Add an event to get the helpers's animations and fill the player with them

Celeste.Mod.mm/Mod/Everest/Everest.Events.cs

@@ -1,4 +1,4 @@
-using Celeste.Mod.UI;
+using Celeste.Mod.UI;
 using Microsoft.Xna.Framework;
 using System;
 using System.Collections.Generic;
@@ -318,6 +318,37 @@ public static class SubHudRenderer {
                 internal static void BeforeRender(_SubHudRenderer renderer, Scene scene)
                     => OnBeforeRender?.Invoke(renderer, scene);
             }
+
+            public static class PlayerSprite {
+                public delegate void GetIdsUsedFillAnimForIdHandler(List<string> ids, string id);
+
+                /// <summary>
+                /// Called during <see cref="patch_PlayerSprite.CreateFramesMetadata(string)"/>, unless <see cref="DoNotFillAnimFor"/> contains its given string.
+                /// <br/> <br/>
+                /// Mods using this should always add an id to <see cref="List{T}"/> ids whether what the <see cref="string"/> id was given, to avoid certain <see cref="string"/> id missing their animations
+                /// <br/>e.g: <code>
+                /// Everest.Event.PlayerSprite.OnGetIdsUsedFillAnimForId += ((ids, id) => {
+                ///     if (id == "player_no_backpack")
+                ///        ids.Add("MyHelper_Anims_NB")
+                ///     else
+                ///        ids.Add("MyHelper_Anims")
+                /// });
+                /// </code></summary>
+                public static event GetIdsUsedFillAnimForIdHandler OnGetIdsUsedFillAnimForId;
+
+                internal static List<string> GetIdsUsedFillAnimFor(string id) {
+                    List<string> ids = new();
+                    OnGetIdsUsedFillAnimForId?.Invoke(new(), id);
+                    return ids;
+                }
+
+                // Put this field here make it so visible
+                /// <summary>
+                /// Filter IDs that should not be fill anim by other IDs during <see cref="patch_PlayerSprite.CreateFramesMetadata(string)"/>,
+                /// <br/>prevent e.g "MyHelper_Anims", ""MyHelper_Anims_NB", "OthersHelper_Anims" ids from senseless filling each other's animations
+                /// </summary>
+                public static HashSet<string> DoNotFillAnimFor = new(StringComparer.CurrentCultureIgnoreCase);
+            }
         }
     }
 }

Celeste.Mod.mm/Patches/PlayerSprite.cs

@@ -1,17 +1,86 @@
-using Celeste;
-using Mono.Cecil;
-using MonoMod;
-using System;
-
-namespace Celeste {
-    public class patch_PlayerSprite : PlayerSprite {
-
-        public patch_PlayerSprite(PlayerSpriteMode mode) : base(mode) {
-            // Do nothing here. MonoMod will ignore this.
-        }
-
-        [MonoModIgnore]
-        [ForceNoInlining]
-        public new extern static void ClearFramesMetadata();
-    }
-}
+using Celeste;
+using Celeste.Mod;
+using Microsoft.Xna.Framework;
+using Mono.Cecil;
+using Monocle;
+using MonoMod;
+using MonoMod.Cil;
+using MonoMod.InlineRT;
+using System;
+using System.Collections.Generic;
+using MonoMod.Utils;
+using System.Reflection.Emit;
+
+namespace Celeste {
+    class patch_PlayerSprite : PlayerSprite {
+        public patch_PlayerSprite(PlayerSpriteMode mode) : base(mode) {
+            // no-op. MonoMod ignores this - we only need this to make the compiler shut up.
+        }
+
+#pragma warning disable CS0108 // Hides inherited member
+        [MonoModIgnore]
+        [PatchPlayerSpriteCreateFramesMetadata]
+        public static void CreateFramesMetadata(string id) {
+        }
+
+        [MonoModIgnore]
+        [ForceNoInlining]
+        public new extern static void ClearFramesMetadata();
+#pragma warning restore CS0108
+
+        private static void fillAnimForID(string id) {
+            List<string> ids = Everest.Events.PlayerSprite.GetIdsUsedFillAnimFor(id);
+            if (ids.Count == 0)
+                return;
+            Dictionary<string, patch_Sprite.Animation> existingAnim = (GFX.SpriteBank.SpriteData[id].Sprite as patch_Sprite).Animations;
+            foreach (string id2 in ids) {
+                foreach (KeyValuePair<string, patch_Sprite.Animation> anim in (GFX.SpriteBank.SpriteData[id2].Sprite as patch_Sprite).Animations) {
+                    if (!existingAnim.ContainsKey(anim.Key)) {
+                        existingAnim[anim.Key] = anim.Value;
+                    }
+                }
+            }
+        }
+    }
+}
+
+namespace MonoMod {
+    [MonoModCustomMethodAttribute(nameof(MonoModRules.PatchPlayerSpriteCreateFramesMetadata))]
+    class PatchPlayerSpriteCreateFramesMetadata : Attribute {
+    }
+
+    static partial class MonoModRules {
+        public static void PatchPlayerSpriteCreateFramesMetadata(ILContext context, CustomAttribute attrib) {
+            MethodReference m_PlayerSprite_fillAnimForID = context.Method.DeclaringType.FindMethod("fillAnimForID");
+
+            FieldReference f_DoNotFillAnimFor = MonoModRule.Modder.Module.GetType("Celeste.Mod.Everest/Events/PlayerSprite").FindField("DoNotFillAnimFor");
+
+            //Explicitly instantiate the generic HashSet<T> type
+            GenericInstanceType genericInst = (GenericInstanceType) context.Module.ImportReference(f_DoNotFillAnimFor.FieldType);
+
+            MethodReference m_temp = context.Module.ImportReference(genericInst.Resolve().FindMethod("Contains"));
+            MethodReference m_HashSet_string_Contains = context.Module.ImportReference(new MethodReference(m_temp.Name, m_temp.ReturnType, genericInst) {
+                HasThis = m_temp.HasThis,
+                ExplicitThis = m_temp.ExplicitThis,
+                CallingConvention = m_temp.CallingConvention,
+            });
+            m_HashSet_string_Contains.Parameters.AddRange(m_temp.Parameters);
+
+            ILCursor cursor = new ILCursor(context);
+
+            // if (DoNotFillAnimFor.Contains(id)) {
+            ILLabel If = cursor.DefineLabel();
+            cursor.EmitLdsfld(f_DoNotFillAnimFor);
+            cursor.EmitLdarg0();
+            cursor.EmitCallvirt(m_HashSet_string_Contains);
+            cursor.EmitBrtrue(If);
+
+            //   fillAnimForID(id);
+            cursor.EmitLdarg0();
+            cursor.EmitCall(m_PlayerSprite_fillAnimForID);
+            // }
+            cursor.EmitBr(If);
+            cursor.MarkLabel(If);
+        }
+    }
+}