function geo = recorder_geometry(P)
% RECORDER_GEOMETRY Bore, tone hole lattice, window, and fingering chart.
%
% The bore runs from the window (x = 0, where the jet drives it) to the open
% foot (x = bore_length_m), with a linear taper from r_head to r_foot; real
% recorder bores are stepped and locally reworked by the maker, so the taper
% here is a first-order stand-in. Eight tone holes: index 1 is the thumb
% hole on the back, 2..8 are finger holes 1..7 from the top down. Hole
% positions are stored as fractions of the design bore length, so scaling
% bore_length_m transposes the whole instrument; radii scale with
% P.hole_scale. The positions and radii below were tuned numerically (see
% the repository README) so that the first-register fingerings land on an
% equal-tempered C major scale at A4 = 440 with the default geometry.
%
% The fingering chart is baroque (English). Each row is one note, columns
% are the eight holes: 0 closed, 1 open, 0.5 pinched (the thumb nail crack
% that vents the second register; modeled as a reduced effective radius).
% Rows 1..10 are the first register C5..D6; rows 11..14 are pinched
% second-register fingerings E6..A6, whose intonation inherits every
% simplification of the model and is honestly worse.

L = P.bore_length_m;

% Tuned hole lattice (fractions of bore length from the window, and radii in
% m at the default geometry). Hole 1 is the thumb; 2..8 are finger holes.
geo.holeFrac = [0.3699 0.4271 0.4640 0.5292 0.6204 0.6519 0.7424 0.8278];
geo.holeRad = [0.0027 0.0032 0.0030 0.0029 0.0033 0.0026 0.0032 0.0025] * P.hole_scale;
geo.holePos = geo.holeFrac * L;
geo.holeChim = P.wall_m * ones(1, 8);

% Fingering chart: thumb, then finger holes 1..7.
%              T  1  2  3  4  5  6  7
geo.fingerings = [ ...
  0  0  0  0  0  0  0  0;   %  1  C5
  0  0  0  0  0  0  0  1;   %  2  D5
  0  0  0  0  0  0  1  1;   %  3  E5
  0  0  0  0  0  1  0  0;   %  4  F5  (fork)
  0  0  0  0  1  1  1  1;   %  5  G5
  0  0  0  1  1  1  1  1;   %  6  A5
  0  0  1  1  1  1  1  1;   %  7  B5
  0  1  0  1  1  1  1  1;   %  8  C6
  1  0  0  1  1  1  1  1;   %  9  C#6
  1  1  0  1  1  1  1  1;   % 10  D6
  0.5 0 0  0  0  0  1  1;   % 11  E6  (pinched E5)
  0.5 0 0  0  0  1  0  1;   % 12  F6  (pinched)
  0.5 0 0  0  1  1  1  1;   % 13  G6  (pinched G5)
  0.5 0 0  1  1  1  1  1;   % 14  A6  (pinched A5)
];
geo.nNotes = 14;

% Equal-tempered targets, A4 = 440: semitones of each row above C5.
semis = [0 2 4 5 7 9 11 12 13 14 16 17 19 21];
geo.fTarget = 440 * 2^(3 / 12) * 2.^(reshape(semis, 1, 14) / 12);

% Bore radius at position x (column or row vector), linear taper.
geo.rHead = P.bore_r_head_m;
geo.rFoot = P.bore_r_foot_m;
geo.boreLen = L;

% Window (mouth) geometry.
geo.Sm = P.cutup_m * P.window_width_m;          % window area
geo.deltaM = 0.7 * sqrt(geo.Sm);                % mouth end correction
end