Add example script to assign VCAs

diff --git a/scripts/_vca_slave_assign.lua b/scripts/_vca_slave_assign.lua
new file mode 100644 (file)
index 0000000..62055b5
--- /dev/null
+++ b/scripts/_vca_slave_assign.lua
@@ -0,0 +1,73 @@
+ardour { ["type"] = "Snippet", name = "VCA Slave Examples",
+       license     = "MIT",
+       author      = "Ardour Team",
+}
+
+function factory () return function ()
+       -- find possible masters & slave, allow selection in dropdown menu
+       local targets = {}
+       local sources = {}
+       local have_masters = false
+       local have_slaves = false
+
+       for v in Session:vca_manager ():vcas() :iter () do -- for each VCA
+               sources [v:name ()] = v
+               have_masters = true
+       end
+
+       for s in Session:get_stripables ():iter () do -- for every track/bus/vca
+               if s:is_monitor () or s:is_auditioner () then goto nextroute end -- skip special routes
+               targets [s:name ()] = s
+               have_slaves = true;
+               ::nextroute::
+       end
+
+       -- bail out if there are no parameters
+       if not have_slaves then
+               LuaDialog.Message ("VCA Slave Example", "No Slavables found", LuaDialog.MessageType.Info, LuaDialog.ButtonType.Close):run ()
+               sources = nil
+               collectgarbage ()
+               return
+       end
+       if not have_masters then
+               LuaDialog.Message ("VCA Slave Example", "No VCA masters found", LuaDialog.MessageType.Info, LuaDialog.ButtonType.Close):run ()
+               targets = nil
+               collectgarbage ()
+               return
+       end
+
+       -- create a dialog, ask user which master to assign to which slave
+       local dialog_options = {
+               { type = "dropdown", key = "master", title = "Control Master", values = sources },
+               { type = "dropdown", key = "slave", title = "Control Slave", values = targets }
+       }
+       local rv = LuaDialog.Dialog ("Select VCA assignment", dialog_options):run ()
+
+       targets = nil -- drop references (the table holds shared-pointer references to all strips)
+       collectgarbage () -- and release the references immediately
+
+       if not rv then return end -- user canceled the operation
+
+       -- parse user response
+       local mst = rv["master"]
+       local slv = rv["slave"]
+       assert (not slv:to_slavable ():isnil ())
+
+       -- test if mst is already controlled by slv (directly or indirectly)
+       -- if so, don't allow the connection
+       if (not slv:to_slavable ():assigned_to (Session:vca_manager(), mst)) then
+               -- if slv is a VCA and is controlled by master, disconnect it
+               if (not slv:to_vca ():isnil () and slv:to_vca ():slaved_to (mst)) then
+                       slv:to_slavable ():unassign (mst)
+               else
+                       slv:to_slavable ():assign (mst)
+               end
+       else
+               LuaDialog.Message ("VCA Slave Example", "Recursive VCA assignment ignored", LuaDialog.MessageType.Info, LuaDialog.ButtonType.Close):run ()
+       end
+
+       -- drop references
+       mst = nil slv = nil
+       collectgarbage ()
+end end
+