/*
* SOFA utility methods for inspecting SOFA file metrics and determining HRTF
* utility compatible layouts.
*
* Copyright (C) 2018-2019 Christopher Fitzgerald
* Copyright (C) 2019 Christopher Robinson
*
* 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.
*
* Or visit: http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
*/
#include "sofa-support.h"
#include <stdio.h>
#include <algorithm>
#include <array>
#include <cmath>
#include <utility>
#include <vector>
#include "mysofa.h"
namespace {
using uint = unsigned int;
using double3 = std::array<double,3>;
/* Produces a sorted array of unique elements from a particular axis of the
* triplets array. The filters are used to focus on particular coordinates
* of other axes as necessary. The epsilons are used to constrain the
* equality of unique elements.
*/
std::vector<double> GetUniquelySortedElems(const std::vector<double3> &aers, const uint axis,
const double *const (&filters)[3], const double (&epsilons)[3])
{
std::vector<double> elems;
for(const double3 &aer : aers)
{
const double elem{aer[axis]};
uint j;
for(j = 0;j < 3;j++)
{
if(filters[j] && std::abs(aer[j] - *filters[j]) > epsilons[j])
break;
}
if(j < 3)
continue;
auto iter = elems.begin();
for(;iter != elems.end();++iter)
{
const double delta{elem - *iter};
if(delta > epsilons[axis]) continue;
if(delta >= -epsilons[axis]) break;
iter = elems.emplace(iter, elem);
break;
}
if(iter == elems.end())
elems.emplace_back(elem);
}
return elems;
}
/* Given a list of azimuths, this will produce the smallest step size that can
* uniformly cover the list. Ideally this will be over half, but in degenerate
* cases this can fall to a minimum of 5 (the lower limit).
*/
double GetUniformAzimStep(const double epsilon, const std::vector<double> &elems)
{
if(elems.size() < 5) return 0.0;
/* Get the maximum count possible, given the first two elements. It would
* be impossible to have more than this since the first element must be
* included.
*/
uint count{static_cast<uint>(std::ceil(360.0 / (elems[1]-elems[0])))};
count = std::min(count, 255u);
for(;count >= 5;--count)
{
/* Given the stepping value for this number of elements, check each
* multiple to ensure there's a matching element.
*/
const double step{360.0 / count};
bool good{true};
size_t idx{1u};
for(uint mult{1u};mult < count && good;++mult)
{
const double target{step*mult + elems[0]};
while(idx < elems.size() && target-elems[idx] > epsilon)
++idx;
good &= (idx < elems.size()) && !(std::abs(target-elems[idx++]) > epsilon);
}
if(good)
return step;
}
return 0.0;
}
/* Given a list of elevations, this will produce the smallest step size that
* can uniformly cover the list. Ideally this will be over half, but in
* degenerate cases this can fall to a minimum of 5 (the lower limit).
*/
double GetUniformElevStep(const double epsilon, std::vector<double> &elems)
{
if(elems.size() < 5) return 0.0;
/* Reverse the elevations so it increments starting with -90 (flipped from
* +90). This makes it easier to work out a proper stepping value.
*/
std::reverse(elems.begin(), elems.end());
for(auto &v : elems) v *= -1.0;
uint count{static_cast<uint>(std::ceil(180.0 / (elems[1]-elems[0])))};
count = std::min(count, 255u);
double ret{0.0};
for(;count >= 5;--count)
{
const double step{180.0 / count};
bool good{true};
size_t idx{1u};
/* Elevations don't need to match all multiples if there's not enough
* elements to check. Missing elevations can be synthesized.
*/
for(uint mult{1u};mult <= count && idx < elems.size() && good;++mult)
{
const double target{step*mult + elems[0]};
while(idx < elems.size() && target-elems[idx] > epsilon)
++idx;
good &= !(idx < elems.size()) || !(std::abs(target-elems[idx++]) > epsilon);
}
if(good)
{
ret = step;
break;
}
}
/* Re-reverse the elevations to restore the correct order. */
for(auto &v : elems) v *= -1.0;
std::reverse(elems.begin(), elems.end());
return ret;
}
} // namespace
const char *SofaErrorStr(int err)
{
switch(err)
{
case MYSOFA_OK: return "OK";
case MYSOFA_INVALID_FORMAT: return "Invalid format";
case MYSOFA_UNSUPPORTED_FORMAT: return "Unsupported format";
case MYSOFA_INTERNAL_ERROR: return "Internal error";
case MYSOFA_NO_MEMORY: return "Out of memory";
case MYSOFA_READ_ERROR: return "Read error";
}
return "Unknown";
}
std::vector<SofaField> GetCompatibleLayout(const size_t m, const float *xyzs)
{
auto aers = std::vector<double3>(m, double3{});
for(size_t i{0u};i < m;++i)
{
float vals[3]{xyzs[i*3], xyzs[i*3 + 1], xyzs[i*3 + 2]};
mysofa_c2s(&vals[0]);
aers[i] = {vals[0], vals[1], vals[2]};
}
auto radii = GetUniquelySortedElems(aers, 2, {}, {0.1, 0.1, 0.001});
std::vector<SofaField> fds;
fds.reserve(radii.size());
for(const double dist : radii)
{
auto elevs = GetUniquelySortedElems(aers, 1, {nullptr, nullptr, &dist}, {0.1, 0.1, 0.001});
/* Remove elevations that don't have a valid set of azimuths. */
auto invalid_elev = [&dist,&aers](const double ev) -> bool
{
auto azims = GetUniquelySortedElems(aers, 0, {nullptr, &ev, &dist}, {0.1, 0.1, 0.001});
if(std::abs(ev) > 89.999)
return azims.size() != 1;
if(azims.empty() || !(std::abs(azims[0]) < 0.1))
return true;
return GetUniformAzimStep(0.1, azims) <= 0.0;
};
elevs.erase(std::remove_if(elevs.begin(), elevs.end(), invalid_elev), elevs.end());
double step{GetUniformElevStep(0.1, elevs)};
if(step <= 0.0)
{
if(elevs.empty())
fprintf(stdout, "No usable elevations on field distance %f.\n", dist);
else
{
fprintf(stdout, "Non-uniform elevations on field distance %.3f.\nGot: %+.2f", dist,
elevs[0]);
for(size_t ei{1u};ei < elevs.size();++ei)
fprintf(stdout, ", %+.2f", elevs[ei]);
fputc('\n', stdout);
}
continue;
}
uint evStart{0u};
for(uint ei{0u};ei < elevs.size();ei++)
{
if(!(elevs[ei] < 0.0))
{
fprintf(stdout, "Too many missing elevations on field distance %f.\n", dist);
return fds;
}
double eif{(90.0+elevs[ei]) / step};
const double ev_start{std::round(eif)};
if(std::abs(eif - ev_start) < (0.1/step))
{
evStart = static_cast<uint>(ev_start);
break;
}
}
const auto evCount = static_cast<uint>(std::round(180.0 / step)) + 1;
if(evCount < 5)
{
fprintf(stdout, "Too few uniform elevations on field distance %f.\n", dist);
continue;
}
SofaField field{};
field.mDistance = dist;
field.mEvCount = evCount;
field.mEvStart = evStart;
field.mAzCounts.resize(evCount, 0u);
auto &azCounts = field.mAzCounts;
for(uint ei{evStart};ei < evCount;ei++)
{
double ev{-90.0 + ei*180.0/(evCount - 1)};
auto azims = GetUniquelySortedElems(aers, 0, {nullptr, &ev, &dist}, {0.1, 0.1, 0.001});
if(ei == 0 || ei == (evCount-1))
{
if(azims.size() != 1)
{
fprintf(stdout, "Non-singular poles on field distance %f.\n", dist);
return fds;
}
azCounts[ei] = 1;
}
else
{
step = GetUniformAzimStep(0.1, azims);
if(step <= 0.0)
{
fprintf(stdout, "Non-uniform azimuths on elevation %f, field distance %f.\n",
ev, dist);
return fds;
}
azCounts[ei] = static_cast<uint>(std::round(360.0f / step));
}
}
fds.emplace_back(std::move(field));
}
return fds;
}