# At Doom's Gate: the E1M1 riff for one speaker
# https://lab.glossema.dev/play/dooms-gate
# Doom, 1993. E minor, 170 bpm: the riff in eighths on a low E, the lead in quarters an octave up.

:local beat 352ms;

:global notes {
  "E3"=165; "Bb3"=233; "B3"=247; "C4"=262; "D4"=294; "E4"=330; "G4"=392;
  "B4"=494; "D5"=587; "E5"=659; "F#5"=740; "G5"=784; "A5"=880; "B5"=988
};

:global durs {
  "w"=($beat * 4);
  "h"=($beat * 2);
  "q"=$beat;
  "e"=($beat / 2)
};

# $play "NOTE:dur" sounds one note; "-" is a rest.
# The gap is carved out of the note, not added after it, so the grid holds at 170.
:global play do={
  :global notes;
  :global durs;
  :local cut [:find $1 ":"];
  :local note [:pick $1 0 $cut];
  :local key [:pick $1 ($cut + 1) [:len $1]];
  :local len ($durs->$key);
  :if ($note != "-") do={
    :beep frequency=($notes->$note) length=($len - 24ms);
  }
  :delay $len;
}

# The riff: two low E's, then the note that walks down, the octave, D, C, B flat, and back up
:local riff {
  "E3:e"; "E3:e"; "E4:e";
  "E3:e"; "E3:e"; "D4:e";
  "E3:e"; "E3:e"; "C4:e";
  "E3:e"; "E3:e"; "Bb3:e";
  "E3:e"; "E3:e"; "B3:e"; "C4:e"
};

# The riff's second half: the walk stops on B flat and holds it
:local held {
  "E3:e"; "E3:e"; "E4:e";
  "E3:e"; "E3:e"; "D4:e";
  "E3:e"; "E3:e"; "C4:e";
  "E3:e"; "E3:e"; "Bb3:h"; "-:e"
};

# The riff's first bar, then the lead's answer set into the gap where the B flat would hold
:local lead1 {
  "E3:e"; "E3:e"; "E4:e";
  "E3:e"; "E3:e"; "D4:e"; "E3:e"; "E3:e";
  "B4:q"; "D5:q"; "F#5:q"; "A5:q";
  "F#5:q"; "D5:q"; "B4:h"
};
:local lead2 {
  "E3:e"; "E3:e"; "E4:e";
  "E3:e"; "E3:e"; "D4:e"; "E3:e"; "E3:e";
  "B4:q"; "G4:q"; "E5:q"; "G5:q";
  "B5:q"; "G5:q"; "E5:h"
};

# 1. Riff: twice in full, hard and even
:put "Riff";
:for i from=1 to=2 do={
  :foreach n in=$riff do={ $play $n; }
  :foreach n in=$held do={ $play $n; }
}

# 2. Lead: the riff, then the lead answers in its gap; twice, the answer climbing
:put "Lead";
:foreach n in=$riff do={ $play $n; }
:foreach n in=$lead1 do={ $play $n; }
:foreach n in=$riff do={ $play $n; }
:foreach n in=$lead2 do={ $play $n; }

# 3. Riff again: once more in full, and the gate shuts on the riff's own first cell
:put "Riff again";
:foreach n in=$riff do={ $play $n; }
:foreach n in=$held do={ $play $n; }
:local shut {"E3:e"; "E3:e"; "E4:w"};
:foreach n in=$shut do={ $play $n; }