Fix multiple, overlapping, instances HouseRules UI appearing. (#575)

Issue: When changing pages in the HR UI, multiple pages are overlapping
onto one another.

Root cause: The process that determines whether or not to load UIs (our
`OnSceneLoaded()` hook function) is triggering the HR UI be loaded
multiple times.

Solution: Our `OnSceneLoaded()` is re-written to be more explicit about
how to determine when to load in the UI. It follows the same approach as
#549: to be very explicit
about which scenes, and on which platforms, constitute being in the
"lobby" where we want to UI rendered.

---

Additional background: Some time back, RG added helpers as part of their
`MotherbrainGlobalVars` class, capturing the exact platform the game is
being run on. This didn't exist before, and so at the time we introduced
a helper (`Common.UI/Environments`) to help us determine that ourselves.
Our method has become a bit flaky as the game as been ported to
different platforms and seen changes in scene numbers. It is now uneeded
as RG has captured that info on their end, which we can piggyback on to
determine the platform and scene more precisely.

Hence the removal of some of the code in `Common.UI/Environments`.

Author: orendain

Common.UI/Environments.cs

@@ -2,42 +2,20 @@
 {
     using UnityEngine.SceneManagement;
 
-    public enum Environment
-    {
-        Hangouts,
-        NonVr,
-        Vr,
-    }
-
     public static class Environments
     {
-        private const int SteamHangoutsSceneIndex = 45;
-        private const int OculusHangoutsSceneIndex = 43;
+        private const int SteamVRHangoutsSceneIndex = 45;
+        private const int RiftHangoutsSceneIndex = 43;
 
-        public static Environment CurrentEnvironment()
+        public static bool IsInHangouts()
         {
-            if (IsPcEdition())
-            {
-                return Environment.NonVr;
-            }
-
-            if (IsInHangouts())
+            if (!MotherbrainGlobalVars.IsRunningOnVRPlatform)
             {
-                return Environment.Hangouts;
+                return false;
             }
 
-            return Environment.Vr;
-        }
-
-        public static bool IsPcEdition()
-        {
-            return MotherbrainGlobalVars.IsRunningOnNonVRPlatform;
-        }
-
-        public static bool IsInHangouts()
-        {
-            return SceneManager.GetActiveScene().buildIndex == SteamHangoutsSceneIndex
-                || SceneManager.GetActiveScene().buildIndex == OculusHangoutsSceneIndex;
+            return SceneManager.GetActiveScene().buildIndex == SteamVRHangoutsSceneIndex
+                || SceneManager.GetActiveScene().buildIndex == RiftHangoutsSceneIndex;
         }
     }
 }

Common.UI/PageStackNavigation.cs

@@ -34,7 +34,7 @@ private PageStackNavigation(PageStack pageStack, IElementCreator elementCreator)
             _nextButton = elementCreator.CreateButton(OnNextPageClick);
             _nextButtonText = elementCreator.CreateButtonText(">");
 
-            if (Environments.CurrentEnvironment() == Environment.NonVr)
+            if (MotherbrainGlobalVars.IsRunningOnNonVRPlatform)
             {
                 InitializeForNonVr();
             }

HouseRules.Configuration/HouseRulesConfigurationBase.cs

@@ -15,8 +15,10 @@ internal static class HouseRulesConfigurationBase
         internal const string ModName = "HouseRules.Configuration";
         internal const string ModAuthor = "DemeoMods Team";
 
-        private const int NonVrSteamLobbySceneIndex = 2;
-        private const int NonVrCombinedSteamLobbySceneIndex = 3;
+        private const int NonVrSteamWindowsLobbySceneIndex = 2;
+        private const int NonVrOculusWindowsLobbySceneIndex = 2;
+        private const int SteamVRLobbySceneIndex = 1;
+        private const int RiftLobbySceneIndex = 1;
 
         private static Action<object>? _logInfo;
         private static Action<object>? _logDebug;
@@ -92,36 +94,62 @@ internal static void OnSceneUnloaded(int buildIndex, string sceneName)
 
         internal static void OnSceneLoaded(int buildIndex, string sceneName)
         {
-            if (buildIndex == 0 || sceneName.Contains("Startup"))
+            if (MotherbrainGlobalVars.SelectedPlatform == MotherbrainPlatform.NonVrSteamWindows)
             {
+                if (buildIndex == NonVrSteamWindowsLobbySceneIndex)
+                {
+                    LogDebug("Recognized lobby in NonVrSteamWindows. Loading UI.");
+                    _ = new GameObject("HouseRulesUiNonVr", typeof(HouseRulesUiNonVr));
+                }
+
                 return;
             }
 
-            if (Environments.IsPcEdition())
+            if (MotherbrainGlobalVars.SelectedPlatform == MotherbrainPlatform.NonVrOculusWindows)
             {
-                if (buildIndex == NonVrSteamLobbySceneIndex || buildIndex == NonVrCombinedSteamLobbySceneIndex)
+                if (buildIndex == NonVrOculusWindowsLobbySceneIndex)
                 {
-                    LogDebug("Recognized lobby in PC. Loading UI.");
+                    LogDebug("Recognized lobby in NonVrOculusWindows. Loading UI.");
                     _ = new GameObject("HouseRulesUiNonVr", typeof(HouseRulesUiNonVr));
                 }
+
+                return;
             }
-            else if (Environments.IsInHangouts() || sceneName.Contains("HobbyShop"))
+
+            if (Environments.IsInHangouts())
             {
                 LogDebug("Recognized lobby in Hangouts. Loading UI.");
                 _ = new GameObject("HouseRulesUiHangouts", typeof(HouseRulesUiHangouts));
+                return;
             }
-            else if (sceneName.Contains("Lobby"))
+
+            if (MotherbrainGlobalVars.SelectedPlatform == MotherbrainPlatform.SteamVR)
             {
-                LogDebug("Recognized lobby in VR. Loading UI.");
-                _ = new GameObject("HouseRulesUiVr", typeof(HouseRulesUiVr));
+                if (buildIndex == SteamVRLobbySceneIndex)
+                {
+                    LogDebug("Recognized lobby in SteamVR. Loading UI.");
+                    _ = new GameObject("HouseRulesUiVr", typeof(HouseRulesUiVr));
+                }
+
+                return;
             }
-            else
+
+            if (MotherbrainGlobalVars.SelectedPlatform == MotherbrainPlatform.Rift)
             {
-                if (HR.SelectedRuleset != Ruleset.None)
+                if (buildIndex == RiftLobbySceneIndex)
                 {
-                    LogDebug("Recognized modded game in VR. Loading UI.");
-                    _ = new GameObject("HouseRulesUiGameVr", typeof(HouseRulesUiGameVr));
+                    LogDebug("Recognized lobby in Rift. Loading UI.");
+                    _ = new GameObject("HouseRulesUiVr", typeof(HouseRulesUiVr));
                 }
+
+                return;
+            }
+
+            // If a scene is loaded while a ruleset is selected, we must have loaded a game level.
+            if (MotherbrainGlobalVars.IsRunningOnVRPlatform && HR.SelectedRuleset != Ruleset.None)
+            {
+                LogDebug("Recognized modded game in VR. Loading UI.");
+                _ = new GameObject("HouseRulesUiGameVr", typeof(HouseRulesUiGameVr));
             }
         }