static void
quaternion_vec4_to_from (mutest_spec_t *spec)
{
graphene_quaternion_t *q;
graphene_vec4_t v, check;
graphene_vec4_init (&v, 1.f, 2.f, 3.f, 4.f);
q = graphene_quaternion_init_from_vec4 (graphene_quaternion_alloc (), &v);
graphene_quaternion_to_vec4 (q, &check);
mutest_expect ("roundtrip between init_from_vec4 and to_vec4 to yield the same vector",
mutest_bool_value (graphene_vec4_near (&v, &check, 0.0001f)),
mutest_to_be_true,
NULL);
graphene_quaternion_free (q);
}
/**
* graphene_quaternion_to_angles:
* @q: a #graphene_quaternion_t
* @deg_x: (out) (optional): return location for the rotation angle on
* the X axis (yaw), in degress
* @deg_y: (out) (optional): return location for the rotation angle on
* the Y axis (pitch), in degrees
* @deg_z: (out) (optional): return location for the rotation angle on
* the Z axis (roll), in degrees
*
* Converts a #graphene_quaternion_t to its corresponding rotations
* on the [Euler angles](http://en.wikipedia.org/wiki/Euler_angles)
* on each axis.
*
* Since: 1.2
*/
void
graphene_quaternion_to_angles (const graphene_quaternion_t *q,
float *deg_x,
float *deg_y,
float *deg_z)
{
graphene_vec4_t v;
graphene_vec4_t sq;
float qx, qy, qz, qw, sqx, sqy, sqz, sqw;
graphene_quaternion_to_vec4 (q, &v);
graphene_vec4_multiply (&v, &v, &sq);
qx = graphene_vec4_get_x (&v);
qy = graphene_vec4_get_y (&v);
qz = graphene_vec4_get_z (&v);
qw = graphene_vec4_get_w (&v);
sqx = graphene_vec4_get_x (&sq);
sqy = graphene_vec4_get_y (&sq);
sqz = graphene_vec4_get_z (&sq);
sqw = graphene_vec4_get_w (&sq);
if (deg_x != NULL)
{
float res = atan2f (2 * (qx * qw - qy * qz), (sqw - sqx - sqy + sqz));
*deg_x = GRAPHENE_RAD_TO_DEG (res);
}
if (deg_y != NULL)
{
float res = asinf (CLAMP (2 * ( qx * qz + qy * qw), -1, 1));
*deg_y = GRAPHENE_RAD_TO_DEG (res);
}
if (deg_z != NULL)
{
float res = atan2f (2 * (qz * qw - qx * qy), (sqw + sqx - sqy - sqz));
*deg_z = GRAPHENE_RAD_TO_DEG (res);
}
}
static void
quaternion_operators_normalize (mutest_spec_t *spec)
{
graphene_quaternion_t q1, q2;
graphene_vec4_t v1, v2;
graphene_quaternion_init (&q1, 1.f, 2.f, 3.f, 4.f);
graphene_quaternion_normalize (&q1, &q2);
graphene_vec4_init (&v1, 1.f, 2.f, 3.f, 4.f);
graphene_vec4_normalize (&v1, &v1);
graphene_quaternion_to_vec4 (&q2, &v2);
mutest_expect ("normalizing a quaternion is the same as normalizing the equivalent vec4",
mutest_bool_value (graphene_vec4_near (&v1, &v2, 0.00001f)),
mutest_to_be_true,
NULL);
}