"""
Functions for calculating geometry.
"""
import math
from shapely import speedups # type: ignore
from shapely.geometry import Polygon, Point # type: ignore
from typing import List
from arcade import PointList
_PRECISION = 2
speedups.enable()
[docs]def are_polygons_intersecting(poly_a: PointList,
poly_b: PointList) -> bool:
"""
Return True if two polygons intersect.
:param PointList poly_a: List of points that define the first polygon.
:param PointList poly_b: List of points that define the second polygon.
:Returns: True or false depending if polygons intersect
:rtype bool:
"""
shapely_polygon_a = Polygon(poly_a)
shapely_polygon_b = Polygon(poly_b)
r2 = False
r1 = shapely_polygon_a.intersects(shapely_polygon_b)
if r1:
r2 = shapely_polygon_a.touches(shapely_polygon_b)
return r1 and not r2
[docs]def is_point_in_polygon(x: float, y: float, polygon_point_list) -> bool:
"""
Use ray-tracing to see if point is inside a polygon
Args:
x:
y:
polygon_point_list:
Returns: bool
"""
shapely_point = Point(x, y)
shapely_polygon = Polygon(polygon_point_list)
return shapely_polygon.contains(shapely_point)
[docs]def get_distance(x1: float, y1: float, x2: float, y2: float):
""" Get the distance between two points. """
return math.hypot(x1 - x2, y1 - y2)
[docs]def clamp(a, low, high):
""" Clamp a number between a range. """
if a > high:
return high
elif a < low:
return low
else:
return a
[docs]def rotate_point(x: float, y: float, cx: float, cy: float,
angle_degrees: float) -> List[float]:
"""
Rotate a point around a center.
:param x: x value of the point you want to rotate
:param y: y value of the point you want to rotate
:param cx: x value of the center point you want to rotate around
:param cy: y value of the center point you want to rotate around
:param angle_degrees: Angle, in degrees, to rotate
:return: Return rotated (x, y) pair
:rtype: (float, float)
"""
temp_x = x - cx
temp_y = y - cy
# now apply rotation
angle_radians = math.radians(angle_degrees)
cos_angle = math.cos(angle_radians)
sin_angle = math.sin(angle_radians)
rotated_x = temp_x * cos_angle - temp_y * sin_angle
rotated_y = temp_x * sin_angle + temp_y * cos_angle
# translate back
rounding_precision = 2
x = round(rotated_x + cx, rounding_precision)
y = round(rotated_y + cy, rounding_precision)
return [x, y]