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sphere.py
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sphere.py
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"""
sphere.py by Thomas on 8/22/2021
"""
from math import sqrt
class Sphere:
"""Sphere is the only 3D shape implemented. Has center, radius and material"""
def __init__(self, center, radius, material):
self.center = center
self.radius = radius
self.material = material
def intersects(self, ray):
"""Checks if ray intersects this sphere. Returns distance to intersection or None if there is no intersection"""
sphere_to_ray = ray.origin - self.center
# a = 1
b = 2 * ray.direction.dot_product(sphere_to_ray)
c = sphere_to_ray.dot_product(sphere_to_ray) - self.radius * self.radius
discriminant = b * b - 4 * c
if discriminant >= 0:
dist = (-b - sqrt(discriminant)) / 2
if dist > 0:
return dist
return None
def normal(self, surface_point):
""""Returns the normal of the surface"""
return (surface_point-self.center).normalize()