def __init__(self,
look_from: Vec3 = Vec3(3.0, 3.0, 2.0),
look_at: Vec3 = Vec3(0.0, 0.0, -1.0),
vec_up: Vec3 = Vec3(0.0, 1.0, 0.0),
v_fov: float = 90.0,
aspect: float = 1.0,
aperture: float = 0.0,
focus_dist: float = 1.0):
self.lens_radius = aperture / 2.0
theta = v_fov * 3.14159 / 180.0
half_height = math.tan(theta / 2.0)
half_width = aspect * half_height
w = unit_vector(look_from - look_at)
self.u = unit_vector(vec_up.cross(w))
self.v = w.cross(self.u)
self.origin = look_from
self.upper_left_corner = look_from - \
half_width*self.u*focus_dist + \
half_height*self.v*focus_dist - w*focus_dist
self.horizontal = 2 * half_width * self.u * focus_dist
self.vertical = -2 * half_height * self.v * focus_dist
def color(ray):
t = hit_sphere(Vec3(0.0, 0.0, -1.0), 0.5, ray)
if t > 0:
N = unit_vector(ray.point_at_parameter(t) - Vec3(0.0, 0.0, -1.0))
return Vec3(N.x + 1.0, N.y + 1.0, N.z + 1.0) * 0.5
unit_direction = unit_vector(ray.direction)
t = 0.5 * (unit_direction.y + 1.0)
return (1 - t) * Vec3(1.0, 1.0, 1.0) + t * Vec3(0.5, 0.7, 1.0)
def scatter(self, r_in: Ray, hit_rec):
if r_in.direction.dot(hit_rec.normal) > 0:
outward_normal = -hit_rec.normal
n1_n2 = self.ref_idx
cosine = self.ref_idx * r_in.direction.dot(
hit_rec.normal) / r_in.direction.norm()
else:
outward_normal = hit_rec.normal
n1_n2 = self.inv_ref_idx
cosine = -r_in.direction.dot(
hit_rec.normal) / r_in.direction.norm()
ret_val, refracted = refract(r_in.direction, outward_normal, n1_n2)
if ret_val:
reflect_prob = schlick(cosine, self.ref_idx)
else:
reflect_prob = 1.0
if random.random() < reflect_prob:
reflected = reflect(unit_vector(r_in.direction), hit_rec.normal)
scattered_ray = Ray(hit_rec.p, reflected)
else:
scattered_ray = Ray(hit_rec.p, refracted)
return True, scattered_ray, self.attenuation
def give_fade_blue_down(ray): # goal color is vec3(.5, .7, 1.0) //blue # start is white(1,1,1) # r's original y val goes from -1, 1 # 1 then *.5, to go 0-1 unit_direction = vec3.unit_vector( ray.direction() ) percent = 0.5*(1.0 + unit_direction.e[1]) return vec3.lerp( vec3.vec3(in_list=[1.0, 1.0, 1.0]), vec3.vec3(in_list=[0.5, 0.7, 1.0]), percent)
def scatter(self, r_in: Ray,
hit_rec):
reflected = reflect( unit_vector(r_in.direction), hit_rec.normal)
scattered_ray = Ray(hit_rec.p, reflected + self.fuzz*random_in_unit_sphere())
attenuation = self.albedo
return (scattered_ray.direction.dot(hit_rec.normal) > 0), \
scattered_ray, \
attenuation
def test_ray():
ray = Ray(Vec3(0.0,0.0,0.0), Vec3(1.0,1.0,1.0))
print("Origin at %s"%ray.origin)
print("Direction is %s"%ray.direction)
print("Unit vector direciton is %s"%unit_vector(ray.direction))
distance = -5.0
print("%f meters gives point %s"%(distance,
ray.point_at_parameter(distance)))
def refract(v_in: Vec3, normal: Vec3, n1_n2: float) -> [bool, Vec3]:
uv_in = unit_vector(v_in)
dt = uv_in.dot(normal)
discriminant = 1.0 - n1_n2 * n1_n2 * (1 - dt * dt)
if discriminant > 0:
refracted = n1_n2 * (uv_in - normal * dt) - normal * (discriminant**
0.5)
return True, refracted
else:
return False, None
def color(ray: Ray, world: Object3DList):
h_rec = HitRecord()
if world.hit(ray, 0.0, float("inf"), h_rec):
return Vec3(h_rec.normal.x+1.0,
h_rec.normal.y+1.0,
h_rec.normal.z+1.0)*0.5
unit_direction = unit_vector(ray.direction)
t = 0.5*(unit_direction.y+1.0)
return (1-t)*Vec3(1.0,1.0,1.0) + t*Vec3(0.5,0.7,1.0)
def color(ray: Ray, world: Object3DList, depth: int):
h_rec = HitRecord()
if world.hit(ray, 0.001, float("inf"), h_rec):
retval, s_ray, attenuation = h_rec.material.scatter(ray, h_rec)
if depth < 50 and retval:
return attenuation * color(s_ray, world, depth + 1)
else:
return Vec3(0.0, 0.0, 0.0)
else:
unit_direction = unit_vector(ray.direction)
t = 0.5 * (unit_direction.y + 1.0)
return (1 - t) * Vec3(1.0, 1.0, 1.0) + t * Vec3(0.5, 0.7, 1.0)
def ray_color(r, start_color=None, end_color=None):
# This implements the linear interpolation discussed in the notes.
# change the start and end vectors for different gradients
if not isinstance(r, Ray):
raise TypeError("Expected 'Ray' object, got {}".format(type(r)))
start_color = start_color if start_color is not None else Vec3(1, 1,
1) # White
end_color = end_color if end_color is not None else Vec3(0.5, 0.7,
1.) # Blue
unit_direction = unit_vector(r.direction)
# scale [-1, 1] to [0, 1]
t = 0.5 * (unit_direction.y + 1.0)
# do the linear interpolation from start to end color
return (1. - t) * start_color + t * end_color
