diff options
author | Matthew Hoops | 2011-07-02 15:23:49 -0400 |
---|---|---|
committer | Matthew Hoops | 2011-07-02 15:23:49 -0400 |
commit | 3aefa913faaf2a98512f02b0581ca8a077876b84 (patch) | |
tree | 9bc5436e68e1dd83bf5013f181ef864c5c35e2d2 /common/fft.h | |
parent | 0aa58b9033ee83b3008a7f4ac48d10baa6c7335d (diff) | |
download | scummvm-rg350-3aefa913faaf2a98512f02b0581ca8a077876b84.tar.gz scummvm-rg350-3aefa913faaf2a98512f02b0581ca8a077876b84.tar.bz2 scummvm-rg350-3aefa913faaf2a98512f02b0581ca8a077876b84.zip |
COMMON: Add an FFT math handler
Based on eos' code which is based on FFmpeg's code
Diffstat (limited to 'common/fft.h')
-rw-r--r-- | common/fft.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/common/fft.h b/common/fft.h new file mode 100644 index 0000000000..17d1ef0055 --- /dev/null +++ b/common/fft.h @@ -0,0 +1,73 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + */ + +// Based on eos' (I)FFT code which is in turn +// based upon the (I)FFT code in FFmpeg +// Copyright (c) 2008 Loren Merritt +// Copyright (c) 2002 Fabrice Bellard +// Partly based on libdjbfft by D. J. Bernstein + +#ifndef COMMON_FFT_H +#define COMMON_FFT_H + +#include "common/scummsys.h" +#include "common/math.h" + +namespace Common { + +/** (Inverse) Fast Fourier Transform. */ +class FFT { +public: + FFT(int bits, int inverse); + ~FFT(); + + /** Do the permutation needed BEFORE calling calc(). */ + void permute(Complex *z); + + /** Do a complex FFT. + * + * The input data must be permuted before. + * No 1.0/sqrt(n) normalization is done. + */ + void calc(Complex *z); + +private: + int _bits; + int _inverse; + + uint16 *_revTab; + + Complex *_expTab; + Complex *_tmpBuf; + + const float *_tSin; + const float *_tCos; + + int _splitRadix; + int _permutation; + + static int splitRadixPermutation(int i, int n, int inverse); +}; + +} // End of namespace Common + +#endif // COMMON_FFT_H |