AActor::GetHorizontalDotProductTo
#include "GameFramework/Actor.h"
Access: public
Specifiers: UFUNCTIONBlueprintCallableconst
Description
Returns the dot product between this actor's forward vector and the horizontal (XY-plane) direction to OtherActor. Ignores Z, making it reliable for checking whether an actor is facing another on flat ground.
Caveats & Gotchas
- • Returns -2.0 on failure and 0.0 for coincident actors — always guard against -2.0 before interpreting the result as a real angle.
- • Flattens both vectors to 2D before computing, so vertical offset between actors is ignored entirely. If you need to account for pitch (e.g., a turret aiming up), use GetDotProductTo instead.
Signature
ENGINE_API float GetHorizontalDotProductTo(const AActor* OtherActor) const;Parameters
| Name | Type | Description | Default |
|---|---|---|---|
| OtherActor | const AActor* | The other actor to compute the horizontal dot product toward. | — |
Return Type
float Example
Simple field-of-view check on the XY plane C++
float HDot = Guard->GetHorizontalDotProductTo(Player);
if (HDot != -2.f && HDot > FMath::Cos(FMath::DegreesToRadians(60.f)))
{
Guard->AlertToPlayer(Player);
}Tags
Version History
Introduced in: 4.0
| Version | Status | Notes |
|---|---|---|
| 5.6 | stable | — |
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