Skip to main content

​
FFTInitializeUnityTable

Initializes a unity roots lookup table used by Fast Fourier Transform functions.

​
Syntax

​
Parameters

pUnityTable   _Out_writes_(uLength)
Type: XMVECTOR* __restrict Caller-provided array of XMVECTOR elements that will be populated with the unity table values. The array passed to pUnityTable must be at least uLength elements long. uLength   _In_
Type: size_t FFT length in frames (sample count / channel count). uLength must be a power of two and greater than 16.

​
Return value

Type: void None.

​
Remarks

Once it is initialized, the table does not need to be initialized again unless you require a different FFT length. Unity tables for FFT lengths of 16 and below are hard-coded into the respective FFT functions: FFT16, FFT8, and FFT4. They do not need to be initialized. All buffer parameters must be 16-byte aligned. Audio data must be FLOAT32 mono.

​
Requirements

Header: xdsp.h Supported platforms: XBOX One family consoles and XBOX Series consoles

​
See also

xdsp FFTInterleaved
Last modified on August 20, 2026