Core/Movement: Corrected values sent in knockback packet when speedXY < 0

Port From (https://github.com/TrinityCore/TrinityCore/commit/732a8ee26199d7f04c692fa64f96955db13cf69d)

Source/Game/Entities/Object/Position.cs

@@ -325,25 +325,6 @@ namespace Game.Entities
             return Math.Abs(Math.Sin(angle)) * GetExactDist2d(pos.GetPositionX(), pos.GetPositionY()) < width;
         }
 
-        public void GetSinCos(float x, float y, out float vsin, out float vcos)
-        {
-            float dx = GetPositionX() - x;
-            float dy = GetPositionY() - y;
-
-            if (Math.Abs(dx) < 0.001f && Math.Abs(dy) < 0.001f)
-            {
-                float o = NormalizeOrientation(GetOrientation() - MathF.PI);
-                vcos = MathF.Cos(o);
-                vsin = MathF.Sin(o);
-            }
-            else
-            {
-                float dist = (float)Math.Sqrt((dx * dx) + (dy * dy));
-                vcos = dx / dist;
-                vsin = dy / dist;
-            }
-        }
-
         public override string ToString()
         {
             return $"X: {posX} Y: {posY} Z: {posZ} O: {Orientation}";

Source/Game/Entities/Unit/Unit.Movement.cs

@@ -235,7 +235,7 @@ namespace Game.Entities
             GetMotionMaster().LaunchMoveSpline(init, 0, MovementGeneratorPriority.Normal, MovementGeneratorType.Point);
         }
 
-        public void KnockbackFrom(float x, float y, float speedXY, float speedZ, SpellEffectExtraData spellEffectExtraData = null)
+        public void KnockbackFrom(Position origin, float speedXY, float speedZ, SpellEffectExtraData spellEffectExtraData = null)
         {
             Player player = ToPlayer();
             if (!player)
@@ -250,11 +250,18 @@ namespace Game.Entities
             }
 
             if (!player)
-                GetMotionMaster().MoveKnockbackFrom(x, y, speedXY, speedZ, spellEffectExtraData);
+                GetMotionMaster().MoveKnockbackFrom(origin, speedXY, speedZ, spellEffectExtraData);
             else
             {
-                float vcos, vsin;
-                GetSinCos(x, y, out vsin, out vcos);
+                float o = GetPosition() == origin ? GetOrientation() + MathF.PI : origin.GetRelativeAngle(this);
+                if (speedXY < 0)
+                {
+                    speedXY = -speedXY;
+                    o = o - MathF.PI;
+                }
+
+                float vcos = MathF.Cos(o);
+                float vsin = MathF.Sin(o);
                 SendMoveKnockBack(player, speedXY, -speedZ, vcos, vsin);
             }
         }

Source/Game/Movement/MotionMaster.cs

@@ -656,7 +656,7 @@ namespace Game.Movement
             init.Launch();
         }
 
-        public void MoveKnockbackFrom(float srcX, float srcY, float speedXY, float speedZ, SpellEffectExtraData spellEffectExtraData = null)
+        public void MoveKnockbackFrom(Position origin, float speedXY, float speedZ, SpellEffectExtraData spellEffectExtraData = null)
         {
             //This function may make players fall below map
             if (_owner.IsTypeId(TypeId.Player))
@@ -670,7 +670,7 @@ namespace Game.Movement
             float dist = 2 * moveTimeHalf * speedXY;
             float max_height = -MoveSpline.ComputeFallElevation(moveTimeHalf, false, -speedZ);
 
-            _owner.GetNearPoint(_owner, out x, out y, out z, dist, _owner.GetAbsoluteAngle(srcX, srcY) + MathFunctions.PI);
+            _owner.GetNearPoint(_owner, out x, out y, out z, dist, _owner.GetAbsoluteAngle(origin) + MathFunctions.PI);
 
             MoveSplineInit init = new(_owner);
             init.MoveTo(x, y, z);

Source/Game/Spells/SpellEffects.cs

@@ -4021,18 +4021,18 @@ namespace Game.Spells
             if (speedxy < 0.01f && speedz < 0.01f)
                 return;
 
-            float x, y;
+            Position origin;
             if (effectInfo.Effect == SpellEffectName.KnockBackDest)
             {
                 if (m_targets.HasDst())
-                    destTarget.GetPosition(out x, out y);
+                    origin = new(destTarget.GetPosition());
                 else
                     return;
             }
-            else //if (GetEffect(i].Effect == SPELL_EFFECT_KNOCK_BACK)
-                m_caster.GetPosition(out x, out y);
+            else //if (effectInfo.Effect == SPELL_EFFECT_KNOCK_BACK)
+                origin = new(m_caster.GetPosition());
 
-            unitTarget.KnockbackFrom(x, y, speedxy, speedz);
+            unitTarget.KnockbackFrom(origin, speedxy, speedz);
         }
 
         [SpellEffectHandler(SpellEffectName.LeapBack)]

Source/Scripts/Spells/Generic.cs

@@ -1446,7 +1446,7 @@ namespace Scripts.Spells.Generic
                     float verticalSpeed = 8.0f;
                     // This method relies on the Dalaran Sewer map disposition and Water Spout position
                     // What we do is knock the player from a position exactly behind him and at the end of the pipe
-                    player.KnockbackFrom(target.GetPositionX(), player.GetPositionY(), horizontalSpeed, verticalSpeed);
+                    player.KnockbackFrom(target.GetPosition(), horizontalSpeed, verticalSpeed);
                 }
             }
         }