diff options
Diffstat (limited to 'source/blender/blenlib/intern/math_rotation.c')
| -rw-r--r-- | source/blender/blenlib/intern/math_rotation.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/source/blender/blenlib/intern/math_rotation.c b/source/blender/blenlib/intern/math_rotation.c index a0ee16bee76..19828e69638 100644 --- a/source/blender/blenlib/intern/math_rotation.c +++ b/source/blender/blenlib/intern/math_rotation.c @@ -372,6 +372,11 @@ void mat3_normalized_to_quat(float q[4], const float mat[3][3]) q[1] = (mat[2][0] + mat[0][2]) * s; q[2] = (mat[2][1] + mat[1][2]) * s; } + + /* Make sure w is nonnegative for a canonical result. */ + if (q[0] < 0) { + negate_v4(q); + } } normalize_qt(q); @@ -556,10 +561,20 @@ void rotation_between_quats_to_quat(float q[4], const float q1[4], const float q * \param r_twist: if not NULL, receives the twist quaternion. * \returns twist angle. */ -float quat_split_swing_and_twist(const float q[4], int axis, float r_swing[4], float r_twist[4]) +float quat_split_swing_and_twist(const float q_in[4], int axis, float r_swing[4], float r_twist[4]) { BLI_assert(axis >= 0 && axis <= 2); + /* The calculation requires a canonical quaternion. */ + float q[4]; + + if (q_in[0] < 0) { + negate_v4_v4(q, q_in); + } + else { + copy_v4_v4(q, q_in); + } + /* Half-twist angle can be computed directly. */ float t = atan2f(q[axis + 1], q[0]); |