diff options
Diffstat (limited to 'source/blender/blenlib/intern/math_rotation.c')
| -rw-r--r-- | source/blender/blenlib/intern/math_rotation.c | 101 |
1 files changed, 60 insertions, 41 deletions
diff --git a/source/blender/blenlib/intern/math_rotation.c b/source/blender/blenlib/intern/math_rotation.c index ff45bbee5c9..180412c4a14 100644 --- a/source/blender/blenlib/intern/math_rotation.c +++ b/source/blender/blenlib/intern/math_rotation.c @@ -275,64 +275,83 @@ void mat3_normalized_to_quat_fast(float q[4], const float mat[3][3]) /* Caller must ensure matrices aren't negative for valid results, see: T24291, T94231. */ BLI_assert(!is_negative_m3(mat)); - /* Check the trace of the matrix - bad precision if close to -1. */ - const float trace = mat[0][0] + mat[1][1] + mat[2][2]; - - if (trace > 0) { - float s = 2.0f * sqrtf(1.0f + trace); - - q[0] = 0.25f * s; - - s = 1.0f / s; - - q[1] = (mat[1][2] - mat[2][1]) * s; - q[2] = (mat[2][0] - mat[0][2]) * s; - q[3] = (mat[0][1] - mat[1][0]) * s; - } - else { - /* Find the biggest diagonal element to choose the best formula. - * Here trace should also be always >= 0, avoiding bad precision. */ - if (mat[0][0] > mat[1][1] && mat[0][0] > mat[2][2]) { - float s = 2.0f * sqrtf(1.0f + mat[0][0] - mat[1][1] - mat[2][2]); - + /* Method outlined by Mike Day, ref: https://math.stackexchange.com/a/3183435/220949 + * with an additional `sqrtf(..)` for higher precision result. + * Removing the `sqrt` causes tests to fail unless the precision is set to 1e-6 or larger. */ + + if (mat[2][2] < 0.0f) { + if (mat[0][0] > mat[1][1]) { + const float trace = 1.0f + mat[0][0] - mat[1][1] - mat[2][2]; + float s = 2.0f * sqrtf(trace); + if (mat[1][2] < mat[2][1]) { + /* Ensure W is non-negative for a canonical result. */ + s = -s; + } q[1] = 0.25f * s; - s = 1.0f / s; - q[0] = (mat[1][2] - mat[2][1]) * s; - q[2] = (mat[1][0] + mat[0][1]) * s; + q[2] = (mat[0][1] + mat[1][0]) * s; q[3] = (mat[2][0] + mat[0][2]) * s; + if (UNLIKELY((trace == 1.0f) && (q[0] == 0.0f && q[2] == 0.0f && q[3] == 0.0f))) { + /* Avoids the need to normalize the degenerate case. */ + q[1] = 1.0f; + } } - else if (mat[1][1] > mat[2][2]) { - float s = 2.0f * sqrtf(1.0f + mat[1][1] - mat[0][0] - mat[2][2]); - + else { + const float trace = 1.0f - mat[0][0] + mat[1][1] - mat[2][2]; + float s = 2.0f * sqrtf(trace); + if (mat[2][0] < mat[0][2]) { + /* Ensure W is non-negative for a canonical result. */ + s = -s; + } q[2] = 0.25f * s; - s = 1.0f / s; - q[0] = (mat[2][0] - mat[0][2]) * s; - q[1] = (mat[1][0] + mat[0][1]) * s; - q[3] = (mat[2][1] + mat[1][2]) * s; + q[1] = (mat[0][1] + mat[1][0]) * s; + q[3] = (mat[1][2] + mat[2][1]) * s; + if (UNLIKELY((trace == 1.0f) && (q[0] == 0.0f && q[1] == 0.0f && q[3] == 0.0f))) { + /* Avoids the need to normalize the degenerate case. */ + q[2] = 1.0f; + } } - else { - float s = 2.0f * sqrtf(1.0f + mat[2][2] - mat[0][0] - mat[1][1]); - + } + else { + if (mat[0][0] < -mat[1][1]) { + const float trace = 1.0f - mat[0][0] - mat[1][1] + mat[2][2]; + float s = 2.0f * sqrtf(trace); + if (mat[0][1] < mat[1][0]) { + /* Ensure W is non-negative for a canonical result. */ + s = -s; + } q[3] = 0.25f * s; - s = 1.0f / s; - q[0] = (mat[0][1] - mat[1][0]) * s; q[1] = (mat[2][0] + mat[0][2]) * s; - q[2] = (mat[2][1] + mat[1][2]) * s; + q[2] = (mat[1][2] + mat[2][1]) * s; + if (UNLIKELY((trace == 1.0f) && (q[0] == 0.0f && q[1] == 0.0f && q[2] == 0.0f))) { + /* Avoids the need to normalize the degenerate case. */ + q[3] = 1.0f; + } } - - /* Make sure W is non-negative for a canonical result. */ - if (q[0] < 0) { - negate_v4(q); + else { + /* NOTE(@campbellbarton): A zero matrix will fall through to this block, + * needed so a zero scaled matrices to return a quaternion without rotation, see: T101848. */ + const float trace = 1.0f + mat[0][0] + mat[1][1] + mat[2][2]; + float s = 2.0f * sqrtf(trace); + q[0] = 0.25f * s; + s = 1.0f / s; + q[1] = (mat[1][2] - mat[2][1]) * s; + q[2] = (mat[2][0] - mat[0][2]) * s; + q[3] = (mat[0][1] - mat[1][0]) * s; + if (UNLIKELY((trace == 1.0f) && (q[1] == 0.0f && q[2] == 0.0f && q[3] == 0.0f))) { + /* Avoids the need to normalize the degenerate case. */ + q[0] = 1.0f; + } } } - normalize_qt(q); + BLI_assert(!(q[0] < 0.0f)); + BLI_ASSERT_UNIT_QUAT(q); } static void mat3_normalized_to_quat_with_checks(float q[4], float mat[3][3]) |