Use UENUM as BitMask

I can’t find any good examples, but what would the correct way to use a UENUM as a Bitmask?

For example:

namespace EBitMask
{
    enum BitMask
    {
        BM_FirstValue = 1    UMETA(DisplayName = "First Value"),
        BM_SecondValue = 2 	UMETA(DisplayName = "Second Value"),
        BM_ThirdValue = 4 	UMETA(DisplayName = "Third Value"),
        BM_FourthValue= 8 	UMETA(DisplayName = "Fourth Value"),
        BM_FifthValue = 16    UMETA(DisplayName = "Fifth Value"),

        //
        BM_Max		UMETA(Hidden),
    };
}

In C++ it should work i think as enum is enum, in blueprint it won’t as it does not know how to handle bit flags, you would need to write some blueprint functions in C++ to be able to operate them in blueprint

It’s better to use hex on flags (0x01,0x02,0x04,0x08,0x10,0x20 ect.), use as many zeros ahead as much as you need to fit all flags

That’s entirely a personal preference. I either use bitshifts when setting them, or using hexadecimals as Shadowriver suggests.

enum BitMask
{
         BM_FirstValue  = (1 << 0)    UMETA(DisplayName = "First Value"),
         BM_SecondValue = (1 << 1)    UMETA(DisplayName = "Second Value"),
         BM_ThirdValue  = (1 << 2)    UMETA(DisplayName = "Third Value"),
         BM_FourthValue = (1 << 3)    UMETA(DisplayName = "Fourth Value"),
         BM_FifthValue  = (1 << 4)    UMETA(DisplayName = "Fifth Value"),
         // ...
         BM_Max        UMETA(Hidden),
};

and

enum BitMask
{
         BM_FirstValue  = 0x01    UMETA(DisplayName = "First Value"),
         BM_SecondValue = 0x02    UMETA(DisplayName = "Second Value"),
         BM_ThirdValue  = 0x04    UMETA(DisplayName = "Third Value"),
         BM_FourthValue = 0x08    UMETA(DisplayName = "Fourth Value"),
         BM_FifthValue  = 0x10    UMETA(DisplayName = "Fifth Value"),
         // ...
         BM_Max        UMETA(Hidden),
};