drafting increasing maximum voice numbers to 256

vm/compiler/song_macros.go

@@ -6,7 +6,8 @@ import (
 
 type SongMacros struct {
 	Song              *sointu.Song
-	VoiceTrackBitmask int
+	VoiceTrackBitmask []byte
+	HasVoiceTrack     bool
 	MaxSamples        int
 }
 
@@ -14,9 +15,13 @@ func NewSongMacros(s *sointu.Song) *SongMacros {
 	maxSamples := s.SamplesPerRow() * s.Score.LengthInRows()
 	p := SongMacros{Song: s, MaxSamples: maxSamples}
 	trackVoiceNumber := 0
+	p.VoiceTrackBitmask = make([]byte, (s.Score.NumVoices()+7)/8)
 	for _, t := range s.Score.Tracks {
+		if t.NumVoices > 0 {
+			p.HasVoiceTrack = true
+		}
 		for b := 0; b < t.NumVoices-1; b++ {
-			p.VoiceTrackBitmask += 1 << trackVoiceNumber
+			p.VoiceTrackBitmask[trackVoiceNumber/8] += 1 << (trackVoiceNumber % 8)
 			trackVoiceNumber++
 		}
 		trackVoiceNumber++ // set all bits except last one