4.8 Transition Guide

Development Programming & Scripting C++
39

OverlapSingle -> OverlapMultiByChannel

Dear Community,

OverlapSingle is deprecated and we must now decide which overlap to use from OverlapMultiByChannel

's an example of how I chose to transition one of my static library functions that performs a Sphere overlap test

Old Code



static FORCEINLINE bool SphereOverlapTest(
	UWorld* World, 
	AActor* ActorToIgnore,
	const FBox& Box,
	FOverlapResult& HitOut,
	ECollisionChannel TraceChannel,
	FQuat Rotation = FQuat::Identity
){
	FCollisionQueryParams TraceParams(FName(TEXT("VictoreCore Trace")), true, ActorToIgnore);
	TraceParams.bTraceComplex = true;
 
	//Ignore Actors
	TraceParams.AddIgnoredActor(ActorToIgnore);
	
	//Re-initialize hit info
	HitOut = FOverlapResult();
	  
	return World->**OverlapSingle**(
		HitOut, 
		Box.GetCenter(), 
		Rotation, 
		TraceChannel, 		//! <~~~~
		FCollisionShape::MakeBox(Box.GetExtent()), 
		TraceParams
	);
}

4.8 Code

Notice I am choosing to always use the first overlap.

Please see comment by Epic regarding this matter.

My current implementation is really only good for knowing if any overlaps occur at all, as the first overlap is not necessarily the closest, as per 's comment above.



//New Code, Implementation is to always use the first overlap from the array.
static FORCEINLINE bool SphereOverlapTest(
	UWorld* World, 
	AActor* ActorToIgnore,
	const FBox& Box,
	FOverlapResult& HitOut,
	ECollisionChannel TraceChannel,
	FQuat Rotation = FQuat::Identity
){
	FCollisionQueryParams TraceParams(FName(TEXT("VictoreCore Trace")), true, ActorToIgnore);
	TraceParams.bTraceComplex = true;
 
	//Ignore Actors
	TraceParams.AddIgnoredActor(ActorToIgnore);
	
	//Re-initialize hit info
	HitOut = FOverlapResult();
	 
	TArray<FOverlapResult> Overlaps;
	bool bAnyOverlaps = World->**OverlapMultiByChannel**(
		Overlaps,
		Box.GetCenter(), 
		Rotation, 
		TraceChannel, 		//! <~~~~
		FCollisionShape::MakeBox(Box.GetExtent()), 
		TraceParams
	);
	if (!bAnyOverlaps || Overlaps.Num() < 1) //extra array access safety check
        {
            return false;
	}

	//Always use first overlap!
	HitOut = Overlaps[0];
	 
	return true;
}

Enjoy!

:slight_smile: