Struct de_pathing::graph::VisibilityGraph

pub struct VisibilityGraph {
    nodes: Vec<GraphNode>,
}

Edge based visibility sub-graph.

Be careful to distinguish between triangle edges and graph edges:

• triangle edge - a geometric edge of a triangle (each triangle has 3).

• graph node - a node in a graph. In the case of VisibilityGraph, each graph node represents a triangle edge.

• graph edge - an edge between two nodes in a graph. In the case of VisibilityGraph, each graph edge represents direct visibility between two triangle edges.

  If triangle edges A and B are connected by a graph edge (i.e. are neighbours in VisibilityGraph), then any point on triangle edge A is accessible (visible) on straight line from any point on triangle B.

  The opposite statement doesn’t always hold: two triangle edges might be fully visible one from another and not share a graph edge. However, such triangles are always connected by a graph path.

Fields

nodes: Vec<GraphNode>

Implementations

impl VisibilityGraph

pub(crate) fn new() -> Self

Returns a new empty visibility graph.

pub(crate) fn len(&self) -> usize

Returns number of nodes in the visibility graph.

pub(crate) fn new_node(&mut self, segment: Segment) -> u32

Prepares a graph node without any neighbours, pushes it to the graph and returns corresponding edge (node) ID.

Only single node must be created when multiple triangles share an edge (have coincidental edge line segment).

Arguments

• segment - line segment of the triangle edge.

pub(crate) fn add_neighbours( &mut self, edge_id: u32, triangle_id: u32, neighbour_a_id: u32, neighbour_b_id: u32 )

Adds 2 neighbours accessible via one of the adjacent triangles to a graph node (triangle edge).

Arguments

• edge_id - ID of the edge whose neighbors are added.

• triangle_id - ID of the traversed triangle (i.e. the triangle containing the source and target edges).

• neighbour_a_id - edge ID of the a neighbor.

• neighbour_b_id - edge ID of the a neighbor.

Panics

Panics if edge_id already stores more than two neighbours.

pub(crate) fn segment(&self, edge_id: u32) -> Segment

Returns a geometry of a graph node (triangle edge).

pub(crate) fn neighbours(&self, edge_id: u32) -> &[Step]

Returns all neighbors of a graph node (triangle edge).