genmidi: Add constants for MIDI notes.

Constant definitions for MIDI notes, so that instrument definitions do
not need to use meaningless numbers.

lumps/genmidi/config.py

@@ -17,11 +17,12 @@
 # event. Some instruments (especially percussion) always play the same
 # note. To specify a fixed note, do this:
 #
-#   Instrument("filename.sbi", note=16)
+#   Instrument("filename.sbi", note=On5.B)
 #
-# (Where the value is the MIDI note number)
+# Value is a MIDI note number; see midi.py for constant definitions.
 
 from instrument import Instrument, NullInstrument
+from midi import *
 
 # General MIDI instruments:
 
@@ -197,17 +198,17 @@ PERCUSSION = [
 	NullInstrument,                         # TODO - #67 High Agogo
 	NullInstrument,                         # TODO - #68 Low Agogo
 	NullInstrument,                         # TODO - #69 Cabasa
-	Instrument("perc70.sbi", note=16),      # #70 Maracas
-	Instrument("perc71.sbi", note=16),      # #71 Short Whistle
-	Instrument("perc72.sbi", note=16),      # #72 Long Whistle
-	Instrument("perc73.sbi", note=16),      # #73 Short Guiro
-	Instrument("perc74.sbi", note=16),      # #74 Long Guiro
-	Instrument("perc75.sbi", note=16),      # #75 Claves
-	Instrument("perc76.sbi", note=16),      # #76 Hi Wood Block
-	Instrument("perc77.sbi", note=16),      # #77 Low Wood Block
-	Instrument("perc78.sbi", note=16),      # #78 Mute Cuica
-	Instrument("perc79.sbi", note=16),      # #79 Open Cuica
-	Instrument("perc80.sbi", note=16),      # #80 Mute Triangle
-	Instrument("perc81.sbi", note=16),      # #81 Open Triangle
+	Instrument("perc70.sbi", note=On5.E),   # #70 Maracas
+	Instrument("perc71.sbi", note=On5.E),   # #71 Short Whistle
+	Instrument("perc72.sbi", note=On5.E),   # #72 Long Whistle
+	Instrument("perc73.sbi", note=On5.E),   # #73 Short Guiro
+	Instrument("perc74.sbi", note=On5.E),   # #74 Long Guiro
+	Instrument("perc75.sbi", note=On5.E),   # #75 Claves
+	Instrument("perc76.sbi", note=On5.E),   # #76 Hi Wood Block
+	Instrument("perc77.sbi", note=On5.E),   # #77 Low Wood Block
+	Instrument("perc78.sbi", note=On5.E),   # #78 Mute Cuica
+	Instrument("perc79.sbi", note=On5.E),   # #79 Open Cuica
+	Instrument("perc80.sbi", note=On5.E),   # #80 Mute Triangle
+	Instrument("perc81.sbi", note=On5.E),   # #81 Open Triangle
 ]
 

lumps/genmidi/midi.py

@@ -0,0 +1,42 @@
+
+# Constants for MIDI notes.
+#
+# For example:
+#    F# in Octave 3:      O3.Fs
+#    C# in Octave -2:     On2.Cs
+#    D-flat in Octave 1:  O1.Db
+#    D in Octave 0:       O0.D
+#    E in Octave 2:       O2.E
+
+class Octave:
+	def __init__(self, base):
+		self.C  = base
+		self.Cs = base + 1
+		self.Db = base + 1
+		self.D  = base + 2
+		self.Ds = base + 3
+		self.Eb = base + 3
+		self.E  = base + 4
+		self.F  = base + 5
+		self.Fs = base + 6
+		self.Gb = base + 6
+		self.G  = base + 7
+		self.Gs = base + 8
+		self.Ab = base + 8
+		self.A  = base + 9
+		self.As = base + 10
+		self.Bb = base + 10
+		self.B  = base + 11
+
+On5 = Octave(0)      # Octave -5
+On4 = Octave(12)     # Octave -4
+On3 = Octave(24)     # Octave -3
+On2 = Octave(36)     # Octave -2
+On1 = Octave(48)     # Octave -1
+O0  = Octave(60)     # Octave 0
+O1  = Octave(72)     # Octave 1
+O2  = Octave(84)     # Octave 2
+O3  = Octave(96)     # Octave 3
+O4  = Octave(108)    # Octave 4
+O5  = Octave(120)    # Octave 5
+