From 3a1d24c7f5323641a7779d0e64975996ec127c4e Mon Sep 17 00:00:00 2001
From: Ovahlord <[email protected]>
Date: Mon, 17 Sep 2018 21:50:43 +0200
Subject: [PATCH] Core/Movement: implement support for EnterCycle spline flag 
*original autor: xvwyh

---
 src/server/game/Entities/Unit/Unit.cpp             | 22 ++++++++---
 src/server/game/Entities/Unit/Unit.h               |  2 +-
 src/server/game/Movement/Spline/MoveSpline.cpp     | 45 ++++++++++++++++++++--
 src/server/game/Movement/Spline/MoveSplineInit.cpp |  1 +
 .../game/Movement/Spline/MovementPacketBuilder.cpp | 14 ++++---
 .../game/Movement/Spline/MovementPacketBuilder.h   |  1 +
 6 files changed, 68 insertions(+), 17 deletions(-)

diff --git a/src/server/game/Entities/Unit/Unit.cpp b/src/server/game/Entities/Unit/Unit.cpp
index 8ccd27b1f3..aa9b65a907 100644
--- a/src/server/game/Entities/Unit/Unit.cpp
+++ b/src/server/game/Entities/Unit/Unit.cpp
@@ -41,6 +41,7 @@
 #include "LootMgr.h"
 #include "MotionMaster.h"
 #include "MovementGenerator.h"
+#include "MovementPacketBuilder.h"
 #include "MovementStructures.h"
 #include "MoveSpline.h"
 #include "MoveSplineInit.h"
@@ -511,19 +512,28 @@ void Unit::UpdateSplineMovement(uint32 t_diff)
     movespline->updateState(t_diff);
     bool arrived = movespline->Finalized();
 
+    if (movespline->isCyclic())
+    {
+        m_splineSyncTimer.Update(t_diff);
+        if (m_splineSyncTimer.Passed())
+        {
+            m_splineSyncTimer.Reset(5000); // Retail value, do not change
+
+            WorldPacket data(SMSG_FLIGHT_SPLINE_SYNC, 4 + GetPackGUID().size());
+            Movement::PacketBuilder::WriteSplineSync(*movespline, data);
+            data.appendPackGUID(GetGUID());
+            SendMessageToSet(&data, true);
+        }
+    }
+
     if (arrived)
         DisableSpline();
 
-    m_movesplineTimer.Update(t_diff);
-    if (m_movesplineTimer.Passed() || arrived)
-        UpdateSplinePosition();
+    UpdateSplinePosition();
 }
 
 void Unit::UpdateSplinePosition()
 {
-    static uint32 const positionUpdateDelay = 400;
-
-    m_movesplineTimer.Reset(positionUpdateDelay);
     Movement::Location loc = movespline->ComputePosition();
 
     if (movespline->onTransport)
diff --git a/src/server/game/Entities/Unit/Unit.h b/src/server/game/Entities/Unit/Unit.h
index 65032ea00a..2ce3e433f1 100644
--- a/src/server/game/Entities/Unit/Unit.h
+++ b/src/server/game/Entities/Unit/Unit.h
@@ -2004,7 +2004,7 @@ class TC_GAME_API Unit : public WorldObject
 
         uint32 m_state;                                     // Even derived shouldn't modify
         uint32 m_CombatTimer;
-        TimeTrackerSmall m_movesplineTimer;
+        TimeTrackerSmall m_splineSyncTimer;
 
         DiminishingReturn m_Diminishing[DIMINISHING_MAX];
         // Manage all Units that are threatened by us
diff --git a/src/server/game/Movement/Spline/MoveSpline.cpp b/src/server/game/Movement/Spline/MoveSpline.cpp
index edda63fa15..1d0901c788 100644
--- a/src/server/game/Movement/Spline/MoveSpline.cpp
+++ b/src/server/game/Movement/Spline/MoveSpline.cpp
@@ -123,9 +123,8 @@ void MoveSpline::init_spline(MoveSplineInitArgs const& args)
     if (args.flags.cyclic)
     {
         uint32 cyclic_point = 0;
-        // MoveSplineFlag::Enter_Cycle support dropped
-        //if (splineflags & SPLINEFLAG_ENTER_CYCLE)
-        //cyclic_point = 1;   // shouldn't be modified, came from client
+        if (splineflags.enter_cycle)
+            cyclic_point = 1;   // shouldn't be modified, came from client
         spline.init_cyclic_spline(&args.path[0], args.path.size(), modes[args.flags.isSmooth()], cyclic_point);
     }
     else
@@ -209,7 +208,10 @@ bool MoveSplineInitArgs::Validate(Unit* unit) const
 #define CHECK(exp) \
     if (!(exp))\
     {\
-        TC_LOG_ERROR("misc.movesplineinitargs", "MoveSplineInitArgs::Validate: expression '%s' failed for GUID: %u Entry: %u", #exp, unit->GetTypeId() == TYPEID_PLAYER ? unit->GetGUID().GetCounter() : unit->ToCreature()->GetSpawnId(), unit->GetEntry());\
+        if (unit)\
+            TC_LOG_ERROR("misc.movesplineinitargs", "MoveSplineInitArgs::Validate: expression '%s' failed for GUID: %u Entry: %u", #exp, unit->GetTypeId() == TYPEID_PLAYER ? unit->GetGUID().GetCounter() : unit->ToCreature()->GetSpawnId(), unit->GetEntry());\
+        else\
+            TC_LOG_ERROR("misc.movesplineinitargs", "MoveSplineInitArgs::Validate: expression '%s' failed for cyclic spline continuation", #exp); \
         return false;\
     }
     CHECK(path.size() > 1);
@@ -275,6 +277,41 @@ MoveSpline::UpdateResult MoveSpline::_updateState(int32& ms_time_diff)
                 point_Idx = spline.first();
                 time_passed = time_passed % Duration();
                 result = Result_NextCycle;
+
+                // Remove first point from the path after one full cycle.
+                // That point was the position of the unit prior to entering the cycle and it shouldn't be repeated with continuous cycles.
+                if (splineflags.enter_cycle)
+                {
+                    splineflags.enter_cycle = false;
+
+                    MoveSplineInitArgs args{ (size_t)spline.getPointCount() };
+                    args.path.assign(spline.getPoints().begin() + spline.first() + 1, spline.getPoints().begin() + spline.last());
+                    args.facing = facing;
+                    args.flags = splineflags;
+                    args.path_Idx_offset = point_Idx_offset;
+                    // MoveSplineFlag::Parabolic | MoveSplineFlag::Animation not supported currently
+                        //args.parabolic_amplitude = ?;
+                        //args.time_perc = ?;
+                    args.splineId = m_Id;
+                    args.initialOrientation = initialOrientation;
+                    args.velocity = 1.0f; // Calculated below
+                    args.HasVelocity = true;
+                    args.TransformForTransport = onTransport;
+                    if (args.Validate(nullptr))
+                    {
+                        // New cycle should preserve previous cycle's duration for some weird reason, even though
+                        // the path is really different now. Blizzard is weird. Or this was just a simple oversight.
+                        // Since our splines precalculate length with velocity in mind, if we want to find the desired
+                        // velocity, we have to make a fake spline, calculate its duration and then compare it to the
+                        // desired duration, thus finding out how much the velocity has to be increased for them to match.
+                        MoveSpline tempSpline;
+                        tempSpline.Initialize(args);
+                        args.velocity = (float)tempSpline.Duration() / Duration();
+
+                        if (args.Validate(nullptr))
+                            init_spline(args);
+                    }
+                }
             }
             else
             {
diff --git a/src/server/game/Movement/Spline/MoveSplineInit.cpp b/src/server/game/Movement/Spline/MoveSplineInit.cpp
index 9fab0ce851..c41a214b66 100644
--- a/src/server/game/Movement/Spline/MoveSplineInit.cpp
+++ b/src/server/game/Movement/Spline/MoveSplineInit.cpp
@@ -88,6 +88,7 @@ namespace Movement
         // correct first vertex
         args.path[0] = real_position;
         args.initialOrientation = real_position.orientation;
+        args.flags.enter_cycle = args.flags.cyclic;
         move_spline.onTransport = (unit->GetTransGUID() != 0);
 
         uint32 moveFlags = unit->m_movementInfo.GetMovementFlags();
diff --git a/src/server/game/Movement/Spline/MovementPacketBuilder.cpp b/src/server/game/Movement/Spline/MovementPacketBuilder.cpp
index 381b41026f..90aee795dd 100644
--- a/src/server/game/Movement/Spline/MovementPacketBuilder.cpp
+++ b/src/server/game/Movement/Spline/MovementPacketBuilder.cpp
@@ -70,8 +70,6 @@ namespace Movement
                 break;
         }
 
-        // add fake Enter_Cycle flag - needed for client-side cyclic movement (client will erase first spline vertex after first cycle done)
-        splineflags.enter_cycle = move_spline.isCyclic();
         data << uint32(splineflags & uint32(~MoveSplineFlag::Mask_No_Monster_Move));
 
         if (splineflags.animation)
@@ -126,10 +124,9 @@ namespace Movement
 
     void WriteUncompressedCyclicPath(Spline<int32> const& spline, ByteBuffer& data)
     {
-        uint32 count = spline.getPointCount() - 3;
-        data << uint32(count + 1);
-        data << spline.getPoint(1); // fake point, client will erase it from the spline after first cycle done
-        data.append<Vector3>(&spline.getPoint(1), count);
+        uint32 count = spline.getPointCount() - 4;
+        data << count;
+        data.append<Vector3>(&spline.getPoint(2), count);
     }
 
     void PacketBuilder::WriteMonsterMove(const MoveSpline& move_spline, WorldPacket& data)
@@ -245,4 +242,9 @@ namespace Movement
 
         data << moveSpline.GetId();
     }
+
+    void PacketBuilder::WriteSplineSync(MoveSpline const& moveSpline, ByteBuffer& data)
+    {
+        data << float(moveSpline.timePassed() / moveSpline.Duration());
+    }
 }
diff --git a/src/server/game/Movement/Spline/MovementPacketBuilder.h b/src/server/game/Movement/Spline/MovementPacketBuilder.h
index ec3ff91b6c..75c7551fdc 100644
--- a/src/server/game/Movement/Spline/MovementPacketBuilder.h
+++ b/src/server/game/Movement/Spline/MovementPacketBuilder.h
@@ -39,6 +39,7 @@ namespace Movement
         static void WriteStopMovement(Vector3 const& loc, uint32 splineId, ByteBuffer& data);
         static void WriteCreateBits(MoveSpline const& moveSpline, ByteBuffer& data);
         static void WriteCreateData(MoveSpline const& moveSpline, ByteBuffer& data);
+        static void WriteSplineSync(MoveSpline const& moveSpline, ByteBuffer& data);
     };
 }
 #endif // TRINITYSERVER_PACKET_BUILDER_H
-- 
2.13.2.windows.1