ex11_2ChangingtheRuleSet.pyde

''' Rule 30 was introduced by Stephan Wolfram in 1983.
    Creating Rule 90 design using Cellular Automation.
    Change the value of w, rows, and cols to explore the design.
'''

w = 5 #width of each cell
rows = 200
cols = 200
#--snip--
ruleset = [0,1,0,1,1,0,1,0] #rule 90

def setup():
    global cells
    size(600,600)
    noStroke()
    #first row:
    cells = []
    for r in range(rows):
        cells.append([])
        for c in range(cols):
            cells[r].append(0)
        cells[0][cols//2] = 1
    cells = generate()

def draw():
    background(255) #white
    #draw the CA
    for i, cell in enumerate(cells): #rows
        for j, v in enumerate(cell): #columns
            if v == 1:
                fill(0)
            else:
                fill(255)
            rect(j*w-(cols*w-width)/2,w*i,w,w)

#connverting from binary to decimal
#the indices are in reverse order, so we subtract the total from 7 to get the proper index of the ruleset.
def rules(a,b,c):
       return ruleset[7 - (4*a + 2*b + c)]

def generate():
       for i, row in enumerate(cells): #look at first row
           for j in range(1,len(row)-1):
               left = row[j-1]
               me = row[j]
               right = row[j+1]
               if i < len(cells) - 1:
                    cells[i+1][j] = rules(left,me,right)
       return cells