XMVectorLerp function (directxmath.h)

Article
02/22/2024

Performs a linear interpolation between two vectors.

Syntax

XMVECTOR XM_CALLCONV XMVectorLerp(
  [in] FXMVECTOR V0,
  [in] FXMVECTOR V1,
  [in] float     t
) noexcept;

Parameters

[in] V0

First vector to interpolate from.

[in] V1

Second vector to interpolate from.

[in] t

Interpolation control factor.

Return value

Returns a vector containing the interpolation.

Remarks

The following pseudocode demonstrates the operation of the function:

XMVECTOR Result;

Result.x = V0.x + t * (V1.x - V0.x);
Result.y = V0.y + t * (V1.y - V0.y);
Result.z = V0.z + t * (V1.z - V0.z);
Result.w = V0.w + t * (V1.w - V0.w);

return Result;

Note it is fairly simple to use this function for doing a cubic interpolation instead of a linear interpolation as follows:


XMVECTOR SmoothStep( XMVECTOR V0, XMVECTOR V1, float t )
{
    t = (t > 1.0f) ? 1.0f : ((t < 0.0f) ? 0.0f : t);  // Clamp value to 0 to 1
    t = t*t*(3.f - 2.f*t);
    return XMVectorLerp( V0, V1, t );
}

Platform Requirements

Microsoft Visual Studio 2010 or Microsoft Visual Studio 2012 with the Windows SDK for Windows 8. Supported for Win32 desktop apps, Windows Store apps, and Windows Phone 8 apps.

Requirements

Requirement	Value
Target Platform	Windows
Header	directxmath.h (include DirectXMath.h)