%%
%% *SpHEAR Project
%%
%% sphear_bf_plot: plot the polar response of a B format signal
%%
%% usage:
%%   [BF] = sphear_bf_plot(BF, fmin, fmax)
%%
%% BF: B format signal array
%% fmin, fmax: range of frequencies to consider (to title plot)
%%
%% Copyright Fernando Lopez-Lezcano 2016
%% nando@ccrma.stanford.edu
%%
%%  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 3 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, see <http://www.gnu.org/licenses/>.

function [BF] = sphear_bf_plot(BF, fmin, fmax, rmax)
  pkg load signal;

  %% to close the polar plots we repeat the first point
  m = size(BF, 1);
  BF(m + 1,:) = BF(1,:);
  theta = (0:m)*(2*pi/m);
  
  %% plot it as a function of angle
  bname = cellstr(['W'; 'X'; 'Y'; 'Z']);

  f = figure;
  for b = 1:4
    subplot(2, 2, b);
    hold on;
    axis square;
    axis([-rmax, rmax, -rmax, rmax]);
    title([char(bname(b)) ": " sprintf("%05.0d", fmin) " to " sprintf("%05.0d", fmax) " Hz"]);

    [xr, yr] = pol2cart(theta', ones(m + 1,1));
    plot(xr, yr);
    [x, y] = pol2cart(theta', abs(BF(:,b)));
    plot(x, y, '.-r', 'LineWidth', 0.5);
  end
  print(f, '-dpng','-color',["figures/sphear_polar_multi_" sprintf("%05d", fmin) "_" sprintf("%05d", fmax) ".png"]);
end