collision v0.3.1 Collision.Polygon.Vertex

A vertex is a point in the Cartesian space where a polygon’s edges meet.

Summary

Types

t()

Vertices in two dimensional space are defined by x and y coordinates

Functions

from_tuple(arg)

Convert a tuple to a Vertex

graham_scan(vertices)

Calculate the convex hull of a list of vertices

round_vertex(vertex)

Rounds the x and y components of a vertex

round_vertices(vertices)

Rounds a list of vertices

to_tuple(vertex)

Convert a vertex to a tuple

Types

t :: Collision.Polygon.Vertex.t

Vertices in two dimensional space are defined by x and y coordinates.

Functions

from_tuple(arg)

Specs

from_tuple({number, number}) :: Collision.Polygon.Vertex.t

Convert a tuple to a Vertex.

Returns: %Vertex{}

Example

iex> Vertex.from_tuple({2, 5})
%Vertex{x: 2, y: 5}

graham_scan(vertices)

Specs

graham_scan([Collision.Polygon.Vertex.t]) :: Collision.Polygon.Vertex.t

Calculate the convex hull of a list of vertices.

In the case of a convex polygon, it returns the polygon’s vertices.

For a concave polygon, it returns a subset of the vertices that form a convex polygon.

Examples

iex> convex_polygon = [
...>   %Vertex{x: 2, y: 2}, %Vertex{x: -2, y: 2},
...>   %Vertex{x: -2, y: -2}, %Vertex{x: 2, y: -2}
...> ]
...> Vertex.graham_scan(convex_polygon)
[%Vertex{x: -2, y: -2}, %Vertex{x: 2, y: -2},
 %Vertex{x: 2, y: 2}, %Vertex{x: -2, y: 2}]

iex> concave_polygon = [
...>   %Vertex{x: 2, y: 2}, %Vertex{x: 0, y: 0}, %Vertex{x: -2, y: 2},
...>   %Vertex{x: -2, y: -2}, %Vertex{x: 2, y: -2}
...> ]
...> Vertex.graham_scan(concave_polygon)
[%Vertex{x: -2, y: -2}, %Vertex{x: 2, y: -2},
%Vertex{x: 2, y: 2}, %Vertex{x: -2, y: 2}]

round_vertex(vertex)

Specs

round_vertex(Collision.Polygon.Vertex.t) :: Collision.Polygon.Vertex.t

Rounds the x and y components of a vertex.

Returns: Vertex.t

Examples

iex> Vertex.round_vertex(%Vertex{x: 1.9999999, y: 1.9999999})
%Vertex{x: 2.0, y: 2.0}

round_vertices(vertices)

Specs

round_vertices([Collision.Polygon.Vertex.t]) :: [Collision.Polygon.Vertex.t]

Rounds a list of vertices.

Returns: [Vertex.t]

Examples

iex> Vertex.round_vertices([
...>   %Vertex{x: 1.9999999, y: 1.99999999}, %Vertex{x: 2.11111111, y: 2.11111111}
...> ])
[%Vertex{x: 2.0, y: 2.0}, %Vertex{x: 2.11111, y: 2.11111}]

to_tuple(vertex)

Specs

to_tuple(Collision.Polygon.Vertex.t) :: {number, number}

Convert a vertex to a tuple.

Returns: {}

Example

iex> Vertex.to_tuple(%Vertex{x: 2, y: 5})
{2, 5}