100 lines
3 KiB
C++
100 lines
3 KiB
C++
/**
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* PANDA 3D SOFTWARE
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* Copyright (c) Carnegie Mellon University. All rights reserved.
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*
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* All use of this software is subject to the terms of the revised BSD
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* license. You should have received a copy of this license along
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* with this source code in a file named "LICENSE."
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*
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* @file fftCompressor.h
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* @author drose
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* @date 2000-12-11
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*/
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#ifndef FFTCOMPRESSOR_H
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#define FFTCOMPRESSOR_H
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#include "pandabase.h"
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#include "pvector.h"
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#include "pointerToArray.h"
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#include "vector_stdfloat.h"
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#include "vector_double.h"
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#include "luse.h"
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class Datagram;
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class DatagramIterator;
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/**
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* This class manages a lossy compression and decompression of a stream of
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* floating-point numbers to a datagram, based a fourier transform algorithm
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* (similar in principle to JPEG compression).
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*
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* Actually, it doesn't do any real compression on its own; it just outputs a
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* stream of integers that should compress much tighter via gzip than the
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* original stream of floats would have.
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*
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* This class depends on the external FFTW library; without it, it will fall
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* back on lossless output of the original data.
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*/
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class EXPCL_PANDA_MATHUTIL FFTCompressor {
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public:
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FFTCompressor();
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static bool is_compression_available();
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void set_quality(int quality);
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int get_quality() const;
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void set_use_error_threshold(bool use_error_threshold);
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bool get_use_error_threshold() const;
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void set_transpose_quats(bool flag);
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bool get_transpose_quats() const;
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void write_header(Datagram &datagram);
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void write_reals(Datagram &datagram, const PN_stdfloat *array, int length);
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void write_hprs(Datagram &datagram, const LVecBase3 *array, int length);
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bool read_header(DatagramIterator &di, int bam_minor_version);
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bool read_reals(DatagramIterator &di, vector_stdfloat &array);
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bool read_hprs(DatagramIterator &di, pvector<LVecBase3> &array,
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bool new_hpr);
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bool read_hprs(DatagramIterator &di, pvector<LVecBase3> &array);
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static void free_storage();
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private:
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enum RunWidth {
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// We write a byte to the datagram at the beginning of each run to encode
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// the width and length of the run. The width is indicated by the top two
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// bits, while the length fits in the lower six, except RW_double, which
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// is a special case.
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RW_width_mask = 0xc0,
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RW_length_mask = 0x3f,
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RW_0 = 0x00,
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RW_8 = 0x40,
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RW_16 = 0x80,
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RW_32 = 0xc0,
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RW_double = 0xff,
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RW_invalid = 0x01
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};
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int write_run(Datagram &datagram, RunWidth run_width,
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const vector_double &run);
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int read_run(DatagramIterator &di, vector_double &run);
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double get_scale_factor(int i, int length) const;
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static double interpolate(double t, double a, double b);
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PN_stdfloat get_compressability(const PN_stdfloat *data, int length) const;
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int _bam_minor_version;
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int _quality;
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bool _use_error_threshold;
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double _fft_offset;
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double _fft_factor;
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double _fft_exponent;
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bool _transpose_quats;
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};
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#endif
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