Source code for arcade.geometry

"""
Functions for calculating geometry.
"""

from typing import cast
from arcade import PointList

_PRECISION = 2


[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: """ for polygon in (poly_a, poly_b): for i1 in range(len(polygon)): i2 = (i1 + 1) % len(polygon) projection_1 = polygon[i1] projection_2 = polygon[i2] normal = (projection_2[1] - projection_1[1], projection_1[0] - projection_2[0]) min_a, max_a, min_b, max_b = (None,) * 4 for poly in poly_a: projected = normal[0] * poly[0] + normal[1] * poly[1] if min_a is None or projected < min_a: min_a = projected if max_a is None or projected > max_a: max_a = projected for poly in poly_b: projected = normal[0] * poly[0] + normal[1] * poly[1] if min_b is None or projected < min_b: min_b = projected if max_b is None or projected > max_b: max_b = projected if cast(float, max_a) <= cast(float, min_b) or cast(float, max_b) <= cast(float, min_a): return False return True
[docs]def is_point_in_polygon(x, y, polygon_point_list): """ Use ray-tracing to see if point is inside a polygon Args: x: y: polygon_point_list: Returns: bool """ n = len(polygon_point_list) inside = False p1x, p1y = polygon_point_list[0] for i in range(n+1): p2x, p2y = polygon_point_list[i % n] if y > min(p1y, p2y): if y <= max(p1y, p2y): if x <= max(p1x, p2x): if p1y != p2y: xints = (y - p1y) * (p2x - p1x) / (p2y - p1y) + p1x # noinspection PyUnboundLocalVariable if p1x == p2x or x <= xints: inside = not inside p1x, p1y = p2x, p2y return inside