from visual import *

a=complex(-0.75,0)
c=complex(0.,0.)


#faces() runs better on VPython/Python 2.4 

scene=display(
            title="a=-3/4 Julia set",
            height=600,width=600,x=0,y=000,fov=1e-8,
            foreground=color.black, background=color.white,
            userspin=0,userzoom=0,
            center=vector(0,0,0),range=(4,4,4))
screen = faces()

number=100 #space-resolution in pixels
MAX=2.0    #half-width of region in complex plane
MAXITS=60  #escape-time resolution


bins=zeros(((number+1),(number+1)))


def julia(a,c,MAX,bins):

    bins=zeros(((number+1),(number+1)))
    for i in arange (0,number+1):
        for j in arange (0,number+1):
            x=-MAX+2*(MAX/number)*i
            y=-MAX+2*(MAX/number)*j
            iter=0
            
            z=complex(x,y)+c
            while ( (abs(z) < 2.0) and (iter<MAXITS) ):
                 z = z*z + a  #JULIA
                 iter += 1

            bins[i,j]=iter
            
    return bins


def draw_region(c,MAX,bins):
    nrm=vector(0,0,1)
    side=2*float(MAX)/float(number)


    for i in arange (0,number+1):
        for j in arange (0,number+1):
            x=-MAX+2*(MAX/number)*i+c.real
            y=-MAX+2*(MAX/number)*j+c.imag
            
            if (bins[i,j]==MAXITS):
                mycolor=color.black
            else:
                mycolor=color.white
                
            screen.append (pos = (x, y, 0.0), color = mycolor, normal = nrm)
            screen.append (pos = (x, y - side, 0.0), color = mycolor, normal = nrm)
            screen.append (pos = (x + side, y, 0.0), color = mycolor, normal = nrm)
            screen.append (pos = (x + side, y, 0.0), color = mycolor, normal = nrm)
            screen.append (pos = (x, y - side, 0.0), color = mycolor, normal = nrm)
            screen.append (pos = (x + side, y - side, 0.0), color = mycolor, normal = nrm)


bins=julia(a,c,MAX,bins)
draw_region(c,MAX,bins)