Spawning transpiler (#2241)

Exiled-Team · Nov 29, 2023 · caaa732 · caaa732
1 parent 96eb33b
commit caaa732
Showing 1 changed file with 74 additions and 29 deletions.
diff --git a/Exiled.Events/Patches/Events/Player/Spawning.cs b/Exiled.Events/Patches/Events/Player/Spawning.cs
@@ -7,21 +7,19 @@
 
 namespace Exiled.Events.Patches.Events.Player
 {
+    using System.Collections.Generic;
     using System.Reflection;
+    using System.Reflection.Emit;
 
     using API.Features;
+    using Exiled.API.Features.Pools;
     using Exiled.Events.Attributes;
     using Exiled.Events.EventArgs.Player;
-
     using HarmonyLib;
-
-    using PlayerRoles;
     using PlayerRoles.FirstPersonControl;
     using PlayerRoles.FirstPersonControl.NetworkMessages;
     using PlayerRoles.FirstPersonControl.Spawnpoints;
 
-    using UnityEngine;
-
     using static HarmonyLib.AccessTools;
 
     /// <summary>
@@ -37,38 +35,85 @@ private static MethodInfo TargetMethod()
             return Method(TypeByName("PlayerRoles.FirstPersonControl.Spawnpoints.RoleSpawnpointManager").GetNestedTypes(all)[1], "<Init>b__2_0");
         }
 
-        private static bool Prefix(ReferenceHub hub, PlayerRoleBase prevRole, PlayerRoleBase newRole)
+        private static IEnumerable<CodeInstruction> Transpiler(IEnumerable<CodeInstruction> instructions, ILGenerator generator)
         {
-            if (newRole.ServerSpawnReason != RoleChangeReason.Destroyed && Player.TryGet(hub, out Player player))
-            {
-                Vector3 oldPosition = hub.transform.position;
-                float oldRotation = (prevRole as IFpcRole)?.FpcModule.MouseLook.CurrentVertical ?? 0;
+            List<CodeInstruction> newInstructions = ListPool<CodeInstruction>.Pool.Get(instructions);
+
+            Label skipLabel = generator.DefineLabel();
+
+            newInstructions[0].labels.Add(skipLabel);
 
-                if (newRole is IFpcRole fpcRole)
+            newInstructions.InsertRange(
+                0,
+                new CodeInstruction[]
                 {
-                    if (newRole.ServerSpawnFlags.HasFlag(RoleSpawnFlags.UseSpawnpoint) && fpcRole.SpawnpointHandler != null && fpcRole.SpawnpointHandler.TryGetSpawnpoint(out Vector3 position, out float horizontalRot))
-                    {
-                        oldPosition = position;
-                        oldRotation = horizontalRot;
-                    }
+                    // if (newRole is IFpcRole)
+                    //  goto skipLabel
+                    new(OpCodes.Ldarg_3),
+                    new(OpCodes.Isinst, typeof(IFpcRole)),
+                    new(OpCodes.Brtrue_S, skipLabel),
+
+                    // Player.Get(hub)
+                    new(OpCodes.Ldarg_1),
+                    new(OpCodes.Call, Method(typeof(Player), nameof(Player.Get), new[] { typeof(ReferenceHub) })),
+                    new(OpCodes.Dup),
+
+                    // Player::Position
+                    new(OpCodes.Callvirt, PropertyGetter(typeof(Player), nameof(Player.Position))),
+
+                    // 0f
+                    new(OpCodes.Ldc_R4, 0f),
+
+                    // oldRole
+                    new(OpCodes.Ldarg_2),
+
+                    // SpawningEventArgs(Player, Vector3, 0, PlayerRoleBase)
+                    new(OpCodes.Newobj, GetDeclaredConstructors(typeof(SpawningEventArgs))[0]),
 
-                    SpawningEventArgs ev = new(player, oldPosition, oldRotation, prevRole);
+                    // Handlers.Player.OnSpawning(ev)
+                    new(OpCodes.Call, Method(typeof(Handlers.Player), nameof(Handlers.Player.OnSpawning))),
+                });
 
-                    Handlers.Player.OnSpawning(ev);
+            int index = newInstructions.FindLastIndex(x => x.opcode == OpCodes.Ldarg_1);
 
-                    hub.transform.position = ev.Position;
-                    fpcRole.FpcModule.MouseLook.CurrentHorizontal = ev.HorizontalRotation;
-                    hub.connectionToClient.Send(new FpcOverrideMessage(ev.Position, ev.HorizontalRotation), 0);
-                }
-                else
+            IEnumerable<Label> labels = newInstructions[index].labels;
+
+            newInstructions.RemoveRange(index, 9);
+
+            newInstructions.InsertRange(
+                index,
+                new[]
                 {
-                    Handlers.Player.OnSpawning(new(player, oldPosition, oldRotation, prevRole));
-                }
+                    // Player.Get(hub)
+                    new CodeInstruction(OpCodes.Ldarg_1).WithLabels(labels),
+                    new(OpCodes.Call, Method(typeof(Player), nameof(Player.Get), new[] { typeof(ReferenceHub) })),
+
+                    // position
+                    new(OpCodes.Ldloc_1),
+
+                    // rotation
+                    new(OpCodes.Ldloc_2),
+
+                    // oldRole
+                    new(OpCodes.Ldarg_2),
 
-                return false;
-            }
+                    // SpawningEventArgs(Player, Vector3, float, PlayerRoleBase)
+                    new(OpCodes.Newobj, GetDeclaredConstructors(typeof(SpawningEventArgs))[0]),
+                    new(OpCodes.Dup),
 
-            return true;
+                    // Handlers.Player.OnSpawning(ev)
+                    new(OpCodes.Call, Method(typeof(Handlers.Player), nameof(Handlers.Player.OnSpawning))),
+
+                    // Set position and horizontal rotation
+                    new(OpCodes.Call, Method(typeof(Spawning), nameof(Send))),
+                });
+
+            for (int z = 0; z < newInstructions.Count; z++)
+                yield return newInstructions[z];
+
+            ListPool<CodeInstruction>.Pool.Return(newInstructions);
         }
+
+        private static void Send(SpawningEventArgs ev) => ev.Player.ReferenceHub.connectionToClient.Send(new FpcOverrideMessage(ev.Position, ev.HorizontalRotation));
     }
-}
+}