def _cast_ray(self, point):
""" Casts a ray from pixel at point coordinates and returns its color.
:param point: tuple with x, y coordinates of the pixel
:param P_inv: inverted camera projection matrix
:return: point color of the nearest wall
"""
ray_direction_cam_frame = self.K_inv @ np.hstack(
[point[0], point[1], 1])
point_on_image_plane_world_frame = self.C2W @ np.hstack(
[ray_direction_cam_frame, 1])
point_on_image_plane_world_frame = point_on_image_plane_world_frame / point_on_image_plane_world_frame[
3]
# p1 - point in camera center, p2 - point on image plane
p1 = self.position
p2 = point_on_image_plane_world_frame[:2]
color = (0, 0, 0)
for wall in self.environment.map.walls:
# q1, q2 - wall vertices
q1 = wall.vertex1
q2 = wall.vertex2
t = intersect_ray_segment(p1, p2, q1, q2)
if t is not None:
# Check that point is in front of the camera
intersection_point = q1 + t * (q2 - q1)
direction = np.dot(p2 - p1, intersection_point - p2)
if direction > 0:
color = wall.get_color_at(t)
return color
def test_intersect_ray_segment_collinear(self):
""" Test for intersect_ray_segment() function when a ray and a line are collinear.
:return:
"""
p1 = np.array([0, 0])
p2 = np.array([4, 0])
q1 = np.array([5, 0])
q2 = np.array([7, 0])
u = intersect_ray_segment(p1, p2, q1, q2)
self.assertIsNone(u)
def test_intersect_ray_segment_intersect(self):
""" Test for intersect_ray_segment() function when there is an intersection.
:return:
"""
p1 = np.array([0, 0])
p2 = np.array([4, 0])
q1 = np.array([5, -1])
q2 = np.array([5, 3])
u = intersect_ray_segment(p1, p2, q1, q2)
self.assertEqual(u, 0.25)
def test_intersect_ray_segment_not_intersect(self):
""" Test for intersect_ray_segment() function when there is no intersection.
:return:
"""
p1 = np.array([0, 0])
p2 = np.array([4, 0])
q1 = np.array([5, 1])
q2 = np.array([5, 3])
u = intersect_ray_segment(p1, p2, q1, q2)
self.assertIsNone(u)