Bias octahedral tangent y axis to avoid errors around 0

core/math/vector3.cpp

@@ -108,7 +108,9 @@ Vector3 Vector3::octahedron_decode(const Vector2 &p_oct) {
 }
 
 Vector2 Vector3::octahedron_tangent_encode(const float sign) const {
+	const float bias = 1.0f / 32767.0f;
 	Vector2 res = this->octahedron_encode();
+	res.y = MAX(res.y, bias);
 	res.y = res.y * 0.5f + 0.5f;
 	res.y = sign >= 0.0f ? res.y : 1 - res.y;
 	return res;