mirror of https://github.com/axmolengine/axmol.git
39 lines
1.3 KiB
C
39 lines
1.3 KiB
C
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#ifndef ALCOMPLEX_H
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#define ALCOMPLEX_H
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#include <complex>
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#include "alspan.h"
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/**
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* Iterative implementation of 2-radix FFT (In-place algorithm). Sign = -1 is
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* FFT and 1 is inverse FFT. Applies the Discrete Fourier Transform (DFT) to
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* the data supplied in the buffer, which MUST BE power of two.
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*/
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void complex_fft(const al::span<std::complex<double>> buffer, const double sign);
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/**
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* Calculate the frequency-domain response of the time-domain signal in the
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* provided buffer, which MUST BE power of two.
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*/
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inline void forward_fft(const al::span<std::complex<double>> buffer)
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{ complex_fft(buffer, -1.0); }
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/**
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* Calculate the time-domain signal of the frequency-domain response in the
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* provided buffer, which MUST BE power of two.
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*/
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inline void inverse_fft(const al::span<std::complex<double>> buffer)
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{ complex_fft(buffer, 1.0); }
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/**
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* Calculate the complex helical sequence (discrete-time analytical signal) of
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* the given input using the discrete Hilbert transform (In-place algorithm).
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* Fills the buffer with the discrete-time analytical signal stored in the
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* buffer. The buffer is an array of complex numbers and MUST BE power of two,
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* and the imaginary components should be cleared to 0.
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*/
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void complex_hilbert(const al::span<std::complex<double>> buffer);
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#endif /* ALCOMPLEX_H */
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