quat

quat — quaternion helpers

Synopsis


#include <g3d/quat.h>

typedef             G3DQuat;
gboolean            g3d_quat_add                        (G3DQuat *qr,
                                                         G3DQuat *q1,
                                                         G3DQuat *q2);
gboolean            g3d_quat_normalize                  (G3DQuat *q);
gboolean            g3d_quat_rotate                     (G3DQuat *q,
                                                         G3DVector *axis,
                                                         G3DFloat angle);
gboolean            g3d_quat_to_matrix                  (G3DQuat *q,
                                                         G3DMatrix *matrix);
gboolean            g3d_quat_to_rotation_xyz            (G3DQuat *q,
                                                         G3DFloat *rx,
                                                         G3DFloat *ry,
                                                         G3DFloat *rz);
gboolean            g3d_quat_trackball                  (G3DQuat *q,
                                                         G3DFloat x1,
                                                         G3DFloat y1,
                                                         G3DFloat x2,
                                                         G3DFloat y2,
                                                         G3DFloat r);

Description

Details

G3DQuat

typedef G3DFloat G3DQuat;

Quaternion element type.

g3d_quat_add ()

gboolean            g3d_quat_add                        (G3DQuat *qr,
                                                         G3DQuat *q1,
                                                         G3DQuat *q2);

Add two quats.

qr :

 result quat

q1 :

 first quat

q2 :

 second quat

Returns :

 TRUE on success, FALSE else

g3d_quat_normalize ()

gboolean            g3d_quat_normalize                  (G3DQuat *q);

normalize the quaternion to a length of 1.0.

q :

 a quaternion

Returns :

 TRUE on success, FALSE else

g3d_quat_rotate ()

gboolean            g3d_quat_rotate                     (G3DQuat *q,
                                                         G3DVector *axis,
                                                         G3DFloat angle);

Encode a rotation around an axis into quaternion.

q :

 resulting quat

axis :

 rotation axis

angle :

 rotation angle

Returns :

 TRUE on success, FALSE else

g3d_quat_to_matrix ()

gboolean            g3d_quat_to_matrix                  (G3DQuat *q,
                                                         G3DMatrix *matrix);

Convert a quaternion to a transformation matrix.

q :

 source quat

matrix :

 resulting matrix

Returns :

 TRUE on success, FALSE else

g3d_quat_to_rotation_xyz ()

gboolean            g3d_quat_to_rotation_xyz            (G3DQuat *q,
                                                         G3DFloat *rx,
                                                         G3DFloat *ry,
                                                         G3DFloat *rz);

Calculate the rotation around the three coordinate axes from a given quaternion.

q :

 a quaternion

rx :

 rotation around x axis

ry :

 rotation around y axis

rz :

 rotation around z axis

Returns :

 TRUE on success, FALSE else

g3d_quat_trackball ()

gboolean            g3d_quat_trackball                  (G3DQuat *q,
                                                         G3DFloat x1,
                                                         G3DFloat y1,
                                                         G3DFloat x2,
                                                         G3DFloat y2,
                                                         G3DFloat r);

Emulate a virtual trackball movement and return rotation as quaternion. The x and y values of the starting and end point of the movement have to be in the range -1.0 .. 1.0.

q :

 resulting quaternion

x1 :

 x value of first point

y1 :

 y value of first point

x2 :

 x value of second point

y2 :

 y value of second point

r :

 radius of virtual trackball, usually 0.8

Returns :

 TRUE on success, FALSE else
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