REF: How to start a GG boss fight in HoG with normal scene transition

[royitaqi]

Anti-approach

Use GameManager.instance.ChangeToScene() won't work, because it doesn't set up all the environment (e.g. enter/leave) necessary for a GG fight. It doesn't trigger USceneManager.activeSceneChanged event for mod to detect transition, too.

The following approaches are closer to normal game, which has the benefits of covering some of the necessary environment automatically.

Source code for the following approaches:

https://github.com/royitaqi/HollowKnight.BossAttacks/blob/ad3b2a8023d9e2f00789344aad193d6ccd7486ef/BossAttacks/Utils/E2eTestUtils.cs

Approach 1: via Scene Change

Notes:

• (good or bad) Hero stuck for a few seconds, then scene suddonly jump into fights. Fast, but abrupt.
• (bad) Flash of black screen during win return's white screen.
• (good) No save on win.
• (bad) Save on death.

            // Death return
            PlayerData.instance.dreamReturnScene = "GG_Workshop";
            PlayerData.instance.bossReturnEntryGate = ReturnDoor;

            // Win return
            BossSceneController.SetupEvent = (self) => {
                self.BossLevel = ChallengeLevel;
                self.DreamReturnEvent = "DREAM RETURN";
                self.OnBossSceneComplete += () =>
                {
                    GameManager.instance.ChangeToScene("GG_Workshop", ReturnDoor, 0);
                };
            };

            // Start fight
            GameManager.instance.BeginSceneTransition(new GameManager.SceneLoadInfo
            {
                SceneName = BossScene,
                EntryGateName = "door_dreamEnter", // Don't miss this. Will cause fight to not start (boss and hero stuck).
                PreventCameraFadeOut = true,
                Visualization = GameManager.SceneLoadVisualizations.GodsAndGlory,
            });

Approach 2: via HoG Statue

Notes:

• (good) Smooth transition into fight. Not too slow.
• (bad) Flash of black screen during win return's white screen.
• (good) No save on win.
• (bad) Save on death.

Assumptions:

• Active scene is GG_Workshop (in order to get a statue GO).

            // Death return
            PlayerData.instance.dreamReturnScene = "GG_Workshop";
            PlayerData.instance.bossReturnEntryGate = ReturnDoor;

            // Win return
            BossSceneController.SetupEvent = (self) => {
                self.BossLevel = ChallengeLevel;
                self.DreamReturnEvent = "DREAM RETURN";
                self.OnBossSceneComplete += () =>
                {
                    GameManager.instance.ChangeToScene("GG_Workshop", ReturnDoor, 0);
                };
            };

            // Start fight
            GameObject statue = USceneManager.GetActiveScene()
                .GetRootGameObjects()
                .First(go => go.name == "GG_Statue_GreyPrince"); // statue name doesn't matter
            var statueControl = statue.transform.GetChild(0).gameObject.LocateMyFSM("GG Boss UI").Fsm;
            statueControl.GetState("Take Control").Transitions[0].ToFsmState = statueControl.GetState("Impact");
            statueControl.Variables.FindFsmString("Return Scene").Value = "GG_Workshop";
            statueControl.Variables.FindFsmString("To Scene").Value = BossScene;
            statueControl.SetState("Take Control");

Approach 3: via Challenge Menu

Notes:

• (good) The most normal way to enter GG fights.
• (good) No flash of black.
• (bad) Save on win.
• (bad) Save on death.

Assumptions:

• The code which selects challenge level in the menu assumes that the menu started at challenge 0. This can be wrong assumption because menu can remember last challenge position.

            // warp
            HeroController.instance.gameObject.transform.position = StatuePos;

            // interact with menu
            yield return new WaitForSeconds(0.1f);
            yield return Up(0.1f);
            yield return new WaitForSeconds(1);
            for (int i =  0; i < ChallengeLevel; i++)
            {
                yield return Down(0.1f);
            }
            yield return Jump(0.1f);