Method find_intersection

pygorithm/geometry/polygon2.py:429–503

Find if the polygons are intersecting and how to resolve it. Distinguish between polygons that are sharing 1 point or a single line (touching) as opposed to polygons that are sharing a 2-dimensional amount of space. The resulting MTV shoul

(poly1, poly2, offset1, offset2, find_mtv = True)

        
    @staticmethod
    def find_intersection(poly1, poly2, offset1, offset2, find_mtv = True):
        """
        Find if the polygons are intersecting and how to resolve it.
        
        Distinguish between polygons that are sharing 1 point or a single line 
        (touching) as opposed to polygons that are sharing a 2-dimensional 
        amount of space.
        
        The resulting MTV should be applied to the first polygon (or its offset), 
        or its negation can be applied to the second polygon (or its offset).
        
        The MTV will be non-null if overlapping is True and find_mtv is True.
        
        .. note::
        
            There is only a minor performance improvement from setting find_mtv to 
            False. It is rarely an improvement to first check without finding 
            mtv and then to find the mtv.
        
        .. caution::
            
            The first value in the mtv could be negative (used to inverse the direction
            of the axis)
        
        This uses the `Seperating Axis Theorem <http://www.dyn4j.org/2010/01/sat/> to 
        calculate intersection.
        
        :param poly1: the first polygon
        :type poly1: :class:`pygorithm.geometry.polygon2.Polygon2`
        :param poly2: the second polygon
        :type poly2: :class:`pygorithm.geometry.polygon2.Polygon2`
        :param offset1: the offset of the first polygon
        :type offset1: :class:`pygorithm.geometry.vector2.Vector2` or None
        :param offset2: the offset of the second polygon
        :type offset2: :class:`pygorithm.geometry.vector2.Vector2` or None
        :param find_mtv: if False, the mtv is always None and there is a small \
        performance improvement
        :type find_mtv: bool
        :returns: (touching, overlapping, (mtv distance, mtv axis))
        :rtype: (bool, bool, (:class:`numbers.Number`, :class:`pygorithm.geometry.vector2.Vector2`) or None)
        """
        
        unique_normals = list(poly1.normals)
        for n in poly2.normals:
            found = False
            for old_n in poly1.normals:
                if math.isclose(n.x, old_n.x) and math.isclose(n.y, old_n.y):
                    found = True
                    break
            if not found:
                unique_normals.append(n)
        
        
        not_overlapping = False
        best_mtv = None
        for norm in unique_normals:
            proj1 = Polygon2.project_onto_axis(poly1, offset1, norm)
            proj2 = Polygon2.project_onto_axis(poly2, offset2, norm)