# Battle City: the stage-start fanfare (NES, Namco 1985), for one speaker
# https://lab.glossema.dev/play/battle-city

# Tuning: equal temperament, A4 = 440 Hz, rounded to whole hertz
:global notes {"C5"=523; "D5"=587; "Eb5"=622; "F5"=698; "G5"=784; "A5"=880; "Ab5"=831; "Bb5"=932; "C6"=1047};

# Clock: 120 beats per minute; every note of the figure is a sixteenth, the held notes a dotted eighth
:local beat 500ms;
:local sixteenth ($beat / 4);
:local held ($sixteenth * 3);
:local dur {"s"=$sixteenth; "h"=$held};
:global gap 20ms;

# Voice: one note, then the clock; the gap after each beep lets the repeated notes articulate
:global play do={
  :global notes;
  :global gap;
  :beep frequency=($notes->$1) length=($2 - $gap);
  :delay $2;
}

# Score: the rising figure (four steps, each sounded twice), the held note, three march steps, the stop
:local melody {
  "C5:s"; "D5:s"; "Eb5:s";   "C5:s"; "D5:s"; "Eb5:s";
  "Eb5:s"; "F5:s"; "G5:s";   "Eb5:s"; "F5:s"; "G5:s";
  "F5:s"; "G5:s"; "A5:s";    "F5:s"; "G5:s"; "A5:s";
  "Ab5:s"; "Bb5:s"; "C6:s";  "Ab5:s"; "Bb5:s"; "C6:s";
  "C6:h";
  "C6:s"; "C6:s"; "C6:s";
  "C6:h"
};

# Performance: twice, a full second of silence between, as the game did on the next stage
:put "Stage";
:for stage from=1 to=2 do={
  :if ($stage > 1) do={ :delay 1000ms };
  :foreach step in=$melody do={
    :local colon [:find $step ":"];
    :local name [:pick $step 0 $colon];
    :local len [:pick $step ($colon + 1) [:len $step]];
    $play $name ($dur->$len);
  }
}