onlytree.py

"""Cherry tree - Complex 2003 - Licence: Python

This example creates a cherry tree and apply a simple
dynamics looks like the effect caused by a small wind.
Each run produces a different tree according to the
initial seed value of the pseudo-random generator.

TODO:

- Embed the tree into a class with keyword arguments
  such as colors, sizes, depth, fullness, etc...
- Add texture to make it more realistic
- Create a small forest
- Implement dynamic looks like the effect of waves of wind

Modifications:
2003.01.24. - Complex (cx@cx.hu) - First release
"""

from visual import *
from math import *
from random import *

leaves=[]
fruits=[]

def random_vector():
    return vector(random(),random(),random())

def fruit(frm,p,a,r):
    f=frame(frame=frm, pos=p)
    cylinder(frame=f, pos=(0,0,0), axis=a, radius=r, color=color.green)
    sphere(frame=f, pos=a, radius=5*r, color=color.red)
    return f
    
def leaf(frm,p,a):
    na=norm(a)
    ex=cross((0,1,0),na)
    ey=cross(ex,na)
    ex=0.075*ex
    ey=0.045*ey
    points=[(0.0,0.1),(0.2,0.3),(0.4,0.5),(0.8,0.3),(1.0,0.0),(0.8,-0.3),(0.4,-0.5),(0.2,-0.3),(0.0,-0.1)]
    f=frame(frame=frm, pos=p)
    ex=rotate(ex, axis=ey, angle=pi*0.5*(random()-0.1))
    cylinder(frame=f, pos=(0,0,0), axis=1.2*ex, radius=0.025*mag(ey), color=color.green)
    c=convex(frame=f, pos=[(x+0.29)*ex+y*ey for x,y in points], color=color.green)
    return f

def tree(frm,p,a,r,c,ml,mr,e,d):
    q,v=p+a,ml*a*(0.8+0.4*random())
    cylinder(frame=frm, pos=p, axis=a, radius=r, color=c)
    sphere(frame=frm, pos=q, radius=r, color=c)
    if d>0 and (d>1 or randrange(3)>0):
	a1,a2=cross(a,(0,0,1)),cross(a,(1,0,0))
	s=rotate(v,axis=a1,angle=e)
	n=3+(randrange(10)>3)
	if d<2: n=2
	for i in range(n):
	    tree(frm, q, rotate(rotate(s,axis=a,angle=2.0*pi/n*i+pi/5.0/d*random()), axis=a,angle=pi/4.0*(random()-0.5)), mr*r, c, ml, mr, e, d-1)
    else:
	b=vector(0,-0.05,0)
	if randrange(3)<1:
	    t=0.1*p+0.9*q
	    fruits.append(fruit(frm,t,rotate(b,axis=a,angle=pi*(1+random())/8.0),0.0025))
	    fruits.append(fruit(frm,t,rotate(b,axis=a,angle=-pi*(1+random())/8.0),0.0025))
	for i in range(3):
	    l=leaf(frm,q,0.5*v)
	    l.rotate(axis=a,angle=2*pi*i/3.0)
	    leaves.append(l)

scene.visible=0
fr=frame(pos=(0,-0.8,0))
cylinder(frame=fr,pos=(0,-0.1,0), axis=(0,0.11,0), color=(0,0.5,0))
tr=tree(fr,vector(0,0,0), vector(0,0.8,0), 0.075, (0.8,0.4,0.1), 0.6, 0.6, pi/3.0, 5)
scene.visible=1

f=3
ai=0
aim=f*100
while 1:
    rate(25)
    a=(ai-aim/2)*pi/50.0
    ai+=f
    if ai>=aim: ai=0
    for i in range(len(leaves)/20):
	for l in (leaves,fruits):
	    o=choice(l)
	    o.rotate(axis=o.up, angle=(a-pi)/200.0)