add rotated method to vector3

data/scripts/types/vector3.lua

@@ -164,6 +164,22 @@ function Vector3:cross(with)
   }
 end
 
+
+function Vector3:rotated(axis, angle)
+  if not is_weak_vector3(axis) then
+    error("Vector3: axis must be a Vector3-like table. Returning Vector3()")
+    return Vector3()
+  end
+
+  axis = Vector3(axis):normalized()
+  local cosa = math.cos(angle)
+  local sina = math.sin(angle)
+  -- __mul is only defined for the left operand (table), numbers don't get metatables.
+  -- as such, the ordering of operations here is specific
+  local v = (self * cosa) + (axis * ((1 - cosa) * self:dot(axis))) + (axis:cross(self) * sina)
+  return v
+end
+
 ---- CONSTANTS
 
 Vector3.UP = Vector3(0, 1, 0)