quat 3 LIBG3D Library quat quaternion helpers #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); G3DQuattypedef G3DFloat G3DQuat; Quaternion element type. g3d_quat_addgboolean 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_normalizegboolean 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_rotategboolean 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_matrixgboolean 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_xyzgboolean 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_trackballgboolean 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