def color_at(self, ray, remaining=5):
intersections = self.intersect_world(ray)
a_hit = hit(intersections)
if a_hit is None:
return BLACK
comps = prepare_computations(a_hit, ray, intersections)
return self.shade_hit(comps, remaining)
def cast_this_point(canvas, canvas_x, canvas_y, world_x, world_y):
spot_on_wall = Point(world_x, world_y, wall_z)
ray = Ray(ray_origin, normalize(spot_on_wall - ray_origin))
xs = intersect(shape, ray)
a_hit = hit(xs)
if a_hit is not None:
color = get_color(a_hit, ray)
write_pixel(canvas, canvas_x, canvas_y, color)
def is_shadowed(world, point, light=None):
if light is None: # This is pretty inefficient. It recomputes intersections below for each light
light = world.light
v = light.position - point
distance = v.magnitude()
direction = v.normalize()
r = Ray(point, direction)
intersections = intersect_world(world, r)
h = hit(intersections)
if h is not None and h.t < distance:
return True
else:
return False
def step_impl(context, i, xs):
_xs = getattr(context, xs)
_i = hit(_xs)
setattr(context, i, _i)
canvas_pixels = 100
pixel_size = wall_size / canvas_pixels
half = wall_size / 2
canvas = Canvas(canvas_pixels, canvas_pixels)
shape = Sphere()
for y in range(canvas_pixels - 1):
world_y = half - pixel_size * y
for x in range(canvas_pixels - 1):
world_x = -half + pixel_size * x
position = Point(world_x, world_y, wall_z)
r = Ray(ray_origin, normalize(position - ray_origin))
xs = intersect(shape, r)
if hit(xs) is not None:
write_pixel(canvas, x, y, RED)
path = Path(__file__).parent / "chap5.png"
canvas_to_png(str(path), canvas)
# Copyright 2020 Bloomberg Finance L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,