Data commit

Task/Musical-scale/Tcl/musical-scale.tcl

@@ -0,0 +1,23 @@
+package require sound
+
+# Encapsulate the tone generation
+set filter [snack::filter generator 1 20000 0.5 sine -1]
+set sound  [snack::sound -rate 22050]
+proc play {frequency length} {
+    global filter sound
+
+    $filter configure $frequency
+    $sound play -filter $filter
+
+    # Need to run event loop; Snack uses it internally
+    after $length {set donePlay 1}
+    vwait donePlay
+
+    $sound stop
+}
+
+# Major scale up, then down; extra delay at ends of scale
+set tonicFrequency 261.63; # C4
+foreach i {0 2 4 5 7 9 11 12 11 9 7 5 4 2 0} {
+    play [expr {$tonicFrequency*2**($i/12.0)}] [expr {$i%12?250:500}]
+}