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#!/usr/bin/python
''' Spectral Harmonographs Copyright 2014 Alan Richmond (Tuxar.uk)
Trace of 4 decaying sine waves, 2 per axis (x & y)(i.e. 2-pendula), with rainbow colour.
I did this in Java some decades ago (Encyclogram; I no longer have the source), this
version is in Python, with PyGame.
It randomly generates a sequence of harmonographs. It's fast, and can be set to go
much faster (or slower) if you want.
Tip: set the display window to fullscreen. On KDE Ubuntu right-click on the title bar,
select More Actions -> Fullscreen
'''
print "Quit: q key, Screenshot: spacebar"
import pygame, sys, random as r
from pygame.locals import *
from math import pi, sin, cos, exp
# EDIT THESE:
width,height=1280,720 # YouTube HD
width,height=1920,1080 # my left monitor
width,height=1280,1024 # my right monitor
#width,height=2560,1440 # YT channel art
dd=0.99995 # decay factor
dt=0.02 # time increment
speed=200 # yes, speed
hui=57*2 # Hue increment
hue,sat,val,aaa=0,100,100,0
sd=0.005 # frequency spread (from integer)
mx=4 # max range for amplitudes & frequencies
def check_event():
global save
for event in pygame.event.get():
if event.type == QUIT:
sys.exit()
elif event.type == KEYDOWN and event.key == K_q:
sys.exit()
elif event.type == KEYDOWN and event.key == K_SPACE:
save=True
print "Saving when finished..."
steps=0
pygame.init()
pygame.event.set_allowed([QUIT, KEYDOWN])
screen = pygame.display.set_mode((width,height),DOUBLEBUF)
screen.set_alpha(None)
fg=pygame.Color(0,0,0,0)
save=False
while True:
while True:
ax1, ax2 = r.randint(-mx,mx), r.randint(-mx,mx)
maxx=abs(ax1)+abs(ax2)
if maxx>0: break
xscale=width/(2*maxx)
while True:
ay1, ay2 = r.randint(0,mx), r.randint(0,mx)
maxy=abs(ay1)+abs(ay2)
if maxy>0: break
yscale=height/(2*maxy)
fx1, fx2 = r.randint(1,mx) + r.gauss(0,sd), r.randint(1,mx) + r.gauss(0,sd)
fy1, fy2 = r.randint(1,mx) + r.gauss(0,sd), r.randint(1,mx) + r.gauss(0,sd)
px1, px2 = r.uniform(0,2*pi), r.uniform(0,2*pi)
py1, py2 = r.uniform(0,2*pi), r.uniform(0,2*pi)
print ax1,ax2,ay1,ay2
print fx1,fx2,fy1,fy2
print px1,px2,py1,py2
dec=1.0
t=0.0 # angle for sin
first=True
while dec>0.015:
# calculate next x,y point along line
x = xscale * dec * (ax1*sin(t * fx1 + px1) + ax2*sin(t * fx2 + px2)) + width/2
y = yscale * dec * (ay1*cos(t * fy1 + py1) + ay2*cos(t * fy2 + py2)) + height/2
dec*=dd # decay
if not first: # ignore any complaint about prev_x,y being undefined
fg.hsva=(hue,sat,val,aaa)
hue = (hue + dt*hui) % 360 # cycle hue
pygame.draw.aaline(screen, fg, (x, y), (prev_x, prev_y), 1)
else:
first=False
prev_x = x # save x,y for next line segment start
prev_y = y
if steps%speed==0: pygame.display.update()
steps+=1
t+=dt # increment angle for sin
check_event()
if save:
pars='shg-{0}_{1}-{2}_{3}-{4}_{5}'.format(ax1,ax2,fx1,fx2,px1,px2)
pygame.image.save(screen, pars+'.jpg')
print "Saved as "+pars+'.jpg'
save=False
screen.fill((0,0,0))