diff options
Diffstat (limited to 'src/gui/math3d/qquaternion.cpp')
| -rw-r--r-- | src/gui/math3d/qquaternion.cpp | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/gui/math3d/qquaternion.cpp b/src/gui/math3d/qquaternion.cpp index 93e396c5a1..2f12accc41 100644 --- a/src/gui/math3d/qquaternion.cpp +++ b/src/gui/math3d/qquaternion.cpp @@ -495,8 +495,9 @@ void QQuaternion::getEulerAngles(float *pitch, float *yaw, float *roll) const // https://ingmec.ual.es/~jlblanco/papers/jlblanco2010geometry3D_techrep.pdf // "A tutorial on SE(3) transformation parameterizations and on-manifold optimization". - // Normalize values even if the length is below the margin. Otherwise we might fail - // to detect Gimbal lock due to cumulative errors. + // We can only detect Gimbal lock when we normalize, which we can't do when + // length is nearly zero. Do so before multiplying co-ordinates, to avoid + // underflow. const float len = length(); const bool rescale = !qFuzzyIsNull(len); const float xps = rescale ? xp / len : xp; |