Explicitly documented that Transform.basis is not necessarily an orthogonal matrix.

Also added a check that in axis-angle rotations, axis is a normalized vector, and modified the docs accordingly.

Fixes #8113.

2 files changed, 7 insertions, 0 deletions

diff --git a/core/math/matrix3.cpp b/core/math/matrix3.cpp
index 5f73d91ef3..f154552a3e 100644
--- a/core/math/matrix3.cpp
+++ b/core/math/matrix3.cpp
@@ -575,6 +575,8 @@ Basis::Basis(const Quat &p_quat) {
 Basis::Basis(const Vector3 &p_axis, real_t p_phi) {
 	// Rotation matrix from axis and angle, see https://en.wikipedia.org/wiki/Rotation_matrix#Rotation_matrix_from_axis_and_angle
 
+	ERR_FAIL_COND(p_axis.is_normalized() == false);
+
 	Vector3 axis_sq(p_axis.x * p_axis.x, p_axis.y * p_axis.y, p_axis.z * p_axis.z);
 
 	real_t cosine = Math::cos(p_phi);
diff --git a/core/math/vector3.h b/core/math/vector3.h
index fc02e66c33..097d6b9480 100644
--- a/core/math/vector3.h
+++ b/core/math/vector3.h
@@ -75,6 +75,7 @@ struct Vector3 {
 
 	_FORCE_INLINE_ void normalize();
 	_FORCE_INLINE_ Vector3 normalized() const;
+	_FORCE_INLINE_ bool is_normalized() const;
 	_FORCE_INLINE_ Vector3 inverse() const;
 
 	_FORCE_INLINE_ void zero();
@@ -385,6 +386,10 @@ Vector3 Vector3::normalized() const {
 	return v;
 }
 
+bool Vector3::is_normalized() const {
+	return Math::isequal_approx(length(), (real_t)1.0);
+}
+
 Vector3 Vector3::inverse() const {
 
 	return Vector3(1.0 / x, 1.0 / y, 1.0 / z);