Sync Player Animations properly

Doing the job of the tf2 devs once again.
This only works if the entity is in view as it changes animations, and bases on simtime.

include/core/netvars.hpp

@@ -177,6 +177,7 @@ public:
     offset_t m_angEyeAnglesLocal;
     offset_t m_nSequence;
     offset_t m_flSimulationTime;
+    offset_t m_flAnimTime;
     offset_t m_angRotation;
 
     offset_t m_hOwnerEntity;

src/core/netvars.cpp

@@ -29,6 +29,7 @@ void NetVars::Init()
     this->m_iClip2             = gNetvars.get_offset("DT_BaseCombatWeapon", "LocalWeaponData", "m_iClip2");
     this->m_Collision          = gNetvars.get_offset("DT_BaseEntity", "m_Collision");
     this->m_flSimulationTime   = gNetvars.get_offset("DT_BaseEntity", "m_flSimulationTime");
+    this->m_flAnimTime         = gNetvars.get_offset("DT_BaseEntity", "AnimTimeMustBeFirst", "m_flAnimTime");
     this->m_angRotation        = gNetvars.get_offset("DT_BaseEntity", "m_angRotation");
 
     IF_GAME(IsTF2())

src/hooks/CMakeLists.txt

@@ -10,6 +10,7 @@ set(files "${CMAKE_CURRENT_LIST_DIR}/CanPacket.cpp"
     "${CMAKE_CURRENT_LIST_DIR}/nographics.cpp"
     "${CMAKE_CURRENT_LIST_DIR}/others.cpp"
     "${CMAKE_CURRENT_LIST_DIR}/Paint.cpp"
+    "${CMAKE_CURRENT_LIST_DIR}/PlayerAnimFix.cpp"
     "${CMAKE_CURRENT_LIST_DIR}/PreDataUpdate.cpp"
     "${CMAKE_CURRENT_LIST_DIR}/RandomInt.cpp"
     "${CMAKE_CURRENT_LIST_DIR}/RunCommand.cpp"

src/hooks/PlayerAnimFix.cpp

@@ -0,0 +1,57 @@
+#include "common.hpp"
+#include "DetourHook.hpp"
+
+namespace hacks::tf2::animfix
+{
+DetourHook frameadvance_detour{};
+typedef float (*FrameAdvance_t)(IClientEntity *, float);
+
+std::vector<float> previous_simtimes;
+
+// Credits to Blackfire62 for telling me how this could be realized
+float FrameAdvance_hook(IClientEntity *self, float flInterval)
+{
+    float newInterval = flInterval;
+
+    // Check if the entity is valid
+    if (self && IDX_GOOD(self->entindex()) && self->entindex() > 0 && self->entindex() <= (int) previous_simtimes.size())
+    {
+        // Check if they are an alive player
+        CachedEntity *ent = ENTITY(self->entindex());
+        // Set new interval based on their simtime
+        if (CE_GOOD(ent) && ent->m_Type() == ENTITY_PLAYER && ent->m_bAlivePlayer())
+        {
+            float simtime = CE_FLOAT(ent, netvar.m_flSimulationTime);
+            // Calculate the time we need to animate by
+            float time_difference = simtime - previous_simtimes.at(ent->m_IDX - 1);
+            if (time_difference > 0.0f)
+                newInterval = time_difference;
+            previous_simtimes.at(ent->m_IDX - 1) = simtime;
+            // If the simtime didn't update we need to make sure that the original function also does not update
+            if (newInterval == 0.0f)
+                CE_FLOAT(ent, netvar.m_flAnimTime) = g_GlobalVars->curtime;
+        }
+    }
+
+    FrameAdvance_t original = (FrameAdvance_t) frameadvance_detour.GetOriginalFunc();
+    float return_value      = original(self, newInterval);
+    frameadvance_detour.RestorePatch();
+    return return_value;
+}
+
+void LevelInit()
+{
+    previous_simtimes.clear();
+    previous_simtimes.resize(g_IEngine->GetMaxClients());
+}
+
+static InitRoutine init([]() {
+    static auto FrameAdvance_signature = gSignatures.GetClientSignature("55 89 E5 57 56 53 83 EC 4C 8B 5D ? 80 BB ? ? ? ? 00 0F 85 ? ? ? ? 8B B3");
+    frameadvance_detour.Init(FrameAdvance_signature, (void *) FrameAdvance_hook);
+    EC::Register(EC::LevelInit, LevelInit, "levelinit_animfix");
+    LevelInit();
+
+    EC::Register(
+        EC::Shutdown, []() { frameadvance_detour.Shutdown(); }, "shutdown_animfix");
+});
+} // namespace hacks::tf2::animfix