(v, lim=1):
	mod = (v[0]**2+v[1]**2)**0.5
	if mod > lim:
		m= lim/mod
		return (v[0]*m, v[1]*m)
	else:
		return v


class p():
	def __init__(self, Q, pos, vel=[0.0,0.0]):
		self.Q = Q
		self.pos = pos
		self.vel = vel
		self.F = [0,0]

	def interact(self, ps):
		self.F = [0.0, 0.0]
		for p in ps:
			if p == self:
				continue

			d = (self.pos[0]-p.pos[0])**2 + (self.pos[1]-p.pos[1])**2
			d = d**0.5
			
			try:
				u = ((p.pos[0]-self.pos[0])/d , (p.pos[1]-self.pos[1])/d)

				self.F[0] -= k * self.Q * p.Q * u[0] / (d**2)
				self.F[1] -= k * self.Q * p.Q * u[1] / (d**2)

				self.F[0] += G / (abs(d)**3) * u[0]
				self.F[1] += G / (abs(d)**3) * u[1]
			except ZeroDivisionError:
				p.pos[0]+=1

	def update_vel(self, At):
		F = uni(self.F, flim)
		self.vel[0] += F[0]*At 
		self.vel[1] += F[1]*At 

	def update_pos(self, At):
		self.pos[0] += self.vel[0]*At
		self.pos[1] += self.vel[1]*At



def redraw():
	bg = [20,20,20]
	screen.fill(bg)
	#pygame.draw.line(screen, (255,255,255), (size-20, 30), (size-20, size-30), 2)
	#pygame.draw.rect(screen, (255,255,255), (size/4, size/4, size/2, size/2), 1)


screen = pygame.display.set_mode((size, size))


ps = []
redraw()

simulating = False
lt = time.time()
while True:
	

	At = (time.time()-lt)*speed
	lt = time.time()
	At = 0.001
	if simulating:
		for pa in ps:
			pa.interact(ps)

		for pa in ps:
			pa.update_vel(At)
			pa.update_pos(At)


	for event in pygame.event.get():
		if event.type == pygame.QUIT:
			raise SystemExit()
		elif event.type == pygame.MOUSEBUTTONDOWN:
			pres = pygame.mouse.get_pressed()
			pos = pygame.mouse.get_pos()
			ps.append(
				p(+1*pres[0]+0*pres[1]-1*pres[2], [pos[0]-size/2,pos[1]-size/2], [0,0])
				)

		elif event.type == pygame.KEYDOWN:

			key = event.dict['key']
			if key == pygame.K_ESCAPE:
				raise SystemExit()
			elif key == pygame.K_SPACE:
				simulating = not simulating
			elif key == pygame.K_r:
				redraw()
				ps = []
				simulating = 0
			elif key == pygame.K_b:
				bold = not bold


	if not trans:
		pygame.gfxdraw.box(screen, (0,0,size,size), bg+[255])
	for pa in ps:
		col = pa.Q == 0 and (0,255,0) or pa.Q < 0 and (255,0,0) or (100,100,255)
		x = int(size/2 +(pa.pos[0])/scale)
		y = int(size/2 +(pa.pos[1])/scale)
		pygame.gfxdraw.pixel(screen, x, y, col)
		if bold:
			pygame.gfxdraw.pixel(screen, x+1, y, col)
			pygame.gfxdraw.pixel(screen, x, y+1, col)
			pygame.gfxdraw.pixel(screen, x+1, y+1, col)
	pygame.display.flip()