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open_toontown_panda3d/panda/src/mathutil/fftCompressor.cxx

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// Filename: fftCompressor.cxx
// Created by: drose (11Dec00)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) 2001 - 2004, Disney Enterprises, Inc. All rights reserved
//
// All use of this software is subject to the terms of the Panda 3d
// Software license. You should have received a copy of this license
// along with this source code; you will also find a current copy of
// the license at http://etc.cmu.edu/panda3d/docs/license/ .
//
// To contact the maintainers of this program write to
// panda3d-general@lists.sourceforge.net .
//
////////////////////////////////////////////////////////////////////
#include "fftCompressor.h"
#include "config_mathutil.h"
#include "config_linmath.h"
#include "datagram.h"
#include "datagramIterator.h"
#include "compose_matrix.h"
#include <math.h>
#ifdef HAVE_FFTW
// hack.....
// this is a hack to help interigate sort out a macro
// in the system poll and select definitions
//
#ifdef howmany
#undef howmany
#endif
#include <rfftw.h>
// These FFTW support objects can only be defined if we actually have
// the FFTW library available.
static rfftw_plan get_real_compress_plan(int length);
static rfftw_plan get_real_decompress_plan(int length);
typedef pmap<int, rfftw_plan> RealPlans;
static RealPlans _real_compress_plans;
static RealPlans _real_decompress_plans;
#endif
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::Constructor
// Access: Public
// Description: Constructs a new compressor object with default
// parameters.
////////////////////////////////////////////////////////////////////
FFTCompressor::
FFTCompressor() {
_bam_minor_version = 0;
set_quality(-1);
_use_error_threshold = false;
_transpose_quats = false;
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::is_compression_available
// Access: Public, Static
// Description: Returns true if the FFTW library is compiled in, so
// that this class is actually capable of doing useful
// compression/decompression work. Returns false
// otherwise, in which case any attempt to write a
// compressed stream will actually write an uncompressed
// stream, and any attempt to read a compressed stream
// will fail.
////////////////////////////////////////////////////////////////////
bool FFTCompressor::
is_compression_available() {
#ifndef HAVE_FFTW
return false;
#else
return true;
#endif
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::set_quality
// Access: Public
// Description: Sets the quality factor for the compression. This is
// an integer in the range 0 - 100 that roughly controls
// how aggressively the reals are compressed; lower
// numbers mean smaller output, and more data loss.
//
// There are a few special cases. Quality -1 means to
// use whatever individual parameters are set in the
// user's Configrc file, rather than the single quality
// dial. Quality 101 or higher means to generate
// lossless output (this is the default if libfftw is
// not available).
//
// Quality 102 writes all four components of quaternions
// to the output file, rather than just three, quality
// 103 converts hpr to matrix (instead of quat) and
// writes a 9-component matrix, and quality 104 just
// writes out hpr directly. Quality levels 102 and
// greater are strictly for debugging purposes, and are
// only available if NDEBUG is not defined.
////////////////////////////////////////////////////////////////////
void FFTCompressor::
set_quality(int quality) {
#ifndef HAVE_FFTW
// If we don't actually have FFTW, we can't really compress anything.
if (_quality <= 100) {
mathutil_cat.warning()
<< "FFTW library is not available; generating uncompressed output.\n";
}
_quality = 101;
#else
_quality = quality;
if (_quality < 0) {
// A negative quality indicates we should read the various
// parameters from individual config variables.
_fft_offset = fft_offset;
_fft_factor = fft_factor;
_fft_exponent = fft_exponent;
} else if (_quality < 40) {
// 0 - 40 :
// fft-offset 1.0 - 0.001
// fft-factor 1.0
// fft-exponent 4.0
double t = (double)_quality / 40.0;
_fft_offset = interpolate(t, 1.0, 0.001);
_fft_factor = 1.0;
_fft_exponent = 4.0;
} else if (_quality < 95) {
// 40 - 95:
// fft-offset 0.001
// fft-factor 1.0 - 0.1
// fft-exponent 4.0
double t = (double)(_quality - 40) / 55.0;
_fft_offset = 0.001;
_fft_factor = interpolate(t, 1.0, 0.1);
_fft_exponent = 4.0;
} else {
// 95 - 100:
// fft-offset 0.001
// fft-factor 0.1 - 0.0
// fft-exponent 4.0
double t = (double)(_quality - 95) / 5.0;
_fft_offset = 0.001;
_fft_factor = interpolate(t, 0.1, 0.0);
_fft_exponent = 4.0;
}
#endif
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::get_quality
// Access: Public
// Description: Returns the quality number that was previously set
// via set_quality().
////////////////////////////////////////////////////////////////////
int FFTCompressor::
get_quality() const {
return _quality;
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::set_use_error_threshold
// Access: Public
// Description: Enables or disables the use of the error threshold
// measurement to put a cap on the amount of damage done
// by lossy compression. When this is enabled, the
// potential results of the compression are analyzed
// before the data is written; if it is determined that
// the compression will damage a particular string of
// reals too much, that particular string of reals is
// written uncompressed.
////////////////////////////////////////////////////////////////////
void FFTCompressor::
set_use_error_threshold(bool use_error_threshold) {
_use_error_threshold = use_error_threshold;
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::get_use_error_threshold
// Access: Public
// Description: Returns whether the error threshold measurement is
// enabled. See set_use_error_threshold().
////////////////////////////////////////////////////////////////////
bool FFTCompressor::
get_use_error_threshold() const {
return _use_error_threshold;
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::set_transpose_quats
// Access: Public
// Description: Sets the transpose_quats flag. This is provided
// mainly for backward compatibility with old bam files
// that were written out with the quaternions
// inadvertently transposed.
////////////////////////////////////////////////////////////////////
void FFTCompressor::
set_transpose_quats(bool flag) {
_transpose_quats = flag;
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::get_transpose_quats
// Access: Public
// Description: Returns the transpose_quats flag. See
// set_transpose_quats().
////////////////////////////////////////////////////////////////////
bool FFTCompressor::
get_transpose_quats() const {
return _transpose_quats;
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::write_header
// Access: Public
// Description: Writes the compression parameters to the indicated
// datagram. It is necessary to call this before
// writing anything else to the datagram, since these
// parameters will be necessary to correctly decompress
// the data later.
////////////////////////////////////////////////////////////////////
void FFTCompressor::
write_header(Datagram &datagram) {
datagram.add_int8(_quality);
if (_quality < 0) {
datagram.add_float64(_fft_offset);
datagram.add_float64(_fft_factor);
datagram.add_float64(_fft_exponent);
}
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::write_reals
// Access: Public
// Description: Writes an array of floating-point numbers to the
// indicated datagram.
////////////////////////////////////////////////////////////////////
void FFTCompressor::
write_reals(Datagram &datagram, const float *array, int length) {
datagram.add_int32(length);
if (_quality > 100) {
// Special case: lossless output.
for (int i = 0; i < length; i++) {
datagram.add_float32(array[i]);
}
return;
}
#ifndef HAVE_FFTW
// If we don't have FFTW, we shouldn't get here.
nassertv(false);
#else
if (length == 0) {
// Special case: do nothing.
return;
}
if (length == 1) {
// Special case: just write out the one number.
datagram.add_float32(array[0]);
return;
}
// Normal case: FFT the array, and write that out.
// First, check the compressability.
bool reject_compression = false;
// This logic needs a closer examination. Not sure it's useful
// as-is.
/*
if (_use_error_threshold) {
// Don't encode the data if it moves too erratically.
float error = get_compressability(array, length);
if (error > fft_error_threshold) {
// No good: the data probably won't compress well. Just write
// out lossless data.
reject_compression = true;
}
}
*/
datagram.add_bool(reject_compression);
if (reject_compression) {
if (mathutil_cat.is_debug()) {
mathutil_cat.debug()
<< "Writing stream of " << length << " numbers uncompressed.\n";
}
for (int i = 0; i < length; i++) {
datagram.add_float32(array[i]);
}
return;
}
// Now generate the Fourier transform.
double *data = (double *)alloca(length * sizeof(double));
int i;
for (i = 0; i < length; i++) {
data[i] = array[i];
}
double *half_complex = (double *)alloca(length * sizeof(double));
rfftw_plan plan = get_real_compress_plan(length);
rfftw_one(plan, data, half_complex);
// Now encode the numbers, run-length encoded by size, so we only
// write out the number of bits we need for each number.
vector_double run;
RunWidth run_width = RW_invalid;
int num_written = 0;
for (i = 0; i < length; i++) {
static const double max_range_32 = 2147483647.0;
static const double max_range_16 = 32767.0;
static const double max_range_8 = 127.0;
double scale_factor = get_scale_factor(i, length);
double num = cfloor(half_complex[i] / scale_factor + 0.5);
// How many bits do we need to encode this integer?
double a = fabs(num);
RunWidth num_width;
if (a == 0.0) {
num_width = RW_0;
} else if (a <= max_range_8) {
num_width = RW_8;
} else if (a <= max_range_16) {
num_width = RW_16;
} else if (a <= max_range_32) {
num_width = RW_32;
} else {
num_width = RW_double;
}
// A special case: if we're writing a string of one-byters and we
// come across a single intervening zero, don't interrupt the run
// just for that.
if (run_width == RW_8 && num_width == RW_0) {
if (i + 1 >= length || half_complex[i + 1] != 0.0) {
num_width = RW_8;
}
}
if (num_width != run_width) {
// Now we need to flush the last run.
num_written += write_run(datagram, run_width, run);
run.clear();
run_width = num_width;
}
run.push_back(num);
}
num_written += write_run(datagram, run_width, run);
nassertv(num_written == length);
#endif
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::write_hprs
// Access: Public
// Description: Writes an array of HPR angles to the indicated
// datagram.
////////////////////////////////////////////////////////////////////
void FFTCompressor::
write_hprs(Datagram &datagram, const LVecBase3f *array, int length) {
#ifndef NDEBUG
if (_quality >= 104) {
// If quality level is at least 104, we don't even convert hpr at
// all. This is just for debugging.
vector_float h, p, r;
h.reserve(length);
p.reserve(length);
r.reserve(length);
for (int i = 0; i < length; i++) {
h.push_back(array[i][0]);
p.push_back(array[i][1]);
r.push_back(array[i][2]);
}
write_reals(datagram, &h[0], length);
write_reals(datagram, &p[0], length);
write_reals(datagram, &r[0], length);
return;
}
if (_quality >= 103) {
// If quality level is 103, we convert hpr to a table of matrices.
// This is just for debugging.
vector_float
m00, m01, m02,
m10, m11, m12,
m20, m21, m22;
for (int i = 0; i < length; i++) {
LMatrix3f mat;
compose_matrix(mat, LVecBase3f(1.0, 1.0, 1.0), LVecBase3f(0.0, 0.0, 0.0),
array[i]);
m00.push_back(mat(0, 0));
m01.push_back(mat(0, 1));
m02.push_back(mat(0, 2));
m10.push_back(mat(1, 0));
m11.push_back(mat(1, 1));
m12.push_back(mat(1, 2));
m20.push_back(mat(2, 0));
m21.push_back(mat(2, 1));
m22.push_back(mat(2, 2));
}
write_reals(datagram, &m00[0], length);
write_reals(datagram, &m01[0], length);
write_reals(datagram, &m02[0], length);
write_reals(datagram, &m10[0], length);
write_reals(datagram, &m11[0], length);
write_reals(datagram, &m12[0], length);
write_reals(datagram, &m20[0], length);
write_reals(datagram, &m21[0], length);
write_reals(datagram, &m22[0], length);
return;
}
#endif
// First, convert the HPR's to quats. We expect quats to have
// better FFT consistency, and therefore compress better, even
// though they have an extra component.
// However, because the quaternion will be normalized, we don't even
// have to write out all three components; any three can be used to
// determine the fourth (provided we ensure consistency of sign).
vector_float qr, qi, qj, qk;
qr.reserve(length);
qi.reserve(length);
qj.reserve(length);
qk.reserve(length);
for (int i = 0; i < length; i++) {
LMatrix3f mat;
compose_matrix(mat, LVecBase3f(1.0, 1.0, 1.0), LVecBase3f(0.0, 0.0, 0.0),
array[i]);
if (_transpose_quats) {
mat.transpose_in_place();
}
LOrientationf rot(mat);
rot.normalize(); // This may not be necessary, but let's not take chances.
if (rot.get_r() < 0) {
// Since rot == -rot, we can flip the quarternion if need be to
// keep the r component positive. This has two advantages.
// One, it makes it possible to infer r completely given i, j,
// and k (since we know it must be >= 0), and two, it helps
// protect against poor continuity caused by inadvertent
// flipping of the quarternion's sign between frames.
// The choice of leaving r implicit rather than any of the other
// three seems to work the best in terms of guaranteeing
// continuity.
rot.set(-rot.get_r(), -rot.get_i(), -rot.get_j(), -rot.get_k());
}
#ifdef NOTIFY_DEBUG
if (mathutil_cat.is_warning()) {
LMatrix3f mat2;
rot.extract_to_matrix(mat2);
if (!mat.almost_equal(mat2, 0.0001)) {
LVecBase3f hpr1, hpr2;
LVecBase3f scale, shear;
decompose_matrix(mat, scale, shear, hpr1);
decompose_matrix(mat2, scale, shear, hpr2);
mathutil_cat.warning()
<< "Converted hpr to quaternion incorrectly!\n"
<< " Source hpr: " << array[i] << ", or " << hpr1 << "\n";
mathutil_cat.warning(false)
<< " Quaternion: " << rot << "\n"
<< " Which represents: hpr " << hpr2 << " scale "
<< scale << "\n";
}
}
#endif
qr.push_back(rot.get_r());
qi.push_back(rot.get_i());
qj.push_back(rot.get_j());
qk.push_back(rot.get_k());
}
// If quality is at least 102, we write all four quat components,
// instead of just the three. This is just for debugging.
#ifndef NDEBUG
if (_quality >= 102) {
write_reals(datagram, &qr[0], length);
}
#endif
write_reals(datagram, &qi[0], length);
write_reals(datagram, &qj[0], length);
write_reals(datagram, &qk[0], length);
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::read_header
// Access: Public
// Description: Reads the compression header that was written
// previously. This fills in the compression parameters
// necessary to correctly decompress the following data.
//
// Returns true if the header is read successfully,
// false otherwise.
////////////////////////////////////////////////////////////////////
bool FFTCompressor::
read_header(DatagramIterator &di, int bam_minor_version) {
_bam_minor_version = bam_minor_version;
_quality = di.get_int8();
if (mathutil_cat.is_debug()) {
mathutil_cat.debug()
<< "Found compressed data at quality level " << _quality << "\n";
}
#ifndef HAVE_FFTW
if (_quality <= 100) {
mathutil_cat.error()
<< "FFTW library is not available; cannot read compressed data.\n";
return false;
}
#endif
set_quality(_quality);
if (_quality < 0) {
_fft_offset = di.get_float64();
_fft_factor = di.get_float64();
_fft_exponent = di.get_float64();
}
return true;
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::read_reals
// Access: Public
// Description: Reads an array of floating-point numbers. The result
// is pushed onto the end of the indicated vector, which
// is not cleared first; it is the user's responsibility
// to ensure that the array is initially empty. Returns
// true if the data is read correctly, false if there is
// an error.
////////////////////////////////////////////////////////////////////
bool FFTCompressor::
read_reals(DatagramIterator &di, vector_float &array) {
int length = di.get_int32();
if (_quality > 100) {
array.reserve(array.size() + length);
// Special case: lossless output.
for (int i = 0; i < length; i++) {
array.push_back(di.get_float32());
}
return true;
}
#ifndef HAVE_FFTW
// If we don't have FFTW, we shouldn't get here.
return false;
#else
if (length == 0) {
// Special case: do nothing.
return true;
}
if (length == 1) {
// Special case: just read in the one number.
array.push_back(di.get_float32());
return true;
}
// Normal case: read in the FFT array, and convert it back to
// (nearly) the original numbers.
// First, check the reject_compression flag. If it's set, we
// decided to just write out the stream uncompressed.
bool reject_compression = di.get_bool();
if (reject_compression) {
array.reserve(array.size() + length);
for (int i = 0; i < length; i++) {
array.push_back(di.get_float32());
}
return true;
}
vector_double half_complex;
half_complex.reserve(length);
int num_read = 0;
while (num_read < length) {
num_read += read_run(di, half_complex);
}
nassertr(num_read == length, false);
nassertr((int)half_complex.size() == length, false);
int i;
for (i = 0; i < length; i++) {
half_complex[i] *= get_scale_factor(i, length);
}
double *data = (double *)alloca(length * sizeof(double));
rfftw_plan plan = get_real_decompress_plan(length);
rfftw_one(plan, &half_complex[0], data);
double scale = 1.0 / (double)length;
array.reserve(array.size() + length);
for (i = 0; i < length; i++) {
array.push_back(data[i] * scale);
}
return true;
#endif
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::read_hprs
// Access: Public
// Description: Reads an array of HPR angles. The result is pushed
// onto the end of the indicated vector, which is not
// cleared first; it is the user's responsibility to
// ensure that the array is initially empty.
//
// new_hpr is a temporary, transitional parameter. If
// it is set false, the hprs are decompressed according
// to the old, broken hpr calculation; if true, the hprs
// are decompressed according to the new, correct hpr
// calculation. See temp_hpr_fix.
////////////////////////////////////////////////////////////////////
bool FFTCompressor::
read_hprs(DatagramIterator &di, vector_LVecBase3f &array, bool new_hpr) {
#ifndef NDEBUG
if (_quality >= 104) {
// If quality level is at least 104, we don't even convert hpr to
// quat. This is just for debugging.
vector_float h, p, r;
bool okflag = true;
okflag =
read_reals(di, h) &&
read_reals(di, p) &&
read_reals(di, r);
if (okflag) {
nassertr(h.size() == p.size() && p.size() == r.size(), false);
for (int i = 0; i < (int)h.size(); i++) {
array.push_back(LVecBase3f(h[i], p[i], r[i]));
}
}
return okflag;
}
if (_quality >= 103) {
// If quality level is 103, we read in a table of 3x3 rotation
// matrices. This is just for debugging.
vector_float
m00, m01, m02,
m10, m11, m12,
m20, m21, m22;
bool okflag = true;
okflag =
read_reals(di, m00) &&
read_reals(di, m01) &&
read_reals(di, m02) &&
read_reals(di, m10) &&
read_reals(di, m11) &&
read_reals(di, m12) &&
read_reals(di, m20) &&
read_reals(di, m21) &&
read_reals(di, m22);
if (okflag) {
for (int i = 0; i < (int)m00.size(); i++) {
LMatrix3f mat(m00[i], m01[i], m02[i],
m10[i], m11[i], m12[i],
m20[i], m21[i], m22[i]);
LVecBase3f scale, shear, hpr;
if (new_hpr) {
decompose_matrix_new_hpr(mat, scale, shear, hpr);
} else {
decompose_matrix_old_hpr(mat, scale, shear, hpr);
}
array.push_back(hpr);
}
}
return okflag;
}
#endif
vector_float qr, qi, qj, qk;
bool okflag = true;
#ifndef NDEBUG
if (_quality >= 102) {
okflag = read_reals(di, qr);
}
#endif
okflag =
okflag &&
read_reals(di, qi) &&
read_reals(di, qj) &&
read_reals(di, qk);
if (okflag) {
nassertr(qi.size() == qj.size() && qj.size() == qk.size(), false);
array.reserve(array.size() + qi.size());
for (int i = 0; i < (int)qi.size(); i++) {
LOrientationf rot;
// Infer the r component from the remaining three.
float qr2 = 1.0 - (qi[i] * qi[i] + qj[i] * qj[i] + qk[i] * qk[i]);
float qr1 = qr2 < 0.0 ? 0.0 : sqrtf(qr2);
rot.set(qr1, qi[i], qj[i], qk[i]);
#ifndef NDEBUG
if (_quality >= 102) {
// If we have written out all four components, use them.
rot[0] = qr[i];
if (!IS_THRESHOLD_EQUAL(qr[i], qr1, 0.001)) {
mathutil_cat.warning()
<< "qr[" << i << "] = " << qr[i] << ", qr1 = " << qr1
<< ", diff is " << qr1 - qr[i] << "\n";
}
} else
#endif
rot.normalize(); // Just for good measure.
LMatrix3f mat;
rot.extract_to_matrix(mat);
if (_transpose_quats) {
mat.transpose_in_place();
}
LVecBase3f scale, shear, hpr;
if (new_hpr) {
decompose_matrix_new_hpr(mat, scale, shear, hpr);
} else {
decompose_matrix_old_hpr(mat, scale, shear, hpr);
}
array.push_back(hpr);
}
}
return okflag;
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::read_hprs
// Access: Public
// Description: Reads an array of HPR angles. The result is pushed
// onto the end of the indicated vector, which is not
// cleared first; it is the user's responsibility to
// ensure that the array is initially empty.
////////////////////////////////////////////////////////////////////
bool FFTCompressor::
read_hprs(DatagramIterator &di, vector_LVecBase3f &array) {
return read_hprs(di, array, temp_hpr_fix);
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::free_storage
// Access: Public, Static
// Description: Frees memory that has been allocated during past runs
// of the FFTCompressor. This is an optional call, but
// it may be made from time to time to empty the global
// cache that the compressor objects keep to facilitate
// fast compression/decompression.
////////////////////////////////////////////////////////////////////
void FFTCompressor::
free_storage() {
#ifdef HAVE_FFTW
RealPlans::iterator pi;
for (pi = _real_compress_plans.begin();
pi != _real_compress_plans.end();
++pi) {
rfftw_destroy_plan((*pi).second);
}
_real_compress_plans.clear();
for (pi = _real_decompress_plans.begin();
pi != _real_decompress_plans.end();
++pi) {
rfftw_destroy_plan((*pi).second);
}
_real_decompress_plans.clear();
#endif
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::write_run
// Access: Private
// Description: Writes a sequence of integers that all require the
// same number of bits. Returns the number of integers
// written, i.e. run.size().
////////////////////////////////////////////////////////////////////
int FFTCompressor::
write_run(Datagram &datagram, FFTCompressor::RunWidth run_width,
const vector_double &run) {
if (run.empty()) {
return 0;
}
nassertr(run_width != RW_invalid, 0);
if (run_width != RW_double) {
// If the width is anything other than RW_double, we write a
// single byte indicating the width and length of the upcoming
// run.
if (run.size() <= RW_length_mask &&
((int)run_width | run.size()) != RW_double) {
// If there are enough bits remaining in the byte, use them to
// indicate the length of the run. We have to be a little
// careful, however, not to accidentally write a byte that looks
// like an RW_double flag.
datagram.add_uint8((int)run_width | run.size());
} else {
// Otherwise, write zero as the length, to indicate that we'll
// write the actual length in the following 16-bit word.
datagram.add_uint8(run_width);
// Assuming, of course, that the length fits within 16 bits.
nassertr(run.size() < 65536, 0);
nassertr(run.size() != 0, 0);
datagram.add_uint16(run.size());
}
}
// Now write the data itself.
vector_double::const_iterator ri;
switch (run_width) {
case RW_0:
// If it's a string of zeroes, we're done!
break;
case RW_8:
for (ri = run.begin(); ri != run.end(); ++ri) {
datagram.add_int8((int)*ri);
}
break;
case RW_16:
for (ri = run.begin(); ri != run.end(); ++ri) {
datagram.add_int16((int)*ri);
}
break;
case RW_32:
for (ri = run.begin(); ri != run.end(); ++ri) {
datagram.add_int32((int)*ri);
}
break;
case RW_double:
for (ri = run.begin(); ri != run.end(); ++ri) {
// In the case of RW_double, we only write the numbers one at a
// time, each time preceded by the RW_double flag. Hopefully
// this will happen only rarely.
datagram.add_int8((PN_int8)RW_double);
datagram.add_float64(*ri);
}
break;
default:
break;
}
return run.size();
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::read_run
// Access: Private
// Description: Reads a sequence of integers that all require the
// same number of bits. Returns the number of integers
// read. It is the responsibility of the user to clear
// the vector before calling this function, or the
// numbers read will be appended to the end.
////////////////////////////////////////////////////////////////////
int FFTCompressor::
read_run(DatagramIterator &di, vector_double &run) {
PN_uint8 start = di.get_uint8();
RunWidth run_width;
int length;
if ((start & 0xff) == RW_double) {
// RW_double is a special case, and requires the whole byte. In
// this case, we don't encode a length, but assume it's only one.
run_width = RW_double;
length = 1;
} else {
run_width = (RunWidth)(start & RW_width_mask);
length = start & RW_length_mask;
}
if (length == 0) {
// If the length was zero, it means the actual length follows as a
// 16-bit word.
length = di.get_uint16();
}
nassertr(length != 0, 0);
run.reserve(run.size() + length);
int i;
switch (run_width) {
case RW_0:
for (i = 0; i < length; i++) {
run.push_back(0.0);
}
break;
case RW_8:
for (i = 0; i < length; i++) {
run.push_back((double)(int)di.get_int8());
}
break;
case RW_16:
for (i = 0; i < length; i++) {
run.push_back((double)(int)di.get_int16());
}
break;
case RW_32:
for (i = 0; i < length; i++) {
run.push_back((double)(int)di.get_int32());
}
break;
case RW_double:
for (i = 0; i < length; i++) {
run.push_back(di.get_float64());
}
break;
default:
break;
}
return length;
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::get_scale_factor
// Access: Private
// Description: Returns the appropriate scaling for the given
// position within the halfcomplex array.
////////////////////////////////////////////////////////////////////
double FFTCompressor::
get_scale_factor(int i, int length) const {
int m = (length / 2) + 1;
int k = (i < m) ? i : length - i;
nassertr(k >= 0 && k < m, 1.0);
return _fft_offset +
_fft_factor * pow((double)(m-1 - k) / (double)(m-1), _fft_exponent);
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::interpolate
// Access: Private, Static
// Description: Returns a number between a and b, inclusive,
// according to the value of t between 0 and 1,
// inclusive.
////////////////////////////////////////////////////////////////////
double FFTCompressor::
interpolate(double t, double a, double b) {
return a + t * (b - a);
}
////////////////////////////////////////////////////////////////////
// Function: FFTCompressor::get_compressability
// Access: Private
// Description: Returns a factor that indicates how erratically the
// values are changing. The lower the result, the
// calmer the numbers, and the greater its likelihood of
// being successfully compressed.
////////////////////////////////////////////////////////////////////
float FFTCompressor::
get_compressability(const float *data, int length) const {
// The result returned is actually the standard deviation of the
// table of deltas between consecutive frames. This number is
// larger if the frames have wildly different values.
if (length <= 2) {
return 0.0;
}
float sum = 0.0;
float sum2 = 0.0;
for (int i = 1; i < length; i++) {
float delta = data[i] - data[i - 1];
sum += delta;
sum2 += delta * delta;
}
float variance = (sum2 - (sum * sum) / (length - 1)) / (length - 2);
if (variance < 0.0) {
// This can only happen due to tiny roundoff error.
return 0.0;
}
float std_deviation = csqrt(variance);
return std_deviation;
}
#ifdef HAVE_FFTW
////////////////////////////////////////////////////////////////////
// Function: get_real_compress_plan
// Description: Returns a FFTW plan suitable for compressing a float
// array of the indicated length.
////////////////////////////////////////////////////////////////////
static rfftw_plan
get_real_compress_plan(int length) {
RealPlans::iterator pi;
pi = _real_compress_plans.find(length);
if (pi != _real_compress_plans.end()) {
return (*pi).second;
}
rfftw_plan plan;
plan = rfftw_create_plan(length, FFTW_REAL_TO_COMPLEX, FFTW_ESTIMATE);
_real_compress_plans.insert(RealPlans::value_type(length, plan));
return plan;
}
////////////////////////////////////////////////////////////////////
// Function: get_real_decompress_plan
// Description: Returns a FFTW plan suitable for decompressing a float
// array of the indicated length.
////////////////////////////////////////////////////////////////////
static rfftw_plan
get_real_decompress_plan(int length) {
RealPlans::iterator pi;
pi = _real_decompress_plans.find(length);
if (pi != _real_decompress_plans.end()) {
return (*pi).second;
}
rfftw_plan plan;
plan = rfftw_create_plan(length, FFTW_COMPLEX_TO_REAL, FFTW_ESTIMATE);
_real_decompress_plans.insert(RealPlans::value_type(length, plan));
return plan;
}
#endif
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