为什么我应该使用1位位域而不是布尔？

Question

UCLASS(abstract, config=Game, BlueprintType, hidecategories=("Pawn|Character|InternalEvents"))
class ENGINE_API ACharacter : public APawn
{
    GENERATED_UCLASS_BODY() 
...
    UPROPERTY(Transient)
    uint32 bClientWasFalling:1; 

    /** If server disagrees with root motion track position, client has to resimulate root motion from last AckedMove. */
    UPROPERTY(Transient)
    uint32 bClientResimulateRootMotion:1;

    /** Disable simulated gravity (set when character encroaches geometry on client, to keep him from falling through floors) */
    UPROPERTY()
    uint32 bSimGravityDisabled:1;

    /** 
     * Jump key Held Time.
     * This is the time that the player has held the jump key, in seconds.
     */
    UPROPERTY(Transient, BlueprintReadOnly, VisibleInstanceOnly, Category=Character)
    float JumpKeyHoldTime;

上面的代码来自UE4.他们似乎使用uint32一位bitfield而不是bools.他们为什么要这样做？

Answer 1

独立bool的至少一个字节长.处理器无法处理较小的单元.但是,我们都知道一个字节可以容纳8位/ bool,所以如果你有一个包含多个bool的数据结构,那么每个字节都不需要一个字节.他们可以共享一个字节.如果你有很多这样的结构,它可能会节省一些内存.