def normal(self, p):
"""
Surface normal at point p, calculated through the gradient
"""
a, b, c = self.a, self.b, self.c
n = Vec(-2 * p.x / a ** 2,
-2 * p.y / b ** 2,
-2 * (p.z + c) / c ** 2)
return n.normalize()
def reflect(self,pos,t):
if t is False or t is None or type(t) is list and (t[0] is False or t[0] is None):
return pos
if type(pos) is Vec and type(t[0]) is Vec:
if type(t[1]) is str:
if t[1]=='y':
dirvec=V(0,1)
if t[1]=='x':
dirvec=V(1,0)
elif type(t[1]) is Vec:
dirvec = t[1]
else:
raise ValueError( "Reflection direction "+str(t[1])+" is not a string or vector")
out=Vec(pos)
out-=t[0]
out=out.reflect(dirvec)
out+=t[0]
return out
else:
return False
