from visual import *
from visual.text import *

#1 draw 3 axis.
xaxis = arrow(pos=(0,0,0), axis=(1,0,0), shaftwidth=0.01, color=color.red)
yaxis = arrow(pos=(0,0,0), axis=(0,1,0), shaftwidth=0.01, color=color.green)
zyaxis = arrow(pos=(0,0,0), axis=(0,0,1), shaftwidth=0.01, color=color.blue)

#1 Space Curve 繪製Helix 曲線
#a=3
#b=0.5
#step = 0.1
#t=arange(0,5*2*pi+step, step)
#curve(x=a*cos(t), y=a*sin(t), z=b*t, color=color.red, radius=0.1)

#2 Twisted Cubic
#step = 0.1
#maxno = 1
#t=arange(-maxno, maxno+step ,step)
#curve(x=t, y=t*t, z=t**3, color=color.white, radius=0.03)
#curve(x=t, y=t*t, z=0, color=color.red, radius=0.01)
#curve(x=t, y=0, z=t**3, color=color.green, radius=0.01)
#curve(x=0, y=t*t, z=t**3, color=color.blue, radius=0.01)

#3
#cylinder(axis = (0,0,2*b*pi), color=color.yellow, radius=a)

#6 參數式，彩色繪製
#t = arange(0, 10, 0.1)
#curve(x=sin(t),y=1.0/(1+t),z=t**0.5,red=cos(t),green=0,blue=0.5*(1-cos(t)) )