FMath::Cos

function Core Since 4.0

#include "GenericPlatform/GenericPlatformMath.h"

Access: public Specifiers: static

Description

Returns the cosine of an angle given in radians. A double overload exists for higher precision. Returns values in the range [-1, 1].

Signature

static UE_FORCEINLINE_HINT float Cos(float Value)

Parameters

Name	Type	Description	Default
Value	float	Angle in radians.	—

Return Type

float

Caveats & Gotchas

• Input is in radians, not degrees. Use FMath::DegreesToRadians to convert.
• When computing both sine and cosine for the same angle (e.g. constructing a rotation matrix), use FMath::SinCos to compute both in a single call — it is significantly cheaper than two separate calls.
• For large input values, floating-point precision degrades. If your angle accumulator grows over time (e.g. total elapsed time * frequency), wrap it with FMath::Fmod(Angle, 2*PI) periodically.

Example

Spawn actors in a circle using sin/cos C++

const int32 Count = 8;
const float Radius = 500.f;
for (int32 i = 0; i < Count; ++i)
{
    float Angle = (2.f * PI * i) / Count;
    FVector Offset(FMath::Cos(Angle) * Radius, FMath::Sin(Angle) * Radius, 0.f);
    SpawnActorAt(GetActorLocation() + Offset);
}

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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