Barnacle prediction fixes

scripting/include/srccoop.inc

@@ -44,6 +44,7 @@
 	#define ENTPATCH_FUNC_TRACKAUTOCHANGE
 	#define ENTPATCH_FUNC_TRACKTRAIN
 	#define ENTPATCH_NPC_RUNTASK
+	#define ENTPATCH_BARNACLE_PREDICTION
 
 	#define PLAYERPATCH_SUIT_SOUNDS
 	#define PLAYERPATCH_PICKUP_FORCEPLAYERTODROPTHISOBJECT
@@ -97,6 +98,7 @@
 	#define ENTPATCH_FUNC_TRACKAUTOCHANGE
 	#define ENTPATCH_FUNC_TRACKTRAIN
 	#define ENTPATCH_NPC_RUNTASK
+	#define ENTPATCH_BARNACLE_PREDICTION
 	#define ENTPATCH_BM_XENTURRET
 	#define ENTPATCH_BM_ICHTHYOSAUR
 	#define ENTPATCH_BM_GARGANTUA

scripting/include/srccoop/entitypatch.inc

@@ -1570,3 +1570,56 @@ public MRESReturn Hook_ScriptedSequenceStartScript(int _this)
 	}
 	return MRES_Ignored;
 }
+
+//------------------------------------------------------
+// npc_barnacle
+// Fixes prediction and view jitter while being grabbed by a barnacle.
+//------------------------------------------------------
+public void Hook_Barnacle_OnGrab(const char[] szOutput, const int iCaller, const int iActivator, const float flDelay)
+{
+	CNPC_Barnacle pBarnacle = CNPC_Barnacle(iCaller);
+
+	// The enemy of the barnacle is not set until after `CNPC_Barnacle::AttachTongueToTarget` is finished executing.
+	// https://github.com/ValveSoftware/source-sdk-2013/blob/0d8dceea4310fde5706b3ce1c70609d72a38efdf/sp/src/game/server/hl2/npc_barnacle.cpp#L1359
+	CreateTimer(0.0, Timer_Barnacle_OnGrab, pBarnacle, TIMER_FLAG_NO_MAPCHANGE);
+}
+
+//------------------------------------------------------
+// npc_barnacle
+// Fixes prediction and view jitter while being grabbed by a barnacle.
+//------------------------------------------------------
+public void Timer_Barnacle_OnGrab(Handle hTimer, const CNPC_Barnacle pBarnacle)
+{
+	if (pBarnacle.IsValid() && pBarnacle.IsAlive())
+	{
+		CBaseEntity pEnemy = pBarnacle.GetEnemy();
+		if (pEnemy != NULL_CBASEENTITY && pEnemy.IsPlayer())
+		{
+			CBasePlayer pPlayer = view_as<CBasePlayer>(pEnemy);
+
+			// Prevents client-side prediction errors for movement while being pulled up.
+			pPlayer.m_fFlags |= FL_ATCONTROLS;
+			// Removes the initial view jitter when being pulled up.
+			pPlayer.SetMoveType(MOVETYPE_FLY);
+			// Remove the view jitter while being pulled up.
+			pPlayer.SetLaggedMovement(0.0);
+		}
+	}
+}
+
+//------------------------------------------------------
+// npc_barnacle
+// Fixes prediction and view jitter while being grabbed by a barnacle.
+//------------------------------------------------------
+public void Hook_Barnacle_OnRelease(const char[] szOutput, const int iCaller, const int iActivator, const float flDelay)
+{
+	CNPC_Barnacle pBarnacle = CNPC_Barnacle(iCaller);
+	CBaseEntity pEnemy = pBarnacle.GetEnemy();
+	if (pEnemy != NULL_CBASEENTITY && pEnemy.IsPlayer())
+	{
+		CBasePlayer pPlayer = view_as<CBasePlayer>(pEnemy);
+		pPlayer.m_fFlags &= ~FL_ATCONTROLS;
+		pPlayer.SetMoveType(MOVETYPE_WALK);
+		pPlayer.SetLaggedMovement(1.0);
+	}
+}

scripting/srccoop.sp

@@ -344,6 +344,11 @@ public void OnPluginStart()
 			}
 		}
 	}
+
+	#if defined ENTPATCH_BARNACLE_PREDICTION
+	HookEntityOutput("npc_barnacle", "OnGrab", Hook_Barnacle_OnGrab);
+	HookEntityOutput("npc_barnacle", "OnRelease", Hook_Barnacle_OnRelease);
+	#endif
 }
 
 #pragma dynamic ENTITYSTRING_LENGTH