From 36e128c60489b32f0d86d4adbed59cf23d88009c Mon Sep 17 00:00:00 2001
From: div0 <div0@f962a42d-fe04-0410-a3ab-8c8b0445ebaa>
Date: Thu, 16 Apr 2009 08:11:41 +0000
Subject: [PATCH] add a MIDI to BGS converter

git-svn-id: svn://svn.icculus.org/nexuiz/trunk@6499 f962a42d-fe04-0410-a3ab-8c8b0445ebaa
---
 misc/tools/midi2bgs.pl | 101 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 misc/tools/midi2bgs.pl

diff --git a/misc/tools/midi2bgs.pl b/misc/tools/midi2bgs.pl
new file mode 100644
index 000000000..27329c0f3
--- /dev/null
+++ b/misc/tools/midi2bgs.pl
@@ -0,0 +1,101 @@
+#!/usr/bin/perl
+
+# converter from Type 1 MIDI files to BGS files that control particle effects on maps
+# usage:
+#   perl midi2bgs.pl filename.mid tracknumber channelnumber offset prefix > filename.bgs
+# track and channel numbers -1 include all events
+# example:
+#   perl midi2bgs.pl filename.mid -1 10 0.3 note_ > filename.bgs
+
+use strict;
+use warnings;
+use MIDI;
+use MIDI::Opus;
+
+my ($filename, $trackno, $channelno, $offset, $noteprefix) = @ARGV;
+my $opus = MIDI::Opus->new({from_file => $filename});
+my $ticksperquarter = $opus->ticks();
+my $tracks = $opus->tracks_r();
+my @tempi = (); # list of start tick, time per tick pairs (calculated as seconds per quarter / ticks per quarter)
+my $tick;
+
+$tick = 0;
+for($tracks->[0]->events())
+{   
+    $tick += $_->[1];
+    if($_->[0] eq 'set_tempo')
+    {   
+        push @tempi, [$_->[1], $_->[2] * 0.000001 / $ticksperquarter];
+    }
+}
+sub tick2sec($)
+{
+    my ($tick) = @_;
+    my $sec = 0;
+    my $curtempo = [0, 0.5 / $ticksperquarter];
+    for(@tempi)
+    {
+        if($_->[0] < $tick)
+        {
+			# this event is in the past
+			# we add the full time since the last one then
+			$sec += ($_->[0] - $curtempo->[0]) * $curtempo->[1];
+        }   
+        else
+        {
+			# if this event is in the future, we break
+			last;
+        }
+		$curtempo = $_;
+    }
+	$sec += ($tick - $curtempo->[0]) * $curtempo->[1];
+	return $sec + $offset;
+}
+
+my @notes = ('c', 'c#', 'd', 'd#', 'e', 'f', 'f#', 'g', 'g#', 'a', 'a#', 'b');
+my @notenames = ();
+for my $octave (0..11)
+{
+	for(@notes)
+	{
+		if($octave <= 3)
+		{
+			push @notenames, uc($_) . ',' x (3 - $octave);
+		}
+		else
+		{
+			push @notenames, lc($_) . "'" x ($octave - 4);
+		}
+	}
+}
+
+my @outevents = (); # format: name, time in seconds, velocity
+$tick = 0;
+for my $thistrackno($trackno >= 0 ? $trackno : (0..@$tracks - 1))
+{
+	for($tracks->[$thistrackno]->events())
+	{
+		$tick += $_->[1];
+		my $t = tick2sec $tick;
+		if($_->[0] eq 'note_on')
+		{
+			my $chan = $_->[2];
+			my $note = $notenames[$_->[3]];
+			my $velocity = $_->[4] / 127.0;
+			push @outevents, [$note, $t, $velocity]
+				if($channelno < 0 || $channelno == $chan);
+		}
+		elsif($_->[0] eq 'note_off')
+		{
+			my $chan = $_->[2];
+			my $note = $notenames[$_->[3]];
+			my $velocity = $_->[4] / 127.0;
+			push @outevents, [$note, $t, 0]
+				if($channelno < 0 || $channelno == $chan);
+		}
+	}   
+}
+for(sort { $a->[0] cmp $b->[0] or $a->[1] <=> $b->[1] } @outevents)
+{
+    printf "%s%s %f %f\n", $noteprefix, @$_;
+}
-- 
2.39.2