/**
* graphene_triangle_get_plane:
* @t: a #graphene_triangle_t
* @res: (out caller-allocates): return location for the plane
*
* Computes the plane based on the vertices of the given #graphene_triangle_t.
*
* Since: 1.2
*/
void
graphene_triangle_get_plane (const graphene_triangle_t *t,
graphene_plane_t *res)
{
graphene_point3d_t a, b, c;
graphene_point3d_init_from_vec3 (&a, &t->a);
graphene_point3d_init_from_vec3 (&b, &t->b);
graphene_point3d_init_from_vec3 (&c, &t->c);
graphene_plane_init_from_points (res, &a, &b, &c);
}
/**
* graphene_triangle_get_points:
* @t: a #graphene_triangle_t
* @a: (out caller-allocates) (optional): return location for the coordinates
* of the first vertex
* @b: (out caller-allocates) (optional): return location for the coordinates
* of the second vertex
* @c: (out caller-allocates) (optional): return location for the coordinates
* of the third vertex
*
* Retrieves the three vertices of the given #graphene_triangle_t and returns
* their coordinates as #graphene_point3d_t.
*
* Since: 1.2
*/
void
graphene_triangle_get_points (const graphene_triangle_t *t,
graphene_point3d_t *a,
graphene_point3d_t *b,
graphene_point3d_t *c)
{
if (a != NULL)
graphene_point3d_init_from_vec3 (a, &t->a);
if (b != NULL)
graphene_point3d_init_from_vec3 (b, &t->b);
if (c != NULL)
graphene_point3d_init_from_vec3 (c, &t->c);
}
/**
* graphene_ray_get_distance_to_plane:
* @r: a #graphene_ray_t
* @p: a #graphene_plane_t
*
* Computes the distance of the origin of the given #graphene_ray_t from the
* given plane.
*
* If the ray does not intersect the plane, this function returns `INFINITY`.
*
* Returns: the distance of the origin of the ray from the plane
*
* Since: 1.4
*/
float
graphene_ray_get_distance_to_plane (const graphene_ray_t *r,
const graphene_plane_t *p)
{
float denom, t;
denom = graphene_vec3_dot (&p->normal, &r->direction);
if (fabsf (denom) < GRAPHENE_FLOAT_EPSILON)
{
graphene_point3d_t tmp;
/* If the ray is coplanar, return 0 */
graphene_point3d_init_from_vec3 (&tmp, &r->origin);
if (fabsf (graphene_plane_distance (p, &tmp)) < GRAPHENE_FLOAT_EPSILON)
return 0.f;
return INFINITY;
}
t = -1.f * (graphene_vec3_dot (&r->origin, &p->normal) + p->constant) / denom;
if (t >= 0.f)
return t;
return INFINITY;
}
/**
* graphene_triangle_get_midpoint:
* @t: a #graphene_triangle_t
* @res: (out caller-allocates): return location for the coordinates of
* the midpoint
*
* Computes the coordinates of the midpoint of the given #graphene_triangle_t.
*
* Since: 1.2
*/
void
graphene_triangle_get_midpoint (const graphene_triangle_t *t,
graphene_point3d_t *res)
{
graphene_vec3_t tmp;
graphene_vec3_add (&t->a, &t->b, &tmp);
graphene_vec3_add (&tmp, &t->c, &tmp);
graphene_vec3_scale (&tmp, (1.f / 3.f), &tmp);
graphene_point3d_init_from_vec3 (res, &tmp);
}
/**
* graphene_ray_get_position_at:
* @r: a #graphene_ray_t
* @t: the distance along the ray
* @position: (out caller-allocates): return location for the position
*
* Retrieves the coordinates of a point at the distance @t along the
* given #graphene_ray_t.
*
* Since: 1.4
*/
void
graphene_ray_get_position_at (const graphene_ray_t *r,
float t,
graphene_point3d_t *position)
{
graphene_vec3_t res;
graphene_vec3_scale (&r->direction, t, &res);
graphene_vec3_add (&res, &r->origin, &res);
graphene_point3d_init_from_vec3 (position, &res);
}
/**
* graphene_ray_get_closest_point_to_point:
* @r: a #graphene_ray_t
* @p: a #graphene_point3d_t
* @res: (out caller-allocates): return location for the closest point3d
*
* Computes the point on the given #graphene_ray_t that is closest to the
* given point @p.
*
* Since: 1.4
*/
void
graphene_ray_get_closest_point_to_point (const graphene_ray_t *r,
const graphene_point3d_t *p,
graphene_point3d_t *res)
{
graphene_vec3_t point, result;
float distance;
graphene_point3d_to_vec3 (p, &point);
graphene_vec3_subtract (&point, &r->origin, &result);
distance = graphene_vec3_dot (&result, &r->direction);
if (distance < 0)
graphene_vec3_init_from_vec3 (&result, &r->origin);
else
{
graphene_vec3_scale (&r->direction, distance, &result);
graphene_vec3_add (&result, &r->origin, &result);
}
graphene_point3d_init_from_vec3 (res, &result);
}
/**
* graphene_ray_get_origin:
* @r: a #graphene_ray_t
* @origin: (out caller-allocates): return location for the origin
*
* Retrieves the origin of the given #graphene_ray_t.
*
* Since: 1.4
*/
void
graphene_ray_get_origin (const graphene_ray_t *r,
graphene_point3d_t *origin)
{
graphene_point3d_init_from_vec3 (origin, &r->origin);
}
