[UE4]GameplayStatics‘s API in common use

keywords: [UE4]GameplayStatics‘s API in common use, GameplayStatics

Common functions

/**
* Counts how many grass foliage instances overlap a given sphere.
*
* @param    Mesh            The static mesh we are interested in counting.
* @param    CenterPosition    The center position of the sphere.
* @param    Radius            The radius of the sphere.
*
* @return Number of foliage instances with their mesh set to Mesh that overlap the sphere.
*/
UFUNCTION(BlueprintCallable, Category = "Foliage", meta = (WorldContext = "WorldContextObject", UnsafeDuringActorConstruction = "true"))
static int32 GrassOverlappingSphereCount(const UObject* WorldContextObject, const UStaticMesh* StaticMesh, FVector CenterPosition, float Radius);

/** 
 * Transforms the given 2D screen space coordinate into a 3D world-space point and direction.
 * @param Player            Deproject using this player's view.
 * @param ScreenPosition    2D screen space to deproject.
 * @param WorldPosition        (out) Corresponding 3D position in world space.
 * @param WorldDirection    (out) World space direction vector away from the camera at the given 2d point.
 */
UFUNCTION(BlueprintPure, Category = "Utilities", meta = (Keywords = "unproject"))
static bool DeprojectScreenToWorld(APlayerController const* Player, const FVector2D& ScreenPosition, FVector& WorldPosition, FVector& WorldDirection);

/** 
 * Transforms the given 3D world-space point into a its 2D screen space coordinate. 
 * @param Player            Project using this player's view.
 * @param WorldPosition        World position to project.
 * @param ScreenPosition    (out) Corresponding 2D position in screen space
 * @param bPlayerViewportRelative    Should this be relative to the player viewport subregion (useful when using player attached widgets in split screen)
 */
UFUNCTION(BlueprintPure, Category = "Utilities")
static bool ProjectWorldToScreen(APlayerController const* Player, const FVector& WorldPosition, FVector2D& ScreenPosition, bool bPlayerViewportRelative = false);

/**
 * Plays a sound directly with no attenuation, perfect for UI sounds.
 *
 * * Fire and Forget.
 * * Not Replicated.
 * @param Sound - Sound to play.
 * @param VolumeMultiplier - Multiplied with the volume to make the sound louder or softer.
 * @param PitchMultiplier - Multiplies the pitch.
 * @param ConcurrencySettings - Override concurrency settings package to play sound with
 * @param StartTime - How far in to the sound to begin playback at
 * @param ConcurrencySettings - Override concurrency settings package to play sound with
 * @param OwningActor - The actor to use as the "owner" for concurrency settings purposes. Allows PlaySound calls to do a concurrency limit per owner.
 */
UFUNCTION(BlueprintCallable, BlueprintCosmetic, Category="Audio", meta=( WorldContext="WorldContextObject", AdvancedDisplay = "2", UnsafeDuringActorConstruction = "true" ))
static void PlaySound2D(const UObject* WorldContextObject, USoundBase* Sound, float VolumeMultiplier = 1.f, float PitchMultiplier = 1.f, float StartTime = 0.f, USoundConcurrency* ConcurrencySettings = nullptr, AActor* OwningActor = nullptr);

/**
* Predict the arc of a virtual projectile affected by gravity with collision checks along the arc.
* Returns true if it hit something.
*
* @param PredictParams              Input params to the trace (start location, velocity, time to simulate, etc).
* @param PredictResult              Output result of the trace (Hit result, array of location/velocity/times for each trace step, etc).
* @return                           True if hit something along the path (if tracing with collision).
*/
static bool PredictProjectilePath(const UObject* WorldContextObject, const FPredictProjectilePathParams& PredictParams, FPredictProjectilePathResult& PredictResult);

The meaning of ProjectWorldToScreen’s return value

Even when the Actor is in LEFT BACK or RIGHT BACK of Camera, ProjectWorldToScreen still would return true,
when Actor is in RIGHT BEHIND of Camera, ProjectWorldToScreen would return false.
So we can use this value to check if is need to update icon’s position on screen for Target Direction Tips logic (Navigation suggestion).

每当我们无能为力的时候，我们就总爱说顺其自然。