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。他们为什么这样做？

Answer 1

独立bool至少有一个字节长。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，你就不需要每个字节都有一个字节。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。

为什么我应该使用1位位域而不是布尔？

1 个答案: