def __init__(self, p1, p2, p3, n1=None, n2=None, n3=None):
super().__init__()
self.p1 = p1
self.p2 = p2
self.p3 = p3
self.n1 = n1
self.n2 = n2
self.n3 = n3
self.smoothed = False
# pre-compute edge vectors
self.e1 = subtract(p2, p1)
self.e2 = subtract(p3, p1)
# pre-compute normal
self.normal = normalize(cross(self.e2, self.e1))
def is_shadowed(self, light_position, hit_point):
vec = subtract(light_position, hit_point)
distance = magnitude(vec)
direction = normalize(vec)
ray = Ray(hit_point, direction)
intersections = self.intersect(ray)
hit_intersection = shadow_hit(intersections)
return hit_intersection is not None and hit_intersection.t < distance
def ray_for_pixel(self, pixel_x, pixel_y):
xoffset = (pixel_x + 0.5) * self.pixel_size
yoffset = (pixel_y + 0.5) * self.pixel_size
world_x = self.half_width - xoffset
world_y = self.half_height - yoffset
pixel = multiply_tuple(self.__inverse_transform,
point(world_x, world_y, -1))
origin = multiply_tuple(self.__inverse_transform, point(0, 0, 0))
direction = normalize(subtract(pixel, origin))
return Ray(origin, direction)
def local_intersect(self, local_ray):
sphere_to_ray = subtract(local_ray.origin, point(0, 0, 0))
a = dot(local_ray.direction, local_ray.direction)
b = 2 * dot(local_ray.direction, sphere_to_ray)
c = dot(sphere_to_ray, sphere_to_ray) - 1
discriminant = b**2 - 4 * a * c
if discriminant < 0:
return []
t1 = (-b - sqrt(discriminant)) / (2 * a)
t2 = (-b + sqrt(discriminant)) / (2 * a)
i1 = Intersection(t1, self)
i2 = Intersection(t2, self)
return [i1, i2]
def main():
canvas_pixels = 500
canvas = Canvas(canvas_pixels, canvas_pixels)
shape = Sphere()
# assign material
shape.material = Material()
shape.material.color = color(1, 0.2, 1)
light_position = point(-10, 10, -10)
light_color = color(1, 1, 1)
light = PointLight(light_position, light_color)
ray_origin = point(0, 0, -5)
wall_z = 10
wall_size = 7.0
pixel_size = wall_size / canvas_pixels
half = wall_size / 2
for y in range(canvas_pixels):
world_y = half - pixel_size * y
for x in range(canvas_pixels):
world_x = -half + pixel_size * x
pos = point(world_x, world_y, wall_z)
r = Ray(ray_origin, normalize(subtract(pos, ray_origin)))
xs = shape.intersect(r)
shape_hit = hit(xs)
if shape_hit is not None:
hit_point = r.position_at(shape_hit.t)
normal = shape_hit.object.normal_at(hit_point)
eye = negate(r.direction)
px_color = lighting(shape_hit.object.material,
shape_hit.object, light, hit_point, eye,
normal)
canvas.set_pixel(x, y, px_color)
with open('render_phong_sphere.ppm', 'w') as out_file:
out_file.write(canvas.to_ppm())
def main():
canvas_pixels = 400
canvas = Canvas(canvas_pixels, canvas_pixels)
red = color(1, 0, 0)
shape = Sphere()
# shrink it along the y axis
#shape.set_transform(scaling(1, 0.5, 1))
# shrink it along the x axis
#shape.set_transform(scaling(0.5, 1, 1))
# shrink it, and rotate it!
# shape.set_transform(multiply_matrix(rotation_z(pi / 4), scaling(0.5, 1,
# 1)))
# shrink it, and skew it!
# shape.set_transform(
# multiply_matrix(shearing(1, 0, 0, 0, 0, 0), scaling(0.5, 1, 1)))
ray_origin = point(0, 0, -5)
wall_z = 10
wall_size = 7.0
pixel_size = wall_size / canvas_pixels
half = wall_size / 2
for y in range(canvas_pixels):
world_y = half - pixel_size * y
for x in range(canvas_pixels):
world_x = -half + pixel_size * x
pos = point(world_x, world_y, wall_z)
r = Ray(ray_origin, normalize(subtract(pos, ray_origin)))
xs = shape.intersect(r)
if hit(xs) is not None:
canvas.set_pixel(x, y, red)
with open('render_sphere.ppm', 'w') as out_file:
out_file.write(canvas.to_ppm())
def local_intersect(self, local_ray):
dir_cross_e2 = cross(local_ray.direction, self.e2)
determinant = dot(self.e1, dir_cross_e2)
if abs(determinant) < self.EPSILON:
return []
f = 1.0 / determinant
p1_to_origin = subtract(local_ray.origin, self.p1)
u = f * dot(p1_to_origin, dir_cross_e2)
if u < 0.0 or u > 1.0:
return []
origin_cross_e1 = cross(p1_to_origin, self.e1)
v = f * dot(local_ray.direction, origin_cross_e1)
if v < 0.0 or (u + v) > 1.0:
return []
t = f * dot(self.e2, origin_cross_e1)
if self.smoothed:
return [Intersection(t, self, u, v)]
return [Intersection(t, self)]
def refracted_color(self, hit, remaining=5):
if remaining <= 0:
return color(0, 0, 0)
if hit.object.material.transparency == 0.0:
return color(0, 0, 0)
n_ratio = hit.n1 / hit.n2
cos_i = dot(hit.eyev, hit.normalv)
sin2_t = n_ratio**2 * (1 - cos_i**2)
if sin2_t > 1.0:
return color(0, 0, 0)
cos_t = sqrt(1.0 - sin2_t)
direction = subtract(multiply(hit.normalv, (n_ratio * cos_i - cos_t)),
multiply(hit.eyev, n_ratio))
refract_ray = Ray(hit.under_point, direction)
return multiply(self.color_at(refract_ray, remaining - 1),
hit.object.material.transparency)
def step_impl(context):
actual = subtract(context.c1, context.c2)
assert_tuple(actual, color(0.2, 0.5, 0.5))
def step_create_eye_vector_v1_from_eye_to_p(context):
context.v1 = normalize(subtract(context.eye, context.p))
def pattern_at(self, point):
distance = subtract(self.color_b, self.color_a)
fraction = point[0] - floor(point[0])
return add(self.color_a, multiply(distance, fraction))
def local_normal_at(self, local_point, hit=None):
return subtract(local_point, point(0, 0, 0))
