From e2ec045cc995bb8767a5f88e8830aa1062921011 Mon Sep 17 00:00:00 2001 From: Campbell Barton Date: Tue, 19 Mar 2019 16:50:18 +1100 Subject: BLI_math: add utility to calculate compatible quaternions --- source/blender/blenlib/BLI_math_rotation.h | 2 ++ source/blender/blenlib/intern/math_rotation.c | 17 +++++++++++++++++ 2 files changed, 19 insertions(+) (limited to 'source/blender/blenlib') diff --git a/source/blender/blenlib/BLI_math_rotation.h b/source/blender/blenlib/BLI_math_rotation.h index 5246d7ad1a9..60adcf8c762 100644 --- a/source/blender/blenlib/BLI_math_rotation.h +++ b/source/blender/blenlib/BLI_math_rotation.h @@ -77,6 +77,8 @@ void add_qt_qtqt(float q[4], const float a[4], const float b[4], const float t); void quat_to_mat3(float mat[3][3], const float q[4]); void quat_to_mat4(float mat[4][4], const float q[4]); +void quat_to_compatible_quat(float q[4], const float a[4], const float old[4]); + void mat3_normalized_to_quat(float q[4], const float mat[3][3]); void mat4_normalized_to_quat(float q[4], const float mat[4][4]); void mat3_to_quat(float q[4], const float mat[3][3]); diff --git a/source/blender/blenlib/intern/math_rotation.c b/source/blender/blenlib/intern/math_rotation.c index a348edaece8..d52c8f54096 100644 --- a/source/blender/blenlib/intern/math_rotation.c +++ b/source/blender/blenlib/intern/math_rotation.c @@ -201,6 +201,23 @@ void pow_qt_fl_normalized(float q[4], const float fac) normalize_v3_length(q + 1, si); } +/** + * Apply the rotation of \a a to \a q keeping the values compatible with \a old. + * Avoid axis flipping for animated f-curves for eg. + */ +void quat_to_compatible_quat(float q[4], const float a[4], const float old[4]) +{ + BLI_ASSERT_UNIT_QUAT(a); + float delta[4]; + float old_unit[4]; + normalize_qt_qt(old_unit, old); + rotation_between_quats_to_quat(delta, old_unit, a); + mul_qt_qtqt(q, old, delta); + if ((q[0] < 0.0f) != (old[0] < 0.0f)) { + negate_v4(q); + } +} + /* skip error check, currently only needed by mat3_to_quat_is_ok */ static void quat_to_mat3_no_error(float m[3][3], const float q[4]) { -- cgit v1.2.3