Feature/state machine (#1705)

* Fix script error in old state machine example

* Add a module with a more complex state machine, that can be created and controlled through the Lua API. Useful for interactive installations

* Add an example asset for the new state machine and rename the old linear "state machine" to luastatemachine


Co-authored-by: Malin Ejdbo <malin.ejdbo@gmail.com>

data/assets/examples/luastatemachine.asset

@@ -0,0 +1,47 @@
+local stateMachineHelper = asset.require('util/lua_state_machine_helper')
+
+local states = {
+  {
+    Title = "Highlight EarthTrail",
+    Play = function ()
+      openspace.setPropertyValue("Scene.EarthTrail.Renderable.Appearance.LineWidth", 10, 1)
+    end,
+    Rewind = function ()
+      openspace.setPropertyValue("Scene.EarthTrail.Renderable.Appearance.LineWidth", 2, 1)
+    end
+  }, 
+  {
+    Title = "Highlight MarsTrail",
+    Play = function ()
+      openspace.setPropertyValue("Scene.EarthTrail.Renderable.Appearance.LineWidth", 2, 1)
+      openspace.setPropertyValue("Scene.MarsTrail.Renderable.Appearance.LineWidth", 10, 1)
+    end,
+    Rewind = function ()
+      openspace.setPropertyValue("Scene.MarsTrail.Renderable.Appearance.LineWidth", 2, 1)
+      openspace.setPropertyValue("Scene.EarthTrail.Renderable.Appearance.LineWidth", 10, 1)
+    end
+  }
+}
+
+local stateMachine
+
+function next()
+  stateMachine.goToNextState()
+end
+
+function previous()
+  stateMachine.goToPreviousState()
+end
+
+asset.onInitialize(function ()
+  stateMachine = stateMachineHelper.createStateMachine(states)
+  openspace.bindKey('RIGHT', 'next()')
+  openspace.bindKey('LEFT', 'previous()')
+end)
+
+
+asset.onDeinitialize(function ()
+  stateMachine = nil
+  openspace.clearKey('RIGHT')
+  openspace.clearKey('LEFT')
+end)

data/assets/examples/statemachine.asset

@@ -1,47 +1,75 @@
-local stateMachineHelper = asset.require('util/state_machine_helper')
+-- Create a state machine with a few different states. The state machine can be controlled through
+-- the scripting commands from the state machine module.
 
-states = {
+local targetNode = function(nodeIdentifier) 
+  return [[
+    openspace.setPropertyValueSingle("NavigationHandler.OrbitalNavigator.RetargetAnchor", nil)
+    openspace.setPropertyValueSingle(
+      "NavigationHandler.OrbitalNavigator.Anchor", 
+      ']] .. nodeIdentifier ..  [['
+    )
+    openspace.setPropertyValueSingle("NavigationHandler.OrbitalNavigator.Aim", '')
+  ]]
+end
+
+local states = {
   {
-    Title = "Highlight EarthTrail",
-    Play = function ()
-      openspace.setPropertyValue("Scene.EarthTrail.Renderable.LineWidth", 10, 1)
-    end,
-    Rewind = function ()
-      openspace.setPropertyValue("Scene.EarthTrail.Renderable.LineWidth", 2, 1)
-    end
-  }, 
+    Identifier = "Constellations",
+    Enter = [[
+      openspace.setPropertyValueSingle('Scene.Constellations.Renderable.Opacity', 1.0, 1.0)
+    ]],
+    Exit = [[
+      openspace.setPropertyValueSingle('Scene.Constellations.Renderable.Opacity', 0.0, 1.0)
+    ]]
+  },
   {
-    Title = "Highlight MarsTrail",
-    Play = function ()
-      openspace.setPropertyValue("Scene.EarthTrail.Renderable.LineWidth", 2, 1)
-      openspace.setPropertyValue("Scene.MarsTrail.Renderable.LineWidth", 10, 1)
-    end,
-    Rewind = function ()
-      openspace.setPropertyValue("Scene.MarsTrail.Renderable.LineWidth", 2, 1)
-      openspace.setPropertyValue("Scene.EarthTrail.Renderable.LineWidth", 10, 1)
-    end
+    Identifier = "Earth",
+    Enter = "openspace.setPropertyValueSingle('Scene.EarthLabel.Renderable.Enabled', true)",
+    Exit = "openspace.setPropertyValueSingle('Scene.EarthLabel.Renderable.Enabled', false)"
+  },
+  {
+    Identifier = "Moon",
+    Enter = "",
+    Exit = ""
   }
 }
 
-local stateMachine
+local transitions = {
+  {
+    From = "Earth",
+    To = "Moon",
+    Action = targetNode("Moon")
+  },
+  {
+    From = "Moon",
+    To = "Earth",
+    Action = targetNode("Earth")
+  },
+  {
+    From = "Earth",
+    To = "Constellations",
+    -- action is optional
+  },
+  {
+    From = "Constellations",
+    To = "Earth"
+  },
+  {
+    From = "Moon",
+    To = "Constellations",
+    Action = targetNode("Earth")
+  },
+  {
+    From = "Constellations",
+    To = "Moon",
+    Action = targetNode("Moon")
+  }
+}
 
-function next() 
-  stateMachine.goToNextState()
-end
+asset.onInitialize(function()
+  -- Setup
+  openspace.setPropertyValueSingle('Scene.Constellations.Renderable.Enabled', true)
+  openspace.setPropertyValueSingle('Scene.Constellations.Renderable.Opacity', 0.0)
 
-function previous()
-  stateMachine.goToPreviousState()
-end
-
-asset.onInitialize(function ()
-  stateMachine = stateMachineHelper.createStateMachine(states)
-  openspace.bindKey('RIGHT', 'next()')
-  openspace.bindKey('LEFT', 'previous()')
-end)
-
-
-asset.onDeinitialize(function ()
-  stateMachine = nil
-  openspace.clearKey('RIGHT')
-  openspace.clearKey('LEFT')
+  openspace.statemachine.createStateMachine(states, transitions, "Earth")
 end)

data/assets/util/lua_state_machine_helper.asset

@@ -1,3 +1,8 @@
+-- Contains the required functions to create a simple Lua state machine, that can step 
+-- forwards and backwards through a list of states.
+--
+-- A state is given as a table with a Title string, and two functions: Play and Rewind
+-- (see example asset)
 
 local goToNextStateFunction = function (machine)
   if (machine.currentStateIndex >= #machine.states) then