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Triangle

Triangle — A triangle described by 3D points

Types and Values

Includes

#include <graphene.h>

Description

graphene_triangle_t represents a triangle in 3D space.

Functions

graphene_triangle_alloc ()

graphene_triangle_t *
graphene_triangle_alloc (void);

Allocates a new graphene_triangle_t.

The contents of the returned structure are undefined.

[constructor]

Returns

the newly allocated graphene_triangle_t structure. Use graphene_triangle_free() to free the resources allocated by this function.

[transfer full]

Since: 1.2


graphene_triangle_free ()

void
graphene_triangle_free (graphene_triangle_t *t);

Frees the resources allocated by graphene_triangle_alloc().

Parameters

Since: 1.2


graphene_triangle_init_from_point3d ()

graphene_triangle_t *
graphene_triangle_init_from_point3d (graphene_triangle_t *t,
                                     const graphene_point3d_t *a,
                                     const graphene_point3d_t *b,
                                     const graphene_point3d_t *c);

Initializes a graphene_triangle_t using the three given 3D points.

Parameters

t

the graphene_triangle_t to initialize

 

a

a graphene_point3d_t.

[nullable]

b

a graphene_point3d_t.

[nullable]

c

a graphene_point3d_t.

[nullable]

Returns

the initialized graphene_triangle_t.

[transfer none]

Since: 1.2


graphene_triangle_init_from_vec3 ()

graphene_triangle_t *
graphene_triangle_init_from_vec3 (graphene_triangle_t *t,
                                  const graphene_vec3_t *a,
                                  const graphene_vec3_t *b,
                                  const graphene_vec3_t *c);

Initializes a graphene_triangle_t using the three given vectors.

Parameters

t

the graphene_triangle_t to initialize

 

a

a graphene_vec3_t.

[nullable]

b

a graphene_vec3_t.

[nullable]

c

a graphene_vec3_t.

[nullable]

Returns

the initialized graphene_triangle_t.

[transfer none]

Since: 1.2


graphene_triangle_get_points ()

void
graphene_triangle_get_points (const graphene_triangle_t *t,
                              graphene_point3d_t *a,
                              graphene_point3d_t *b,
                              graphene_point3d_t *c);

Retrieves the three vertices of the given graphene_triangle_t and returns their coordinates as graphene_point3d_t.

Parameters

t

a graphene_triangle_t

 

a

return location for the coordinates of the first vertex.

[out caller-allocates][optional]

b

return location for the coordinates of the second vertex.

[out caller-allocates][optional]

c

return location for the coordinates of the third vertex.

[out caller-allocates][optional]

Since: 1.2


graphene_triangle_get_vertices ()

void
graphene_triangle_get_vertices (const graphene_triangle_t *t,
                                graphene_vec3_t *a,
                                graphene_vec3_t *b,
                                graphene_vec3_t *c);

Retrieves the three vertices of the given graphene_triangle_t.

Parameters

t

a graphene_triangle_t

 

a

return location for the first vertex.

[out caller-allocates][optional]

b

return location for the second vertex.

[out caller-allocates][optional]

c

return location for the third vertex.

[out caller-allocates][optional]

Since: 1.2


graphene_triangle_get_area ()

float
graphene_triangle_get_area (const graphene_triangle_t *t);

Computes the area of the given graphene_triangle_t.

Parameters

Returns

the area of the triangle

Since: 1.2


graphene_triangle_get_midpoint ()

void
graphene_triangle_get_midpoint (const graphene_triangle_t *t,
                                graphene_point3d_t *res);

Computes the coordinates of the midpoint of the given graphene_triangle_t.

The midpoint G is the centroid of the triangle, i.e. the intersection of its medians.

Parameters

t

a graphene_triangle_t

 

res

return location for the coordinates of the midpoint.

[out caller-allocates]

Since: 1.2


graphene_triangle_get_normal ()

void
graphene_triangle_get_normal (const graphene_triangle_t *t,
                              graphene_vec3_t *res);

Computes the normal vector of the given graphene_triangle_t.

Parameters

t

a graphene_triangle_t

 

res

return location for the normal vector.

[out caller-allocates]

Since: 1.2


graphene_triangle_get_plane ()

void
graphene_triangle_get_plane (const graphene_triangle_t *t,
                             graphene_plane_t *res);

Computes the plane based on the vertices of the given graphene_triangle_t.

Parameters

t

a graphene_triangle_t

 

res

return location for the plane.

[out caller-allocates]

Since: 1.2


graphene_triangle_get_bounding_box ()

void
graphene_triangle_get_bounding_box (const graphene_triangle_t *t,
                                    graphene_box_t *res);

Computes the bounding box of the given graphene_triangle_t.

Parameters

t

a graphene_triangle_t

 

res

return location for the box.

[out caller-allocates]

Since: 1.2


graphene_triangle_get_barycoords ()

bool
graphene_triangle_get_barycoords (const graphene_triangle_t *t,
                                  const graphene_point3d_t *p,
                                  graphene_vec2_t *res);

Computes the barycentric 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 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:

The returned graphene_vec2_t contains the following values, in order:

  • res.x = u

  • res.y = v

Parameters

t

a graphene_triangle_t

 

p

a graphene_point3d_t.

[nullable]

res

return location for the vector with the barycentric coordinates.

[out caller-allocates]

Returns

true if the barycentric coordinates are valid

Since: 1.2


graphene_triangle_contains_point ()

bool
graphene_triangle_contains_point (const graphene_triangle_t *t,
                                  const graphene_point3d_t *p);

Checks whether the given triangle t contains the point p .

Parameters

Returns

true if the point is inside the triangle

Since: 1.2


graphene_triangle_equal ()

bool
graphene_triangle_equal (const graphene_triangle_t *a,
                         const graphene_triangle_t *b);

Checks whether the two given graphene_triangle_t are equal.

Parameters

Returns

true if the triangles are equal

Since: 1.2

Types and Values

graphene_triangle_t

typedef struct {
} graphene_triangle_t;

A triangle.

Since: 1.2

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