Camera Catchup Speed Trigger (for high speed situations)

Ahorn/lang/en_gb.lang

@@ -273,3 +273,6 @@ placements.entities.SpringCollab2020/SeekerStatueCustomColors.tooltips.trailColo
 # Custom Respawn Time Refill
 placements.entities.SpringCollab2020/CustomRespawnTimeRefill.tooltips.twoDash=Whether the refill should give two dashes.
 placements.entities.SpringCollab2020/CustomRespawnTimeRefill.tooltips.respawnTime=The delay (in seconds) before the refill respawns after being collected.
+
+# Camera Catchup Speed Trigger
+placements.triggers.SpringCollab2020/CameraCatchupSpeedTrigger.tooltips.catchupSpeed=Raise this value to have the camera scroll quicker to its target. Vanilla values are 8 during the temple fall cutscene, and 1 everywhere else.

Ahorn/triggers/cameraCatchupSpeed.jl

@@ -0,0 +1,15 @@
+module SpringCollab2020CameraCatchupSpeedTrigger
+
+using ..Ahorn, Maple
+
+@mapdef Trigger "SpringCollab2020/CameraCatchupSpeedTrigger" CameraCatchupSpeedTrigger(x::Integer, y::Integer, width::Integer=Maple.defaultTriggerWidth, height::Integer=Maple.defaultTriggerHeight,
+    catchupSpeed::Number=1.0)
+
+const placements = Ahorn.PlacementDict(
+    "Camera Catchup Speed (Spring Collab 2020)" => Ahorn.EntityPlacement(
+        CameraCatchupSpeedTrigger,
+        "rectangle"
+    )
+)
+
+end

SpringCollab2020Module.cs

@@ -32,6 +32,7 @@ public override void Load() {
             BlockJellySpawnTrigger.Load();
             StrawberryIgnoringLighting.Load();
             SeekerCustomColors.Load();
+            CameraCatchupSpeedTrigger.Load();
         }
 
         public override void LoadContent(bool firstLoad) {
@@ -59,6 +60,7 @@ public override void Unload() {
             BlockJellySpawnTrigger.Unload();
             StrawberryIgnoringLighting.Unload();
             SeekerCustomColors.Unload();
+            CameraCatchupSpeedTrigger.Unload();
         }
 
         public override void PrepareMapDataProcessors(MapDataFixup context) {

Triggers/CameraCatchupSpeedTrigger.cs

@@ -0,0 +1,56 @@
+using Celeste.Mod.Entities;
+using Microsoft.Xna.Framework;
+using Mono.Cecil.Cil;
+using Monocle;
+using MonoMod.Cil;
+using MonoMod.RuntimeDetour;
+using System;
+
+namespace Celeste.Mod.SpringCollab2020.Triggers {
+    [CustomEntity("SpringCollab2020/CameraCatchupSpeedTrigger")]
+    [Tracked]
+    class CameraCatchupSpeedTrigger : Trigger {
+        private static ILHook playerOrigUpdateHook;
+
+        public static void Load() {
+            playerOrigUpdateHook = new ILHook(typeof(Player).GetMethod("orig_Update"), modPlayerOrigUpdate);
+        }
+
+        public static void Unload() {
+            playerOrigUpdateHook?.Dispose();
+        }
+
+        private static void modPlayerOrigUpdate(ILContext il) {
+            ILCursor cursor = new ILCursor(il);
+
+            // we're looking for: 1f - (float)Math.Pow(0.01f / num2, Engine.DeltaTime)
+            if (cursor.TryGotoNext(
+                instr => instr.MatchLdcR4(0.01f),
+                instr => instr.OpCode == OpCodes.Ldloc_S,
+                instr => instr.MatchDiv())) {
+
+                // and we want to position the cursor just after loading num2
+                cursor.Index += 2;
+
+                Logger.Log("SpringCollab2020/CameraCatchupSpeedTrigger", $"Inserting code to mod camera catchup speed at {cursor.Index} in IL for Player.orig_Update()");
+
+                // this delegate will allow us to turn num2 into something else.
+                cursor.Emit(OpCodes.Ldarg_0);
+                cursor.EmitDelegate<Func<float, Player, float>>((orig, self) => {
+                    CameraCatchupSpeedTrigger trigger = self.CollideFirst<CameraCatchupSpeedTrigger>();
+                    if (trigger != null) {
+                        return trigger.catchupSpeed;
+                    }
+                    return orig;
+                });
+            }
+        }
+
+
+        private float catchupSpeed;
+
+        public CameraCatchupSpeedTrigger(EntityData data, Vector2 offset) : base(data, offset) {
+            catchupSpeed = data.Float("catchupSpeed", 1f);
+        }
+    }
+}