[11720] Implement spline movement subsystem

Spline movement controls movements of server-side controlled units (monster movement, taxi movement, etc).
Proper implementation of effects such as charge, jump, cyclic movement will rely on it.
However, need improve our states system before.

Technical changes:

 1. Added linear, catmullrom and bezier3 splines which based on client's algorthims. They can be reused for proper transport position interpolation.
 2. Precission increased. There are no more position desync issues since client's position calculation formulas used.
 3. Now possible to move by paths with multiple points, send whole path to client.

src/game/movement/MoveSplineInit.cpp

@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2005-2011 MaNGOS <http://getmangos.com/>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "MoveSplineInit.h"
+#include "MoveSpline.h"
+#include "packet_builder.h"
+#include "../Unit.h"
+
+namespace Movement
+{
+    UnitMoveType SelectSpeedType(uint32 moveFlags)
+    {
+        if (moveFlags & MOVEFLAG_FLYING)
+        {
+            if ( moveFlags & MOVEFLAG_BACKWARD /*&& speed_obj.flight >= speed_obj.flight_back*/ )
+                return MOVE_FLIGHT_BACK;
+            else
+                return MOVE_FLIGHT;
+        }
+        else if (moveFlags & MOVEFLAG_SWIMMING)
+        {
+            if (moveFlags & MOVEFLAG_BACKWARD /*&& speed_obj.swim >= speed_obj.swim_back*/)
+                return MOVE_SWIM_BACK;
+            else
+                return MOVE_SWIM;
+        }
+        else if (moveFlags & MOVEFLAG_WALK_MODE)
+        {
+            //if ( speed_obj.run > speed_obj.walk )
+            return MOVE_WALK;
+        }
+        else if (moveFlags & MOVEFLAG_BACKWARD /*&& speed_obj.run >= speed_obj.run_back*/)
+            return MOVE_RUN_BACK;
+
+        return MOVE_RUN;
+    }
+
+    void MoveSplineInit::Launch()
+    {
+        MoveSpline& move_spline = *unit.movespline;
+
+        Vector3 real_position(unit.GetPositionX(),unit.GetPositionY(),unit.GetPositionZ());
+        // there is a big chane that current position is unknown if current state is not finalized, need compute it
+        // this also allows calculate spline position and update map position in much greater intervals
+        if (!move_spline.Finalized())
+            real_position = move_spline.ComputePosition();
+
+        if (args.path.empty())
+        {
+            // should i do the things that user should do?
+            MoveTo(real_position);
+        }
+
+        // corrent first vertex
+        args.path[0] = real_position;
+        uint32 moveFlags = unit.m_movementInfo.GetMovementFlags();
+        if (args.flags.walkmode)
+            moveFlags |= MOVEFLAG_WALK_MODE;
+        else
+            moveFlags &= ~MOVEFLAG_WALK_MODE;
+
+        moveFlags |= (MOVEFLAG_SPLINE_ENABLED|MOVEFLAG_FORWARD);
+        
+        if (args.velocity == 0.f)
+            args.velocity = unit.GetSpeed(SelectSpeedType(moveFlags));
+
+        if (!args.Validate())
+            return;
+
+        unit.m_movementInfo.SetMovementFlags((MovementFlags)moveFlags);
+        move_spline.Initialize(args);
+
+        WorldPacket data(SMSG_MONSTER_MOVE, 64);
+        data << unit.GetPackGUID();
+        PacketBuilder::WriteMonsterMove(move_spline, data);
+        unit.SendMessageToSet(&data,true);
+    }
+
+    MoveSplineInit::MoveSplineInit(Unit& m) : unit(m)
+    {
+        // mix existing state into new
+        args.flags.walkmode = unit.m_movementInfo.HasMovementFlag(MOVEFLAG_WALK_MODE);
+        args.flags.flying = unit.m_movementInfo.HasMovementFlag((MovementFlags)(MOVEFLAG_FLYING|MOVEFLAG_LEVITATING));
+    }
+
+    void MoveSplineInit::SetFacing(const Unit * target)
+    {
+        args.flags.EnableFacingTarget();
+        args.facing.target = target->GetObjectGuid().GetRawValue();
+    }
+}