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Gnome::Graphene::N-Triangle

Description

A triangle.

Class initialization

new

:native-object

Create an object using a native object from elsewhere. See also Gnome::N::TopLevelSupportClass.

multi method new ( N-Object :$native-object! )

alloc

Allocates a new Gnome::Graphene::N-Triangle.

The contents of the returned structure are undefined.

method alloc ( --> Gnome::Graphene::Triangle \)

Methods

contains-point

Checks whether the given triangle $t contains the point $p.

method contains-point ( N-Object $p --> gboolean )

  • $p; a graphene_point3d_t

Return value; true if the point is inside the triangle.

equal

Checks whether the two given Gnome::Graphene::N-Triangle are equal.

method equal ( N-Object $b --> gboolean )

  • $b; a Gnome::Graphene::N-Triangle

Return value; true if the triangles are equal.

free

Frees the resources allocated by .alloc().

method free ( )

get-area

Computes the area of the given Gnome::Graphene::N-Triangle.

method get-area (--> Num )

Return value; the area of the triangle.

get-barycoords

Computes the [barycentric coordinates](http://en.wikipedia.org/wiki/Barycentric_coordinate_system) of the given point $p.

The point $p must lie on the same plane as the triangle $t; if the point is not coplanar, the result of this function is undefined.

If we place the origin in the coordinates of the triangle's A point, the barycentric coordinates are u, which is on the AC vector; and v which is on the AB vector:

![](triangle-barycentric.png)

The returned graphene_vec2_t contains the following values, in order:

  • res.x = u

  • res.y = v

method get-barycoords ( N-Object $p, N-Object $res --> gboolean )

  • $p; a graphene_point3d_t

  • $res; return location for the vector with the barycentric coordinates

Return value; true if the barycentric coordinates are valid.

get-bounding-box

Computes the bounding box of the given Gnome::Graphene::N-Triangle.

method get-bounding-box ( N-Object $res )

  • $res; return location for the box

get-midpoint

Computes the coordinates of the midpoint of the given Gnome::Graphene::N-Triangle.

The midpoint G is the [centroid](https://en.wikipedia.org/wiki/Centroid#Triangle_centroid) of the triangle, i.e. the intersection of its medians.

method get-midpoint ( N-Object $res )

  • $res; return location for the coordinates of the midpoint

get-normal

Computes the normal vector of the given Gnome::Graphene::N-Triangle.

method get-normal ( N-Object $res )

  • $res; return location for the normal vector

get-plane

Computes the plane based on the vertices of the given Gnome::Graphene::N-Triangle.

method get-plane ( N-Object $res )

  • $res; return location for the plane

get-points

Retrieves the three vertices of the given Gnome::Graphene::N-Triangle and returns their coordinates as graphene_point3d_t.

method get-points ( N-Object $a, N-Object $b, N-Object $c )

  • $a; return location for the coordinates of the first vertex

  • $b; return location for the coordinates of the second vertex

  • $c; return location for the coordinates of the third vertex

get-uv

Computes the UV coordinates of the given point $p.

The point $p must lie on the same plane as the triangle $t; if the point is not coplanar, the result of this function is undefined. If $p is undefined, the point will be set in (0, 0, 0).

The UV coordinates will be placed in the $res vector:

  • res.x = u

  • res.y = v

See also: .get-barycoords()

method get-uv ( N-Object $p, N-Object $uv-a, N-Object $uv-b, N-Object $uv-c, N-Object $res --> gboolean )

  • $p; a graphene_point3d_t

  • $uv-a; the UV coordinates of the first point

  • $uv-b; the UV coordinates of the second point

  • $uv-c; the UV coordinates of the third point

  • $res; a vector containing the UV coordinates of the given point $p

Return value; true if the coordinates are valid.

get-vertices

Retrieves the three vertices of the given Gnome::Graphene::N-Triangle.

method get-vertices ( N-Object $a, N-Object $b, N-Object $c )

  • $a; return location for the first vertex

  • $b; return location for the second vertex

  • $c; return location for the third vertex

init-from-float

Initializes a Gnome::Graphene::N-Triangle using the three given arrays of floating point values, each representing the coordinates of a point in 3D space.

method init-from-float ( Num() $a, Num() $b, Num() $c --> N-Object )

  • $a; an array of 3 floating point values.

  • $b; an array of 3 floating point values.

  • $c; an array of 3 floating point values.

Return value; the initialized Gnome::Graphene::N-Triangle.

init-from-point3d

Initializes a Gnome::Graphene::N-Triangle using the three given 3D points.

method init-from-point3d ( N-Object $a, N-Object $b, N-Object $c --> N-Object )

  • $a; a graphene_point3d_t

  • $b; a graphene_point3d_t

  • $c; a graphene_point3d_t

Return value; the initialized Gnome::Graphene::N-Triangle.

init-from-vec3

Initializes a Gnome::Graphene::N-Triangle using the three given vectors.

method init-from-vec3 ( N-Object $a, N-Object $b, N-Object $c --> N-Object )

  • $a; a graphene_vec3_t

  • $b; a graphene_vec3_t

  • $c; a graphene_vec3_t

Return value; the initialized Gnome::Graphene::N-Triangle.