fixes #1537 #1528

also fixes feet layering of gold with grass. Unifies gen1/gen2 grass layering into a single system

src/core/Music.lua

@@ -501,6 +501,12 @@ function Music.setFilterLevel(level)
   applyFilter(state.loopSource)
 end
 
+function Music.setPitch(pitch)
+  pitch = pitch or 1.0
+  if state.source then pcall(state.source.setPitch, state.source, pitch) end
+  if state.loopSource then pcall(state.loopSource.setPitch, state.loopSource, pitch) end
+end
+
 -- re-apply persisted audio options (Game calls this on boot and after
 -- loading a save)
 function Music.applyOptions(opts)