Merge branch 'master' into temp-sculpt-roll-mappingtemp-sculpt-roll-mapping

1 files changed, 16 insertions, 0 deletions

diff --git a/source/blender/blenlib/tests/BLI_math_rotation_test.cc b/source/blender/blenlib/tests/BLI_math_rotation_test.cc
index e37b212e1df..0c8ae38c386 100644
--- a/source/blender/blenlib/tests/BLI_math_rotation_test.cc
+++ b/source/blender/blenlib/tests/BLI_math_rotation_test.cc
@@ -3,6 +3,7 @@
 #include "testing/testing.h"
 
 #include "BLI_math_base.h"
+#include "BLI_math_matrix.h"
 #include "BLI_math_rotation.h"
 #include "BLI_math_rotation.hh"
 #include "BLI_math_vector.hh"
@@ -138,6 +139,21 @@ TEST(math_rotation, quat_to_mat_to_quat_near_0001)
   test_quat_to_mat_to_quat(0.30f, -0.030f, -0.30f, 0.95f);
 }
 
+/* A zeroed matrix converted to a quaternion and back should not add rotation, see: T101848 */
+TEST(math_rotation, quat_to_mat_to_quat_zeroed_matrix)
+{
+  float matrix_zeroed[3][3] = {{0.0f}};
+  float matrix_result[3][3];
+  float matrix_unit[3][3];
+  float out_quat[4];
+
+  unit_m3(matrix_unit);
+  mat3_normalized_to_quat(out_quat, matrix_zeroed);
+  quat_to_mat3(matrix_result, out_quat);
+
+  EXPECT_M3_NEAR(matrix_unit, matrix_result, FLT_EPSILON);
+}
+
 TEST(math_rotation, quat_split_swing_and_twist_negative)
 {
   const float input[4] = {-0.5f, 0, sqrtf(3) / 2, 0};