求帮忙、求大神

.......，要干什么，说明白点~~

Assets/Standard Assets/Water (Pro Only)/Water4/Sources/Scripts/PlanarReflection.cs(163,54): error CS1061: Type `UnityEngine.Camera' does not contain a definition for `CalculateObliqueMatrix' and no extension method `CalculateObliqueMatrix' of type `UnityEngine.Camera' could be found (are you missing a using directive or an assembly reference? 这怎么弄？