Fix Quaternion.FromDirection giving bogus output when fed a perfect down vector

Source/Engine/Core/Math/Quaternion.cpp

@@ -294,6 +294,10 @@ Quaternion Quaternion::FromDirection(const Float3& direction)
     {
         RotationAxis(Float3::Left, PI_OVER_2, orientation);
     }
+    else if (Float3::Dot(direction, Float3::Down) >= 0.999f)
+    {
+        RotationAxis(Float3::Right, PI_OVER_2, orientation);
+    }
     else
     {
         Float3 right, up;

Source/Engine/Core/Math/Quaternion.cs

@@ -654,6 +654,10 @@ namespace FlaxEngine
             {
                 orientation = RotationAxis(Float3.Left, Mathf.PiOverTwo);
             }
+            else if (Float3.Dot(direction, Float3.Down) >= 0.999f)
+            {
+                orientation = RotationAxis(Float3.Right, Mathf.PiOverTwo);
+            }
             else
             {
                 var right = Float3.Cross(direction, Float3.Up);