Class Node

pvtrace/scene/node.py:14–166

A node in a scene graph. Each node represents a new coordinate system with position and orientation relative to it's parent node.

class Node(NodeMixin, Transformable):
    """ A node in a scene graph. Each node represents a new coordinate system
    with position and orientation relative to it's parent node.
    """

    def __init__(
        self, name=None, parent=None, location=None, geometry=None, light=None
    ):
        super(Node, self).__init__(location=location)
        self.name = name
        self.parent = parent
        self.geometry = geometry
        self.light = light

    def __repr__(self):
        return "Node({})".format(self.name)

    def look_at(self, vector: tuple) -> None:
        """ Align the node so that the Z axis is pointing along the vector.
        """
        raise NotImplementedError()

    # Convert between coordinate systems

    def transformation_to(self, node: Node) -> np.ndarray:
        """ Transformation matrix from this node to another node.
        
            Parameters
            ----------
            node : Node
                The other node.
        
            Returns
            -------
            numpy.ndarray
                Homogeneous transformation matrix.
        """
        if self == node:
            return np.identity(4)
        upwards, common, downwards = Walker().walk(self, node)
        transforms = tuple(map(lambda x: x.pose, upwards))
        transforms = transforms + tuple(map(lambda x: np.linalg.inv(x.pose), downwards))
        if len(transforms) == 1:
            transform = transforms[0]
        else:
            transform = np.linalg.multi_dot(transforms[::-1])
        return transform

    def point_to_node(self, point: tuple, node: Node) -> tuple:
        """ Convert local point into the the other node coordinate system.
        
            The `node` must be somewhere in the hierarchy tree.
        
        Parameters
        ----------
        point : tuple of float
            Cartesian point `(x, y, z)` in the local coordinate system.
        node : Node