Fix Velocity Slowdown during turn

Slowdown mechanic now uses the angular velocity and not ticks, to prevent issue OpenApoc#1310

game/state/city/vehicle.cpp

@@ -1,5 +1,7 @@
 #ifndef _USE_MATH_DEFINES
 #define _USE_MATH_DEFINES
+#include "game/state/gametime.h"
+#include <cstdlib>
 #endif
 #include "game/state/city/vehicle.h"
 #include "framework/configfile.h"
@@ -96,8 +98,8 @@ const UString &StateObject<Vehicle>::getId(const GameState &state, const sp<Vehi
 
 class FlyingVehicleMover : public VehicleMover
 {
-  public:
-	FlyingVehicleMover(Vehicle &v) : VehicleMover(v) {}
+    public:
+          FlyingVehicleMover(Vehicle &v) : VehicleMover(v) {}
 	// Vehicle is considered idle whenever it's at goal in its tile, even if it has missions to do
 	void updateIdle(GameState &state)
 	{
@@ -560,7 +562,6 @@ class FlyingVehicleMover : public VehicleMover
 					// d += 0.12f * (float)M_PI;
 					vehicle.ticksToTurn = floorf(d / vehicle.angularVelocity);
 
-					// FIXME: Introduce proper turning speed
 					// Here we just slow down velocity if we're moving too quickly
 					if (vehicle.position != vehicle.goalPosition)
 					{
@@ -573,21 +574,9 @@ class FlyingVehicleMover : public VehicleMover
 						             2.0f);
 						if (ticksToMove < vehicle.ticksToTurn)
 						{
-							vehicle.velocity *= (float)ticksToMove / (float)vehicle.ticksToTurn;
+							vehicle.velocity *= std::abs(vehicle.angularVelocity) * TURNING_SLOW_DOWN_CORRECTION;
 						}
 
-						//@kgd192 log velocity data in relation to angular velocity for research
-						std::ofstream velocityLog("velocitylog.csv", std::ios_base::app);
-						velocityLog << ("angular, " + std::to_string(vehicle.angularVelocity) + "\n");
-						velocityLog << ("old velocity," + std::to_string(vehicle.velocity.x) +
-						           "," + std::to_string(vehicle.velocity.y) + "," +
-						                std::to_string(vehicle.velocity.z) + "\n");
-						// Slow down in relation to angular Velocity
-						auto turningV = vehicle.velocity;
-						turningV = vehicle.velocity * std::abs(vehicle.angularVelocity);
-						velocityLog << ("new velocity," + std::to_string(turningV.x) +
-						           "," + std::to_string(turningV.y) + "," +
-						                std::to_string(turningV.z) + "\n");
 					}
 				}
 			}

game/state/city/vehicle.h

@@ -57,6 +57,9 @@ static const int FV_SCRAPPED_COST_PERCENT = 25;
 static const int FUEL_TICKS_PER_SECOND = 144;
 // How much ticks is required to spend one unit of fuel
 static const int FUEL_TICKS_PER_UNIT = 40000;
+// Correction factor for turning slowdown mechanic, pure found by data analysis, could not establish any logical conclution
+static const float TURNING_SLOW_DOWN_CORRECTION = 38.893f;
+
 
 class Image;
 class TileObjectVehicle;