FFTInitializeUnityTable

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

void FFTInitializeUnityTable(XMVECTOR* pUnityTable, size_t uLength);

Parameters

pUnityTable

[out] Caller-provided array of XVECTOR elements that will be populated with the unity table values. The array passed to pUnityTable must be at least uLength elements long.

uLength

[in] The FFT length in frames (sample count / channel count). uLength must be a power of two and must be greater than 16.

Remarks

Once initialized, the table does not need to be initialized again unless you want 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 32-bit float mono.